目的 探讨18α-甘草次酸对游离脂肪酸（FFAs）致HepG2细胞脂毒性的保护作用及经线粒体途径调节的分子机制。方法 给予1 mmol/L FFAs，油酸（OA）-棕榈酸（PA）（2：1）建立体外HepG2细胞脂肪变性模型，细胞分为对照组、模型组和18α-甘草次酸低、中、高剂量（10、20、40 μmol/L）组，阳性药（凋亡抑制剂Z-VAD-FMK，10 μmol/L）组，采用MTT法检测细胞活力，用Hoechst33258染色法观察细胞凋亡；免疫荧光染色法观察Bax蛋白激活情况；Western blotting检测细胞色素C在线粒体和胞浆的分布情况；Caspase-3酶活检测试剂盒测定细胞内Caspase-3活性。结果 18α-甘草次酸能保护FFAs致HepG2细胞活力下降，减少HepG2细胞脂性凋亡数量；18α-甘草次酸能下调Bax蛋白激活，减少细胞色素C的释放，从而阻止Caspase-3活性的增高，且呈剂量相关性。结论 18α-甘草次酸对FFAs致HepG2细胞的脂毒性中存在保护作用，其作用机制与抑制线粒体凋亡通路有关。

Objective To investigate the protective effect of 18α-glycyrrhetic acid on lipotoxicity in HepG2 cells induced by free fatty acids (FFAs) and its potential cellular pathway. Methods The HepG2 cell steatosis model in vitro were incubated with 1 mmol/L FFAs, oleic acid (OA)-palmitic acid (PA) (2:1). The HepG2 cells were randomly divided into control group, model group, 18α-glycyrrhetic acid 10, 20, and 40 μmol/L groups, Z-VAD-FMK group. Cell viability was assessed by MTT method. Cell apoptosis was determined by Hoechst 33258. Bax activation was detected by immuno fluorescence staining. Mitochondrial dysfunction was analyzed by detecting cytochrome C release by Western blotting method. Caspase-3 enzyme activity was determined by Caspase-3 enzyme activity kit. Results 18α-Glycyrrhetic acid could protect the decrease of HepG2 cell activity and reduce the number of lipid apoptosis in HepG2. 18α-Glycyrrhetic acid could reduce the activation of Bax protein and decrease the release of cytochrome C. Thus, 18α-glycyrrhetic acid could decrease the Caspase-3 enzyme activity, and they were dose-dependent. Conclusion 18α-Glycyrrhetic acid has the protection of lipotoxicity in HepG2 cells induced by FFAs, and its mechanism may be related to inhibition of mitochondrial apoptosis pathway.

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四川省科技厅科技支撑计划（2014SZ0140）；成都中医药大学校基金资助项目（ZRYB201003）