卡介菌多糖核酸对哮喘大鼠肺组织IL-12/STAT4信号通路的影响

目的探讨卡介菌多糖核酸(BCG-PSN)对支气管哮喘大鼠肺组织白介素12/信号转导子及转录激活子4(IL-12/STAT4)信号通路的影响及其在气道炎症中的作用。方法将40只雄性SD大鼠随机分成正常对照组(A组),哮喘模型组(B组),卡介菌多糖核酸组(C组)和地塞米松组(D组),每组10只。采用鸡清卵蛋白(OVA)致敏和激发的方法制备哮喘大鼠模型。苏木精-伊红(HE)染色观察肺组织病理形态学改变,用免疫组化法观察IL-12和STAT4在大鼠哮喘模型肺组织中的表达分布。结果模型组肺组织IL-12和STAT4蛋白表达较少,其平均灰度值显著高于对照组(P<0.01);地塞米松组和卡介菌多糖核酸组肺组织IL-12和STAT4蛋白表达较多,其平均灰度值显著低于哮喘组(P<0.01),而地塞米松组和卡介菌多糖核酸组之间差异无统计学意义;卡介菌多糖核酸组STAT4的表达与IL-12呈正相关(r为0.908,P<0.01)。结论卡介菌多糖核酸调节气道炎症可能是通过调控IL-12/STAT4信号通路的基因表达实现的。

Effects of BCG-PSN on the IL-12/STAT4 signal transduction pathway in asthmatic rats

To evaluate the effects of BCG-PSN on the IL-12/STAT4 signal transduction pathway and the airway inflammation in asthmatic rats,40 male healthy SD rats were recruited and randomly divided into 4 groups with 10 rats in each group: normal control group(group A),asthma model group(group B),BCG-PSN group(group C) and Dexamethasone group(group D).The model of asthmatic rats was established by using OVA sensitization and challenge.For all the groups,the pathology morphological changes were observed by HE staining,while IL-12 and STAT4 protein expressions were detected by immunohistochemical method.In the asthma model group,IL-12 and STAT4 protein expressions of lung tissue were lower than those in the normal control group(P < 0.01).On the contrary,in the Dexamethasone group and BCG-PSN group,IL-12 and STAT4 protein expressions of lung tissue were higher than those in the asthma model group(P < 0.01).For indexes mentioned above,there were no significant differences between Dexamethasone group and BCG-PSN group.The correlation analysis indicated that the STAT4 protein expression was positively correlated with IL-12 expression level in BCG-PSN group(P < 0.01).All these results indicated that BCG-PSN can adjust airway inflammation by regulating the gene expression of IL-12/STAT4 signal transduction pathway in asthmatic rats.