STAT3-RORγt-IL-17信号通路在中性粒细胞哮喘小鼠模型中的作用

Role of STAT3-RORγt-IL-17 signaling pathway in neutrophil asthma mice

目的探讨信号转导和转录激活因子3(STAT3)-维甲酸相关核孤儿受体γt(RORγt)-白细胞介素17(IL-17)信号通路在中性粒细胞哮喘小鼠气道炎症中的作用机制。方法本研究为实验研究。按随机数字表法将36只雌性BALB/C小鼠分为3组:正常对照组、嗜酸粒细胞哮喘组、中性粒细胞哮喘组, 每组12只。腹腔注射卵清蛋白(OVA)致敏、雾化OVA激发制备嗜酸粒细胞哮喘模型;OVA腹腔注射联合脂多糖经鼻滴入、OVA雾化激发制备中性粒细胞哮喘模型;正常对照组以生理盐水代替OVA致敏及激发。收集支气管肺泡灌洗液(BALF)计算细胞总数及HE染色行分类计数。肺组织HE染色观察病理改变, 免疫组织化学法检测STAT3、RORγt蛋白表达, 流式细胞术检测肺组织Th17细胞比例。酶联免疫吸附试验法检测血清及BALF中IL-17、IL-6水平。结果与正常对照组比较, 嗜酸粒细胞哮喘组气道炎性细胞浸润显著, BALF细胞总数及中性粒细胞比例增高(P值均<0.01), 血清和BALF中IL-17、IL-6含量增加(P值均<0.05), 肺组织Th17细胞比例增多(P<0.01);与嗜酸粒细胞哮喘组比较, 中性粒细胞哮喘组气道炎性细胞增多, BALF细胞总数及中性粒细胞比例增高, 嗜酸粒细胞比例减低(P值均<0.05), 血清和BALF中IL-17、IL-6含量及肺组织Th17细胞比例增多(P值均<0.05), 与正常对照组和嗜酸粒细胞哮喘组比较, 中性粒细胞哮喘组肺组织STAT3、RORγt蛋白表达均增强(P值均<0.05)。结论 STAT3-RORγt-IL-17信号通路参与哮喘不同炎症表型发病机制, 但在中性粒细胞型哮喘的气道炎症中发挥更为重要的作用。

Objective To investigate the mechanism of signal transducer and activator of transcription 3(STAT3)-retinoic acid-related orphan receptor gamma t(RORγt)-interleukin-17(IL-17)signaling pathway in airway inflammation in neutrophil asthma mice.Methods This was an experimental study.A total of 36 female BALB/C mice were randomly divided into three groups:neutrophilic asthma group,eosinophilic asthma group,and normal control group.The eosinophilic asthma model was sensitized by intraperitoneal injecting ovalbumin(OVA)and challenged with an aerosol of OVA.The neutrophilic asthma model was sensitized by OVA and intranasal infusion of lipopolysaccharide,challenged with an aerosol of OVA.The normal control group was sensitized and challenged by normal saline instead of OVA.Bronchoalveolar lavage fluid(BALF)was collected and the total number of the cells was counted.After HE staining,the cells were classified and the numbers counted.Pathological changes of lung tissue were observed after HE staining,STAT3 and RORγt were detected by immunohistochemistry,and the proportion of Th17 cells in lung tissue was detected by flow cytometry.The levels of IL-17 and IL-6 in serum and BALF were detected by enzyme linked immunosorbent assay.Results Compared with normal control group,the eosinophilic asthma group had significant airway inflammatory cell infiltration,increased total number of BALF cells and proportion of neutrophils(P<0.01),raised levels of IL-17 and IL-6 in BALF and serum(P<0.05),and elevated proportion of CD4+IL-17+T cells(P<0.01).Compared with the eosinophilic asthma group,the neutrophilic asthma group showed increased airway inflammatory cells,elevated total number of BALF cells and proportion of neutrophils(P<0.05),decreased proportion of eosinophils(P<0.05),increased levels of IL-17 and IL-6 in serum and BALF,and enhanced proportion of CD4+IL-17+T cells(P<0.05).Compared with the normal control and eosinophilic asthma groups,the neutrophilic asthma group manifested elevated expressions of STAT3 and RORγt in lung tissue(P<0.05).Conclusions STAT3-RORγt-IL-17 signaling pathway is involved in the pathogenesis of different inflammatory phenotypes of asthma and plays a more important role in the pathogenesis of neutrophilic asthma.