Search Results (353)

Background/Objectives: Using a well-established model of streptozotocin-induced diabetic retinopathy (DR), this study sought to evaluate the neuroprotective effect of intravitreal Forskolin (FSK) on retinal ganglion cell survival and glial activation and explore the association of circulating miR-200b with metabolic and oxidative stress in DR. Methods: A total of 18 male Wistar rats were divided into a control group (n = 6) and a streptozotocin-induced diabetic group (n = 12), which were further divided into diabetic control and FSK-treated groups (n = 6 each). Total antioxidant capacity (TAC), total peroxide (TP), triglycerides (TGs), total cholesterol, and high-density lipoprotein cholesterol (HDL-C) were measured. qRT-PCR analysis for miRNA-200b and immunohistochemistry were performed. Results: Diabetic rats showed oxidative stress and hyperlipidemia associated with increased circulating miR-200b levels. The retina showed reduced neuron numbers (Caspase-3), altered glial and astrocyte staining (IBA1, GFAP), and changes in microglia/macrophage morphology and distribution. Intravitreal FSK improved retinal ganglion cell survival and reduced glial activation, while systemic lipid profile and oxidative stress markers remained largely unchanged. Circulating miR-200b levels showed a positive correlation with oxidative stress markers across groups. Conclusions: Intravitreal FSK was able to limit the disease exacerbation via improved neuronal survival through inhibition of apoptosis. FSK did not produce observable qualitative changes in GFAP expression or IBA1+ cell morphology under the conditions tested. Full article

Trans,trans-2,4-decadienal (tt-DDE), the primary aldehyde component found in cooking oil fumes, is a prevalent environmental pollutant. However, its potential adverse effects on ocular development remain largely unexplored. This study evaluated its toxicity on ocular development and angiogenesis in zebrafish larvae, as well as on human retinal vascular endothelial cells (HRECs). Zebrafish (Danio rerio) larvae at 48 h post-fertilization were microinjected intraocularly with various doses of tt-DDE (65.87–521.3 mM) for 24 h. We observed dose-dependent impairments in ocular development following tt-DDE exposure. It significantly reduced eye size and inhibited the intraocular vascular area at concentrations of 128.9 mM and above. Histopathological analysis revealed retinal structural disorganization, eye shrinkage, and a clear dose-dependent increase in acridine orange (AO) fluorescence intensity. Apoptosis assays confirmed a significant escalation in ocular cell death at higher exposure doses. Additionally, our results demonstrated that tt-DDE (5–100 μM) significantly reduced the viability of HRECs in vitro. These findings suggest that early-life exposure to tt-DDE impairs ocular development in zebrafish by inducing histopathological damage, inhibiting angiogenesis, and promoting apoptosis, and also exerts direct cytotoxicity to human retinal cells. This study underscores the potential risk of tt-DDE exposure as an environmental factor contributing to ocular developmental toxicity. Full article

Non-arteritic anterior ischemic optic neuropathy (NAION) is a leading cause of sudden vision loss, yet no effective therapy exists to preserve retinal ganglion cells (RGCs) after ischemic injury. Nostoc commune (NC), an edible cyanobacterium with established antioxidant and anti-inflammatory activities, has emerged as a potential functional bioresource with relevance to ocular health. Here, we investigated the therapeutic effects of a crude aqueous extract of NC using a rodent model of anterior ischemic optic neuropathy (rAION). NC treatment significantly improved RGC survival, reduced apoptosis, attenuated macrophage and microglial activation (ED-1, Iba1), suppressed proinflammatory cytokine expression (IL-6), enhanced the reparative marker Ym1+2, and preserved optic-nerve myelination. Functionally, NC administration restored visual signaling as demonstrated by improved Flash Visual Evoked Potential amplitudes. Immunoblot analysis showed increased phosphorylation of PI3K/AKT/mTOR/p70S6K signaling components in retinal tissue following NC treatment. Proteomic profiling further demonstrated that NC extract comprises a coordinated repertoire of phycobiliproteins, antioxidant enzymes, and stress-response proteins that may collectively contribute to its biological effects. Together, these findings suggest that Nostoc commune extract may serve as a promising functional food-derived candidate for protecting RGCs and preserving visual function following ischemic optic neuropathy. Further studies are required to identify its active constituents, optimize formulation strategies, and evaluate its translational potential. Full article

