肠道菌群失调加剧变应性鼻炎小鼠肺部炎症机理研究

Research on the mechanism of intestinal flora imbalance worsening lung inflammation in mice with allergic rhinitis

目的探讨肠道菌群失调对变应性鼻炎小鼠肺部Th1/Th2失衡的影响及其机制。方法取SPF级雌性Balb/c小鼠21只,随机分成3组,正常组(Control)、变应性鼻炎组(Allergic rhinitis,AR;生理盐水干预两周后构建AR小鼠模型)、变应性鼻炎+抗生素组(AR+antibiotic;抗生素干预两周后构建AR小鼠模型)。流式细胞术分析Treg细胞比例、酶联免疫法(Elisa)检测血清中卵清蛋白特异性IgE(OVA-sIgE)、肺泡灌洗液中IL-2、IL-4、IL-5、IL-10及IFN-γ水平,苏木精-伊红染色法(Hematoxylin-eosin staining,HE)分析鼻、肺部炎症水平,Western Blot检测肺部T-bet、Gata3蛋白表达水平。结果抗生素干预后,AR+antibiotic组小鼠菌群多样性显著低于未干预组(AR组、Control组),而行为学评分明显高于AR组和Control组;流式细胞术结果表明AR+antibiotic组较AR组Treg细胞比例进一步下降;HE结果显示AR+antibiotic组较AR组和Control组炎症加重,气管上皮细胞脱落以及鼻黏膜水肿加重;Elisa结果表明抗生素干预后能促进肺泡中IL-4、IL-5的释放,抑制IFN-γ、IL-2、IL-10的释放;肺组织蛋白水平分析表明抗生素干预能进一步降低T-bet表达,增加Gata3表达。结论抗生素引起的肠道菌群失调可通过抑制肺组织中T-bet表达,促进Gata3表达,诱导AR小鼠肺部Th1/Th2失衡,加重其肺部炎症。

Objective To explore the effect and mechanism of the intestinal flora imbalance caused by antibiotics on the Th1/Th2 imbalance in the lungs of mice with allergic rhinitis.Methods Twenty-one SPF female Balb/c mice were randomly divided into 3 groups,normal group(Control),allergic rhinitis group(AR;AR mice received two weeks of normal saline intervention),allergic rhinitis+antibiotic group(AR+antibiotic;AR mice received two weeks of antibiotic intervention).Flow cytometry analyzed the proportion of Treg cells,enzyme-linked immunoassay(Elisa)to detected serum ovalbumin-specific IgE(OVA-sIgE),IL-2,IL-4,IL-5,IL-10,and IFN-γlevels in alveolar lavage fluid,hematoxylin-eosin staining(HE)was used to analyze nasal and lung inflammation,and Western blot was used to detect lung T-bet and Gata3 protein expression levels.Results After antibiotic intervention,the diversity of the AR+antibiotic group was significantly lower than that of the non-intervention group(AR group,Control group),and the behavioral score was significantly higher than the AR group and the Control group;the results of flow cytometry showed the proportion of Treg cells in the AR+antibiotic group was further decreased compared with the AR group;The results of HE showed that the AR+antibiotic group had more inflammation,tracheal epithelial cell shedding and nasal mucosal edema than the AR group and the normal group;Elisa results showed that antibiotic intervention can promote the release of IL-4 and IL-5 in the alveoli and inhibit the release of IL-2,IL-10 and IFN-γ;analysis of lung tissue protein levels showed that antibiotic intervention can further reduce the expression of T-bet and increase the expression of Gata3.Conclusion The imbalance of intestinal flora caused by antibiotics can inhibit the expression of T-bet in lung tissues and promote the expression of Gata3,induce the imbalance of Th1/Th2 in the lungs of AR mice,and aggravate the inflammation of the lungs.