磷脂酰肌醇3激酶对哮喘大鼠气道上皮细胞诱导型一氧化氮合酶表达的调控作用

Effect of phosphatidylinositol 3-kinase on inducible nitric oxide synthase in bronchiole epithelial cells of asthmatic rat

目的:探讨磷脂酰肌醇3激酶(PI3K)抑制剂wortmannin对哮喘大鼠支气管上皮细胞诱导型一氧化氮合酶(iNOS)表达的影响。方法:24只成年哮喘大鼠随机分成对照组、哮喘组以及PI3K抑制剂wortmannin干预组。对支气管肺泡灌洗液(BALF)细胞总数及嗜酸性粒细胞进行计数,免疫组织化学检测大鼠支气管上皮细胞iNOS蛋白的表达,RT-PCR检测肺组织iNOSmRNA的表达,分光光度计检测肺组织PI3K活性、iNOS活性及NO含量。结果:哮喘组大鼠BALF细胞总数计数及嗜酸性粒细胞分类均高于对照组;PI3K抑制剂wortmannin干预组BALF嗜酸性粒细胞计数及分类明显低于哮喘组,差异显著。哮喘组肺组织PI3K活性、iNOS活性及NO含量高于对照组,PI3K抑制剂wortmannin干预组肺组织PI3K活性、iNOS活性及NO含量低于哮喘组。哮喘组大鼠支气管上皮细胞iNOS蛋白及肺组织iNOS mRNA表达较对照组明显增强,但PI3K抑制剂wortmannin组iNOS蛋白及mRNA表达均明显弱于哮喘组。结论:PI3K可调节哮喘大鼠气道iNOS表达,影响哮喘气道炎症反应。

AIM： To investigate the effect of phosphatidylinositol 3 - kinase （PI3K） inhibitor wortmannin on expression of inducihle nitric oxide synthase （iNOS） in bronehiole epithelial cells of asthma rat. METHODS ： 24 male Sprague- Dawley rats were randomly divided into 3 group, namely control group, asthma group and PI3K inhibitor wortmannin ＋ asthma group. The numbers of total cells and eosinophil cells in bronehoalveolar lavage fluid （BALF） were counted. The expression of inducible nitric oxide synthase was detected by immunohistochemistry method, and iNOS mRNA was detected by reverse transcriptionpolymerase chain reaction （RT- PCR）. The activity of PI3K, iNOS and content of NO in lung homogenates were tested by spectrophotometry. RESULTS ： The numbers of eosinophils and the ratios of eosinophils to total cells in BALF in asthma group were significantly higher than those in control group, while those in wortmannin ＋ asthma group were decreased compared to asthma group. The activity of PI3K, iNOS and content of NO in lung homogenats in asthma group were significantly higher than those in control group, while those in wortmannin ＋ asthma group were decreased compared to asthma group. The expression of iNOS protein in bronchiole epithelial cells and mRNA in lung homogenates in asthma group were markedly increased compared to control group, while those in wortmannin ＋ asthma group were decreased compared to asthma group. CONCLUSION： PI3K regulates the expression of iNOS in airway of asthma rat and affects inflammatory reaction in airway.