Diabetic retinopathy is increasingly recognized as a neurovascular disorder rather than a purely vascular disease; however, therapeutic strategies targeting retinal neurodegeneration remain limited. In this study, we investigated the protective effects of norrin against hyperglycemia-induced retinal neurodegeneration and elucidated its underlying molecular mechanisms in diabetic mice. We found that retinal neurodegeneration may precede microvascular leakage in diabetic retinas. Norrin, which is expressed in the inner retina, was significantly downregulated under diabetic conditions. Intravitreal supplementation of norrin markedly attenuated hyperglycemia-induced neurodegenerative processes, leading to retinal ganglion cell (RGC) apoptosis, including oxidative stress, inflammation, and neuropathological alterations such as reactive gliosis, glutamate excitotoxicity, and synaptic dysfunction. Norrin also reduced hyperglycemia-induced microvascular leakage and RGC apoptosis by normalizing vascular endothelial growth factor (VEGF) overexpression and restoring pigment epithelium-derived factor (PEDF) levels. Notably, PEDF upregulated by norrin effectively suppressed neurodegenerative processes induced by hyperglycemia or VEGF, thereby preserving RGC function. These findings identify norrin as a critical modulator of hyperglycemia-induced retinal neurodegeneration through restoration of the VEGF–PEDF balance. Our results highlight norrin as a potential therapeutic target for early neurodegenerative changes in diabetic retinopathy. Full article

This study aimed to investigate the effects of resveratrol (RES) and carboplatin (CPT), alone and in combination, on cell viability, apoptosis, cell cycle progression, mitochondrial function, and oxidative stress in Y79 retinoblastoma (RB) cells. Particular emphasis was placed on evaluating the synergistic potential of the combination and elucidating the interconnected molecular mechanisms underlying its anticancer effects. Y79 cells were treated with RES, CPT, and their combinations. Cell viability and synergy were assessed using the MTT assay and combination index (CI) analysis. Apoptosis (annexin V/PI), cell cycle distribution (propidium iodide (PI) staining), intracellular ROS production (DCFH-DA), and mitochondrial membrane potential (JC-1) were evaluated by flow cytometry. ROS dependency was further examined using N-acetylcysteine (NAC) pretreatment. Expression levels of apoptosis- and cell cycle-related genes (BAX, BCL-2, CASP3, CASP9, CCNB1, and CDK1) were analyzed by RT-qPCR. Cytoskeletal alterations were assessed by immunocytochemistry. In addition, the antitumor effects of the combination were validated in a three-dimensional (3D) tumor spheroid model. RES and CPT reduced cell viability in a dose- and time-dependent manner and demonstrated synergistic effects (CI < 1) at selected concentrations. Combination treatment significantly increased apoptosis, induced G2/M phase arrest, enhanced ROS accumulation, and promoted mitochondrial depolarization compared with single-agent treatments. NAC pretreatment attenuated ROS generation and partially restored cell viability, supporting a contributory role of oxidative stress in combination-induced cytotoxicity. At the transcriptional level, the RES + CPT combination significantly increased the BAX/BCL-2 ratio and upregulated CASP3 and CASP9 expression, while downregulating CCNB1 and CDK1, consistent with mitochondrial apoptotic activation and G2/M arrest. Immunocytochemical analysis revealed pronounced cytoskeletal disruption and apoptotic morphology in the combination group. Importantly, in the 3D spheroid model, co-treatment markedly reduced spheroid size and viability and enhanced cell death compared with monotherapies. The combination of RES and CPT exerts a synergistic anticancer effect in Y79 RB cells through coordinated mechanisms involving ROS accumulation, mitochondrial dysfunction, caspase activation, and G2/M phase arrest. The attenuation of cytotoxicity by NAC and the validation of efficacy in a 3D tumor spheroid model strengthen the mechanistic relevance of these findings. These results support further preclinical investigation of this combination strategy in in vivo models and normal retinal cell systems. Full article

