致敏大鼠肺组织一氧化氮的变化与气道炎症关系的研究

Correlation between nitric oxide and inflammation in the bronchial and lung tissues of sensitized rats

目的 探讨致敏大鼠肺组织一氧化氮(NO)的变化及其与气道炎症的关系。方法 采用原位杂交及免疫组化技术(ABC法),观察卵蛋白致敏大鼠过敏性气道炎症肺组织中诱导型一氧化氮合酶(iNOS)基因表达与气道炎性细胞、活化T淋巴细胞间的关系。结果 iNOSmRNA主要表达于致敏大鼠肺泡巨噬细胞及细支气管上皮细胞,与肺组织匀浆中NO代谢产物增高相一致。定量分析结果表明,反复激发组气道嗜酸性粒细胞(Eos)〔(2267±486)平均每视野计数,下同〕和淋巴细胞(3433±542)较一次致敏组Eos(1896±305)和淋巴细胞(3053±432)有增多趋势,IL2R阳性淋巴细胞明显增高(积分光密度37940±8942比1559±4143,P<005)。随着炎症进展,iNOSmRNA表达量亦增高(积分光密度24440±3417比13340±2632,P<005),并与气道IL2R阳性T淋巴细胞数有显著正相关关系(n=12,r=0.70,P<005)。结论 致敏大鼠肺组织NO水平增高与肺泡巨噬细胞及小支气管上皮细胞iNOSmRNA表达增高相关,并与气道活化T淋巴细胞增高相关。提示增多的内源性NO可能参与了哮喘气道炎症发病机制中的T淋巴细胞活化过程。

Objective To investigate the relations between intrinsic nitric oxide (NO) and airways inflammation in sensitized rats. Methods By using in situ hybridization and immunohistochemical staining (ABC), we measured iNOS mRNA expression in lung tissues and the number of inflammatory cells and activation of T lymphocytes in the airways. Then the correlations between them were analyzed. Results In situ hybridization demonstrated that iNOS mRNA was mainly expressed in alveolar macrophages and bronchiole epithelial cells. There was a significant positive correlation between iNOS mRNA expression and increased NO - 2 level in lung tissues. Compared with that of rats sensitized once only (group B), the optical density ( A value) of membrane interleukin 2 receptor (mIL 2R) positive cells in group C (rats repeatedly sensitized and stimulated) significantly increased (379.40±89.42 vs 155.9±41.43, P <0.05). But the increase in the numbers of eosinophils and lymphocytes was not statistically significant. With the development of inflammation, iNOS mRNA expression also significantly increased (244.40±34.17 vs 133.40±26.32, P <0.05). There was significant positive correlation between iNOS mRNA expression and mIL 2R positive T lymphocytes in the airways of sensitized rats ( n =12, r =0.70, P <0.05). Conclusion These results suggest that intrinsic NO at an increased level promote the activation of lymphocytes, which plays an important role on the pathogenesis of asthmatic airways inflammation.