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20 pages, 2929 KiB

Open AccessArticle

Multiplex Analysis Platform for Endocrine Disruption Prediction Using Zebrafish

by Sergio Jarque, Jone Ibarra, Maria Rubio-Brotons, Jessica García-Fernández and Javier Terriente

Int. J. Mol. Sci. 2019, 20(7), 1739; https://doi.org/10.3390/ijms20071739 - 8 Apr 2019

Cited by 24 | Viewed by 5013

Abstract

Small fish are an excellent experimental model to screen endocrine-disrupting compounds, but current fish-based assays to detect endocrine disruption have not been standardized yet, meaning that there is not consensus on endpoints and biomarkers to be measured. Moreover, exposure conditions may vary depending [...] Read more.

Small fish are an excellent experimental model to screen endocrine-disrupting compounds, but current fish-based assays to detect endocrine disruption have not been standardized yet, meaning that there is not consensus on endpoints and biomarkers to be measured. Moreover, exposure conditions may vary depending on the species used as the experimental model and the endocrine pathway evaluated. At present, a battery of a wide range of assays is usually needed for the complete assessment of endocrine activities. With the aim of providing a simple, robust, and fast assay to assess endocrine-disrupting potencies for the three major endocrine axes, i.e., estrogens, androgens, and thyroid, we propose the use of a panel of eight gene expression biomarkers in zebrafish larvae. This includes brain aromatase (cyp19a1b) and vitellogenin 1 (vtg1) for estrogens, cytosolic sulfotransferase 2 family 2 (sult2st3) and cytochrome P450 2k22 (cyp2k22) for androgens, and thyroid peroxidase (tpo), transthyretin (ttr), thyroid receptor α (trα), and iodothyronine deiodinase 2 (dio2) for thyroid metabolism. All of them were selected according to their responses after exposure to the natural ligands 17β-estradiol, testosterone, and 3,3′,5-triiodo-L-thyronine (T3), respectively, and subsequently validated using compounds reported as endocrine disruptors in previous studies. Cross-talk effects were also evaluated for all compounds. Full article

(This article belongs to the Special Issue Zebrafish 2.0: A Model for Toxicological Research)

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14 pages, 1696 KiB

Open AccessArticle

Safety Assessment of Compounds after In Vitro Metabolic Conversion Using Zebrafish Eleuthero Embryos

by Arianna Giusti, Xuan-Bac Nguyen, Stanislav Kislyuk, Mélanie Mignot, Cecilia Ranieri, Johan Nicolaï, Marlies Oorts, Xiao Wu, Pieter Annaert, Noémie De Croze, Marc Léonard, Annelii Ny, Deirdre Cabooter and Peter de Witte

Int. J. Mol. Sci. 2019, 20(7), 1712; https://doi.org/10.3390/ijms20071712 - 6 Apr 2019

Cited by 10 | Viewed by 4879

Abstract

Zebrafish-based platforms have recently emerged as a useful tool for toxicity testing as they combine the advantages of in vitro and in vivo methodologies. Nevertheless, the capacity to metabolically convert xenobiotics by zebrafish eleuthero embryos is supposedly low. To circumvent this concern, a [...] Read more.

Zebrafish-based platforms have recently emerged as a useful tool for toxicity testing as they combine the advantages of in vitro and in vivo methodologies. Nevertheless, the capacity to metabolically convert xenobiotics by zebrafish eleuthero embryos is supposedly low. To circumvent this concern, a comprehensive methodology was developed wherein test compounds (i.e., parathion, malathion and chloramphenicol) were first exposed in vitro to rat liver microsomes (RLM) for 1 h at 37 °C. After adding methanol, the mixture was ultrasonicated, placed for 2 h at −20 °C, centrifuged and the supernatant evaporated. The pellet was resuspended in water for the quantification of the metabolic conversion and the detection of the presence of metabolites using ultra high performance liquid chromatography-Ultraviolet-Mass (UHPLC-UV-MS). Next, three days post fertilization (dpf) zebrafish eleuthero embryos were exposed to the metabolic mix diluted in Danieau’s medium for 48 h at 28 °C, followed by a stereomicroscopic examination of the adverse effects induced, if any. The novelty of our method relies in the possibility to quantify the rate of the in vitro metabolism of the parent compound and to co-incubate three dpf larvae and the diluted metabolic mix for 48 h without inducing major toxic effects. The results for parathion show an improved predictivity of the toxic potential of the compound. Full article

(This article belongs to the Special Issue Zebrafish 2.0: A Model for Toxicological Research)

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17 pages, 2668 KiB

Open AccessArticle

Thyroid Hormone Disruptors Interfere with Molecular Pathways of Eye Development and Function in Zebrafish

by Lisa Baumann, Helmut Segner, Albert Ros, Dries Knapen and Lucia Vergauwen

Int. J. Mol. Sci. 2019, 20(7), 1543; https://doi.org/10.3390/ijms20071543 - 27 Mar 2019

Cited by 33 | Viewed by 5429

Abstract

The effects of thyroid hormone disrupting chemicals (THDCs) on eye development of zebrafish were investigated. We expected THDC exposure to cause transcriptional changes of vision-related genes, which find their phenotypic anchoring in eye malformations and dysfunction, as observed in our previous studies. Zebrafish [...] Read more.

The effects of thyroid hormone disrupting chemicals (THDCs) on eye development of zebrafish were investigated. We expected THDC exposure to cause transcriptional changes of vision-related genes, which find their phenotypic anchoring in eye malformations and dysfunction, as observed in our previous studies. Zebrafish were exposed from 0 to 5 days post fertilization (dpf) to either propylthiouracil (PTU), a thyroid hormone synthesis inhibitor, or tetrabromobisphenol-A (TBBPA), which interacts with thyroid hormone receptors. Full genome microarray analyses of RNA isolated from eye tissue revealed that the number of affected transcripts was substantially higher in PTU- than in TBBPA-treated larvae. However, multiple components of phototransduction (e.g., phosphodiesterase, opsins) were responsive to both THDC exposures. Yet, the response pattern for the gene ontology (GO)-class “sensory perception” differed between treatments, with over 90% down-regulation in PTU-exposed fish, compared to over 80% up-regulation in TBBPA-exposed fish. Additionally, the reversibility of effects after recovery in clean water for three days was investigated. Transcriptional patterns in the eyes were still altered and partly overlapped between 5 and 8 dpf, showing that no full recovery occurred within the time period investigated. However, pathways involved in repair mechanisms were significantly upregulated, which indicates activation of regeneration processes. Full article

(This article belongs to the Special Issue Zebrafish 2.0: A Model for Toxicological Research)

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18 pages, 3090 KiB

Open AccessArticle

Comparison the Effect of Ferutinin and 17β-Estradiol on Bone Mineralization of Developing Zebrafish (Danio rerio) Larvae

by Hoda Zare Mirakabad, Mohammad Farsi, Saeed Malekzadeh Shafaroudi, Abdolreza Bagheri, Mehrdad Iranshahi and Nasrin Moshtaghi

Int. J. Mol. Sci. 2019, 20(6), 1507; https://doi.org/10.3390/ijms20061507 - 26 Mar 2019

Cited by 7 | Viewed by 5355

Abstract

There is an urgent need to develop novel drugs for osteoporosis which occurs due to estrogen deficiency. Phytoestrogens derived from medicinal plants would be the best alternative to chemical drugs with harmful side effects. The main purpose of the present study was to [...] Read more.

There is an urgent need to develop novel drugs for osteoporosis which occurs due to estrogen deficiency. Phytoestrogens derived from medicinal plants would be the best alternative to chemical drugs with harmful side effects. The main purpose of the present study was to investigate the effect of ferutinin compared to 17β-estradiol (E2) on bone mineralization of zebrafish larvae. Regarding the lack of publications, the histology analysis was performed after exposure to E2 to find effective treatment on bone mineralization of developing zebrafish larvae. Then, the larvae were exposed to four concentrations of ferutinin at three time points to assess the mortality, the expression of some related genes and histology of the ceratohyal and hyomandibular of treated larvae. The RT-PCR result of the treatment groups demonstrated the similar expression pattern in the larvae which were exposed to 1.25 μg/mL of ferutinin and 2 µM of E2 at 2 dpf, which confirmed the result of histology analysis. In addition, RT-qPCR of high concentration of ferutinin and E2 demonstrated that bmp2a/b and esr1 were downregulated and upregulated when the larvae were exposed to 5 μg/mL of ferutinin and 10 µM of E2, respectively. Full article

(This article belongs to the Special Issue Zebrafish 2.0: A Model for Toxicological Research)

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21 pages, 2243 KiB

Open AccessArticle

Optimizing the Use of Zebrafish Feeding Trials for the Safety Evaluation of Genetically Modified Crops

by Isabelle J. Gabriëls, Lucia Vergauwen, Marthe De Boevre, Stefan Van Dongen, Ronny Blust, Sarah De Saeger, Mia Eeckhout, Marc De Loose and Dries Knapen

Int. J. Mol. Sci. 2019, 20(6), 1472; https://doi.org/10.3390/ijms20061472 - 23 Mar 2019

Cited by 3 | Viewed by 3863

Abstract

In Europe, the toxicological safety of genetically modified (GM) crops is routinely evaluated using rodent feeding trials, originally designed for testing oral toxicity of chemical compounds. We aimed to develop and optimize methods for advancing the use of zebrafish feeding trials for the [...] Read more.

