兔放射性肺纤维化形成过程中一氧化氮含量变化及诱导型一氧化氮合成酶的表达

Dynamic change of nitric oxide content and expression of inducible nitric oxide synthase during radiation-induced pulmonary fibrosis in rabbits

目的:观察兔放射性肺纤维化形成过程中一氧化氮(NO)含量变化及诱导型一氧化氮合成酶(iNOS)的表达。方法:实验兔20只,采用6mVX线对左全肺进行照射,25Gy,1次。分别于照射前、照射后1,3,6个月各处死5只动物,处死前进行左肺肺泡灌洗。采用铜-镉还原法检测灌洗液中的NO含量,免疫组化法检测肺组织中iNOS的表达。结果:NO含量在照射后1个月明显升高,照射后3～6个月显著降低;在照射前及照射后3～6个月,肺间质细胞内几乎未见iNOS阳性表达;在照射后1个月,肺间质中iNOS表达阳性细胞明显增多。结论:NO可能是放射性肺纤维化形成过程中的一个独立影响因素,其含量的变化可能与iNOS蛋白活性改变有关。

Objective： To observe the dynamic change of nitric oxide （ NO ）content and the expression of inducible nitric oxide synthase （iNOS） during radiation-induced pulmonary fibrosis in rabbits. Methods： The left lungs of 20 rabbits were irradiated with 6 MV X-rays, with the radiation dose of 25 Gy. The rabbits were killed before and 1,3 ,and 6 months after the radiation ,respectively. Alveolar lavage of the left hmg was performed before the rabbits were killed,and the content of NO in the alveolar lavage fluid was measured by cadmium-copper reduction. The expression of iNOS in the lung was detected by immunohistochemical method. Results： The content of NO significantly increased 1 month after the radiation and significantly decreased from 3 to 6 months after the radiation. The number of pulmonary interstitial cells positive for iNOS increased remarkably 1 month after the radiation,but no expression of iNOS was found in the pulmonary interstitial cells before and 3 and 6 months after the radiation. Conclusion： NO may be an independent factor in the process of radiation-induced pulmonary fibrosis,and the change of NO content is correlated with the activity of iNOS.