饮用水有机提取物对大鼠肝脏CYP1A2与CYP2E1酶活性及蛋白表达的影响

Effects on Enzyme Activities and Protein Expressions of CYP1A2 and CYP2E1 in Rats by Exposure to Organic Extracts from Drinking Water

[目的]探讨饮用水有机提取物对大鼠肝脏代谢酶CYP1A2与CYP2E1酶活性及蛋白表达的影响,为当地饮用水有机物污染的安全性评价及肝脏毒性机制的阐明提供依据。[方法]采用固相萃取法提取水样中有机污染物,40只SD大鼠随机分成4组,分别为对照组(玉米油)和低、中、高3个染毒组[剂量分别为5、20、80 L/(kg·d)],经口灌胃亚慢性染毒(12周)。荧光分光光度法和活性比色法分别测定CYP1A2与CYP2E1酶活性。采用Western blot法检测CYP1A2、CYP2E1的蛋白质表达水平。[结果]与对照组相比,高剂量组的CYP1A2酶活性明显升高,差异具有统计学意义(P<0.05);CYP2E1酶活性在中、高剂量组均明显升高(P<0.05)。随着染毒剂量的增加,CYP1A2的蛋白表达量在高剂量组升高(P<0.05);与对照组相比,CYP2E1的蛋白表达量在中、高剂量组均增加,差异具有统计学意义(P<0.05)。[结论]该地较高剂量的饮用水有机提取物可上调CYP1A2及CYP2E1的蛋白质表达,从而诱导CYP1A2和CYP2E1酶活性的增强。此可能为饮用水有机提取物肝脏毒性的重要机制之一。

[ Objective ] To examine the enzyme activities and protein expressions of liver CYP1A2 and CYP2E1 in rats exposed to organic extracts from drinking water, and to provide evidence for health risk assessment for local drinking water and elucidation of its hepatotoxicity. [ Methods ] Organic pollutants in drinking water were extracted by solid-phase extraction method. A total of 40 SD rats were randomly divided into four groups. The control group was administered with corn oil. The exposed groups were administered respectively with the organic extracts at 5, 20, and 80 L/（kg· d）. The exposure by gavage lasted 12 weeks. Fluorescence spectrophotometry and chromatometry were applied to evaluate the activities of CYP1A2 and CYP2E1 respectively. The protein levels of CYP1A2 and CYP2E1 were measured by Western blot method. [ Results ]Compared with the control group, the enzyme activity of CYP1A2 in the 80 L/（kg·d） group increased remarkably （P〈 0.05）; the enzyme activities of CYP2E 1 in the 20 L/（kg· d） group and 80 L/（kg· d） group both increased significantly （P 〈 0.05）. With the rise of exposing dose, the expression of CYP1A2 protein significantly increased in the 80L/（kg· d） group （P 〈 0.05）. Compared with the control group, the expression of CYP2E1 protein obviously increased in the 20L/（kg· d） group and the 80 L/（kg· d） group （P〈 0.05）. [ Conclusion] Exposed to high level of organic extracts from the local drinking water could result in the up-regulated expressions of CYP1A2 and CYP2E1 proteins, and then induce the rise of CYP1A2 and CYP2E1 enzyme activities. This might be one of the important mechanisms for liver damage.