Oxidative stress-induced RPE cell death is a major cause of AMD pathogenesis. However, the exact modes of oxidative stress-driven retinal death remain elusive. To address this knowledge gap, we investigated the role of DJ-1, an antioxidant protein we previously characterized in the retina, in cell death regulation. Specifically, we analyzed cell death pathways in the retinas of DJ-1 knockout (KO) mice, with or without sodium iodate (NaIO₃) injection. We quantified MAPK signaling protein activation by Western blot. The distribution of the cell death executioners, activated caspase 3, and pMLKL, was investigated. The effects of caspase and necroptosis inhibitors in mice previously injected with NaIO₃ were determined. Significant increases in JNK1/2 activation and FOXO1 levels were detected in RPE lysates when DJ-1 KO mice were injected with 10 mg/kg NaIO₃. The immunoreactivity of active caspase-3 and pMLKL was stronger in the retinas of DJ-1 KO compared with C57BL mice. These immunoreactivities further increased in the degenerating outer retina post NaIO₃ injection and were stronger in the retina of DJ-1 KO compared with C57BL mice at both doses of NaIO₃. ZVAD treatment rescued retinal degeneration to varying degrees in DJ-1 KO mice. However, necrostatin (Nec-1) alleviated retinal degeneration in both DJ-1 KO and C57BL mice, suggesting that apoptosis is a major cell death modality in the absence of DJ-1. Overall, oxidative stress-induced RPE and retinal cell death involve activation of both apoptosis and necroptosis in the absence of DJ-1. Full article

Artificial optical radiation, spanning from 100 nm to 1 mm, encompasses ultraviolet (UV) and infrared (IR) light. UV light is well known for its risks on the skin and eyes. Recently, there has been growing interest in light at 405 nm (violet-blue light, VBL) due to its antimicrobial properties and perceived safety for mammalian cells when administered in controlled amounts. This research delved into the impact of 405 nm VBL on corneal and retinal pigment epithelial cell cultures. ARPE-19 and corneal BCE C/D 1b cells were exposed to VBL for varying doses, according at different exposure times, to evaluate cell viability, oxidative stress levels and apoptotic indicators. A 3D printed prototype with 14 LEDs centred at 405 nm wavelength was used to ensure uniform distribution of light during exposure. Cell viability was assessed using the MTT assay, measurement of oxygen species (ROS) production was carried out, and Western blot analysis was employed to study catalase and SOD-1 expression and apoptotic marker activation. Exposure to 405 nm VBL for both term (3 h) and prolonged durations (9 h) led to a weak decrease in cell viability in ARPE-19 cells, whereas the effect on BCE C/D 1b cells was negligible. There was no increase in ROS production, with catalase and SOD-1 expression remaining stable, suggesting no pro-oxidative stress effects in these models. Moreover, no activation of caspase-3 and accumulation of cytochrome C were found. Based on our results, exposure to 405 nm light at regulated levels does not pose a threat to the viability of the tested cell lines and does not lead to oxidative stress and apoptosis under these conditions. These results suggest a favourable cytocompatibility profile for these specific ocular cell models, laying a foundation for further investigations into its ocular safety. Full article

