宫内TCDD暴露对雄性胎鼠胎盘类固醇生成关键基因的影响

Effect of intrauterine exposure to TCDD on key steroidogenesis genes in placenta of male fetal rat

目的探讨关键生长期宫内2,3,7,8-四氯二苯并二英(TCDD)暴露对子代生长发育和胎盘类固醇合成关键基因的影响。方法孕SD大鼠随机分为TCDD染毒组(100,500 ng/kg)和对照组(纯玉米油),记录GD 19 d妊娠结局并测定胎鼠生长发育指标,实时荧光定量PCR法测定雄胎鼠胎盘类固醇生成关键基因(P450scc、P450c17、3β-HSD)的表达水平。结果 (1)孕鼠剖宫日当天各组的肝脏重量和脏器系数差别有统计学意义(P<0.05),500ng/kg组孕鼠肝脏质量小于对照组;(2)对照组与染毒组不良妊娠率差别有统计学意义(P<0.05);(3)染毒组的雄胎鼠体重均低于对照组,胎盘重量均高于对照组;(4)染毒组雄胎鼠的一般生长发育指标均低于对照组,但仅100ng/kg组雄性胎鼠尾长与对照组比较差别有统计学意义(P<0.05);(5)染毒组雄鼠胎盘P450scc、P450c17、3β-HSD mRNA表达均低于对照组。对照组胎盘P450scc、P450c17、3β-HSD mRNA表达水平分别为100 ng/kg组和500ng/kg组的1.63、1.42、1.49倍和1.63、1.14、1.41倍。结论性别性腺决定期宫内TCDD暴露可对雄胎鼠一般生长指标产生影响,并可影响其胎盘类固醇生成关键基因的表达。

Objective To observe the impact of intrauterine exposure to TCDD on development and steroidogenesis genes in placenta of male fetal rats. Methods Pregnant SD rats were randomly divided into three groups: low-dose of TCDD group( 100 ng/kg),high-dose of TCDD group( 500 ng/kg) and control group( corn oil only),all were received intragastric administration during 8—14 day after gestation. Record pregnancy outcomes and measure various growth and developmental indicators, meanwhile,the expression levels of steroidogenesis-related genes( P450scc、P450c17、3β-HSD) in placentas of male fetal rats was also detected with real-time quantitative PCR. Results( 1) There were statistically differences( P < 0. 05) among groups in liver weights and coefficients of pregnant rats,the liver weight of 500 ng / kg group was significant lower than that of control group.( 2) Adverse pregnancy rate showed statistically differences between exposed groups and control group( P < 0. 05).( 3) Body weights of male fetal rats in TCCD-exposed groups were lower than that of controls,while the placental weights were highter than that of control group.( 4) The general growth and development indicators of male fetal rats in TCDDexposed groups showed a reducing trend compared with the control group,but only the tail length of low-dose group had statistically difference( P < 0. 05).( 5) The gene expression levels of P450scc,P450c17,and 3β-HSD in fetal male placentas of TCDD exposed groups were obviously lower than that of the control group,their levels in control group were 1. 63 time,1. 42 time,1. 49 time of the 100 ng / kg group and were 1. 63 time,1. 14 time,and 1. 41 time of the 500 ng / kg group,respectively. Conclusion TCDD exposure during gonadal sex determination period could effect general growth and developmental of male fetal rats,and might impact the expression of steroidogenesis key genes in the placenta of fetal male rats.