低氧促进Th17细胞浸润于肺组织并与肺血管改建相关

目的:观察低压低氧时肺组织中维甲酸相关孤儿受体(ROR)γt的mRNA表达水平及白细胞介素17(IL-17)水平的变化,探讨Th17细胞与缺氧肺血管改建的关系。方法:50只雄性BALB/c小鼠按低氧时间随机分为0 d、3 d、7 d、14 d和28 d组,每组10只。低压低氧组小鼠均置入模拟海拔6 000 m的低压舱内饲养3 d、7 d、14 d和28 d。常氧组置常压常氧环境下饲养(即0 d组)。于相应时点通过心导管检测右室收缩压,随后快速处死取材,测量右心室重量指数,用流式细胞术检测脾脏组织Th17细胞(CD4+IL-17+RORγt+)的比例,用ELISA法检测血清中IL-4、IL-6、IL-17水平及肺组织中IL-17水平,采用real-time PCR法检测肺组织RORγt的mRNA表达水平。结果:与对照组(0 d组)相比,低压低氧7 d、14 d和28 d组小鼠右心室收缩压力、右心肥厚指数和血清IL-17含量均升高,其差异有统计学意义(P0.05);脾脏组织中IL-17+RORγt+CD4+T细胞的百分比随缺氧时间延长呈上升趋势,14 d和28 d组与对照组相比差异显著(P0.01);7 d、14 d和28 d组肺组织中RORγt的mRNA表达与对照组相比显著升高,差异有统计学意义(P0.05或P0.01);14 d和28 d组肺组织中IL-17水平与对照组相比显著升高(P0.01)。肺组织中RORγt的mRNA表达水平、IL-17表达量与心室收缩压、右室肥厚指数呈显著正相关。结论:低压低氧促进脾脏T0细胞向Th17细胞分化,肺组织中RORγt的mRNA表达水平及IL-17水平显著升高,提示Th17细胞可能参与缺氧性肺动脉高压及肺血管改建的发生。

Relationship between Th17 cells infiltrated in lungs and pulmonary vascular reconstruction under hypobarric hypoxia

AIM: To investigate the changes of retinoid-related orphan receptor γt(RORγt) mRNA and interleukin-17(IL-17) protein in the lung tissue under hypobaric hypoxia, and the relationship between Th17 cells and hypoxic pulmonary vascular reconstruction. METHODS: Male BALB/c mice(n=50) were randomly divided into control group and 3 d, 7 d, 14 d and 28 d hypobaric hypoxia groups. The mice in hypobaric hypoxia groups were housed in a hypobaric hypoxia chamber(simulated altitude of 6 000 m) for 3 d, 7 d, 14 d or 28 d. The mice in control group were housed in normal pressure and oxygen environment. The hemodynamic data were recorded by cardiac catheterization. The hypertrophy of right ventricle was evaluated by the ratio of weight of the right ventricle to the weight of the left ventricle plus interventri-cular septum, and the right ventricular weight over body weight. The spleen was collected and the proportions of the Th17(CD4⁺IL-17⁺RORγt⁺) cells were detected by flow cytometry. The serum levels of IL-4, IL-6 and IL-17 and the change of IL-17 in the lung tissue were measured by ELISA. The mRNA expression of RORγt in the spleen and lung tissues was measured by RT-qPCR. RESULTS: Compared with control group, the mouse right ventricular systolic pressure, the hypertrophy index of right ventricle and the serum IL-17 level were significantly elevated in hypoxia groups, which was consistent with the results of flow cytometry. The mRNA expression of RORγt in the lung tissue was also significantly increased in 7 d, 14 d and 28 d hypoxia groups. The expression of IL-17 in the lung tissue was significantly increased in 14 d and 28 d hypoxia groups. CONCLUSION: Hypoxia promotes differentiation of Th0 cells to Th17 cells in the spleen. The Th17 cells infiltrated in the lung tissue under hypobarric hypoxia are involved in pulmonary vascular reconstruction.