香烟烟雾暴露小鼠中CD4^+Foxp3^+调节性T细胞中组蛋白去乙酰化酶的表达及意义

The expression and significance of histone deacetylase in CD4^+Foxp3^+ regulatory T cells in cigarette smoke-exposure mice

目的:探讨香烟烟雾暴露小鼠CD4+Foxp3+调节性T细胞(Treg细胞)中组蛋白去乙酰化酶(HDAC)的表达及意义。方法:将40只健康的雄性Balb/c小鼠随机分为对照组、HDAC阻滞剂曲古菌素A(TSA)组、烟熏组、烟熏+TSA组。烟熏组香烟烟雾暴露24周建立小鼠肺气肿模型,苏木精—伊红(HE)染色观察小鼠肺组织形态学改变。免疫磁珠分选纯度大于90%的Treg细胞,实时荧光定量PCR(qPCR)法检测Treg细胞中HDAC2、HDAC5、HDAC7、HDAC9等mRNA表达水平。流式细胞术检测Treg细胞中表达细胞毒性T淋巴细胞抗原4(CTLA-4)的比率、Treg增殖能力及其对效应Teff细胞增殖抑制作用。结果:烟熏组的平均内衬间隔(MLI)为(53.1±8.7)μm,明显高于对照组的(28.2±1.2)μm(P<0.05),成功建立肺气肿模型。与对照组比较,TSA组和烟熏组Treg细胞HDAC2、HDAC5、HDAC7、HDAC9 mRNA相对表达量降低,Treg细胞中CTLA-4表达率及其分裂指数升高,Teff细胞分裂指数下降(P<0.05);加入TSA进行体外干预后,与烟熏组比较,烟熏+TSA组Treg细胞CTLA-4表达率升高,Treg细胞增殖能力及对效应Teff细胞的增殖抑制作用均增强(P<0.05)。结论:在香烟烟雾诱导的肺气肿小鼠中,CD4+Foxp3+Treg细胞HDAC表达下降,HDAC可能参与吸烟所致的Treg细胞免疫功能失衡。

Objective：To evaluate the expression of histone deacetylase（HDAC）in CD4＋Foxp3＋regulatory T（Treg）cells and the function in cigarette smoke-induced emphysema mice.Methods：40 male Balb/c mice were randomly divided into control group,trichostatin A（TSA,a HDAC inhibitor）group,smoke exposure（SE）group and SE＋TSA group,with 10 mice in each group.Morphological changes of lung tissues were observed by hematoxylin eosin（HE）staining.The mRNA expressions of HDAC2,HDAC5,HDAC7 and HDAC9 were determined by qPCR.The expression of cytotoxic T lymphocyte associated antigen-4（CTLA-4）in Treg cells,the proliferation ability of Treg cells and its inhibitory effect on the Teff cells proliferation were detected by flow cytometry.Results：The mean linear intercepts（MLI）was higher in the SE group than that in the control group（P〈0.05）,suggesting that the mice emphysema model was successfully established.The HDAC2,HDAC5,HDAC7 and HDAC9 mRNA levels and the Teff cells proliferation rate were significantly decreased,while the positive expression rate of CTLA-4 in the Treg cells and the proliferation rate of Treg cells were increased in SE group and TSA group,compared with the control group（P〈0.05）.The positive rate of CTLA-4 expression,the proliferation ability of Treg cells and its inhibitory effect on the Teff cells proliferation were enhanced by the treatment of TSA in SE mice（P〈0.05）.Conclusion：The expression of HDAC in CD4＋Foxp3＋Treg cells was down-regulated in cigarette smoke-induced emphysema mice.HDAC might be involved in the immune imbalance of Treg cells induced by smoking.