调节性T细胞表达CD39和CD73在小鼠哮喘模型发病中的作用

The role of CD39 and CD73 expressed by regulatory T cell in the pathogenesis of asthma in mice

目的:探讨CD39和CD73阳性的CD4+CD25+Foxp3+T淋巴细胞(Treg细胞)对支气管哮喘(简称哮喘)小鼠气道炎症的影响。方法:将16只BALB/c成年雌性小鼠随机分为哮喘组(n=8)和对照组(n=8)。用卵清蛋白进行哮喘造模后,取小鼠血清检测总Ig E,采用高效液相色谱法行支气管肺泡灌洗液上清液三磷酸腺苷(adenosine-triphosphate,ATP)检测,取左肺组织行苏木精-伊红(hematoxylin eosin,HE)染色,观察小鼠肺组织的炎症改变;右肺上叶行CD39 m RNA、CD73 m RNA、Foxp3 m RNA检测;余右肺制成单细胞悬液,采用流式细胞术检测CD39+Treg和CD73+Treg细胞数量,计算其占Treg细胞百分比。结果 :哮喘组小鼠的血清总Ig E较对照组显著上升(P<0.01),支气管肺泡灌洗液中ATP较对照组升高(P<0.05),病理组织切片检查发现肺部炎症改变明显。哮喘组小鼠肺组织中CD39m RNA、CD73 m RNA、Foxp3 m RNA表达量分别为(0.54±0.11)×10-3、(1.11±0.36)×10-3、(0.08±0.03)×10-3,对照组则分别为(0.88±0.25)×10-3、(1.88±0.37)×10-3、(0.11±0.02)×10-3,2组间差异有统计学意义(P均<0.05)。流式细胞术检测发现,哮喘组小鼠肺组织的CD39+Treg、CD73+Treg细胞百分比较对照组略有下降趋势,但差异尚无统计学意义。结论:肺局部CD39+Treg和CD73+Treg细胞数量减少和(或)功能障碍导致的细胞外ATP清除率降低,可能是哮喘气道炎症发生的重要机制之一。

Objective To investigate the effects of CD39 and CD73 expressed by CD4^＋CD25^＋Foxp3^＋regulatory T lymphocytes（Treg cells） on airway inflammation and its mechanism in mice with bronchial asthma（asthma）. Methods：Sixteen adult female BALB/c mice were randomly divided into asthma group（n=8） and control group（n=8）. All mice were sacrificed 24 h after the last challenge, and the total Ig E in serum was measured by enzyme linked immunosorbent assay（ELISA）; adenosine triphosphate（ATP） level in the supernatant of bronchoalveolar lavage fluid（BALF） was measured by high performance liquid chromatography（HPLC）. Sample of left lung was stained with hematoxylin eosin（HE） to observe the inflammatory change; upper lobe of right lung was tested for CD39, CD73, Foxp3 m RNA detection; single cell suspen-sion from the rest right lung was used to examine the proportions of CD39^＋Treg and CD73^＋Treg cells in relative to Treg cells by flow cytometry. Results： The serum level of total Ig E was significantly increased in asthma group than that in control group（P〈0.01）, and so was the ATP level in BALF（P〈0.05）. Pathological examination showed that pulmonary inflammatory changes were obvious in asthma group. The expressions of CD39, CD73 and Foxp3 m RNA in asthma group were（0.54±0.11）×10^-3,（1.11±0.36）×10^-3,（0.08±0.03）×10^-3, and that in control group were（0.88 ±0.25） ×10^-3,（1.88 ±0.37）×10^-3,（0.11±0.02）×10^-3, the differences between the two groups were statistically significant（P〈0.05）. FACS test found that the proportions of CD39^＋Treg cells and CD73^＋Treg cells in asthma group were decreased when compared with the control group, but the difference had not reached statistical significance. Conclusions： The decrease and/or dysfunction of CD39^＋Treg and CD73^＋Treg cells in lung may induce the reduction of extracellular ATP clearance, and it may be one of the important mechanisms of airway inflammation in asthma.