葡萄糖神经酰胺葡萄糖基转移酶siRNA对7702肝细胞增殖的影响及机制研究*

目的 探讨糖鞘脂合成代谢在肝细胞增殖中的可能作用机制。方法 体外培养肝细胞株7702细胞,利用UDP-葡萄糖神经酰胺葡萄糖基转移酶（UGCG）siRNA转染肝细胞。采用MTT法检测细胞增殖,采用实时荧光定量PCR法检测Bcl-2、Bax和Caspase 3基因水平,采用Western blot法检测肝细胞Caspase 3蛋白表达情况。结果 UGCG siRNA干扰组细胞糖化神经酰胺合成酶基因水平比对照组明显下调（P<0.05）;干扰糖化神经酰胺合成酶基因表达后,转染组细胞Bcl-2 mRNA水平显著下降（P<0.05）,Bax mRNA水平显著升高,Caspase 3 mRNA及其蛋白表达水平均上调（P值均<0.05）。结论 糖化神经酰胺合成酶的缺乏引起的鞘脂代谢改变可能参与肝细胞的增殖的过程中,这可能与BCL2/BAX调节的细胞信号通路有关。

Impact of UGCG siRNA on 7702 hepatocyte proliferation in vitro

Objective To investigate the impact of UGCG siRNA on 7702 hepatocyte proliferation in vitro. Methods The 7702 hepatocytes were cultured in vitro and UDP-glucose ceramide glucosyltransferase（UGCG） siRNA was transfected into the hepatocytes. MTT was performed to detect the cell proliferation,the Bcl-2,Bax,Caspase 3 gene were detected by real-time quantitative PCR,and the expression of Caspase 3 protein in hepatocytes was detected by Western blot. Results UGCG siRNA successfully down-regulated glucosylceramide synthase mRNA levels as compared to that in the control（P<; 0.05）;the proliferation of hepatocytes was inhibited（P<; 0.05） after transfection of the glycosylated ceramide synthase gene,Bcl-2 mRNA decreased（P<; 0.05）,Bax mRNA increased （P<; 0.05）,and the expression of Caspase 3 protein was significantly upregulated（P<; 0.05）. Conclusion The changes of sphingolipid metabolism caused by the lack of glucosylceramide synthase is involved in hepatocyte proliferation, which might be related to the regulation of BCL2/BAX signal pathway.