槲皮素通过促进Nrf2转位拮抗人肝细胞酒精性氧化损伤

目的探讨槲皮素诱导Ⅰ型血红素氧化酶(HO-1)对肝细胞酒精性氧化损伤的保护效应及相关信号通路。方法乙醇(100 mmol/L)孵育的人原代肝细胞经槲皮素(100μmol/L)处理24h后,测定细胞HO-1活性、Nrf2转位表达及细胞相应的氧化损伤程度;在此基础上,联合应用HO-1及各(MAPK)通路抑制剂,观察上述指标的变化。结果槲皮素处理使HO-1进一步升高,并明显减轻乙醇孵育所导致的细胞GSH耗竭、MDA升高及胞内门冬氨酸转氨酶(AST)与乳酸脱氢酶(LDH)的释放;HO-1诱导剂血红素也具有类似的效应,而HO-1抑制剂锌原卟啉Ⅸ及p38与细胞外信号调节激酶(extracellular regulated protein kinase,ERK)抑制剂(SB203580与PD98059)则明显抑制了Nrf2的转位活化及槲皮素的保护效应。结论槲皮素通过诱导HO-1保护肝细胞免受酒精性氧化损伤,其信号通路与p38及ERK活化促使Nrf2转位入核启动HO-1表达有关。

QUERCETIN PROTECTS HUMAN HEPATOCYTES FROM ETHANOL-DERIVED OXIDATIVE STRESS BY INDUCING Nrf2 TRANSLOCATION

Objective To explore the protective effect and related signaling pathways of heme oxygenase-1(HO-1) induced by quercetin on human hepatocytes against ethanol-derived oxidative stress.Method Primary human hepatocytes incubated with ethanol(100 mmol/L) were subjected to quercetin(100 μmol/L) for 24 h,and the HO-1 activity,Nrf2 translocation and the degree of cellular oxidative damage were determined.Then the hepatocytes were treated by various inhibitors of mitogen activated protein kinase(MAPK) pathways involved in HO-1 induction and above indices were measured.Result Quercetin treatment for ethanol-incubated hepatocytes further stimulated HO-1 activity,inhibited GSH depletion and the release of cellular LDH and AST,and attenuated the lipid peroxidation reflected by MDA in the presence of ethanol.HO-1 induction by hemin exhibited the similar protective effects,but zinc protoporphyrin Ⅸ(an inhibitor of HO-1) and p38 or ERK inhibitors(SB203580 and PD98059) blocked the protective effects originated from quercetin.Additionally,SB203580 and PD98059 inhibited Nrf2 translocation and activation into nuclear induced by quercetin.Conclusion Quercetin protected hepatocytes from ethanol-derived oxidative stress by inducing HO-1 via p38 and ERK/Nrf2 signaling pathways.