氧化应激在氯乙醛联合棕榈酸致肝细胞脂肪变性中的作用

Effects of oxidative stress on hepatic steatosis induced by chloroacetaldehyde combined with palmitic acid

目的探讨氯乙醛(氯乙烯的主要代谢物,CAA)、棕榈酸(饱和脂肪酸的重要成分之一,PA)以及二者联合对HepG2细胞脂肪变性的作用机制。方法不同浓度CAA、PA和氧化应激抑制剂N-乙酰基半胱氨酸(NAC)处理HepG2细胞24或48 h,CCK-8法检测细胞活力。根据细胞活力实验结果设定对照组、4.5μmol/L CAA组、9μmol/L CAA组、PA(100μmol/L)组、4.5μmol/L CAA+PA组、9μmol/L CAA+PA组、NAC(2 mM)组、NAC+4.5μmol/L CAA+PA组、NAC+9μmol/L CAA+PA组。染毒48 h后,进行油红O染色和检测各组细胞中甘油三酯(TG)和总胆固醇(TC)的含量评估细胞脂肪变性的情况;检测细胞中丙二醛(MDA)、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)和还原性谷胱甘肽(GSH)的水平,评估氧化应激的情况。结果HepG2细胞存活率随CAA、PA和NAC浓度升高而下降;9μmol/L CAA组和PA组细胞出现明显脂肪变性,联合组细胞脂肪变性更为明显,NAC预处理可减轻CAA联合PA引起的HepG2细胞脂肪变性。联合组MDA含量明显高于对照组和单一暴露组,而联合组SOD、GSH-Px和GSH含量明显低于对照组和单一暴露组,NAC预处理可减轻CAA联合PA诱导的氧化应激。结论CAA联合PA通过激活氧化应激诱导肝脂肪变性,二者之间可能具有相加作用。

Objective To investigate the mechanism of chloroacetaldehyde(CAA,the main metabolite of vinyl chloride),palmitic acid(PA,one of the important components of saturated fatty acids)and their combination on steatosis of HepG2 cells.Methods HepG2 cells were treated with different concentrations of CAA or PA or N-acetyl-L-cysteine(NAC,oxidative stress inhibitor)for 24 h or 48 h.The cell viability of HepG2 cells was detected by CCK-8 assay.According to the result of cell viability,they were divided into control group,4.5μmol/L CAA group,9μmol/L CAA group,PA(100 mmol/L)group,4.5μmol/L CAA+PA group,9μmol/L CAA+PA group,NAC(2 mM)group,NAC+4.5μmol/L CAA+PA group,NAC+9μmol/L CAA+PA group.After 48 h of exposure,Oil Red O staining and the contents of triglyceride(TG)and total cholesterol(TC)in each group were detected to evaluate the steatosis of HepG2 cells.The levels of malondialdehyde(MDA),superoxide dismutase(SOD),glutathione peroxidase(GSH-Px)and reduced glutathione(GSH)in cells were detected to evaluate the condition of oxidative stress.Results The survival rate of HepG2 cells decreased with the increase of CAA or PA or NAC concentration.9μmol/L CAA group and PA group HepG2 cells showed obvious steatosis.In the combination groups steatosis of HepG2 cells was most obvious compared with other groups.NAC pretreatment reduced the steatosis of HepG2 cells caused by CAA combined with PA.The MDA content in the combination group was significantly higher than that in the control group and the single-exposure groups,while the contents of SOD,GSH-Px and GSH in the combination group were significantly lower than those in the control group and the singleexposure groups.Pretreatment with NAC reduced the oxidative stress induced by CAA combined with PA.Conclusion CAA combined with PA induces hepatic steatosis by activating oxidative stress,and the joint action between the two may be additive effect.