二噁英对小鼠异位子宫内膜影响的分子机制研究

Study of Molecular Mechanism on Effect of TCDD on Development of Ectopic Endometrium in Mouse

【目的】探讨四氯二苯并二噁英(TCDD)对子宫内膜异位症小鼠模型的影响及其分子学机制。【方法】采用小鼠自体子宫内膜移植法建立小鼠子宫内膜异位症模型,分别给予TCDD0、l、3、10μg/kg剂量灌胃,每21d1次,于建模术后3、6、9周处死,鉴定异位病灶的形成,测量异位病灶体积。采用免疫组化法和RT-PCR法检测各组小鼠异位子宫内膜组织中芳香烃受体(AhR)和细胞色素P4501A1(CYP1A1)表达水平。【结果】①染毒组小鼠异位病灶体积的增加与染毒剂量和时间具有明显的正相关性(r=为0.727、0.553,均P<0.05);②染毒组小鼠异位子宫内膜AhR蛋白较对照组增强(P<0.05);且随染毒剂量增加和染毒时间延长,AhR蛋白表达相应增加(r分别为0.687、0.442,均P<0.01);③随染毒剂量增加,CYP1A1蛋白表达相应增加(r=0.640,P<0.01),对照组未检测到CYP1A1蛋白表达;④染毒组小鼠异位子宫内膜AhR mRNA较对照组增强(P<0.05)。随染毒剂量增加和暴露时间延长,AhR mRNA表达相应增加(r分别为0.565、0.635,P<0.01);⑤随染毒剂量的增加,CYP1A1 mRNA表达明显增加(r=0.659,P<0.01),对照组小鼠异位子宫内膜病灶中未检测到CYP1A1 mRNA。【结论】TCDD可促进小鼠模型异位子宫内膜病灶的发展,其机制可能与AhR及其下游基因CYP1A1激活有关。AhR及CYP1A1的表达增强是二噁英暴露的生化指标。

Objective To investigate the effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin（TCDD） on development of endometriosis in a mouse model from perspective of molecular mechanism.Methods The endometriosis mouse model was established with autotransplantation of endometrium.Twenty-one days prior to induction surgery which produces endometriosis,female mice were pretreated with 2,3,7,8-tetrachlorodibenzo-p-dioxin（TCDD） at 0,3,or 10 mg TCDD /kg.Animals were treated again at the time of surgery and at 3,6,and 9 weeks following surgery.Evaluation of ectopic focuses diameter were made at 3,6,9 weeks post surgery.The AhR and CYP1A1 expression on ectopic endometrium were identified by immunohistochemistry and RT-PCR assays.Results ①With increased time and dose of TCDD exposure,it produced a dose-dependent increase in endometriotic site diameter when all time points were pooled within each dose in mice（r=0.727 and 0.553 respectively,both P0.05）.②The expression of AhR protein on ectopic focuses in mice were higher in the TCDD exposure group than those in control group,and presented time-dose dependent increase（r=0.687 and 0.442,both P0.01）.③The higher dose of exposure increased,the higher CYP1A1 protein expressions enhanced（r=0.640,P0.01）.④As compared with the control group,the expression of AhR mRNA in ectopic focuses of mice were higher in the TCDD exposure group,and show time-dose dependent increase（r=0.565 and 0.635,both P0.01）.⑤The higher dose of exposure increased,the higher CYP1A1 mRNA expression enhanced（r=0.659,P0.01）.Conclusion TCDD can promote progression of ectopic focus of endometriosis in the mouse model,and one of molecular mechanism of TCDD for development of EMS is the activated AhR and its reaction gene of CYP1A1.The activated AhR and CYP1A1 can be acted as biochemical indicator to TCDD exposure.