聚肌胞对RSV感染哮喘加重小鼠气道分泌TSLP和炎症的影响

Effect of polyI:C on secretion of thymic stromal lymphopoietin and airway inflammation in mice with respiratory syncytial virus-induced asthma exacerbation

目的探讨聚肌胞(poly I:C)对呼吸道合胞病毒(RSV)感染哮喘加重小鼠气道分泌胸腺基质淋巴细胞生成素(TSLP)和气道炎症的影响。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、OVA/RSV组、OVA/RSV/polyI:C组;应用OVA腹腔注射致敏、OVA气道雾化结合RSV滴鼻激发哮喘,聚肌胞1mg/kg肌肉注射;无创肺功能检测各组小鼠气道反应性;ELISA法检测小鼠血清IL-4、IL-5、IL-13、IFN-γ水平;ELISA法检测气管灌洗液(BALF)中TSLP含量;BALF行细胞分类计数;病理观察小鼠肺组织炎症反应,免疫组化观察小鼠气道上皮细胞TSLP表达水平。结果无创肺功能检测显示聚肌胞抑制RSV感染哮喘加重小鼠气道反应性的增高,OVA/RSV/polyI:C组小鼠Penh值明显低于OVA/RSV组(P<0.01);OVA/RSV/polyI:C组小鼠血清IL-4、IL-5、IL-13和BALF中TSLP浓度均明显低于OVA/RSV组(P<0.05);OVA/RSV/poly I:C组小鼠BALF细胞总数、嗜酸性粒细胞数及淋巴细胞数明显少于OVA/RSV组(P<0.05);病理观察显示聚肌胞减轻RSV感染哮喘小鼠气道炎症细胞浸润;免疫组化染色证实聚肌胞抑制RSV感染哮喘小鼠气道上皮细胞TSLP表达。结论聚肌胞前期注射减少RSV感染哮喘加重小鼠气道上皮细胞表达TSLP,抑制哮喘小鼠气道炎症反应。

Objective To investigate the effects of polyinosinic-polycytidylic acid（polyI：C） on the production of thymic stromal lymphopoietin（TSLP） and airway inflammation in mice with exacerbated asthma induced by respiratory syncytial virus（RSV）.Methods Thirty-two female BALB/c mice were randomly divided into 4 groups,namely the PBS control group,OVA group,OVA/RSV group,and OVA/RSV/polyI：C group.In the latter 3 groups,the mice were sensitized by OVA and stimulated with nebulized OVA.RSV was inoculated into the nasal cavity of the sensitized mice and polyI：C（1 mg/kg） was intramuscularly administered.The airway response to metacholine was examined,and the serum levels of IL-4,IL-5,IL-13,and IFN-γ and TSLP in the supernatants of bronchoalveolar lavage fluid（BALF） were detected using ELISA.The total BALF cells,eosinophils,lymphocytes and neutrophils were counted.The lung specimens were collected to observe the inflammation with HE staining,and immunohistochemistry was employed to determine TSLP production in the airway epithelial cells.Results The mice in RSV/OVA/polyI：C group showed a significantly lower airway responsiveness to metacholine than those in OVA/RSV group（P0.01）.Compared with OVA/RSV group,RSV/OVA/polyI：C group showed significantly lower serum levels of IL-4,IL-5,IL-13 and TSLP in BALF（P0.05）,with also lower total BALF cells,eosinophils and lymphocytes（P0.05） and lessened infiltration of the airway inflammatory cells.Immunohistochemistry of TSLP also demonstrated a lower production of TSLP in the airway epithelial cells in RSV/OVA/polyI：C group than in OVA/RSV group.Conclusions polyI：C can inhibit the increase in TSLP production in the airway epithelial cells after RSV infection and relieve airway inflammation in mice with RSV-induced asthma exacerbation.