雌激素受体及胆汁酸代谢相关基因在胆汁淤积孕鼠胎鼠肝脏中的表达

目的探讨雌激素受体(estrogen receptor,ERα)与胆汁酸代谢相关基因胆固醇7α羟化酶(cholesterol 7α-hydroxylase,CYP7A1)、胆固醇27α羟化酶(cholesterol 27-hydroxylase,CYP27A1)、胆固醇12α羟化酶(cholesterol 12α-hydroxylase,CYP8B1)mRNA在妊娠期肝内胆汁淤积孕鼠胎鼠肝脏中的表达及其意义。方法将60只清洁级SD孕鼠自孕第13天均分为2组:对照组孕鼠皮下注射精制植物油2.0 mL.kg-1.d-1;研究组孕鼠皮下注射17-α-乙炔雌二醇1.25 mg.kg-1.d-1。2组孕鼠分别于妊娠第13、17、21天断尾采母鼠血2 mL检测血清生物化学指标,于妊娠第21天处死。抽取母鼠、胎鼠血并提取母鼠、胎鼠肝脏组织。应用酶联免疫吸附试验检测2组孕鼠以及胎鼠血清中胆酸浓度;应用实时定量PCR技术检测各组胎鼠肝脏ERα、CYP7A1、CYP27A1、CYP8B1的mRNA表达量。结果①胆酸指标比较:在妊娠第17天时对照组、研究组母鼠胆汁酸浓度分别为(24.6±1.3)μmol/L、(58.7±3.2)μmol/L,研究组母鼠胆汁酸浓度明显高于对照组(t=2.462,P<0.05);在妊娠第21天时对照组、研究组母鼠胆汁酸浓度分别为(26.5±3.1)μmol/L、(66.4±2.7)μmol/L,研究组母鼠胆汁酸浓度与妊娠第17天时研究组以及对照组相比(F=5.43,P<0.05),差异有统计学意义。②胎鼠肝脏CYP7A1 mRNA、CYP27A1 mRNA、CYP8B1 mRNA表达:研究组中CYP7A1 mRNA(1.25±0.01)、CYP27A1 mRNA(2.05±0.03)、CYP8B1 mRNA明显高于对照组(0.35±0.02、0.75±0.03、0.85±0.02),P值均<0.05,差异有统计学意义。③胎鼠肝脏雌激素受体的表达:研究组中ERαmRNA(0.75±0.02)明显高于对照组ERαmRNA(0.45±0.01)。结论妊娠期肝内胆汁淤积症(intrahepatic cholestasis of pregnancy,ICP)孕鼠胎鼠肝细胞ER、CYP7A1、CYP27A1、CYP8B1的表达升高,胆汁酸的合成与代谢调节机制存在障碍,可能是导致ICP胎儿围生期死亡发生的原因之一。

Expression of Estrogen Receptor mRNA and Genes Related to Regulation of Bile acid Metabolism in Fetal Rat Liver of Pregnant Rats with Intrahepatic Cholestasis

Objective To study the expression of estrogen receptor(ER) and gene related to regulation of bile acid metabolism in fetal rat liver of pregnant rats with intrahepatic cholestasis. Methods Sixty clean SD pregnant rats were selected and divided into two groups at random. ① Since the 13th day of pregnancy after taking blood, the rats in control group were injected subcutaneously with refined vegetable oil 2.5 mL·kg^-1·d^-1, study group was injected subcutaneously with the 17-α-ethynylestradiol(EE) 1.25 mg·kg^-1·d^-1 till the 17th day. ② On the 21st day, all rats were killed. Then the fetus livers were collected for study. ③ The levels of serum total bile acid(TBA) were examined by ELISA. The expression of ER, CYP7A1, CYP27A1, CYP8B1(mRNA) in fetal rat liver was examined by real-time PCR. Results ① The levels of TBA were significantly higher in study group mother rats(58.7±3.2)μmol/L than that of control group(24.6±1.3)μmol/L on the 17th day(P<0.05); The levels of TBA were higher in study group mother rats(66.4±2.7)μmol/L than that of control group(26.5±3.1)μmol/L on the 21st day(P<0.05）. The levels of TBA were higher in study group fetus rats（28.4±2.6）μmol/L than that of control group（10.5±3.1）μmol/L on the 21st day. ② The expression of CYP7A1 mRNA（1.25±0.01）, CYP27A1 mRNA（2.05±0.03）, CYP8B1 mRNA（1.85±0.01） in study group fetus liver increased as compared to control group（0.35±0.02, 0.75±0.03, 0.85±0.02, respectively）（P<0.05）. 3) The expression of ERα mRNA in study group（0.75±0.02）was higher than that of control group（0.45±0.01）（P<0.05）. Conclusion The expression of ERα, CYP7A1, CYP27A1, CYP8B1(mRNA ) increased in the fetal rat liver of pregnant rats with intrahepatic cholestasis, resulting in increased synthesis of bile acids, which may be one of the mechanisms of perinatal death of the fetal rats.