18α-甘草酸下调“胶原蛋白凝胶三明治”培养的大鼠肝细胞P450酶活性及mRNA表达

18 α-Glycyrrhizic acid down-regulated the activities and mRNA expression of cytochrome P450 isoenzymes in rat hepatocyte sandwich cultures

研究 18α 甘草酸 (18α GA)对肝细胞主要细胞色素P4 50 (CYP)药物代谢酶的影响 ,并初步探讨其分子机理 .采用“胶原蛋白凝胶三明治”培养的原代大鼠肝细胞 ,加 18α GA孵育 ,酶学测定CYP1A1(7 乙氧基异口恶唑O 脱乙基酶 ,EROD) ,CYP2E1(苯胺羟化酶 ,ANH)和CYP3A(红霉素N 脱甲基酶 ,ERD)活性 ,逆转录聚合酶链反应测定CYP1A1,CYP2E1和CYP3A1mRNA表达水平 .结果可见 ,18α GA浓度依赖性 (50～ 4 0 0mg·L- 1)抑制大鼠肝细胞EROD ,ANH和ERD活性 ,2 0 0mg·L- 1作用最强 ,抑制率分别可达 59.6 % ,6 9.7%和 4 4 .7% ,且呈时间依赖性 ,于d 4达高峰 ;浓度依赖性 (50～ 2 0 0mg·L- 1)抑制CYP1A1,CYP2E1和CYP3A1mRNA表达水平 ,分别可达 4 4 .5% ,58.1%和 37.0 % .上述结果表明 18α GA在转录水平下调大鼠肝细胞CYP1A1。

To study the effect and mechanisms of 18 α-glycyrrhizic acid (18 α-GA) on cytochrome P450 (CYP) enzymes, the expression of CYP1A1, CYP2E1 and CYP3A was determined in rat hepatocyte sandwich cultures by using enzyme assay and semi-quantitative reverse transcriptase-polymerase chain reaction(RT-PCR). The results showed that the activities of CYP1A1 (7-ethoxyresorufin O-deethylase, EROD), CYP2E1(aniline hydroxylase, ANH) and CYP3A (erythromycin N-demethylase, ERD) were decreased in concentration-dependent manner after treatment with 18 α-GA(50-400 mg·L -1 ), and at the concentration of 200 mg·L -1 inhibitory rate reached the maximum (the maximum inhibitory rate was 59.6%, 69.7% and 44.7%, respectively). The time course revealed that the inhibition reached plateau level at d 4 of culure. 18 α-GA Decreased CYP1A1, CYP2E1 and CYP3A1 mRNA expression in dose-dependent manner, the maximum inhibitory rate was 44.5% , 58.1% and 37.1%, respectively. The results suggest that 18 α-GA down-regulate CYP expression at the transcriptive levels.