Objective:To investigate the effect of apoptosis of oxidant-antioxidant change on anoxia-reoxygen injury to cortical neurons in vitro. Methods:Acute glucose-oxygen deprivation and subsequent reoxygenation were used to establish anoxia-reoxygenation injury model in cultured cortical neurons. They were randomly divided into 2 groups:control group,groups with different reoxygenation time(3 h,6 h,12 h and 24 h). The content of dehydrogenase(LDH), glutathione(GSH) and NO, the activity of NOS and glutathion peroxidase(GPx) were measured by assay kits. The morphology of apoptotic cells was observed by Hochest33258 staining. Results:Compared with the control group,the level of LDH,NO and cell apoptotic rate was obviously increased,while the activity of GPx was decreased in reoxygenation groups(P < 0.05);The activity of NOS was obviously increased and the GSH level was decreased at reoxygenation 3 h and 6 h(P < 0.05), but there was no significant difference at reoxygenation 24 h(P > 0.05). Conclusion:The imbalance between the system of oxidation and reduction may be one of the reasons inducing neurons apoptosis as reoxygenation time extending in vitro.