In Europe, the toxicological safety of genetically modified (GM) crops is routinely evaluated using rodent feeding trials, originally designed for testing oral toxicity of chemical compounds. We aimed to develop and optimize methods for advancing the use of zebrafish feeding trials for the safety evaluation of GM crops, using maize as a case study. In a first step, we evaluated the effect of different maize substitution levels. Our results demonstrate the need for preliminary testing to assess potential feed component-related effects on the overall nutritional balance. Next, since a potential effect of a GM crop should ideally be interpreted relative to the natural response variation (i.e., the range of biological values that is considered normal for a particular endpoint) in order to assess the toxicological relevance, we established natural response variation datasets for various zebrafish endpoints. We applied equivalence testing to calculate threshold equivalence limits (ELs) based on the natural response variation as a method for quantifying the range within which a GM crop and its control are considered equivalent. Finally, our results illustrate that the use of commercial control diets (CCDs) and null segregant (NS) controls (helpful for assessing potential effects of the transformation process) would be valuable additions to GM safety assessment strategies. Full article

(This article belongs to the Special Issue Zebrafish 2.0: A Model for Toxicological Research)

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9 pages, 963 KiB

Open AccessArticle

An Integrative Evaluation Method for the Biological Safety of Down and Feather Materials

by Toshikatsu Kawada, Junya Kuroyanagi, Fumiyoshi Okazaki, Mizuki Taniguchi, Hiroko Nakayama, Narumi Suda, Souta Abiko, Satoshi Kaneco, Norihiro Nishimura and Yasuhito Shimada

Int. J. Mol. Sci. 2019, 20(6), 1434; https://doi.org/10.3390/ijms20061434 - 21 Mar 2019

Cited by 6 | Viewed by 4140

Abstract

Background: Down and feather materials have been commonly used and promoted as natural stuffing for warm clothing and bedding. These materials tend to become more allergenic as they become contaminated with microorganisms, in addition to being subjected to several kinds of chemical treatments. [...] Read more.

Background: Down and feather materials have been commonly used and promoted as natural stuffing for warm clothing and bedding. These materials tend to become more allergenic as they become contaminated with microorganisms, in addition to being subjected to several kinds of chemical treatments. The biological or chemical contaminants in these materials pose a major risk to human health, to consumers and manufacturers alike. Here, we report the development of an integrative evaluation method for down and feather materials to assess bacterial contamination and in vivo toxicity. Methods: To assess bacterial contamination, we quantified 16S ribosomal RNA, performed culture tests, and established a conversion formula. To determine in vivo toxicity, we performed a zebrafish embryo toxicity testing (ZFET). Results: Washing the material appropriately decreases the actual number of bacteria in the down and feather samples; in addition, after washing, 16S rRNA sequencing revealed that the bacterial compositions were similar to those in rinse water. The ZFET results showed that even materials with low bacterial contamination showed high toxicity or high teratogenicity, probably because of the presence of unknown chemical additives. Conclusions: We established an integrative evaluation method for down and feather safety, based on bacterial contamination with in vivo toxicity testing. Full article

(This article belongs to the Special Issue Zebrafish 2.0: A Model for Toxicological Research)

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16 pages, 2368 KiB

Open AccessArticle

A Smart Imaging Workflow for Organ-Specific Screening in a Cystic Kidney Zebrafish Disease Model

by Gunjan Pandey, Jens H. Westhoff, Franz Schaefer and Jochen Gehrig

Int. J. Mol. Sci. 2019, 20(6), 1290; https://doi.org/10.3390/ijms20061290 - 14 Mar 2019

Cited by 16 | Viewed by 6406

Abstract

The zebrafish is being increasingly used in biomedical research and drug discovery to conduct large-scale compound screening. However, there is a lack of accessible methodologies to enable automated imaging and scoring of tissue-specific phenotypes at enhanced resolution. Here, we present the development of [...] Read more.

The zebrafish is being increasingly used in biomedical research and drug discovery to conduct large-scale compound screening. However, there is a lack of accessible methodologies to enable automated imaging and scoring of tissue-specific phenotypes at enhanced resolution. Here, we present the development of an automated imaging pipeline to identify chemical modifiers of glomerular cyst formation in a zebrafish model for human cystic kidney disease. Morpholino-mediated knockdown of intraflagellar transport protein Ift172 in Tg(wt1b:EGFP) embryos was used to induce large glomerular cysts representing a robustly scorable phenotypic readout. Compound-treated embryos were consistently aligned within the cavities of agarose-filled microplates. By interfacing feature detection algorithms with automated microscopy, a smart imaging workflow for detection, centring and zooming in on regions of interests was established, which enabled the automated capturing of standardised higher resolution datasets of pronephric areas. High-content screening datasets were processed and analysed using custom-developed heuristic algorithms implemented in common open-source image analysis software. The workflow enables highly efficient profiling of entire compound libraries and scoring of kidney-specific morphological phenotypes in thousands of zebrafish embryos. The demonstrated toolset covers all the aspects of a complex whole organism screening assay and can be adapted to other organs, specimens or applications. Full article

(This article belongs to the Special Issue Zebrafish 2.0: A Model for Toxicological Research)

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30 pages, 5551 KiB

Open AccessArticle

From mRNA Expression of Drug Disposition Genes to In Vivo Assessment of CYP-Mediated Biotransformation during Zebrafish Embryonic and Larval Development

by Evy Verbueken, Chloé Bars, Jonathan S. Ball, Jelena Periz-Stanacev, Waleed F. A. Marei, Anna Tochwin, Isabelle J. Gabriëls, Ellen D. G. Michiels, Evelyn Stinckens, Lucia Vergauwen, Dries Knapen, Chris J. Van Ginneken and Steven J. Van Cruchten

Int. J. Mol. Sci. 2018, 19(12), 3976; https://doi.org/10.3390/ijms19123976 - 10 Dec 2018

Cited by 28 | Viewed by 4780

Abstract

The zebrafish (Danio rerio) embryo is currently explored as an alternative for developmental toxicity testing. As maternal metabolism is lacking in this model, knowledge of the disposition of xenobiotics during zebrafish organogenesis is pivotal in order to correctly interpret the outcome [...] Read more.

The zebrafish (Danio rerio) embryo is currently explored as an alternative for developmental toxicity testing. As maternal metabolism is lacking in this model, knowledge of the disposition of xenobiotics during zebrafish organogenesis is pivotal in order to correctly interpret the outcome of teratogenicity assays. Therefore, the aim of this study was to assess cytochrome P450 (CYP) activity in zebrafish embryos and larvae until 14 d post-fertilization (dpf) by using a non-specific CYP substrate, i.e., benzyloxy-methyl-resorufin (BOMR) and a CYP1-specific substrate, i.e., 7-ethoxyresorufin (ER). Moreover, the constitutive mRNA expression of CYP1A, CYP1B1, CYP1C1, CYP1C2, CYP2K6, CYP3A65, CYP3C1, phase II enzymes uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) and sulfotransferase 1st1 (SULT1ST1), and an ATP-binding cassette (ABC) drug transporter, i.e., abcb4, was assessed during zebrafish development until 32 dpf by means of quantitative PCR (qPCR). The present study showed that trancripts and/or the activity of these proteins involved in disposition of xenobiotics are generally low to undetectable before 72 h post-fertilization (hpf), which has to be taken into account in teratogenicity testing. Full capacity appears to be reached by the end of organogenesis (i.e., 120 hpf), although CYP1—except CYP1A—and SULT1ST1 were shown to be already mature in early embryonic development. Full article

(This article belongs to the Special Issue Zebrafish 2.0: A Model for Toxicological Research)

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1619 KiB

Open AccessArticle

Effects of Hydroxylated Polybrominated Diphenyl Ethers in Developing Zebrafish Are Indicative of Disruption of Oxidative Phosphorylation

by Jessica Legradi, Marinda Van Pomeren, Anna-Karin Dahlberg and Juliette Legler

Int. J. Mol. Sci. 2017, 18(5), 970; https://doi.org/10.3390/ijms18050970 - 3 May 2017

Cited by 16 | Viewed by 5139

Abstract

Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) have been detected in humans and wildlife. Using in vitro models, we recently showed that OH-PBDEs disrupt oxidative phosphorylation (OXPHOS), an essential process in energy metabolism. The goal of the current study was to determine the in vivo [...] Read more.

Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) have been detected in humans and wildlife. Using in vitro models, we recently showed that OH-PBDEs disrupt oxidative phosphorylation (OXPHOS), an essential process in energy metabolism. The goal of the current study was to determine the in vivo effects of OH-PBDE reported in marine wildlife. To this end, we exposed zebrafish larvae to 17 OH-PBDEs from fertilisation to 6 days of age, and determined developmental toxicity as well as OXPHOS disruption potential with a newly developed assay of oxygen consumption in living embryos. We show here that all OH-PBDEs tested, both individually and as mixtures, resulted in a concentration-dependant delay in development in zebrafish embryos. The most potent substances were 6-OH-BDE47 and 6′-OH-BDE49 (No-Effect-Concentration: 0.1 and 0.05 µM). The first 24 h of development were the most sensitive, resulting in significant and irreversible developmental delay. All substances increased oxygen consumption, an effect indicative of OXPHOS disruption. Our results suggest that the induced developmental delay may be caused by disruption of OXPHOS. Though further studies are needed, our findings suggest that the environmental concentrations of some OH-PBDEs found in Baltic Sea wildlife in the Baltic Sea may be of toxicological concern. Full article

(This article belongs to the Special Issue Zebrafish: A Model for Toxicological Research)

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4958 KiB

Open AccessArticle

Altered Adipogenesis in Zebrafish Larvae Following High Fat Diet and Chemical Exposure Is Visualised by Stimulated Raman Scattering Microscopy

by Marjo J. Den Broeder, Miriam J. B. Moester, Jorke H. Kamstra, Peter H. Cenijn, Valentina Davidoiu, Leonie M. Kamminga, Freek Ariese, Johannes F. De Boer and Juliette Legler

Int. J. Mol. Sci. 2017, 18(4), 894; https://doi.org/10.3390/ijms18040894 - 24 Apr 2017

Cited by 53 | Viewed by 9555

Abstract

Early life stage exposure to environmental chemicals may play a role in obesity by altering adipogenesis; however, robust in vivo methods to quantify these effects are lacking. The goal of this study was to analyze the effects of developmental exposure to chemicals on [...] Read more.

