不明原因复发性流产小鼠模型CD4^+CD25^+ Treg的比例及Foxp3表达的变化

Change of CD4^+CD25^+ Treg percentage and Foxp3 expression level in URSA mouse model

目的分析比较小鼠正常妊娠模型和流产模型中CD4+CD25+调节性T细胞CD4+CD25+Treg的比例、Foxp3蛋白表达水平及胎盘吸收率,探讨CD4+CD25+Treg与不明原因复发性流产的关系。方法以雌性CBA/J×雄性Balb/c为对照组,以雌性CBA/J×雄性DBA/2J为流产组,各10对,于妊娠第14天采用流式细胞术(flow cytometry,FCM)分析CD4+CD25+Treg在CD4+细胞中所占比例,Western blot检测并比较2组CD4+T细胞中Foxp3的表达,并观察2组小鼠的胎盘吸收情况。结果流产组CD4+CD25+Treg所占比例为(10.1±0.59)%低于对照组(15.5±0.78)%(P<0.05)。流产组胚胎吸收率为(25.6±3.5)%,明显高于对照组(2.4±1.6)%(P<0.01)。流产组Foxp3谱带密度相对值为0.30±0.018,低于正常组的0.68±0.025(P<0.05)。结论小鼠的自然流产模型建立成功,流产组孕鼠CD4+CD25+Treg的比例和Foxp3蛋白表达水平明显低于正常妊娠组,提示流产组高流产率可能与CD4+CD25+Treg数量和Foxp3的表达减少有关,CD4+CD25+Treg细胞的数量减少和功能缺陷可能是不明原因复发性流产的发生机制之一。

To study the role of CD4＋CD25＋Treg in unexplained recurrent spontaneous abortion, we investigate the percentage of CD4＋CD25＋Freg and the Foxp3 expression level in normal pregnancy and abortion mouse model. An immunological model of abortion was used, in which the mating combination CBA/JxDBM2J represents the abortion group, while using the combination CBA/J xBalb/c as a normal pregnancy control. On 14th day of pregnancy, the females were sacrificed. We analyzed the percentage of CD4 ＋CD25 ＋rreg in spleen ceils by flow cytometry, detecte the expression level of Foxp3 by Western blot, and then calculated the ratio of abortions （resorption plus normal implantation sites）. The results showed that in spleen, the percentage of CD4＋CD25＋Treg in CD4＋T ceils was significantly lower in mice of abortion group compared with those in control group [（10.1±0.59）% vs （15.5±0.78）%, （P〈0.05）]; embryo resorption in abortion group was significantly higher than that in the control group [（25.6±3.5）% vs （2.4±1.6）%, （P〈0.01）]; relative value of Foxp3 band density in abortion group was significantly lower than the normal group [（0.68 ±0.025） vs （0.30 ±0.018）, （P〈0.05） ]. This study might provide evidence for that high abortion rate may result from the decreased frequencies of CD4＋CD25＋Treg and low expression level of Foxp3. The lack of CD4＋CD25＋Treg and its deficiency may be a cause of unexplained recurrent spontaneous abortion.