一氧化氮和过氧亚硝基阴离子在肠缺血再灌注致肺损伤中的作用

EFFECTS OF NITRIC OXIDE AND PEROXYNITRITE ANION ON LUNG INJURY INDUCED BY INTESTINAL ISCHEMIA-REPERFUSION IN RATS

目的观察肠缺血再灌注 (ischemia reperfusion ,I/R)致肺损伤时肺组织中一氧化氮 (nitricoxide ,NO)及过氧亚硝基阴离子 (peroxynitriteanion ,ONOO-)的变化及作用。方法夹闭大鼠肠系膜上动脉造成肠缺血模型 ,测定假手术组、缺血再灌注组、假手术 +氨基胍及缺血再灌注 +氨基胍组的肺组织学变化以及肺组织匀浆中超氧化物歧化酶 (superoxidedismutase,SOD)活性和丙二醛 (malondialdehyde,MDA)、NO-2 /NO-3 含量变化 ;应用免疫组化方法测定肺组织中诱导型一氧化氮合酶 (inducibleNOsynthase ,iNOS)及ONOO-体内生成标志物硝基酪氨酸(nitrotyrosine ,NT)的变化。结果肠I/R后肺组织出现水肿、出血及中性粒细胞浸润征象。与假手术组相比 ,缺血再灌注组肺组织MDA和NO-2 /NO-3 的含量显著增高 (P <0 .0 5 ) ,SOD活性则显著降低 (P <0 .0 5 ) ,且出现大量iNOS及NT阳性信号。缺血再灌注组 +AG组肺组织MDA和NO-2 /NO-3 的含量显著低于缺血再灌注组 (P <0 .0 5 ) ,SOD活性显著高于缺血再灌注组 (P <0 .0 5 ) ,NT阳性信号减弱。结论肠I/R致肺损伤时肺组织中有大量NO和ONOO-产生并参与介导了此种肺损伤的发生。

ObjectiveTo evaluate effects of nitric oxide(NO) and peroxynitrite anion (ONOO -) on lung injury following intestinal ischemia-reperfusion(I/R) in rats.MethodsA rat model of intestinal ischemia was made by clamping superior mesenteric artery. The animals were divided into four groups: sham operation (SHAM), 2 h ischemia followed by 2 h reperfusion (I/R), sham operation pretreated with aminoguanidine (AG) - an inhibitor of inducible NO synthase (iNOS) (SHAM +AG) and I/R+AG. The contents of malondialdehyde (MDA), NO - 2/NO - 3, activities of superoxide dismutase (SOD) and morphological changes in the lung were examined. Immunohistochemical staining was used to determine the activity of iNOS and nitrotyrosine(NT)-a specific 'footprint' of peroxynitrite. ResultsThe morphology revealed evidence for lung edema, hemorrhage and polymorphonuclear sequestration in the lungs after intestinal I/R. Compared with SHAM, the contents of MDA and NO - 2/NO - 3 increased significantly (P< 0.05) and the activities of SOD decreased markedly (P< 0.05) in the I/R group. Increased positive staining of iNOS and NT was found in the lungs in the I/R group. Compared with I/R group, the contents of MDA and NO - 2/NO - 3 decreased significantly (P< 0.05) and the activities of SOD increased markedly (P< 0.05), while NT staining was decreased in the I/R+AG group.ConclusionNO and ONOO - are increased in the lungs after intestinal I/R, which are involved in oxidant-mediated lung injury following intestinal I/R.