Early life stage exposure to environmental chemicals may play a role in obesity by altering adipogenesis; however, robust in vivo methods to quantify these effects are lacking. The goal of this study was to analyze the effects of developmental exposure to chemicals on adipogenesis in the zebrafish (Danio rerio). We used label-free Stimulated Raman Scattering (SRS) microscopy for the first time to image zebrafish adipogenesis at 15 days post fertilization (dpf) and compared standard feed conditions (StF) to a high fat diet (HFD) or high glucose diet (HGD). We also exposed zebrafish embryos to a non-toxic concentration of tributyltin (TBT, 1 nM) or Tris(1,3-dichloroisopropyl)phosphate (TDCiPP, 0.5 µM) from 0–6 dpf and reared larvae to 15 dpf under StF. Potential molecular mechanisms of altered adipogenesis were examined by qPCR. Diet-dependent modulation of adipogenesis was observed, with HFD resulting in a threefold increase in larvae with adipocytes, compared to StF and HGD. Developmental exposure to TBT but not TDCiPP significantly increased adipocyte differentiation. The expression of adipogenic genes such as pparda, lxr and lepa was altered in response to HFD or chemicals. This study shows that SRS microscopy can be successfully applied to zebrafish to visualize and quantify adipogenesis, and is a powerful approach for identifying obesogenic chemicals in vivo. Full article

(This article belongs to the Special Issue Zebrafish: A Model for Toxicological Research)

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4423 KiB

Open AccessArticle

ZeGlobalTox: An Innovative Approach to Address Organ Drug Toxicity Using Zebrafish

by Carles Cornet, Simone Calzolari, Rafael Miñana-Prieto, Sylvia Dyballa, Els Van Doornmalen, Helma Rutjes, Thierry Savy, Davide D’Amico and Javier Terriente

Int. J. Mol. Sci. 2017, 18(4), 864; https://doi.org/10.3390/ijms18040864 - 19 Apr 2017

Cited by 76 | Viewed by 10975

Abstract

Toxicity is one of the major attrition causes during the drug development process. In that line, cardio-, neuro-, and hepatotoxicities are among the main reasons behind the retirement of drugs in clinical phases and post market withdrawal. Zebrafish exploitation in high-throughput drug screening [...] Read more.

Toxicity is one of the major attrition causes during the drug development process. In that line, cardio-, neuro-, and hepatotoxicities are among the main reasons behind the retirement of drugs in clinical phases and post market withdrawal. Zebrafish exploitation in high-throughput drug screening is becoming an important tool to assess the toxicity and efficacy of novel drugs. This animal model has, from early developmental stages, fully functional organs from a physiological point of view. Thus, drug-induced organ-toxicity can be detected in larval stages, allowing a high predictive power on possible human drug-induced liabilities. Hence, zebrafish can bridge the gap between preclinical in vitro safety assays and rodent models in a fast and cost-effective manner. ZeGlobalTox is an innovative assay that sequentially integrates in vivo cardio-, neuro-, and hepatotoxicity assessment in the same animal, thus impacting strongly in the 3Rs principles. It Reduces, by up to a third, the number of animals required to assess toxicity in those organs. It Refines the drug toxicity evaluation through novel physiological parameters. Finally, it might allow the Replacement of classical species, such as rodents and larger mammals, thanks to its high predictivity (Specificity: 89%, Sensitivity: 68% and Accuracy: 78%). Full article

(This article belongs to the Special Issue Zebrafish: A Model for Toxicological Research)

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17687 KiB

Open AccessArticle

Morphofunctional Alterations in Zebrafish (Danio rerio) Gills after Exposure to Mercury Chloride

by Rachele Macirella and Elvira Brunelli

Int. J. Mol. Sci. 2017, 18(4), 824; https://doi.org/10.3390/ijms18040824 - 13 Apr 2017

Cited by 50 | Viewed by 8778

Abstract

Mercury (Hg) is a global pollutant that may exert its toxic effects on living organisms and is found in both aquatic and terrestrial ecosystems in three chemical forms; elemental, organic, and inorganic. The inorganic form (iHg) tends to predominantly accumulate in aquatic environments. [...] Read more.

Mercury (Hg) is a global pollutant that may exert its toxic effects on living organisms and is found in both aquatic and terrestrial ecosystems in three chemical forms; elemental, organic, and inorganic. The inorganic form (iHg) tends to predominantly accumulate in aquatic environments. The gill apparatus is a very dynamic organ that plays a fundamental role in gas exchange, osmoregulation, acid-base regulation, detoxification, and excretion, and the gills are the primary route of waterborne iHg entrance in fish. In the present work we investigated the morphofunctional and ultrastructural effects in Danio rerio gills after 96 h exposure to two low HgCl₂ concentrations (7.7 and 38.5 µg/L). Our results clearly demonstrated that a short-term exposure to low concentrations of mercury chloride resulted in gill morphology alterations and in the modifications of both Na^+/K⁺-ATPase and metallothioneins (MTs) expression pattern. The main morphological effects recorded in this work were represented by hyperplasia and ectopia of chloride cells (CCs), lamellar fusion, increased mucous secretion, alteration of pavement cells (PVCs), detachment of the secondary epithelium, pillar cell degeneration, degeneration, and apoptosis. Trough immunohistochemistry and real-time PCR analysis also showed a dose-related modulation of Na⁺/K⁺-ATPase and MTs. Full article

(This article belongs to the Special Issue Zebrafish: A Model for Toxicological Research)

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6319 KiB

Open AccessArticle

Zebrafish as an Alternative Vertebrate Model for Investigating Developmental Toxicity—The Triadimefon Example

by Maria Zoupa and Kyriaki Machera

Int. J. Mol. Sci. 2017, 18(4), 817; https://doi.org/10.3390/ijms18040817 - 12 Apr 2017

Cited by 65 | Viewed by 9073

Abstract

Triadimefon is a widely used triazole fungicide known to cause severe developmental defects in several model organisms and in humans. The present study evaluated in detail the developmental effects seen in zebrafish embryos exposed to triadimefon, confirmed and expanded upon previous phenotypic findings [...] Read more.

Triadimefon is a widely used triazole fungicide known to cause severe developmental defects in several model organisms and in humans. The present study evaluated in detail the developmental effects seen in zebrafish embryos exposed to triadimefon, confirmed and expanded upon previous phenotypic findings and compared them to those observed in other traditional animal models. In order to do this, we exposed embryos to 2 and 4 µg/mL triadimefon and evaluated growth until 120 h post-fertilization (hpf) through gross morphology examination. Our analysis revealed significant developmental defects at the highest tested concentration including somite deformities, severe craniofacial defects, a cleft phenotype along the three primary neural divisions, a rigorously hypoplastic or even absent mandible and a hypoplastic morphology of the pharyngeal arches. Interestingly, massive pericardial edemas, abnormal shaped hearts, brachycardia and inhibited or absent blood circulation were also observed. Our results revealed that the presented zebrafish phenotypes are comparable to those seen in other organism models and those derived from human observations as a result of triadimefon exposure. We therefore demonstrated that zebrafish provide an excellent system for study of compounds with toxic significance and can be used as an alternative model for developmental toxicity studies to predict effects in mammals. Full article

(This article belongs to the Special Issue Zebrafish: A Model for Toxicological Research)

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Open AccessArticle

Triazole Fungicides Inhibit Zebrafish Hatching by Blocking the Secretory Function of Hatching Gland Cells

by Javiera F. De la Paz, Natalia Beiza, Susana Paredes-Zúñiga, Misque S. Hoare and Miguel L. Allende

Int. J. Mol. Sci. 2017, 18(4), 710; https://doi.org/10.3390/ijms18040710 - 4 Apr 2017

Cited by 70 | Viewed by 7126

Abstract

In animals, hatching represents the transition point from a developing embryo to a free-living individual, the larva. This process is finely regulated by many endogenous and environmental factors and has been shown to be sensitive to a variety of chemical agents. It is [...] Read more.

In animals, hatching represents the transition point from a developing embryo to a free-living individual, the larva. This process is finely regulated by many endogenous and environmental factors and has been shown to be sensitive to a variety of chemical agents. It is commonly evaluated in bioassays in order to establish the effects of different agents on early development and reproductive capabilities in fish and other aquatic animals. In fish, the breakdown of the chorion is achieved by the secretion of choriolysin by hatching gland cells (HGCs) into the perivitelline space (PVS), coupled with spontaneous movements of the developing larva. In this work, we used zebrafish to assay the effects of a family of widely used agrochemicals—triazoles Triadimefon (FON), Triadimenol (NOL) and free triazole (1,2,4-T)—on hatching success. We found a strong inhibition of hatching by triazole exposure which was correlated with morphological changes and a reduction in the secretory function of the HGCs. As a consequence, the release of choriolytic enzymes by HGCs was reduced. We also found that HGC secretion reduction after exposure to FON can be rescued by co-incubation with a dopamine D2 receptor antagonist but not by antagonists of the D1-like receptors. This suggests a specific pathway through which this family of fungicides may be impairing a critical event in the fish life cycle. Full article

(This article belongs to the Special Issue Zebrafish: A Model for Toxicological Research)

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Open AccessArticle

Methylmercury Induced Neurotoxicity and the Influence of Selenium in the Brains of Adult Zebrafish (Danio rerio)

by Josef Daniel Rasinger, Anne-Katrine Lundebye, Samuel James Penglase, Ståle Ellingsen and Heidi Amlund

Int. J. Mol. Sci. 2017, 18(4), 725; https://doi.org/10.3390/ijms18040725 - 29 Mar 2017

Cited by 36 | Viewed by 7439

Abstract

The neurotoxicity of methylmercury (MeHg) is well characterised, and the ameliorating effects of selenium have been described. However, little is known about the molecular mechanisms behind this contaminant-nutrient interaction. We investigated the influence of selenium (as selenomethionine, SeMet) and MeHg on mercury accumulation [...] Read more.

