铜绿假单胞菌介导的支气管扩张大鼠炎症反应和Th17/Treg表达的研究

Effects of pseudomonas aeruginosa-mediated bronchiectasis on th17/Treg cell imbalance and inflammatory responses in rats

目的探讨铜绿假单胞菌感染对支气管扩张发病的作用机制,为该病的临床治疗提供理论依据。方法将30只SD大鼠按随机数字表法分为正常对照组、假手术组和支气管扩张模型组(模型组),每组10只,对大鼠气管注射铜绿假单胞菌,把支气管扩张模型建立起来;假手术组只做气管切开后缝合,正常对照组不予任何处理。术后第14天测定3组大鼠一般情况,苏木素-伊红(HE)染色观察肺组织病理学改变,流式细胞术测定外周血辅助性T细胞17(T helper cell 17,Th17)和调节性T细胞(T regulatory cell,Treg)的表达,酶联免疫吸附试验(ELISA)检测血清白细胞介素(IL)-17、IL-6、IL-10、转化生长因子(TGF)-β的表达。结果与正常对照组和假手术组比较,模型组用力肺活量(FVC)、0.3 s用力呼吸容积(FEV0.3)、用力呼气峰值流速(PEF)明显下降,而FEV0.3/FVC比值升高(P<0.05)。光镜下观察,模型组大鼠支气管扩张明显,有明显的炎症病理性改变。模型组与正常对照组、假手术组分别比较,血清IL-17明显升高(P<0.01)、IL-6明显升高(P<0.01)、IL-10明显降低(P<0.01)、TGF-β明显降低(P<0.01)、Th17表达显著升高(P<0.01)、Treg表达明显降低(P<0.01)、Th17/Treg比值升高(P<0.01)。结论铜绿假单胞菌介导的支气管扩张大鼠炎症反应升高,与Th17/Treg表达失衡有关,导致肺功能下降。

Objective To investigate the mechanism of Pseudomonas aeruginosa(P.aeruginosa) infection on the pathogenesis of bronchiectasis, and to provide scientific clues for clinical treatment of the disease. Methods Thirty SD rats were divided into normal control group, sham operation group and bronchiectasis model group according to the random number table, with 10 rats in each group. The model of bronchiectasis was established by injecting P.aeruginosa into the trachea of rats. The rats in the sham operation group were only sutured after tracheotomy, and the normal control group did not receive any treatment. General conditions of the three groups of rats were measured on the 14th day after the operation. The pulmonary histopathological changes were observed with hematoxylin-eosin(HE) staining. The expression of Th17(CD4+IL17) and Treg(CD4+CD25+Foxp3+Treg) in peripheral blood was determined by flow cytometry, and the expression of serum IL-17, IL-6, IL-10 and TGF-β was detected by ELISA.Results Compared with the normal and sham operation groups, the forced vital capacity(FVC), 0.3 s forced breathing volume(FEV0.3), FEV0.3/FVC, and forced peak expiratory flow rate(PEF) in the model group were significantly reduced. Under the light microscope, the rats in the model group had obvious bronchial dilatation, and noteworthy inflammatory pathological changes. Compared with the normal group or the sham operation group, the expression of IL-17 and IL-6 in the model group was significantly increased(P<0.01). On the contrary, IL-10 and TGF-β expression was significantly reduced(P<0.01). Furthermore, the Th17 expression was significantly increased(P<0.01). Treg expression was significantly decreased(P<0.01). The Th17/Treg ratio was also increased(P<0.01). Conclusion The increased inflammatory response in bronchodilatation rats induced by P.aeruginosa is associated with the imbalance of Th17/Treg expression, leads to decreased lung function.