Search Results (6)

Triplophysa yarkandensis, a unique saline-alkali tolerant fish in the Tarim River Basin, exhibits unclear adaptive mechanisms of its digestive system to saline-alkali stressors. This study compared the histological characteristics of the digestive system in fish reared in saline-alkali water (salinity 5.89, alkalinity 125.60) and freshwater. Histological characteristics were analyzed using hematoxylin-eosin staining, and parameters were quantified via Image-Pro Plus software, with statistical comparisons performed using independent sample t-tests. Key findings included a 2.7-fold increase in oropharyngeal club cell density (48.50 ± 2.68 vs. 17.80 ± 2.04, p < 0.01) with denser stratified squamous epithelium in the saline-alkali group; a 74% increase in esophageal goblet cells (104.42 ± 6.67 vs. 59.94 ± 4.68, p < 0.01) alongside a 39% reduction in mucosal fold height; 87%, 24%, and 51% increases in villi number across the foregut, midgut, and hindgut, respectively, with an 84% elevation in midgut goblet cells (p < 0.01); and mild vacuolization in the hepatopancreas. Results indicate that T. yarkandensis adapts via synergistic strategies of enhanced digestive mucus secretion, epithelial structural optimization, and hepatopancreatic metabolic reprogramming. The coordinated villi proliferation and mucus secretion enhance nutrient absorption and osmotic barrier function, providing a theoretical basis for saline-alkali aquaculture. Full article

The Caco-2 in vitro model of the intestinal barrier is a well-established system for the investigation of the intestinal fate of orally ingested chemicals and drugs, and it has been used for over ten years by pharmaceutical industries as a model for absorption in preclinical studies. The Caco-2 model shows a fair correlation with in vivo drug absorption, though some inherent biases remain unresolved. Its main limitation lies in the lack of structural complexity, as it does not replicate the diverse cell types and mucus layer present in the human intestinal epithelium. Consequently, the development of advanced in vitro models of the intestinal barrier, that more structurally resemble the human intestinal epithelium physiology, has increased the potential applications of these models. Recently, Caco-2-based advanced intestinal models have proven effective in predicting nanomaterial uptake and transport across the intestinal barrier. The aim of this review is to provide a state-of-the-art of human in vitro intestinal barrier models for the study of translocation/uptake of nanoparticles relevant for oral exposure, including inorganic nanomaterials, micro/nano plastic, and fiber nanomaterials. The main effects of the above-mentioned nanomaterials on the intestinal barrier are also reported. Full article

With the rise in global plastic production and the presence of plastic waste in the environment, microplastics are considered an emerging environmental contaminant. Human exposure and the impact of microplastics on human health are not well studied. Recent studies have observed the presence of microplastics in human tissues and several studies have noted toxicity in in vitro and in vivo mammalian models. We examined the impact of polystyrene nano- and microplastics in increasingly complex intestinal cell models. Using an undifferentiated Caco-2 mono-culture model, we assessed particle association, cytotoxicity, and particle clearance/retention, whereas in differentiated mono- and tri-culture transwell models, we assessed membrane integrity and particle translocation. Only 50 nm and 500 nm particles were internalized in the undifferentiated cells; however, no signs of cellular toxicity were observed at any concentrations tested. Additionally, polystyrene particles had no impact on barrier integrity, but the 50 nm particles were able to cross to the basolateral side, albeit attenuated in the tri-culture model that had a mucus layer. This study reduced some of the variability common to MNPL testing across various in vitro models, but further testing is needed to fully understand the potential effects of human MNPL exposure. Full article

The transport of living fish is an important part of the fish farming process. The transport usually causes fish stress. This study evaluated the effects of transport temperature and vibration frequency on water quality, blood biochemical parameters, gill histomorphology, oxidative stress, and meat quality of pearl gentian groupers after transport. First, 1-year-old groupers (450 ± 25 g) were transported in plastic bags for 48 h, including the following treatments: no shaking, transported at 15 °C, shaking at 70 rpm, transported at 15 °C (15 °C/70 rpm); shaking at 120 rpm, transported at 15 °C (15 °C/120 rpm); no shaking, transported at 25 °C; shaking at 70 rpm, transported at 25 °C (25 °C/70 rpm); and shaking at 120 rpm, transported at 25 °C (25 °C/120 rpm). Serum, liver, gill, and muscle samples were collected for testing at 0, 12, 24, 36, and 48 h of exposure. During the 48 h transport, total ammonia nitrogen (TAN), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-PX), and malondialdehyde (MDA) were significantly increased in the transport group compared to the control group. In the early stage of transportation, aspartate aminotransferase (AST), alanine aminotransferase (ALT), cortisol (COR), lactate dehydrogenase (LDH), and glucose (GLU) in the transportation groups were significantly higher than those in the control group, while the water quality pH and dissolved oxygen (DO) levels decreased significantly. Compared with untransported fish, the total free amino acid (TFAA) content increased by 40.27% and 31.74% in the 25 °C/70 rpm and 25 °C/120 rpm groups, respectively. In addition, the results of hematoxylin–eosin staining and scanning electron microscopy showed that the epithelial cells in the high-speed group were swollen, the gill lamella was severely curved, and a large amount of mucus was secreted. This study explores the basic information of transportation, which will help to select the conditions that are more suitable for the successful transportation of pearl gentian groupers. Full article

Extensive environmental pollution by microplastics has increased the risk of human exposure to plastics. However, the biosafety of polypropylene microplastics (PP-MPs), especially of PP particles < 10 μm, in mammals has not been studied. Thus, here, we explored the mechanism of action and effect of exposure to small and large PP-MPs, via oral ingestion, on the mouse intestinal tract. Male C57BL/6 mice were administered PP suspensions (8 and 70 μm; 0.1, 1.0, and 10 mg/mL) for 28 days. PP-MP treatment resulted in inflammatory pathological damage, ultrastructural changes in intestinal epithelial cells, imbalance of the redox system, and inflammatory reactions in the colon. Additionally, we observed damage to the tight junctions of the colon and decreased intestinal mucus secretion and ion transporter expression. Further, the apoptotic rate of colonic cells significantly increased after PP-MP treatment. The expression of pro-inflammatory and pro-apoptosis proteins significantly increased in colon tissue, while the expression of anti-inflammatory and anti-apoptosis proteins significantly decreased. In summary, this study demonstrates that PP-MPs induce colonic apoptosis and intestinal barrier damage through oxidative stress and activation of the TLR4/NF-κB inflammatory signal pathway in mice, which provides new insights into the toxicity of MPs in mammals. Full article

The skin, gills, and gut are the most extensively studied mucosal organs in fish. These mucosal structures provide the intimate interface between the internal and external milieus and serve as the indispensable first line of defense. They have highly diverse physiological functions. Their role in defense can be highlighted in three shared similarities: their microanatomical structures that serve as the physical barrier and hold the immune cells and the effector molecules; the mucus layer, also a physical barrier, contains an array of potent bioactive molecules; and the resident microbiota. Mucosal surfaces are responsive and plastic to the different changes in the aquatic environment. The direct interaction of the mucosa with the environment offers some important information on both the physiological status of the host and the conditions of the aquatic environment. Increasing attention has been directed to these features in the last year, particularly on how to improve the overall health of the fish through manipulation of mucosal functions and on how the changes in the mucosa, in response to varying environmental factors, can be harnessed to improve husbandry. In this short review, we highlight the current knowledge on how mucosal surfaces respond to various environmental factors relevant to aquaculture and how they may be exploited in fostering sustainable fish farming practices, especially in controlled aquaculture environments. Full article