川芎嗪对肝药物代谢酶CYP3A4的影响及机制研究

Effects of tetramethylpyrazine on drug metabolizing enzyme CYP3A4 in HepG2 cells and its mechanism

目的探讨川芎嗪对HepG2细胞中肝药物代谢酶CYP3A4的影响及其作用机制。方法采用不同浓度的川芎嗪作用于HepG2细胞48 h,MTT法检测细胞活力,并选取对细胞存活率影响较小的浓度进行实验。设置空白组、酮唑康组、不同浓度川芎嗪组以及酮唑康和不同浓度川芎嗪共同给药组,CYP3A4和PXR转染各组细胞,采用荧光素酶报告基因技术检测各给药组对CYP3A4和PXR酶活性的影响。并提取各组细胞蛋白,采用Western blot法检测HepG2细胞的CYP3A4和PXR蛋白表达水平。结果川芎嗪可以使CYP3A4酶活性增加,并呈剂量依赖性,还可使CYP3A4蛋白表达水平上调;川芎嗪可剂量依赖性地增加PXR转录活性,并使PXR蛋白水平升高。结论川芎嗪能通过激活PXR受体而对药物代谢酶CYP3A4起诱导作用。

Objective To study the effects of tetramethylpyrazineon on the activity of CYP3 A4 in HepG2 cell and its mechanism. Methods The HepG2 cells were treated with different concentrations of tetramethylpyrazine for 48 hours and then the optical density（ OD） value was determined by MTT,and the concentration was selected which had little influence on the survival rate of the cells. Blank group,ketoconazole group,group of different concentration of tetramethylpyrazine,and group of both ketoconazole and different concentration of tetramethylpyrazine were set up.CYP3 A4 plasmid and PXR plasmid were transfected into the HepG2 cells and then different concentration of tetramethylpyrazine,ketoconazole and both ketoconazole and different concentration of tetramethylpyrazine were incubated with the HepG2 cells. Effects of different concentrations of tetramethylpyrazine on the activities of CYP3 A4 and PXR enzymes were detected by luciferase reporter gene technique. The expression of CYP3 A4 and PXR protein in HepG2 cells was detected by Western blot. Results Tetramethylpyrazine could increase the activity of CYP3 A4 in a dose-dependent manner,and also increase the expression level of CYP3 A4 protein. Tetramethylpyrazine could increase the PXR transcription activity and increase the PXR protein level in a dose-dependent manner. Conclusion Tetramethylpyrazine can induce the drug metabolizing enzyme CYP3 A4 by activating PXR receptor.