Background: Age-related macular degeneration (AMD) is a leading cause of vision loss and is strongly associated with mitochondrial dysfunction in retinal pigment epithelial cells. Mitochondrial-derived peptides, including Humanin and its analogs, have demonstrated cytoprotective effects in AMD-related cellular models. However, the effects of shorter Humanin-derived fragments in disease-specific mitochondrial models remain incompletely characterized. Methods: Transmitochondrial retinal pigment epithelial cybrid cell lines containing mitochondria from AMD patients or age-matched normal donors were treated with HNF₁₄, a 14-amino acid Humanin fragment peptide. Cellular metabolic activity, cytotoxicity, oxidative stress, apoptotic signaling, inflammatory markers, angiogenic factor expression, and amyloid-β_1–42-induced apoptosis were evaluated using biochemical assays, protein analyses, and live-cell imaging approaches. Results: HNF₁₄ treatment was associated with improved metabolic activity and reduced cytotoxicity in AMD cybrids, with minimal effects in normal cybrids. HNF₁₄ significantly reduced intracellular and mitochondrial oxidative stress, suppressed apoptotic and inflammatory markers, and decreased VEGF-A protein expression in AMD cybrids. In addition, HNF₁₄ attenuated amyloid-β_1–42-induced apoptotic signaling in AMD cybrids. These effects were selective for cybrids containing AMD-derived mitochondria. Conclusions: This study demonstrates that HNF₁₄ mitigates mitochondrial and cellular stress responses in AMD transmitochondrial cybrid cells. The findings indicate that a short Humanin-derived fragment retains cytoprotective activity in a disease-specific mitochondrial context and support further investigation of mitochondrial-derived peptides as modulators of mitochondrial dysfunction relevant to AMD pathophysiology. Full article

Purpose: To investigate the mechanisms by which plasma extracellular vesicles (EVs) from preterm infants with bronchopulmonary dysplasia (BPD) elicit inflammation and abnormal angiogenesis in neonatal mouse retinas. Methods: EVs from the plasma of 7-day-old preterm infants, born between 23^0/7 and 29^6/7 weeks of gestation, with BPD or without BPD (nBPD) at 36 weeks postmenstrual ages, were adoptively transferred into postnatal day 3 (P3) mice via intravenous retro-orbital sinus injection. Inflammation and pathological neovascularization in neonatal mouse retinas were examined by immunohistochemistry of retinal flat mounts for Allograft Inflammatory Factor 1 (AIF1), CD206, or Glial Fibrillary Acidic Protein (GFAP) and isolectin-B4 (IB4) staining on P17. Retinal inflammation-related transcripts were assessed by qRT-PCR. Proteomic profiles of BPD and nBPD EVs were examined by Liquid Chromatograph Mass Spectrometer/Mass Spectrometer (LC-MS/MS) and Gene Set Enrichment Analysis (GSEA). Results: Adoptively transferred EVs from BPD and nBPD infants crossed the blood–retinal barrier (BRB) in recipient mouse pups. BPD-EVs increased retinal activated microglia, Müller cells, and twisted proliferative neovascularization compared to nBPD-EVs. BPD-EVs also elevated retinal transcripts regulating inflammation and angiogenesis, including NOD-, LRR- and pyrin domain-containing protein 3 (Nlrp3), Apoptosis-associated speck-like protein containing a caspase recruitment domain (Asc), Caspase 3 (Casp3), Caspase 8 (Casp8), Gasdermin D (Gsdmd), Il1β, Il6, Aif1, and Vascular endothelial growth factor (Vegf). Proteomics analysis revealed that BPD-EVs had significantly elevated levels of inflammation and angiogenesis-related proteins compared to nBPD-EVs. Conclusions: BPD-EVs promote inflammation and abnormal neovascularization by upregulating genes related to apoptosis and inflammation in neonatal mouse retinas. EV protein profiles suggest that elevated levels of proteins such as Defensin alpha 1B (DEFA1B), Insulin-like growth factor binding protein 2 (IGFBP2), CD5 antigen-like (CD5L), von Willebrand factor (vWF), and Tenascin C (TNC) in BPD-EVs may contribute to the observed inflammation and angiogenesis. Full article

