Epigallocatechin gallate suppresses 1-methy1-4-phenyl-pyridinium-induced the damage of oxidative stress in PC12 cells by activating nuclear factor-related factor 2 / 中华神经科杂志

ABSTRACT

Objective To investigate the relationship between the neuroprotective effect of epigallocatechin gallate ( EGCG ) for PC12 cells induced by 1-methyl-4-phenyl-pyridinium ( MPP+ ) and activating nuclear factor-related factor 2 ( NRF2 ).Methods Well differentiated PC12 cells treated with MPP+ were used as the in vitro cell models,and PC12 cells were pretreated with different concentrations of EGCG.MTT assay was used to investigate the cell viability.Western blot was used to observe the expression of NRF2 in cells and distribution in the nucleus and the cytoplasm.Real-time PCR was used to observe the antioxidant enzymes,HO-1 and NQO1 mRNA expression.Results Pretreatment of PC12 cells with different concentrations of EG CG for an hour could restore cell viability.Western blot showed that expression of NRF2 in cells treated with MPP+ for 24 hours was increased 148％ +5％ compared with the control group (t =6.102,P ＜0.01 ).The level of NRF2 in EGCG pretreated group was 188％ + 6％ compared with the control group(t =11.172,P ＜0.01 ).Moreover the NRF2 protein level in the nuclear was also increased.Western blot showed that the NRF2 protein level in the nuclear was 258％ +2％ compared with the control group (t =21.995,P ＜ 0.01 ).Further research found U 120,an inhibitor of ERK,could inhibit the effect of EGCG.The levels of NRF2 in both samples were 148％ ± 15％ and 158％ ± 1％ compared with their respective control groups(t =6.118,8.058,both P ＜0.01 ).In accordance with the NRF2 data,real-time PCR indicated that the levels of HO-1 and NQO1 mRNA expression increased obviously in the group pretreated with EGCG.Likewise,U120 could also inhibit HO-1 and NQO1 mRNA expression induced by EGCG.Conclusions EGCG can repair oxidative damage to PC12 cells induced by MPP+.The protective effect may be related through the ways to activate ERK-NRF2 and induce downstream of antioxidant enzyme expression,such as HO-1 and NQO1.