Effects of epigallocatechin gallate on rotenone-induced injury in PC12 cells

OBJECTIVE To investigate the protective effect of epigallocatechin gallate(EGCG) on rotenone-induced injury in rat pheochromocytoma(PC12) cells and to explore potential mechanisms.METHODS EGCG 1,5 and 10 μmol·L-1 were added to cultivated rat PC12 cells,and 30 min later,rotenone 25 nmol·L-1 was added and then coincubated for 24 h.The cell viability was assessed by MTT assay.Hoechst33258 was employed to observe morphological changes of cell nucleus.Apoptosis rate was detected by flow cytometry using AnnexinⅤ and propidum iodide(PI).Mitochondrial membrane potential was measured by JC-1 staining.RESULTS Compared with(77.0±2.9)% in rotenone-treated group,cell survival in EGCG 1,5 and 10 μmol·L-1 groups was significantly higher(79.8±2.3)%,(82.4±2.2)% and(88.3±2.0)%,respectively(P0.05).Hochest33258 staining demonstrated that EGCG improved the nuclear changes morphologically.Compared with control group,the apoptosis rate was significantly increased in rotenone-model cells by 8.2-fold but was significantly reduced by 46%,25% and 63% in EGCG 1,5 and 10 μmol·L-1 groups(P0.01).Compared with 30.6% in rotenone group,the apoptosis rate in EGCG 1,5 and 10 μmol·L-1 was reduced to 30.6%,14%,and 15.7%,respectively,by FCM analysis.Meanwhile,the mitochondrial membrane potential of EGCG 1,5 and 10 μmol·L-1 groups increased 2.48-,3.96-and 4.04-fold compared with rotenone-treated group(P0.01).CONCLUSION EGCG exhibits inhibitory effect on rotenone induced apoptosis in rat PC12 cells,which is possibly due to its ability to stabilize mitochondrial membrane potential.