Preventive Effect of EGCG against Rotenone-induced Apoptosis in PC12 Cells

Objective:To investigate the potential protective effect of epigallocatechin-3-gallate(EGCG)on rotenone-induced apoptosis of PC12 cells and the possible mechanisms.Methods:PC12 cells were treated with 1 μmol/L rotenone for 24 h to establish a model of Parkinson's disease(PD).Based on this model,PC12 cells were pretreated with EGCG(5 μmol/L)for 30 min before rotenone treated.The cell survival was determined by the CCK-8 method.Apoptosis was detected by flow cytometry.Intracellular reactive oxygen species(ROS)was assessed by FCM using the fluorescent dyes,dihydroethidium(DHE)and dihydrorhodamine 123(DHR123).Caspase-3 activity and mitochondrial membrane potential were also measured.The expression of Bcl-2 was detected by Western blot.Results:From the data of CCK-8,the cell proliferation of PC12 cells was inhibited by rotenone,and the cell survival rate was(38.5±4.3)%.After treated with rotenone for 24 h,the apoptosis rate of PC12 cells was 37.7%.The fluorescence intensity of DHE and DHR123 was increased to 231% and 335% of controls,respectively.Mitochondrial membrane potential was decreased to 45% of controls,and the activity of caspase-3 increased to 145% of controls.The Western blot showed that rotenone down-regulated Bcl-2.The differences were all statistically significant as compared with control group.However,after pretreated with EGCG for 30 min,the cell survival rate was(69.6±5.6)%,and the apoptosis rate of PC12 cells was 21.4%,and the fluorescence intensity of DHE and DHR123 was 178% and 287% of control,and the activity of caspase-3 was 120% of controls.The expression of Bcl-2 was up-regulated.The differences were all statistically significant as compared with rotenone group.Conclusion:These results demonstrated the protective effective action of EGCG on PC12 cells in the rotenone-induced cell model of PD,and the mechanism of this protective effect may be related to alleviating the cell damage from oxidative stress with its antioxidant and anti-apoptosis property.