Protective effect of ginsenoside Rg1 on 661W cells exposed to oxygen-glucose deprivation/reperfusion via keap1/nrf2 pathway

AIM:To construct an in vitro model of oxygen-glucose deprivation/reperfusion(OGD/R)induced injury to the optic nerve and to study the oxidative damage mechanism of ischemia-reperfusion(I/R)injury in 661W cells and the protective effect of ginsenoside Rg1.METHODS:The 661W cells were treated with different concentrations of Na2S2O4 to establish OGD/R model in vitro.Apoptosis,intracellular reactive oxygen species(ROS)levels and superoxide dismutase(SOD)levels were measured at different time points during the reperfusion injury process.The injury model was pretreated with graded concentrations of ginsenoside Rg1.Real-time polymerase chain reaction(PCR)was used to measure the expression levels of cytochrome C(cyt C)/B-cell lymphoma-2(Bcl2)/Bcl2 associated protein X(Bax),heme oxygenase-1(HO-1),caspase9,nuclear factor erythroid 2-related factor 2(nrf2),kelch-like ECH-associated protein 1(keap1)and other genes.Western blot was used to detect the expression of nrf2,phosphorylated nrf2(pnrf2)and keap1 protein levels.RESULTS:Compared to the untreated group,the cell activity of 661W cells treated with Na2S2O4 for 6 and 8h decreased(P<0.01).Additionally,the ROS content increased and SOD levels decreased significantly(P<0.01).In contrast,treatment with ginsenoside Rg1 reversed the cell viability and SOD levels in comparison to the Na_(2)S_(2)O_(4)treated group(P<0.01).Moreover,Rg1 reduced the levels of caspase3,caspase9,and cyt C,while increasing the Bcl2/Bax level.These differences were all statistically significant(P<0.05).Western blot analysis showed no significant difference in the protein expression levels of keap1 and nrf2 with Rg1 treatment,however,Rg1 significantly increased the ratio of pnrf2/nrf2 protein expression compared to the Na_(2)S_(2)O_(4)treated group(P<0.001).CONCLUSION:The OGD/R process is induced in 661W cells using Na_(2)S_(2)O_(4).Rg1 inhibits OGD/R-induced oxidative damage and alleviates the extent of apoptosis in 661W cells through the keap1/nrf2 pathway.These results suggest a potential protective effect of Rg1 against retinal I/R injury.