肺气肿小鼠肺组织中白细胞介素21的变化及其对CD4＋T细胞分化的影响

Expression of interleukin-21 in the lungs of mice with emphysema and its effects on the differentiation of CD4＋ T cell

目的探讨香烟烟雾暴露肺气肿小鼠肺部白细胞介素（IL）-21的变化及其对CD4＋T细胞分化的影响。方法加只雄性Balb／c小鼠随机分为对照组和烟熏组各10只。24周香烟烟雾暴露法建立小鼠肺气肿模型。HE染色观察小鼠肺组织的改变，计算平均内衬间隔和肺泡破坏指数；流式细胞术检测小鼠肺实质中CD4＋IL-21R＋T细胞比例；酶联免疫吸附测定（ELISA）检测小鼠肺实质中IL-21水平；分离烟熏组肺单个核细胞，分为空白组、共培养组2个亚组，后者与IL-21共培养，在24及48h时分别通过流式细胞术检测Th1及Th17细胞比例。结果烟熏组的平均内衬间隔和肺泡破坏指数[（48．6±4．8）μm和44．9±2．8]均显著高于对照组[（32．4±4．0）μm和28．1±2．1]（均P〈0．05）。烟熏组肺实质中CD4＋IL-21R＋T细胞比例（4．1％±1．5％）较对照组（1．4％±0．4％）显著增高（P〈0．05）。烟熏组IL-21水平[（851±28）ng／L]较对照组[（415±39）ng／L]显著增高（P〈0．05）。小鼠肺实质中IL-21水平与平均内衬间隔、肺泡破坏指数呈显著正相关（r值分别为0．892和0．955，均P〈0．05）。在体外共培养24、48h后共培养组Th17细胞及Th1细胞比例均显著高于空白组（均P〈0．05）。结论IL-21可能通过诱导CD4＋T细胞向Th1及Th17细胞分化，促进肺内Th1、Th17型细胞反应，参与肺气肿的形成与发展。

Objective To evaluate the expression of interleukin （IL） -21 in a cigarette smoke- induced mice model of emphysema and explore its effects on the differentiation of CD4 ＋T cell. Methods Twenty male Balb/c mice were randomly divided into two groups： control group and smoke-exposed group. Morphological changes were evaluated by mean hnear intercepts and alveolar destructive index. The proportion of CD4 ＋IL-21R＋ cells in lungs of mice was determined by flow cytometry. And the levels of IL-21 in lungs of mice were analyzed by enzyme-linked immunosorbent assay （ELISA）. Fresh lung mononuclear cells were isolated from the smoke-exposed group and divided further into two sub-groups ： blank sub-group and co-culture sub-group. Two sub-groups were cuhured in medium with or without IL-21 for 24 h and 48 h. The proportions of Thl and Thl7 ceils in cell culture medium were determined by flow cytometry. Results Mean linear intercepts and alveolar destructive index in the smoke-exposed group （ （48. 6 ± 4. 8） txm and 44. 9 ± 2. 8） were significantly higher than the control group （ （ 32. 4 ± 4. 0） p±m and 28.1 ± 2. 1, both P 〈0. 05）. In lungs, the percentage of CD4 ＋IL-21R±T cells in the smoke-exposed group （4. 1% ± 1.5% ） significantly increased than that in the control group （ 1.4% ± 0. 4% ） （ P 〈 0. 05 ）. The levels of IL-21 in lung of the smoke-exposed group （（851 ± 28 ） ng/L） were higher than those in the control group （（415 ±39） ng/L, P 〈0. 05）. In lungs, the levels of IL-21 had positive correlations with mean linear intercepts and alveolar destructive index （ r = 0. 892 and 0. 955, both P 〈 0. 05 ）. The percentages of Thl and Thl7 cells in cell culture medium of the co-culture sub-group for 24 h and 48 h significantly increased versus those in the blank group （ all P 〈 0.05）. Conclusion IL-21 may participate in the occurrence and development of emphysema through the induced differentiation of CD±T cells and the promotion of Thl and Thl7-cell responses in lungs.