The neurotoxicity of methylmercury (MeHg) is well characterised, and the ameliorating effects of selenium have been described. However, little is known about the molecular mechanisms behind this contaminant-nutrient interaction. We investigated the influence of selenium (as selenomethionine, SeMet) and MeHg on mercury accumulation and protein expression in the brain of adult zebrafish (Danio rerio). Fish were fed diets containing elevated levels of MeHg and/or SeMet in a 2 × 2 full factorial design for eight weeks. Mercury concentrations were highest in the brain tissue of MeHg-exposed fish compared to the controls, whereas lower levels of mercury were found in the brain of zebrafish fed both MeHg and SeMet compared with the fish fed MeHg alone. The expression levels of proteins associated with gap junction signalling, oxidative phosphorylation, and mitochondrial dysfunction were significantly (p < 0.05) altered in the brain of zebrafish after exposure to MeHg and SeMet alone or in combination. Analysis of upstream regulators indicated that these changes were linked to the mammalian target of rapamycin (mTOR) pathways, which were activated by MeHg and inhibited by SeMet, possibly through a reactive oxygen species mediated differential activation of RICTOR, the rapamycin-insensitive binding partner of mTOR. Full article

(This article belongs to the Special Issue Zebrafish: A Model for Toxicological Research)

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Open AccessArticle

Comparison of the In Vivo Biotransformation of Two Emerging Estrogenic Contaminants, BP2 and BPS, in Zebrafish Embryos and Adults

by Vincent Le Fol, François Brion, Anne Hillenweck, Elisabeth Perdu, Sandrine Bruel, Selim Aït-Aïssa, Jean-Pierre Cravedi and Daniel Zalko

Int. J. Mol. Sci. 2017, 18(4), 704; https://doi.org/10.3390/ijms18040704 - 25 Mar 2017

Cited by 31 | Viewed by 5593

Abstract

Zebrafish embryo assays are increasingly used in the toxicological assessment of endocrine disruptors. Among other advantages, these models are 3R-compliant and are fit for screening purposes. Biotransformation processes are well-recognized as a critical factor influencing toxic response, but major gaps of knowledge exist [...] Read more.

Zebrafish embryo assays are increasingly used in the toxicological assessment of endocrine disruptors. Among other advantages, these models are 3R-compliant and are fit for screening purposes. Biotransformation processes are well-recognized as a critical factor influencing toxic response, but major gaps of knowledge exist regarding the characterization of functional metabolic capacities expressed in zebrafish. Comparative metabolic studies between embryos and adults are even scarcer. Using ³H-labeled chemicals, we examined the fate of two estrogenic emerging contaminants, benzophenone-2 (BP2) and bisphenol S (BPS), in 4-day embryos and adult zebrafish. BPS and BP2 were exclusively metabolized through phase II pathways, with no major qualitative difference between larvae and adults except the occurrence of a BP2-di-glucuronide in adults. Quantitatively, the biotransformation of both molecules was more extensive in adults. For BPS, glucuronidation was the predominant pathway in adults and larvae. For BP2, glucuronidation was the major pathway in larvae, but sulfation predominated in adults, with ca. 40% conversion of parent BP2 and an extensive release of several conjugates into water. Further larvae/adults quantitative differences were demonstrated for both molecules, with higher residue concentrations measured in larvae. The study contributes novel data regarding the metabolism of BPS and BP2 in a fish model and shows that phase II conjugation pathways are already functional in 4-dpf-old zebrafish. Comparative analysis of BP2 and BPS metabolic profiles in zebrafish larvae and adults further supports the use of zebrafish embryo as a relevant model in which toxicity and estrogenic activity can be assessed, while taking into account the absorption and fate of tested substances. Full article

(This article belongs to the Special Issue Zebrafish: A Model for Toxicological Research)

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Zebrafish Embryo as an In Vivo Model for Behavioral and Pharmacological Characterization of Methylxanthine Drugs

by Ram Manohar Basnet, Michela Guarienti and Maurizio Memo

Int. J. Mol. Sci. 2017, 18(3), 596; https://doi.org/10.3390/ijms18030596 - 9 Mar 2017

Cited by 34 | Viewed by 9175

Abstract

Zebrafish embryo is emerging as an important tool for behavior analysis as well as toxicity testing. In this study, we compared the effect of nine different methylxanthine drugs using zebrafish embryo as a model. We performed behavioral analysis, biochemical assay and Fish Embryo [...] Read more.

Zebrafish embryo is emerging as an important tool for behavior analysis as well as toxicity testing. In this study, we compared the effect of nine different methylxanthine drugs using zebrafish embryo as a model. We performed behavioral analysis, biochemical assay and Fish Embryo Toxicity (FET) test in zebrafish embryos after treatment with methylxanthines. Each drug appeared to behave in different ways and showed a distinct pattern of results. Embryos treated with seven out of nine methylxanthines exhibited epileptic-like pattern of movements, the severity of which varied with drugs and doses used. Cyclic AMP measurement showed that, despite of a significant increase in cAMP with some compounds, it was unrelated to the observed movement behavior changes. FET test showed a different pattern of toxicity with different methylxanthines. Each drug could be distinguished from the other based on its effect on mortality, morphological defects and teratogenic effects. In addition, there was a strong positive correlation between the toxic doses (TC₅₀) calculated in zebrafish embryos and lethal doses (LD₅₀) in rodents obtained from TOXNET database. Taken together, all these findings elucidate the potentiality of zebrafish embryos as an in vivo model for behavioral and toxicity testing of methylxanthines and other related compounds. Full article

(This article belongs to the Special Issue Zebrafish: A Model for Toxicological Research)

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Open AccessCommunication

Changes in Brain Monoamines Underlie Behavioural Disruptions after Zebrafish Diet Exposure to Polycyclic Aromatic Hydrocarbons Environmental Mixtures

by Caroline Vignet, Verena M. Trenkel, Annick Vouillarmet, Giampiero Bricca, Marie-Laure Bégout and Xavier Cousin

Int. J. Mol. Sci. 2017, 18(3), 560; https://doi.org/10.3390/ijms18030560 - 4 Mar 2017

Cited by 26 | Viewed by 5319

Abstract

Zebrafish were exposed through diet to two environmentally relevant polycyclic aromatic hydrocarbons (PAHs) mixtures of contrasted compositions, one of pyrolytic (PY) origin and one from light crude oil (LO). Monoamine concentrations were quantified in the brains of the fish after six month of [...] Read more.

Zebrafish were exposed through diet to two environmentally relevant polycyclic aromatic hydrocarbons (PAHs) mixtures of contrasted compositions, one of pyrolytic (PY) origin and one from light crude oil (LO). Monoamine concentrations were quantified in the brains of the fish after six month of exposure. A significant decrease in noradrenaline (NA) was observed in fish exposed to both mixtures, while a decrease in serotonin (5HT) and dopamine (DA) was observed only in LO-exposed fish. A decrease in metabolites of 5HT and DA was observed in fish exposed to both mixtures. Several behavioural disruptions were observed that depended on mixtures, and parallels were made with changes in monoamine concentrations. Indeed, we observed an increase in anxiety in fish exposed to both mixtures, which could be related to the decrease in 5HT and/or NA, while disruptions of daily activity rhythms were observed in LO fish, which could be related to the decrease in DA. Taken together, these results showed that (i) chronic exposures to PAHs mixtures disrupted brain monoamine contents, which could underlie behavioural disruptions, and that (ii) the biological responses depended on mixture compositions. Full article

(This article belongs to the Special Issue Zebrafish: A Model for Toxicological Research)

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Evaluating Complex Mixtures in the Zebrafish Embryo by Reconstituting Field Water Samples: A Metal Pollution Case Study

by Ellen D. G. Michiels, Lucia Vergauwen, An Hagenaars, Erik Fransen, Stefan Van Dongen, Steven J. Van Cruchten, Lieven Bervoets and Dries Knapen

Int. J. Mol. Sci. 2017, 18(3), 539; https://doi.org/10.3390/ijms18030539 - 2 Mar 2017

Cited by 15 | Viewed by 5428

Abstract

Accurately assessing the toxicity of complex, environmentally relevant mixtures remains an important challenge in ecotoxicology. The goal was to identify biological effects after exposure to environmental water samples and to determine whether the observed effects could be explained by the waterborne metal mixture [...] Read more.

Accurately assessing the toxicity of complex, environmentally relevant mixtures remains an important challenge in ecotoxicology. The goal was to identify biological effects after exposure to environmental water samples and to determine whether the observed effects could be explained by the waterborne metal mixture found in the samples. Zebrafish embryos were exposed to water samples of five different sites originating from two Flemish (Mol and Olen, Belgium) metal contaminated streams: “Scheppelijke Nete” (SN) and “Kneutersloop” (K), and a ditch (D), which is the contamination source of SN. Trace metal concentrations, and Na, K, Mg and Ca concentrations were measured using ICP-MS and were used to reconstitute site-specific water samples. We assessed whether the effects that were observed after exposure to environmental samples could be explained by metal mixture toxicity under standardized laboratory conditions. Exposure to “D” or “reconstituted D” water caused 100% mortality. SN and reconstituted SN water caused similar effects on hatching, swim bladder inflation, growth and swimming activity. A canonical discriminant analysis confirmed a high similarity between both exposure scenarios, indicating that the observed toxicity was indeed primarily caused by metals. The applied workflow could be a valuable approach to evaluate mixture toxicity that limits time and costs while maintaining biological relevance. Full article

(This article belongs to the Special Issue Zebrafish: A Model for Toxicological Research)

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Open AccessArticle

Effect of Photon Hormesis on Dose Responses to Alpha Particles in Zebrafish Embryos

by Candy Yuen Ping Ng, Shuk Han Cheng and Kwan Ngok Yu

Int. J. Mol. Sci. 2017, 18(2), 385; https://doi.org/10.3390/ijms18020385 - 11 Feb 2017

Cited by 4 | Viewed by 4917

Abstract

Photon hormesis refers to the phenomenon where the biological effect of ionizing radiation with a high linear energy transfer (LET) value is diminished by photons with a low LET value. The present paper studied the effect of photon hormesis from X-rays on dose [...] Read more.

