Abstract: ObjectiveTo observe whether taurine has protective effects against N-methyl-D-aspartate(NMDA)-induced excitototxicity,especially in retinal histopathological structure and ultrastructure in rat.MethodA rat model of retinal excitotoxicity injury induced by intravitreal injection of 5μl 4mmol/L NMDA in one eye.Twenty adult male Sprague-Dawley rats were divided into four groups:normal control,intravitreal injection of PBS control,NMDA group,NMDA injection and taurine treated group(intraperitoneal injection with 25mg/kg taurine).At the 4^th d of intravitreal injection,the retinal damage was evaluated by measurement of the thickness of whole retina and inner retinal layer,and observation of retinal ultrastructure.ResultsAfter injection of NMDA,the overall thickness of retina were reduced(P<0.001),especially in inner retinal layer(P <0.001)compared to controls.Degenerative changes were observed in neural cells of inner nuclear layerand ganglion cells layer by electr on microscopy.These damages can be prevented by 25mg/kg taurine effectively.ConclusionTaurine treatment can effectively prevent the damage of NMDA-induced retinal histopathological structure and ultrastructure in rat.