Objective To investigate the inhibitory effect of epigallocatechin gallate(EGCG)on oxidative damage to the retina in a rat model of dry age-related macular degeneration(AMD)induced by sodium iodate.Methods A total of 36 male specific pathogen-free Sprague-Dawley rats were randomly divided into the blank control group,sodium iodate group and sodium iodate+EGCG group,with 12 rats in each group.Rats in the sodium iodate group and the sodium io-date+EGCG group were given 50 mg-kg·1 sodium iodate by tail vein injection by weight to build dry AMD models,while rats in the blank control group were administered with an equal volume of normal saline.Following the modeling proce-dure,rats in the sodium iodate+EGCG group received an intravitreal injection of 4 μL EGCG(0.5 g·L-1)into their right eyes,while the right eyes of rats in both the blank control and sodium iodate groups were treated with the same volume of normal saline.After 21 days,the rats were sacrificed,and ocular samples were collected for detection.Histopathological changes of the retinal tissues in each group were examined using hematoxylin and eosin(HE)staining.Additionally,the levels of superoxide dismutase(SOD),glutathione peroxidase(GSH-Px),and malondialdehyde(MDA)in the retinal tis-sues were quantified.Western blot analysis was conducted to assess the protein expression levels of nuclear factor ery-throid-2-related factor 2(Nrf2),NADPH quinone oxidoreductase 1(NQO1),and heme oxygenase-1(HO-1)in the retinas.Furthermore,real-time quantitative polymerase chain reaction was performed to evaluate the relative messenger ribonucleic acid(mRNA)expression levels of Nrf2,NQO1 and HO-1 in the retinas of the rats.Results HE staining revealed that,in comparison to the blank control group,the entire retinal layer in the sodium iodate group exhibited injury,characterized by noticeable injury of the retinal pigment epithelial cells and disordered outer nuclear layer with wavy transformation.The so-dium iodate+EGCG group demonstrated ameliorated retinal injury across all layers compared to the sodium iodate group.Compared to the blank control group,the levels of SOD and GSH-Px were significantly reduced(both P＜0.01),while the level of MDA was significantly elevated(P＜0.01)in the sodium iodate group.Compared with the sodium iodate group,the sodium iodate+EGCG group showed a significant increase in the levels of SOD and GSH-Px(both P＜0.01),along-side a substantial decrease in the content of MDA(P＜0.01).Western blot analyses demonstrated that compared with the blank control group,the protein expression levels of Nrf2,NQO1 and HO-1 were significantly elevated in the sodium iodate group(all P＜0.01);compared with the sodium iodate group,the sodium iodate+EGCG group exhibited relatively higher protein expression levels of Nrf2,NQO1 and HO-1(all P＜0.05).The results from real-time quantitative polymerase chain reaction indicated that the relative mRNA expression levels of Nrf2,NQO1 and HO-1 in the retinas of rats in the sodium io-date group were significantly greater than those in the blank control group(all P＜0.05);compared with the sodium iodate group,the sodium iodate+EGCG group showed a significant increase in the relative mRNA expression levels of Nrf2,NQO1 and HO-1(all P＜0.05).Conclusion EGCG can improve the capacity to scavenge oxygen free radicals by promo-ting the upregulation of Nrf2 expression.This activation subsequently enhances the expression of downstream products such as NQO1 and HO-1,leading to increased levels of SOD and GSH-Px while simultaneously reducing the MDA level.Consequently,this process inhibits oxidative damage to the retina in rats with dry AMD induced by sodium iodate.