Objective Several lines of evidences indicated that autophagy was involved in ischemic brain injury.Ischemia/reperfusion injury may lead to autophagic cell death, while some studies also suggested that autophagy can be beneficial by eliminating damaged organelles and mis-folded proteins.Therefore, it is necessary to determine whether autophagy is protective or detrimental in ischemia/reperfusion (OGD/Rep.) injury.Methods To deal with this issue, the primary cultured rat cortex neurons were carried out.After 7 days culture in vitro, the culture medium was replaced by glucose-free DMEM and neurons were subjected to a sealed chamber completely infused with oxygen-free gas (95% N2+5% CO2).After incubation in 37 ℃ for 2 h, reperfusion was performed by the presence of glucose (4.5 g/L) and oxygen (5% CO2+air) in 37 ℃ for 24 h.Neurons were treated with 3-methyladenosine (3-MA) and bafilomycin A1 (BafA1), two well accepted autophagy inhibitors, when reperfusion commenced.Cell viability was deteced by methyl thiazolyl tetrazolium (MTT) assay.Results OGD/Rep.decreased cell viability to (67.4±1.6)% of control group (P<0.01).Treatment with both 3-MA and BafA1 further decreased cell viability in a concentration-dependent manner (P<0.05 vs OGD/Rep.group), suggesting a protective role of autophagy in our model.In addtion, treatement with 3-MA or BafA1 in the first 4 h-period of reperfusion aggratated neuronal cell injury as well, but not in the first 2 h-or the second 4 h-period of reperfusion.These results suggested that there may be a time-window for autophagy regulation in OGD/Rep.-induced neuron injury.Conclusion Autophagy may play a protective role in OGD/Rep.-induced neuron cell injury.Autophagy in reperfusion phase could be a novel target for cerebral ischemia therapy.