雷公藤内酯醇对肝细胞色素P450的诱导及机制研究

Investigation of inductive effect of triptolide on cytochrome P450s in rat hepatocytes and HepG2 cells and possible mechanism

目的探索雷公藤内酯醇(triptolide,TP)对肝细胞中细胞色素P450(CYPs)的诱导及可能机制。方法 TP处理大鼠原代肝细胞或Hep G2细胞后,采用实时定量PCR和Western blot等方法检测CYPs的表达水平变化,并结合特异性抑制剂或基因敲低的方法分析TP诱导CYPs的可能机制。结果 TP能够分别诱导大鼠CYP1A2、2C7、2C11、2C12、2D2、2E1和3A1的mRNA表达,50 nmol·L^(-1)时诱导倍数分别为18.5、2.2、31.2、3.2、21.5、88.3、34.0;100 nmol·L^(-1)时诱导倍数分别为20.3、4.6、29.6、23.1、61.1、83.0、38.5。HepG2细胞中人CYP1A1、2B6、2C9、2C19、2D6、2E1和3A4也被TP诱导。大鼠原代肝细胞内核受体PXR和CAR的活性被TP下调;TP可上调肝细胞内p53的蛋白水平,p53活性抑制后TP对部分CYPs的诱导作用受到抑制。结论 TP可在肝细胞水平诱导CYPs表达,该诱导作用可能不通过核受体,p53可能参与了TP对部分CYPs的诱导作用。

Aim Toinvestigatingtheinductionof CYPs in hepatocytes or HepG2 cells by triptolide（TP） andthepossiblemechanism.Methods AfterTPtreat-ment,the expression of CYPs in rat primary hepato-cytes or human HepG2 cells was detected by real-time PCR and Western blot assays.Specific inhibitors or gene knockdown method were employed to analyze the possiblemechanism.Results Theexpressionof CYP1A2,2C7,2C11,2C12,2D2,2E1 and 3A1 in rat primary hepatocytes was induced by TP.The fold was 19,2,31,3,21,88 and 34 at 50 nmol·L-1, respectively while at 100 nmol·L-1 it was 20,5,30,23,61,83 and 38,respectively.In HepG2 cells,the expression of human CYP1A1,2B6,2C9,2C19, 2D6,2E1 and 3A4 was also induced by TP.The ac-tivities of nuclear receptor PXR and CAR were inhibi-ted.TP upregulated p53 expression,and the induction of several CYPs caused by TP was blocked when p53 wasinhibited.Conclusions TPinducesCYPsexpres-sion in rat hepatocytes and HepG2 cells.Nuclear re-ceptors may not be involved in TP induced CYPs, while the mechanism may partly attribute to p53.