AIM:To observe the expression of Nogo-A and NgR in rat retinal ischemia-reperfusion(RIR) acute injury and to investigate their significance and correlation. METHODS: Ninety adult SD rats were randomly divided into normal group(6 rats), experimental group(RIR group,42 rats) and sham group(42 rats).The experimental group and sham group were subdivided into 0 hour,6,12,24,48,72 and 168 hours subgroups according to different time after RIR injury.Six rats were bring into every subgroup.Ligating the ratssingle common carotid artery was used to establish animal models of rat retinal ischemia. Pathomorphology was detected by hematoxylin and eosin stain and the expression of Nogo-A and NgR was measured by immunohistochemistry. RESULTS: Compared with normal group, the expression of Nogo-A and NgR in sham group had no statistically significant difference (P>0.05). Compared with sham group ,experimental group had the expression of Nogo-A gradually increased in 12 hours after RIR(P<0.05), peaked in 48 hours(P<0.01),decreased in 72 hours(P<0.05) and reached in normal leavel in 168 hours(P>0.05); the expression of NgR increased in 6 hours after RIR(P<0.05), peaked in 48 hours(P<0.01),decreased in 72 hours(P<0.05) and reached in normal leavel in 168 hours(P>0.05). The expression of Nogo-A and NgR in experimental group showed a positive correlation(P<0.01). CONCLUSION: Nogo-A and NgR expressed at each time point after RIR as a parabola.NgR expressed prior to Nogo-A.They were all peaked at 48 hours after RIR.The expression of Nogo-A and NgR closely related to RIR injury, with a collaborative relationship between the two.