Photon hormesis refers to the phenomenon where the biological effect of ionizing radiation with a high linear energy transfer (LET) value is diminished by photons with a low LET value. The present paper studied the effect of photon hormesis from X-rays on dose responses to alpha particles using embryos of the zebrafish (Danio rerio) as the in vivo vertebrate model. The toxicity of these ionizing radiations in the zebrafish embryos was assessed using the apoptotic counts at 20, 24, or 30 h post fertilization (hpf) revealed through acridine orange (AO) staining. For alpha-particle doses ≥ 4.4 mGy, the additional X-ray dose of 10 mGy significantly reduced the number of apoptotic cells at 24 hpf, which proved the presence of photon hormesis. Smaller alpha-particle doses might not have inflicted sufficient aggregate damages to trigger photon hormesis. The time gap T between the X-ray (10 mGy) and alpha-particle (4.4 mGy) exposures was also studied. Photon hormesis was present when T ≤ 30 min, but was absent when T = 60 min, at which time repair of damage induced by alpha particles would have completed to prevent their interactions with those induced by X-rays. Finally, the drop in the apoptotic counts at 24 hpf due to photon hormesis was explained by bringing the apoptotic events earlier to 20 hpf, which strongly supported the removal of aberrant cells through apoptosis as an underlying mechanism for photon hormesis. Full article

(This article belongs to the Special Issue Zebrafish: A Model for Toxicological Research)

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Transcriptional and Behavioral Responses of Zebrafish Larvae to Microcystin-LR Exposure

by Eleni Tzima, Iliana Serifi, Ioanna Tsikari, Ainhoa Alzualde, Ioannis Leonardos and Thomais Papamarcaki

Int. J. Mol. Sci. 2017, 18(2), 365; https://doi.org/10.3390/ijms18020365 - 9 Feb 2017

Cited by 19 | Viewed by 6710

Abstract

Microcystins are cyclic heptapeptides that constitute a diverse group of toxins produced by cyanobacteria. One of the most toxic variants of this family is microcystin-LR (MCLR) which is a potent inhibitor of protein phosphatase 2A (PP2A) and induces cytoskeleton alterations. In this study, [...] Read more.

Microcystins are cyclic heptapeptides that constitute a diverse group of toxins produced by cyanobacteria. One of the most toxic variants of this family is microcystin-LR (MCLR) which is a potent inhibitor of protein phosphatase 2A (PP2A) and induces cytoskeleton alterations. In this study, zebrafish larvae exposed to 500 μg/L of MCLR for four days exhibited a 40% reduction of PP2A activity compared to the controls, indicating early effects of the toxin. Gene expression profiling of the MCLR-exposed larvae using microarray analysis revealed that keratin 96 (krt96) was the most downregulated gene, consistent with the well-documented effects of MCLR on cytoskeleton structure. In addition, our analysis revealed upregulation in all genes encoding for the enzymes of the retinal visual cycle, including rpe65a (retinal pigment epithelium-specific protein 65a), which is critical for the larval vision. Quantitative real-time PCR (qPCR) analysis confirmed the microarray data, showing that rpe65a was significantly upregulated at 50 μg/L and 500 μg/L MCLR in a dose-dependent manner. Consistent with the microarray data, MCLR-treated larvae displayed behavioral alterations such as weakening response to the sudden darkness and hypoactivity in the dark. Our work reveals new molecular targets for MCLR and provides further insights into the molecular mechanisms of MCLR toxicity during early development. Full article

(This article belongs to the Special Issue Zebrafish: A Model for Toxicological Research)

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Cell Imaging Counting as a Novel Ex Vivo Approach for Investigating Drug-Induced Hepatotoxicity in Zebrafish Larvae

by Xuan-Bac Nguyen, Stanislav Kislyuk, Duc-Hung Pham, Angela Kecskés, Jan Maes, Deirdre Cabooter, Pieter Annaert, Peter De Witte and Annelii Ny

Int. J. Mol. Sci. 2017, 18(2), 356; https://doi.org/10.3390/ijms18020356 - 8 Feb 2017

Cited by 12 | Viewed by 6412

Abstract

Drug-induced liver injury (DILI) is the most common reason for failures during the drug development process and for safety-related withdrawal of drugs from the pharmaceutical market. Therefore, having tools and techniques that can detect hepatotoxic properties in drug candidates at an early discovery [...] Read more.

Drug-induced liver injury (DILI) is the most common reason for failures during the drug development process and for safety-related withdrawal of drugs from the pharmaceutical market. Therefore, having tools and techniques that can detect hepatotoxic properties in drug candidates at an early discovery stage is highly desirable. In this study, cell imaging counting was used to measure in a fast, straightforward, and unbiased way the effect of paracetamol and tetracycline, (compounds known to cause hepatotoxicity in humans) on the amount of DsRed-labeled hepatocytes recovered by protease digestion from Tg(fabp10a:DsRed) transgenic zebrafish. The outcome was in general comparable with the results obtained using two reference methods, i.e., visual analysis of liver morphology by fluorescence microscopy and size analysis of fluorescent 2D liver images. In addition, our study shows that administering compounds into the yolk is relevant in the framework of hepatotoxicity testing. Taken together, cell imaging counting provides a novel and rapid tool for screening hepatotoxicants in early stages of drug development. This method is also suitable for testing of other organ-related toxicities subject to the organs and tissues expressing fluorescent proteins in transgenic zebrafish lines. Full article

(This article belongs to the Special Issue Zebrafish: A Model for Toxicological Research)

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A Mixture of Persistent Organic Pollutants and Perfluorooctanesulfonic Acid Induces Similar Behavioural Responses, but Different Gene Expression Profiles in Zebrafish Larvae

by Abdolrahman Khezri, Thomas W. K. Fraser, Rasoul Nourizadeh-Lillabadi, Jorke H. Kamstra, Vidar Berg, Karin E. Zimmer and Erik Ropstad

Int. J. Mol. Sci. 2017, 18(2), 291; https://doi.org/10.3390/ijms18020291 - 29 Jan 2017

Cited by 42 | Viewed by 6064

Abstract

Persistent organic pollutants (POPs) are widespread in the environment and some may be neurotoxic. As we are exposed to complex mixtures of POPs, we aimed to investigate how a POP mixture based on Scandinavian human blood data affects behaviour and neurodevelopment during early [...] Read more.

Persistent organic pollutants (POPs) are widespread in the environment and some may be neurotoxic. As we are exposed to complex mixtures of POPs, we aimed to investigate how a POP mixture based on Scandinavian human blood data affects behaviour and neurodevelopment during early life in zebrafish. Embryos/larvae were exposed to a series of sub-lethal doses and behaviour was examined at 96 h post fertilization (hpf). In order to determine the sensitivity window to the POP mixture, exposure models of 6 to 48 and 48 to 96 hpf were used. The expression of genes related to neurological development was also assessed. Results indicate that the POP mixture increases the swimming speed of larval zebrafish following exposure between 48 to 96 hpf. This behavioural effect was associated with the perfluorinated compounds, and more specifically with perfluorooctanesulfonic acid (PFOS). The expression of genes related to the stress response, GABAergic, dopaminergic, histaminergic, serotoninergic, cholinergic systems and neuronal maintenance, were altered. However, there was little overlap in those genes that were significantly altered by the POP mixture and PFOS. Our findings show that the POP mixture and PFOS can have a similar effect on behaviour, yet alter the expression of genes relevant to neurological development differently. Full article

(This article belongs to the Special Issue Zebrafish: A Model for Toxicological Research)

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In Vitro Biotransformation of Two Human CYP3A Probe Substrates and Their Inhibition during Early Zebrafish Development

by Evy Verbueken, Derek Alsop, Moayad A. Saad, Casper Pype, Els M. Van Peer, Christophe R. Casteleyn, Chris J. Van Ginneken, Joanna Wilson and Steven J. Van Cruchten

Int. J. Mol. Sci. 2017, 18(1), 217; https://doi.org/10.3390/ijms18010217 - 22 Jan 2017

Cited by 20 | Viewed by 6300

Abstract

At present, the zebrafish embryo is increasingly used as an alternative animal model to screen for developmental toxicity after exposure to xenobiotics. Since zebrafish embryos depend on their own drug-metabolizing capacity, knowledge of their intrinsic biotransformation is pivotal in order to correctly interpret [...] Read more.

