喹乙醇对HepG2细胞抗氧化系统的影响

Olaquindox weakened the antioxidant system in human hepatoma G2 cells

目的:观察喹乙醇对人肝癌细胞(HepG2)抗氧化系统的影响,探讨喹乙醇诱导HepG2细胞氧化性损伤的机制。方法:分别将0、200、400、800μg/ml的喹乙醇作用于HepG2细胞24h后,检测各组细胞内抗氧化酶/物的变化;另设800μg/ml的喹乙醇作用于HepG2细胞3h后,再用超氧化物歧化酶(SOD)(100μg/ml)、过氧化氢酶(CAT)(100μg/ml)及SOD(100μg/ml)+CAT(100μg/ml)分别作用细胞3h的各实验组,采用分子探针2’,7’-二氯荧光黄双乙酸盐(2,7-dichlorodihydrofluorescein diacetate,DCFDA)检测各组处理后细胞内活性氧含量的变化。结果:不同浓度的喹乙醇作用HepG2细胞24h后,细胞总ATPase、Na+K+-ATPase及Ca2+Mg2+-ATPase和细胞内SOD、谷胱甘肽(GSH)及谷胱甘肽过氧化物酶(GSH-PX)活性随喹乙醇浓度的升高而下降(P<0.05或P<0.01),且具有一定的剂量-效应关系,细胞内CAT活性较对照组下降(P<0.01),但无剂量-效应关系,而细胞内丙二醛(MDA)水平随喹乙醇浓度的升高而增加(P<0.05或P<0.01),且呈一定的剂量-效应关系。经喹乙醇(800μg/ml)处理细胞后,再分别用CAT、SOD及SOD+CAT处理的各组,其ROS含量与单纯喹乙醇(800μg/ml)组相比分别减少80%(P<0.01)、40%及95%(P<0.01)。结论:喹乙醇可使体外培养HepG2细胞的抗氧化系统受到一定的破坏,且产生的ROS形式以H2O2为主。

OBJECTIVE：To investigate the effect of olaquindox on the antioxidant system in human hepatoma G2（HepG2） cells. METHODS： HepG2 cells were treated with 0,200,400 and 800 μg/ml olaquindox in 24 h. The activities of superoxide dismutase（SOD） and catalase（CAT）,the level of malondialdehyde（MDA）,the activities of glutathione （GSH） and glutathione peroxidase （GSH-PX）,Na＋K＋-ATPase and Ca2＋Mg2＋-ATPase were measured. SOD or CAT,and the combination of SOD＋CAT were incubated for 3 h with olaquindox-treated HepG2 cells. The levels of reactive oxygen species （ROS） were evaluated by 2,7-dichlorodihydrofluorescein diacetate（DCFDA）. RESULTS： Olaquindox decreased the levels of T-ATPase,Na＋K＋-ATPase and Ca2＋Mg2＋-ATPase,SOD,GSH ,GSH-PX,in HepG2 cells（P0.05 or P0.01）,with a dose-response relationship. After HepG2 cells were treated with olaquindox,the activity of CAT was decreased when compared with the control（P0.01）. Olaquindox led to a dose-dependent increase in the level of MDA（P0.05 or P0.01）. While HepG2 cells were treated with olaquindox （800 μg/ml）,CAT,SOD and SOD＋CAT reduced ROS about 80% ,40%and 95%,respectively（P0.01）. CONCLUSION： Olaquindox disrupted the antioxidant system in HepG2 cells. Our results indicated that olaquindox-induced HepG2 cells predominantly generated H2O2,which could be scavenged by CAT.