目的: 探讨人参皂苷Rh4对人肝癌HepG2细胞凋亡的作用及机制.方法: 采用MTT比色法测定不同浓度(10、20和40 μmol/L)人参皂苷Rh4对人肝癌HepG2细胞活力的抑制作用;用流式细胞术检测定细胞凋亡率;通过Hoechst 33258和TUNEL染色观察人参皂苷Rh4诱导人肝癌HepG2细胞凋亡的形态学变化;Western blot法检测凋亡相关蛋白Bax、Bcl-2、caspase-3和caspase-9的表达情况.结果: 人参皂苷Rh4能够明显促进人肝癌HepG2细胞的凋亡,且呈剂量依赖性;TUNEL和Hoechst 33258染色实验结果表明,人参皂苷Rh4作用24 h后,细胞呈现明显皱缩、肿胀、破裂等凋亡形态;Western blot分析结果表明,随着人参皂苷Rh4给药浓度的增加,抗凋亡蛋白Bcl-2 表达量逐渐下降,而促凋亡蛋白Bax、cleaved caspase-3和caspase-9的表达逐渐升高.结论: 人参皂苷Rh4可诱导人肝癌HepG2细胞凋亡,其作用机制可能与下调Bcl-2以及上调Bax、cleaved caspase-3 和caspase-9蛋白表达有关.%AIM: To investigate the apoptosis and molecular mechanism of human hepatocellular carcinoma HepG2 cells induced by ginsenoside Rh4.METHODS: Human hepatocellular carcinoma HepG2 cells were treated with ginsenoside Rh4 at doses of 10, 20 and 40 μmol/L, and the inhibitory effect of ginsenoside Rh4 on HepG2 cell viability was measured by MTT assay.The apoptotic rate of HepG2 cells was analyzed by flow cytometry.The morphological changes of the HepG2 cells were observed by Hoechst 33258 and TUNEL staining.The expression of apoptosis-related proteins Bax, Bcl-2, caspase-3 and caspase-9 was determined by Western blot.RESULTS: Ginsenoside Rh4 promoted apoptosis of HepG2 cells in a dose-dependent manner.TUNEL and Hoechst 33258 staining showed that the cells appeared obvious shrinking, swelling and rupture after treated with ginsenoside Rh4 for 24 h.The results of Western blot showed that with the increasing concentrations of ginsenoside Rh4, the expression of pro-apoptotic proteins Bax, cleaved caspase-3 and caspase-9 increased, while anti-apoptotic protein Bcl-2 decreased gradually.CONCLUSION: Ginsenoside Rh4 induces apoptosis of human hepatocellular carcinoma HepG2 cells, and the main mechanism may be related to down-regulation of Bcl-2 and up-regulation of Bax, cleaved caspase-3, and caspase-9.
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