At present, the zebrafish embryo is increasingly used as an alternative animal model to screen for developmental toxicity after exposure to xenobiotics. Since zebrafish embryos depend on their own drug-metabolizing capacity, knowledge of their intrinsic biotransformation is pivotal in order to correctly interpret the outcome of teratogenicity assays. Therefore, the aim of this in vitro study was to assess the activity of cytochrome P450 (CYP)—a group of drug-metabolizing enzymes—in microsomes from whole zebrafish embryos (ZEM) of 5, 24, 48, 72, 96 and 120 h post-fertilization (hpf) by means of a mammalian CYP substrate, i.e., benzyloxy-methyl-resorufin (BOMR). The same CYP activity assays were performed in adult zebrafish liver microsomes (ZLM) to serve as a reference for the embryos. In addition, activity assays with the human CYP3A4-specific Luciferin isopropyl acetal (Luciferin-IPA) as well as inhibition studies with ketoconazole and CYP3cide were carried out to identify CYP activity in ZLM. In the present study, biotransformation of BOMR was detected at 72 and 96 hpf; however, metabolite formation was low compared with ZLM. Furthermore, Luciferin-IPA was not metabolized by the zebrafish. In conclusion, the capacity of intrinsic biotransformation in zebrafish embryos appears to be lacking during a major part of organogenesis. Full article

(This article belongs to the Special Issue Zebrafish: A Model for Toxicological Research)

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Retinoic Acid Protects and Rescues the Development of Zebrafish Embryonic Retinal Photoreceptor Cells from Exposure to Paclobutrazol

by Wen-Der Wang, Hwei-Jan Hsu, Yi-Fang Li and Chang-Yi Wu

Int. J. Mol. Sci. 2017, 18(1), 130; https://doi.org/10.3390/ijms18010130 - 11 Jan 2017

Cited by 29 | Viewed by 7786

Abstract

Paclobutrazol (PBZ) is a widely used fungicide that shows toxicity to aquatic embryos, probably through rain-wash. Here, we specifically focus on its toxic effect on eye development in zebrafish, as well as the role of retinoic acid (RA), a metabolite of vitamin A [...] Read more.

Paclobutrazol (PBZ) is a widely used fungicide that shows toxicity to aquatic embryos, probably through rain-wash. Here, we specifically focus on its toxic effect on eye development in zebrafish, as well as the role of retinoic acid (RA), a metabolite of vitamin A that controls proliferation and differentiation of retinal photoreceptor cells, in this toxicity. Embryos were exposed to PBZ with or without RA from 2 to 72 h post-fertilization (hpf), and PBZ-treated embryos (2–72 hpf) were exposed to RA for additional hours until 120 hpf. Eye size and histology were examined. Expression levels of gnat1 (rod photoreceptor marker), gnat2 (cone photoreceptor marker), aldehyde dehydrogenases (encoding key enzymes for RA synthesis), and phospho-histone H3 (an M-phase marker) in the eyes of control and treated embryos were examined. PBZ exposure dramatically reduces photoreceptor proliferation, thus resulting in a thinning of the photoreceptor cell layer and leading to a small eye. Co-treatment of PBZ with RA, or post-treatment of PBZ-treated embryos with RA, partially rescues photoreceptor cells, revealed by expression levels of marker proteins and by retinal cell proliferation. PBZ has strong embryonic toxicity to retinal photoreceptors, probably via suppressing the production of RA, with effects including impaired retinal cell division. Full article

(This article belongs to the Special Issue Zebrafish: A Model for Toxicological Research)

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Neurotoxicity of a Biopesticide Analog on Zebrafish Larvae at Nanomolar Concentrations

by Ahmed Nasri, Audrey J. Valverde, Daniel B. Roche, Catherine Desrumaux, Philippe Clair, Hamouda Beyrem, Laurent Chaloin, Alain Ghysen and Véronique Perrier

Int. J. Mol. Sci. 2016, 17(12), 2137; https://doi.org/10.3390/ijms17122137 - 19 Dec 2016

Cited by 12 | Viewed by 6200

Abstract

Despite the ever-increasing role of pesticides in modern agriculture, their deleterious effects are still underexplored. Here we examine the effect of A6, a pesticide derived from the naturally-occurring α-terthienyl, and structurally related to the endocrine disrupting pesticides anilinopyrimidines, on living zebrafish larvae. We [...] Read more.

Despite the ever-increasing role of pesticides in modern agriculture, their deleterious effects are still underexplored. Here we examine the effect of A6, a pesticide derived from the naturally-occurring α-terthienyl, and structurally related to the endocrine disrupting pesticides anilinopyrimidines, on living zebrafish larvae. We show that both A6 and an anilinopyrimidine, cyprodinyl, decrease larval survival and affect central neurons at micromolar concentrations. Focusing on a superficial and easily observable sensory system, the lateral line system, we found that defects in axonal and sensory cell regeneration can be observed at much lower doses, in the nanomolar range. We also show that A6 accumulates preferentially in lateral line neurons and hair cells. We examined whether A6 affects the expression of putative target genes, and found that genes involved in apoptosis/cell proliferation are down-regulated, as well as genes reflecting estrogen receptor activation, consistent with previous reports that anilinopyrimidines act as endocrine disruptors. On the other hand, canonical targets of endocrine signaling are not affected, suggesting that the neurotoxic effect of A6 may be due to the binding of this compound to a recently identified, neuron-specific estrogen receptor. Full article

(This article belongs to the Special Issue Zebrafish: A Model for Toxicological Research)

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3D Visualization of Developmental Toxicity of 2,4,6-Trinitrotoluene in Zebrafish Embryogenesis Using Light-Sheet Microscopy

by Juneyong Eum, Jina Kwak, Hee Joung Kim, Seoyoung Ki, Kooyeon Lee, Ahmed A. Raslan, Ok Kyu Park, Md Ashraf Uddin Chowdhury, Song Her, Yun Kee, Seung-Hae Kwon and Byung Joon Hwang

Int. J. Mol. Sci. 2016, 17(11), 1925; https://doi.org/10.3390/ijms17111925 - 17 Nov 2016

Cited by 14 | Viewed by 7840

Abstract

Environmental contamination by trinitrotoluene is of global concern due to its widespread use in military ordnance and commercial explosives. Despite known long-term persistence in groundwater and soil, the toxicological profile of trinitrotoluene and other explosive wastes have not been systematically measured using in [...] Read more.

Environmental contamination by trinitrotoluene is of global concern due to its widespread use in military ordnance and commercial explosives. Despite known long-term persistence in groundwater and soil, the toxicological profile of trinitrotoluene and other explosive wastes have not been systematically measured using in vivo biological assays. Zebrafish embryos are ideal model vertebrates for high-throughput toxicity screening and live in vivo imaging due to their small size and transparency during embryogenesis. Here, we used Single Plane Illumination Microscopy (SPIM)/light sheet microscopy to assess the developmental toxicity of explosive-contaminated water in zebrafish embryos and report 2,4,6-trinitrotoluene-associated developmental abnormalities, including defects in heart formation and circulation, in 3D. Levels of apoptotic cell death were higher in the actively developing tissues of trinitrotoluene-treated embryos than controls. Live 3D imaging of heart tube development at cellular resolution by light-sheet microscopy revealed trinitrotoluene-associated cardiac toxicity, including hypoplastic heart chamber formation and cardiac looping defects, while the real time PCR (polymerase chain reaction) quantitatively measured the molecular changes in the heart and blood development supporting the developmental defects at the molecular level. Identification of cellular toxicity in zebrafish using the state-of-the-art 3D imaging system could form the basis of a sensitive biosensor for environmental contaminants and be further valued by combining it with molecular analysis. Full article

(This article belongs to the Special Issue Zebrafish: A Model for Toxicological Research)

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Programmed Effects in Neurobehavior and Antioxidative Physiology in Zebrafish Embryonically Exposed to Cadmium: Observations and Hypothesized Adverse Outcome Pathway Framework

by Sander Ruiter, Josefine Sippel, Manon C. Bouwmeester, Tobias Lommelaars, Piet Beekhof, Hennie M. Hodemaekers, Frank Bakker, Evert-Jan Van den Brandhof, Jeroen L. A. Pennings and Leo T. M. Van der Ven

Int. J. Mol. Sci. 2016, 17(11), 1830; https://doi.org/10.3390/ijms17111830 - 2 Nov 2016

Cited by 25 | Viewed by 5501

Abstract

Non-communicable diseases (NCDs) are a major cause of premature mortality. Recent studies show that predispositions for NCDs may arise from early-life exposure to low concentrations of environmental contaminants. This developmental origins of health and disease (DOHaD) paradigm suggests that programming of an embryo [...] Read more.

Non-communicable diseases (NCDs) are a major cause of premature mortality. Recent studies show that predispositions for NCDs may arise from early-life exposure to low concentrations of environmental contaminants. This developmental origins of health and disease (DOHaD) paradigm suggests that programming of an embryo can be disrupted, changing the homeostatic set point of biological functions. Epigenetic alterations are a possible underlying mechanism. Here, we investigated the DOHaD paradigm by exposing zebrafish to subtoxic concentrations of the ubiquitous contaminant cadmium during embryogenesis, followed by growth under normal conditions. Prolonged behavioral responses to physical stress and altered antioxidative physiology were observed approximately ten weeks after termination of embryonal exposure, at concentrations that were 50–3200-fold below the direct embryotoxic concentration, and interpreted as altered developmental programming. Literature was explored for possible mechanistic pathways that link embryonic subtoxic cadmium to the observed apical phenotypes, more specifically, the probability of molecular mechanisms induced by cadmium exposure leading to altered DNA methylation and subsequently to the observed apical phenotypes. This was done using the adverse outcome pathway model framework, and assessing key event relationship plausibility by tailored Bradford-Hill analysis. Thus, cadmium interaction with thiols appeared to be the major contributor to late-life effects. Cadmium-thiol interactions may lead to depletion of the methyl donor S-adenosyl-methionine, resulting in methylome alterations, and may, additionally, result in oxidative stress, which may lead to DNA oxidation, and subsequently altered DNA methyltransferase activity. In this way, DNA methylation may be affected at a critical developmental stage, causing the observed apical phenotypes. Full article

(This article belongs to the Special Issue Zebrafish: A Model for Toxicological Research)

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Screening the Toxicity of Selected Personal Care Products Using Embryo Bioassays: 4-MBC, Propylparaben and Triclocarban

by Tiago Torres, Isabel Cunha, Rosário Martins and Miguel M. Santos

Int. J. Mol. Sci. 2016, 17(10), 1762; https://doi.org/10.3390/ijms17101762 - 21 Oct 2016

Cited by 53 | Viewed by 7317

Abstract

Recently, several emerging pollutants, including Personal Care Products (PCPs), have been detected in aquatic ecosystems, in the ng/L or µg/L range. Available toxicological data is limited, and, for certain PCPs, evidence indicates a potential risk for the environment. Hence, there is an urgent [...] Read more.

