呼吸道合胞病毒感染促进哮喘小鼠气道分泌TSLP和Th2炎症反应

Respiratory syncytial virus infection promotes the production of thymic stromal lymphopoietin and accelerates Th2 inflammation in mouse airway

目的探讨呼吸道合胞病毒(RSV)对哮喘小鼠胸腺基质淋巴细胞生成素(TSLP)分泌的影响,以探索RSV对哮喘小鼠Th1/Th2免疫反应的调节作用。方法雌性BALB/c小鼠32只,随机分成4组,分别为磷酸盐缓冲液(PBS)对照组、鸡卵白蛋白(OVA)组、RSV组、OVA/RSV组;应用OVA腹腔注射致敏、OVA气道雾化结合RSV滴鼻激发哮喘;无创肺功能检测小鼠气道反应性,ELISA法检测小鼠血清IL-4、IFN-γ、IL-5、IL-13水平;ELISA法检测气管灌洗液(BALF)TSLP含量并进行细胞分类计数;小鼠肺组织病理观察炎症反应,免疫组化观察小鼠气管上皮细胞TSLP表达水平。结果RSV感染促进哮喘小鼠呼吸道分泌TSLP增加,OVA/RSV组小鼠TSLP浓度达(2.13±0.05)ng/ml,高于其他组(P<0.01);同时促进IL-4、IL-5、IL-13等Th2型细胞因子的分泌,并增加IFN-γ分泌;OVA/RSV组BALF细胞总数、嗜酸性粒细胞数、中性粒细胞数、淋巴细胞数与其他各组比较均明显增加;无创肺功能检测显示OVA/RSV组小鼠气道反应性明显增高,乙酰甲胆碱浓度达6.25mg/ml时,Penh值(318.66±50.87)明显增加,与其他各组比较具有统计学意义(P<0.01);病理观察显示RSV感染明显加重哮喘小鼠气道炎症细胞浸润;免疫组化染色证实RSV/OVA组小鼠气道上皮细胞TSLP表达量较高。结论RSV感染可以增加小鼠气道上皮细胞表达TSLP,促进Th2细胞因子的表达,加重哮喘小鼠肺部Th2炎症反应。

Objective To investigate the effect of respiratory syncytial virus （RSV） infection on the production of thymic strornal lymphopoietin （TSLP） and Th1/Th2 balance in asthmatic mice. Methods Thirty-two female BALB/c mice were randomly divided into 4 groups, namely the PBS group, ovalbumin （OVA） group, RSV group and OVA/RSV group. The mice were sensitized by OVA and then stimulated with nebulized OVA, and RSV was inoculated into the nasal cavity of the mice. BUXCO noninvasive lung function detection was performed to examine the airway response to metacholine, and enzyme-linked immunosorbent assay （ELISA） was used to detect the serum levels of IL-4, IL-5, IL-13, and WN-y in the mice. The cells in the bronchoalveolar lavage fluid （BALF） were counted and classified, and the supematants of the BALF were used for the detection of TSLP. Histopathological changes in the lung tissues of the mice were examined using HE staining, and immunohistochemistry using anti-mouse TSLP antibody was performed to examine TSLP expressions in the airway epithelial cells. Results RSV infection promoted the production of TSLP in the asthmatic mice, and the concentration of TSLP in OVA/RSV group （2.13±0.05 ng/ml） was significantly higher than that in the other groups （P〈0.01）. RSV infection increased the serum levels of IL-4, IL-5, IL-13, and IFN-γ in the mice. The total BALF cells, eosinophils, lymphocytes and neutrophils in OVA/RSV group were significantly higher than those in the other groups; noninvasive lung function examination showed higher Penh value in OVA/RSV group （318.66±50.87） than in the other groups when the inhaled metacholine increased to 6.25 mg/ml （P〈0.01）. More obvious and extensive airway inflammatory cell infiltration in OVA/RSV group were observed, and immunohistochemical staining also showed higher expression of TSLP in the airway epithelial cells of OVA/RSV group.Conclusion RSV infection promotes the production of TSLP in the airway epithelial cells and increases the level of Th2 cytokines in asthmatic mice. Concurrent RSV infection can exacerbate Th2 inflammatory reaction in asthmatic mice.