Morphological Characteristics Of Mice AMD Model Induced By NaIO₃ And The Therapeutic Effect Of Rapamycin On Diseased Retina

Age-related macular degeneration（AMD）is a complex retinal disease and its pathogenesis has not been fully clarified.There is no feasible treatment strategy for this disease yet.Sodium iodate（NaIO₃）is a strong oxidant,which is often injected into rodents to establish AMD models in many studies.Rapamycin is an immunosuppressant that has been applied clinically.Some studies have shown that it has neuroprotective effect,but its therapeutic effect on retinal AMD is still unclear.In this study,the AMD models were established by injection of 35 mg/kg sodium iodate（NaIO₃）into the tail vein.Then the treated mice intraperitoneally received rapamycin（2 mg/kg）once a day.The retinal structure was observed by H&E staining,followed by counting the cell numbers and thickness of the outer nuclear layer（ONL）and inner nuclear layer（INL）.The retinal pigment epithelium（RPE）,photoreceptors outer segments,astrocyte,Müller cells and microglia were viewed by specific immunostaing.Furthermore,we detected the expression level of inflammation-related factors（IL-6,MCP-1 and TNF-α）and oxidative stress indexes（SOD,GSH and MDA）.Finally,tunel-staining was used to detect the apoptosis.According to these results,35 mg/kg NaIO₃ had a time-dependent damage on retina.After 7 days of NaIO₃ induction,the retina was damaged significantly,the cell numbers and thickness of ONL and INL was decreased.The structure of RPE and photoreceptors was damaged in a time-dependent manner.And NaIO₃ also activated astrocyte,Müller cells and microglia cells.Rapamycin can alleviate the damage of NaIO₃ to retinal tissue and inhibit glial proliferation.Rapamycin alleviates the damage of NaIO₃ to the retina by inhibiting retinal inflammation,oxidative stress and apoptosis.This study discussed the characteristics of NaIO₃ induced retinopathy and the therapeutic effect of rapamycin on this disease.The results showed that Na O₃ induces time dependent damage to the retinal structure,and rapamycin can protect the retina from damage by reducing retinal inflammation response,oxidative stress overexpression,and apoptosis level.This study is expected to provide more experimental data for the research and treatment of retinal degeneration.