Recently, several emerging pollutants, including Personal Care Products (PCPs), have been detected in aquatic ecosystems, in the ng/L or µg/L range. Available toxicological data is limited, and, for certain PCPs, evidence indicates a potential risk for the environment. Hence, there is an urgent need to gather ecotoxicological data on PCPs as a proxy to improve risk assessment. Here, the toxicity of three different PCPs (4-Methylbenzylidene Camphor (4-MBC), propylparaben and triclocarban) was tested using embryo bioassays with Danio rerio (zebrafish) and Paracentrotus lividus (sea urchin). The No Observed Effect Concentration (NOEC) for triclocarban was 0.256 µg/L for sea urchin and 100 µg/L for zebrafish, whereas NOEC for 4-MBC was 0.32 µg/L for sea urchin and 50 µg/L for zebrafish. Both PCPs impacted embryo development at environmentally relevant concentrations. In comparison with triclocarban and 4-MBC, propylparaben was less toxic for both sea urchin (NOEC = 160 µg/L) and zebrafish (NOEC = 1000 µg/L). Overall, this study further demonstrates the sensitivity of embryo bioassays as a high-throughput approach for testing the toxicity of emerging pollutants. Full article

(This article belongs to the Special Issue Zebrafish: A Model for Toxicological Research)

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Exposure to Zinc Sulfate Results in Differential Effects on Olfactory Sensory Neuron Subtypes in Adult Zebrafish

by James T. Hentig and Christine A. Byrd-Jacobs

Int. J. Mol. Sci. 2016, 17(9), 1445; https://doi.org/10.3390/ijms17091445 - 31 Aug 2016

Cited by 25 | Viewed by 7967

Abstract

Zinc sulfate is a known olfactory toxicant, although its specific effects on the olfactory epithelium of zebrafish are unknown. Olfactory organs of adult zebrafish were exposed to zinc sulfate and, after 2, 3, 5, 7, 10 or 14 days, fish were processed for [...] Read more.

Zinc sulfate is a known olfactory toxicant, although its specific effects on the olfactory epithelium of zebrafish are unknown. Olfactory organs of adult zebrafish were exposed to zinc sulfate and, after 2, 3, 5, 7, 10 or 14 days, fish were processed for histological, immunohistochemical, ultrastructural, and behavioral analyses. Severe morphological disruption of the olfactory organ was observed two days following zinc sulfate exposure, including fusion of lamellae, epithelial inflammation, and significant loss of anti-calretinin labeling. Scanning electron microscopy revealed the apical surface of the sensory region was absent of ciliated structures, but microvilli were still present. Behavioral analysis showed significant loss of the ability to perceive bile salts and some fish also had no response to amino acids. Over the next several days, olfactory organ morphology, epithelial structure, and anti-calretinin labeling returned to control-like conditions, although the ability to perceive bile salts remained lost until day 14. Thus, exposure to zinc sulfate results in rapid degeneration of the olfactory organ, followed by restoration of morphology and function within two weeks. Zinc sulfate appears to have a greater effect on ciliated olfactory sensory neurons than on microvillous olfactory sensory neurons, suggesting differential effects on sensory neuron subtypes. Full article

(This article belongs to the Special Issue Zebrafish: A Model for Toxicological Research)

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Exogenous Nitric Oxide Suppresses in Vivo X-ray-Induced Targeted and Non-Targeted Effects in Zebrafish Embryos

by E.Y. Kong, W.K. Yeung, T.K.Y. Chan, S.H. Cheng and K.N. Yu

Int. J. Mol. Sci. 2016, 17(8), 1321; https://doi.org/10.3390/ijms17081321 - 12 Aug 2016

Cited by 15 | Viewed by 6194

Abstract

The present paper studied the X-ray-induced targeted effect in irradiated zebrafish embryos (Danio rerio), as well as a non-targeted effect in bystander naïve embryos partnered with irradiated embryos, and examined the influence of exogenous nitric oxide (NO) on these targeted and [...] Read more.

The present paper studied the X-ray-induced targeted effect in irradiated zebrafish embryos (Danio rerio), as well as a non-targeted effect in bystander naïve embryos partnered with irradiated embryos, and examined the influence of exogenous nitric oxide (NO) on these targeted and non-targeted effects. The exogenous NO was generated using an NO donor, S-nitroso-N-acetylpenicillamine (SNAP). The targeted and non-targeted effects, as well as the toxicity of the SNAP, were assessed using the number of apoptotic events in the zebrafish embryos at 24 h post fertilization (hpf) revealed through acridine orange (AO) staining. SNAP with concentrations of 20 and 100 µM were first confirmed to have no significant toxicity on zebrafish embryos. The targeted effect was mitigated in zebrafish embryos if they were pretreated with 100 µM SNAP prior to irradiation with an X-ray dose of 75 mGy but was not alleviated in zebrafish embryos if they were pretreated with 20 µM SNAP. On the other hand, the non-targeted effect was eliminated in the bystander naïve zebrafish embryos if they were pretreated with 20 or 100 µM SNAP prior to partnering with zebrafish embryos having been subjected to irradiation with an X-ray dose of 75 mGy. These findings revealed the importance of NO in the protection against damages induced by ionizing radiations or by radiation-induced bystander signals, and could have important impacts on development of advanced cancer treatment strategies. Full article

(This article belongs to the Special Issue Zebrafish: A Model for Toxicological Research)

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Open AccessArticle

Longitudinal Effects of Embryonic Exposure to Cocaine on Morphology, Cardiovascular Physiology, and Behavior in Zebrafish

by Eric J. Mersereau, Cody A. Boyle, Shelby Poitra, Ana Espinoza, Joclyn Seiler, Robert Longie, Lisa Delvo, Megan Szarkowski, Joshua Maliske, Sarah Chalmers, Diane C. Darland and Tristan Darland

Int. J. Mol. Sci. 2016, 17(6), 847; https://doi.org/10.3390/ijms17060847 - 31 May 2016

Cited by 12 | Viewed by 6457

Abstract

A sizeable portion of the societal drain from cocaine abuse results from the complications of in utero drug exposure. Because of challenges in using humans and mammalian model organisms as test subjects, much debate remains about the impact of in utero cocaine exposure. [...] Read more.

A sizeable portion of the societal drain from cocaine abuse results from the complications of in utero drug exposure. Because of challenges in using humans and mammalian model organisms as test subjects, much debate remains about the impact of in utero cocaine exposure. Zebrafish offer a number of advantages as a model in longitudinal toxicology studies and are quite sensitive physiologically and behaviorally to cocaine. In this study, we have used zebrafish to model the effects of embryonic pre-exposure to cocaine on development and on subsequent cardiovascular physiology and cocaine-induced conditioned place preference (CPP) in longitudinal adults. Larval fish showed a progressive decrease in telencephalic size with increased doses of cocaine. These treated larvae also showed a dose dependent response in heart rate that persisted 24 h after drug cessation. Embryonic cocaine exposure had little effect on overall health of longitudinal adults, but subtle changes in cardiovascular physiology were seen including decreased sensitivity to isoproterenol and increased sensitivity to cocaine. These longitudinal adult fish also showed an embryonic dose-dependent change in CPP behavior, suggesting an increased sensitivity. These studies clearly show that pre-exposure during embryonic development affects subsequent cocaine sensitivity in longitudinal adults. Full article

(This article belongs to the Special Issue Zebrafish: A Model for Toxicological Research)

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Review

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20 pages, 1692 KiB

Open AccessReview

The Olfactory System of Zebrafish as a Model for the Study of Neurotoxicity and Injury: Implications for Neuroplasticity and Disease

by Erika Calvo-Ochoa and Christine A. Byrd-Jacobs

Int. J. Mol. Sci. 2019, 20(7), 1639; https://doi.org/10.3390/ijms20071639 - 2 Apr 2019

Cited by 55 | Viewed by 16459

Abstract

The olfactory system, composed of the olfactory organs and the olfactory bulb, allows organisms to interact with their environment and through the detection of odor signals. Olfaction mediates behaviors pivotal for survival, such as feeding, mating, social behavior, and danger assessment. The olfactory [...] Read more.

The olfactory system, composed of the olfactory organs and the olfactory bulb, allows organisms to interact with their environment and through the detection of odor signals. Olfaction mediates behaviors pivotal for survival, such as feeding, mating, social behavior, and danger assessment. The olfactory organs are directly exposed to the milieu, and thus are particularly vulnerable to damage by environmental pollutants and toxicants, such as heavy metals, pesticides, and surfactants, among others. Given the widespread occurrence of olfactory toxicants, there is a pressing need to understand the effects of these harmful compounds on olfactory function. Zebrafish (Danio rerio) is a valuable model for studying human physiology, disease, and toxicity. Additionally, the anatomical components of the zebrafish olfactory system are similar to those of other vertebrates, and they present a remarkable degree of regeneration and neuroplasticity, making it an ideal model for the study of regeneration, reorganization and repair mechanisms following olfactory toxicant exposure. In this review, we focus on (1) the anatomical, morphological, and functional organization of the olfactory system of zebrafish; (2) the adverse effects of olfactory toxicants and injury to the olfactory organ; and (3) remodeling and repair neuroplasticity mechanisms following injury and degeneration by olfactory toxicant exposure. Full article

(This article belongs to the Special Issue Zebrafish 2.0: A Model for Toxicological Research)

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26 pages, 1102 KiB

Open AccessReview

Zebrafish Models of Neurodevelopmental Disorders: Limitations and Benefits of Current Tools and Techniques

by Raquel Vaz, Wolfgang Hofmeister and Anna Lindstrand

Int. J. Mol. Sci. 2019, 20(6), 1296; https://doi.org/10.3390/ijms20061296 - 14 Mar 2019

Cited by 69 | Viewed by 17379

Abstract

For the past few years there has been an exponential increase in the use of animal models to confirm the pathogenicity of candidate disease-causing genetic variants found in patients. One such animal model is the zebrafish. Despite being a non-mammalian animal, the zebrafish [...] Read more.