Diabetic retinopathy (DR) is a progressive retinal disorder and a leading cause of vision impairment worldwide affecting the livelihood of millions. Its pathogenesis is driven by chronic hyperglycemia-induced neuronal and microvascular injury, leading to capillary occlusion, increased vascular permeability, and the eventual formation of fragile neo vessels. These changes mark the progression from non-proliferative diabetic retinopathy (NPDR) to proliferative diabetic retinopathy (PDR). Diabetic macular edema (DME), characterized by blood–retinal barrier disruption and macular fluid accumulation, further contributes to vision loss. This review provides an integrative perspective on the cellular and molecular mechanisms of DR, highlighting both vascular and neuroglial contributions to retinal pathology. Current therapeutic approaches, including anti-VEGF agents and corticosteroids, offer symptomatic relief but are limited by the need for repeated administration and variability in patient response. Emerging evidence implicates the role of thioredoxin-interacting protein (TXNIP) as one of mediators of the disease progression. Strongly upregulated under hyperglycaemic stress, TXNIP induces oxidative damage, inflammation, and neuronal apoptosis, exacerbating neurovascular dysfunction. We explore potential therapeutic strategies such as gene therapy, TXNIP-targeted molecular interventions, and stem cell-based approaches aimed at achieving long-term modulation of disease mechanisms. This article thus attempts to address a comprehensive understanding of DR pathophysiology and innovative new strategies to improve long-term visual outcomes. Full article

Pteridium aquilinum (L.) Kuhn, known as bracken fern, is considered a poisonous plant due to its toxic substances. This species contains toxic substances and enzymes: thiaminase and an anti-thiamine substance, which cause thiamine deficiency syndrome. Prunasin induces acute cyanide poisoning. Ptaquiloside causes haematuria, retinal atrophy, immunodeficiency, and lymphoproliferative disorders. It also induces carcinogenesis in livestock, and in animals and human cell lines. Ptaquiloside has been found in the milk of cattle, goats, and sheep that grazed on P. aquilinum in pastures. Ptaquiloside is water-soluble and washes away from the plants into the soil with rainwater. It has been found in streams and groundwater wells. The International Agency for Research on Cancer has classified bracken fern as a Group 2B carcinogen. However, P. aquilinum has long been used as a folk remedy in various regions. Several studies have identified its medicinal value and bioactive compounds with potential pharmacological activity. Pterosin B and its analogues exhibit anti-osteoarthritis, anti-Alzheimer’s disease, neuroprotective, anti-cardiomyocyte hypertrophy, anti-diabetic, and smooth muscle relaxant properties. Ptaquiloside also induces apoptosis in certain human cancer cell lines and acts as an anticancer agent. Therefore, pterosins and ptaquiloside have therapeutic properties. Other compounds, including some flavonoids and polysaccharides, act as antimicrobial, antifungal, and immunomodulatory agents. Based on their structures, it is possible to develop medicines with these therapeutic properties, particularly those containing pterosins and ptaquiloside. However, more research is needed on their use in medicinal treatments. Full article

Autophagy is a fundamental catabolic process that degrades and recycles intracellular components, serving as a key survival mechanism in neurons. In glaucomatous optic neuropathy, autophagy has been linked to both protection of retinal ganglion cells (RGCs) and their accelerated loss, yet its precise impact remains unresolved. In this study, we established and validated a straightforward rat model of retinal ischemia/reperfusion (I/R) using double circumlimbal sutures, which reliably produced RGC apoptosis, retinal thinning, and axonal degeneration compared with controls. Early after reperfusion (1–6 h), robust induction of the autophagy marker LC3B was observed, but this activation diminished within 48 h. Other autophagy-related proteins, including ATG4, ATG7, Beclin-1, and p62, followed similar temporal patterns, while components of the mammalian target of rapamycin (mTOR) pathway displayed an inverse time course. Pharmacologic suppression of mTOR with intravitreal rapamycin administered prior to ischemia provided the most significant neuroprotection, whereas post-injury treatment yielded minimal benefit. Collectively, these findings indicate that timely stimulation of autophagy before retinal ischemic injury can enhance RGC survival and may represent a therapeutic potential for glaucoma management. Full article

