Catapol might protect against retinal ischaemia by anti‐oxidation, anti‐ischaemia, Wnt pathway inhibition and VEGF downregulation

• Published in: Acta ophthalmologica (Oxford, England) Vol. 102; no. S279
• Main Authors: Chao, Howard Wen‐Haur, Chao, Hsiao‐Ming
• Format: Journal Article
• Language: English
• Published: Malden Wiley Subscription Services, Inc 01.01.2024
• Subjects: Cell number; Cell viability; Dkk1 protein; Electrophysiology; Electroretinograms; Eye; Ferulic acid; Gelatinase B; Glaucoma; Hydrogen peroxide; Hydroxyl radicals; Immunohistochemistry; Ischemia; Macular degeneration; Oxidative stress; Penicillin; Reactive oxygen species; Reperfusion; Retina; Retinal ganglion cells; Streptomycin; Vascular endothelial growth factor; Western blotting; Wnt protein
• ISSN: 1755-375X; 1755-3768
• DOI: 10.1111/aos.15872

Aims/Purpose: Retinal ischaemic disorders, including retinal vascular occlusion, age‐related macular degeneration and glaucoma, pose a threat to vision. This study examines the potential protective effects of catalpol against retinal ischaemia. Methods: RGC‐5 cells were cultured in DMEM with 10% FBS, penicillin (100 U/mL) and streptomycin (100 mg/mL) at 37°C. Cell viability was assessed using the MTT assay. H2O2 (1 mM)/OGD induced oxidative stress and ischaemic‐like injury. Catalpol or vehicle was administered 15 min before the insult. Retinal ischaemia was induced in Wistar rat eyes by increasing intraocular pressure to 120 mmHg for 60 min, followed by reperfusion. Intravitreous injections of catalpol (0.5 or 0.25 mM), WNT inhibitor Dkk1 (1 μg/4 μL), anti‐VEGF lucentis (20 μg/2 μL), or anti‐VEGF eyelea (80 μg/4 μL) were given 1 day before or after retinal ischaemia. Effects were evaluated using electrophysiology, histopathology, immunohistochemistry, fluorogold retrograde labeling, and Western blotting. Results: H2O2 (1 mM)/OGD significantly (p < 0.001) reduced RGC‐5 cell viability by inducing reactive oxygen species and ischaemic‐like insult. Pretreatment with catalpol (0.5 mM) dose‐dependently attenuated this oxidative/ischaemic‐like effect (p < 0.05), suggesting its antioxidative properties. Pre‐ischaemic treatment with catalpol (0.5 and 0.25 mM) dose‐dependently and significantly (p < 0.05; 0.5 mM) mitigated ischaemia‐induced reductions in ERG b‐wave amplitude and RGC cell number. Compared to eyes treated with DKK1, lucentis, or eyelea, catalpol appeared to protect against retinal ischaemia by downregulating WNT and VEGF expression (downstream). Conclusions: Catalpol may provide protection against retinal ischaemia through antioxidation and anti‐ischaemic mechanisms by downregulating the upstream WNT pathway and downstream VEGF concentration. References 1. Chao, et al. Ferulic acid, but not tetramethylpyrazine, significantly attenuates retinal ischaemia/reperfusion‐induced alterations by acting as a hydroxyl radical scavenger. J. Ocul. Pharm. Ther. 24:461–472, 2008. 2. Liu, et al. Baicalein significantly protects hRPE cells against H2O2‐induced oxidative stress by scavenging ROS and down‐regulating the expression of MMP9 and VEGF. J. Ocul. Pharm. Ther. 26:421–429, 2010.