For the past few years there has been an exponential increase in the use of animal models to confirm the pathogenicity of candidate disease-causing genetic variants found in patients. One such animal model is the zebrafish. Despite being a non-mammalian animal, the zebrafish model has proven its potential in recapitulating the phenotypes of many different human genetic disorders. This review will focus on recent advances in the modeling of neurodevelopmental disorders in zebrafish, covering aspects from early brain development to techniques used for modulating gene expression, as well as how to best characterize the resulting phenotypes. We also review other existing models of neurodevelopmental disorders, and the current efforts in developing and testing compounds with potential therapeutic value. Full article

(This article belongs to the Special Issue Zebrafish 2.0: A Model for Toxicological Research)

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Zebrafish as a Model Organism for the Development of Drugs for Skin Cancer

by Fatemeh Bootorabi, Hamed Manouchehri, Reza Changizi, Harlan Barker, Elisabetta Palazzo, Annalisa Saltari, Mataleena Parikka, Carlo Pincelli and Ashok Aspatwar

Int. J. Mol. Sci. 2017, 18(7), 1550; https://doi.org/10.3390/ijms18071550 - 18 Jul 2017

Cited by 46 | Viewed by 10843

Abstract

Skin cancer, which includes melanoma and squamous cell carcinoma, represents the most common type of cutaneous malignancy worldwide, and its incidence is expected to rise in the near future. This condition derives from acquired genetic dysregulation of signaling pathways involved in the proliferation [...] Read more.

Skin cancer, which includes melanoma and squamous cell carcinoma, represents the most common type of cutaneous malignancy worldwide, and its incidence is expected to rise in the near future. This condition derives from acquired genetic dysregulation of signaling pathways involved in the proliferation and apoptosis of skin cells. The development of animal models has allowed a better understanding of these pathomechanisms, with the possibility of carrying out toxicological screening and drug development. In particular, the zebrafish (Danio rerio) has been established as one of the most important model organisms for cancer research. This model is particularly suitable for live cell imaging and high-throughput drug screening in a large-scale fashion. Thanks to the recent advances in genome editing, such as the clustered regularly-interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) methodologies, the mechanisms associated with cancer development and progression, as well as drug resistance can be investigated and comprehended. With these unique tools, the zebrafish represents a powerful platform for skin cancer research in the development of target therapies. Here, we will review the advantages of using the zebrafish model for drug discovery and toxicological and phenotypical screening. We will focus in detail on the most recent progress in the field of zebrafish model generation for the study of melanoma and squamous cell carcinoma (SCC), including cancer cell injection and transgenic animal development. Moreover, we will report the latest compounds and small molecules under investigation in melanoma zebrafish models. Full article

(This article belongs to the Special Issue Zebrafish: A Model for Toxicological Research)

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801 KiB

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Utilizing Zebrafish Visual Behaviors in Drug Screening for Retinal Degeneration

by Logan Ganzen, Prahatha Venkatraman, Chi Pui Pang, Yuk Fai Leung and Mingzhi Zhang

Int. J. Mol. Sci. 2017, 18(6), 1185; https://doi.org/10.3390/ijms18061185 - 2 Jun 2017

Cited by 44 | Viewed by 10279

Abstract

Zebrafish are a popular vertebrate model in drug discovery. They produce a large number of small and rapidly-developing embryos. These embryos display rich visual-behaviors that can be used to screen drugs for treating retinal degeneration (RD). RD comprises blinding diseases such as Retinitis [...] Read more.

Zebrafish are a popular vertebrate model in drug discovery. They produce a large number of small and rapidly-developing embryos. These embryos display rich visual-behaviors that can be used to screen drugs for treating retinal degeneration (RD). RD comprises blinding diseases such as Retinitis Pigmentosa, which affects 1 in 4000 people. This disease has no definitive cure, emphasizing an urgency to identify new drugs. In this review, we will discuss advantages, challenges, and research developments in using zebrafish behaviors to screen drugs in vivo. We will specifically discuss a visual-motor response that can potentially expedite discovery of new RD drugs. Full article

(This article belongs to the Special Issue Zebrafish: A Model for Toxicological Research)

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1232 KiB

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Zebrafish as a Vertebrate Model System to Evaluate Effects of Environmental Toxicants on Cardiac Development and Function

by Swapnalee Sarmah and James A. Marrs

Int. J. Mol. Sci. 2016, 17(12), 2123; https://doi.org/10.3390/ijms17122123 - 16 Dec 2016

Cited by 118 | Viewed by 9653

Abstract

Environmental pollution is a serious problem of the modern world that possesses a major threat to public health. Exposure to environmental pollutants during embryonic development is particularly risky. Although many pollutants have been verified as potential toxicants, there are new chemicals in the [...] Read more.

Environmental pollution is a serious problem of the modern world that possesses a major threat to public health. Exposure to environmental pollutants during embryonic development is particularly risky. Although many pollutants have been verified as potential toxicants, there are new chemicals in the environment that need assessment. Heart development is an extremely sensitive process, which can be affected by environmentally toxic molecule exposure during embryonic development. Congenital heart defects are the most common life-threatening global health problems, and the etiology is mostly unknown. The zebrafish has emerged as an invaluable model to examine substance toxicity on vertebrate development, particularly on cardiac development. The zebrafish offers numerous advantages for toxicology research not found in other model systems. Many laboratories have used the zebrafish to study the effects of widespread chemicals in the environment on heart development, including pesticides, nanoparticles, and various organic pollutants. Here, we review the uses of the zebrafish in examining effects of exposure to external molecules during embryonic development in causing cardiac defects, including chemicals ubiquitous in the environment and illicit drugs. Known or potential mechanisms of toxicity and how zebrafish research can be used to provide mechanistic understanding of cardiac defects are discussed. Full article

(This article belongs to the Special Issue Zebrafish: A Model for Toxicological Research)

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Zebrafish as an In Vivo Model to Assess Epigenetic Effects of Ionizing Radiation

by Eva Yi Kong, Shuk Han Cheng and Kwan Ngok Yu

Int. J. Mol. Sci. 2016, 17(12), 2108; https://doi.org/10.3390/ijms17122108 - 15 Dec 2016

Cited by 13 | Viewed by 5664

Abstract

Exposure to ionizing radiations (IRs) is ubiquitous in our environment and can be categorized into “targeted” effects and “non-targeted” effects. In addition to inducing deoxyribonucleic acid (DNA) damage, IR exposure leads to epigenetic alterations that do not alter DNA sequence. Using an appropriate [...] Read more.

Exposure to ionizing radiations (IRs) is ubiquitous in our environment and can be categorized into “targeted” effects and “non-targeted” effects. In addition to inducing deoxyribonucleic acid (DNA) damage, IR exposure leads to epigenetic alterations that do not alter DNA sequence. Using an appropriate model to study the biological effects of radiation is crucial to better understand IR responses as well as to develop new strategies to alleviate exposure to IR. Zebrafish, Danio rerio, is a scientific model organism that has yielded scientific advances in several fields and recent studies show the usefulness of this vertebrate model in radiation biology. This review briefly describes both “targeted” and “non-targeted” effects, describes the findings in radiation biology using zebrafish as a model and highlights the potential of zebrafish to assess the epigenetic effects of IR, including DNA methylation, histone modifications and miRNA expression. Other in vivo models are included to compare observations made with zebrafish, or to illustrate the feasibility of in vivo models when the use of zebrafish was unavailable. Finally, tools to study epigenetic modifications in zebrafish, including changes in genome-wide DNA methylation, histone modifications and miRNA expression, are also described in this review. Full article

(This article belongs to the Special Issue Zebrafish: A Model for Toxicological Research)

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Zebrafish: A Model for the Study of Toxicants Affecting Muscle Development and Function

by Magda Dubińska-Magiera, Małgorzata Daczewska, Anna Lewicka, Marta Migocka-Patrzałek, Joanna Niedbalska-Tarnowska and Krzysztof Jagla

Int. J. Mol. Sci. 2016, 17(11), 1941; https://doi.org/10.3390/ijms17111941 - 19 Nov 2016

Cited by 59 | Viewed by 13248

Abstract

The rapid progress in medicine, agriculture, and allied sciences has enabled the development of a large amount of potentially useful bioactive compounds, such as drugs and pesticides. However, there is another side of this phenomenon, which includes side effects and environmental pollution. To [...] Read more.

The rapid progress in medicine, agriculture, and allied sciences has enabled the development of a large amount of potentially useful bioactive compounds, such as drugs and pesticides. However, there is another side of this phenomenon, which includes side effects and environmental pollution. To avoid or minimize the uncontrollable consequences of using the newly developed compounds, researchers seek a quick and effective means of their evaluation. In achieving this goal, the zebrafish (Danio rerio) has proven to be a highly useful tool, mostly because of its fast growth and development, as well as the ability to absorb the molecules diluted in water through its skin and gills. In this review, we focus on the reports concerning the application of zebrafish as a model for assessing the impact of toxicants on skeletal muscles, which share many structural and functional similarities among vertebrates, including zebrafish and humans. Full article

(This article belongs to the Special Issue Zebrafish: A Model for Toxicological Research)

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