Hypoxic eye diseases represent a pivotal yet often underappreciated contributor to the onset and progression of many retinal disorders. When hypoxia persists or exceeds the tissue’s compensatory capacity, it triggers pathological retinal neovascularization, blood–retinal barrier disruption, and neuronal apoptosis, ultimately resulting in irreversible visual impairment. Connexins (Cxs) form gap junction channels and hemichannels and regulate retinal cell proliferation, differentiation, and survival, thereby playing a central regulatory role in the pathogenesis of hypoxic ocular diseases. In addition to gap junctions, Cx hemichannels promote transmission of molecules between intra- and extracellular environments, further influencing retinal homeostasis under hypoxic stress. This review synthesizes recent progress in understanding connexins in localized and systemic hypoxic eye diseases. We focus on the molecular mechanisms underlying the development and progression of hypoxia-induced ocular pathology, with particular emphasis on the emerging potential of Cxs as novel therapeutic targets for hypoxic ocular diseases. Following a systematic literature search, the electronic databases PubMed and EMBASE were consulted, with the search deadline set at December 2025. The search terms employed were as follows: hypoxia, connexin, gap junctions, hemichannels. Full article

KCNV2 encodes Kv8.2, an electrically silent voltage-gated potassium channel subunit that is expressed in photoreceptors. Disease-causing variants in KCNV2 cause a monogenic disorder which is classified clinically as cone dystrophy with supernormal rod response (CDSRR). Here, we generated KCNV2-deficient human retinal organoids as a tool for gene therapy vector potency assessment. The organoids were derived from two separate sources: by generating IPSCs from patient blood and by gene editing of a control cell line. Eight KCNV2 gene therapy vectors were assessed in retinal organoids; Kv8.2 protein levels and its in situ interactions with potassium channel binding partners were quantitatively assessed. We show significant enhancements in vector potency and specificity by transgene codon optimisation and the use of the photoreceptor-specific rhodopsin kinase (RK) promoter, respectively. Single-cell RNA sequencing was performed in transduced retinal organoids to assess the performance of the AAV vectors at single-cell resolution. KCNV2-deficient photoreceptors had an upregulation in genes associated with apoptosis, oxidative stress, and hypoxia pathways which were partially restored in AAV-KCNV2 transduced photoreceptors. These data show how human retinal organoids can be used to evaluate AAV gene therapy vector potency in vitro in a physiologically relevant model for the selection of lead therapeutic candidates and to help minimise the use of animals in preclinical development. Full article

Background/Objectives: Octenidine dihydrochloride (OCT-D) is a broad-spectrum antiseptic with high chemical stability, low toxicity, and no reported microbial resistance, making it a strong candidate for use on mucosal surfaces. Despite increasing interest in its potential ophthalmic applications, limited data exist regarding its cellular effects on ocular tissues. This study aimed to investigate the cytotoxic, apoptotic, inflammatory, and transcriptional responses induced by OCT-D in human conjunctival (IOBA-NHC) and retinal pigment epithelial (ARPE-19) cells. Methods: Cells were exposed to varying concentrations of OCT-D, and viability was assessed using the WST-1 assay to determine IC₅₀ and IC₅₀/2 values. These concentrations were subsequently used in molecular assays. Pro-inflammatory cytokines (IL-6, IL-1β, TNF-α, IFN-γ) were quantified by ELISA. Apoptotic activation was evaluated through caspase-3/7 activity assays. Gene expression analysis of apoptotic (Bax, Bcl-2), DNA damage-related (ATM, Rad51), and inflammatory markers was performed using RT-qPCR. Results: OCT-D induced a marked, dose-dependent reduction in cell viability in both cell lines, with ARPE-19 showing greater sensitivity. Caspase-3/7 activity increased significantly at IC₅₀ and IC₅₀/2, confirming intrinsic apoptotic activation. OCT-D markedly suppressed the release of key inflammatory cytokines and downregulated transcription of inflammatory genes. RT-qPCR revealed upregulation of pro-apoptotic and DNA damage-associated genes, demonstrating coordinated activation of apoptotic and genomic stress pathways. Conclusion: OCT-D triggers integrated cytotoxic, apoptotic, and immunomodulatory responses in conjunctival and retinal epithelial cells. While these findings provide important mechanistic insights into OCT-D’s cellular effects, further studies using primary cells, advanced 3D ocular models, and disease-relevant systems are required to support its potential translational use in ophthalmology. Full article