肾脏缺血再灌注损伤后一氧化氮合酶的变化

目的　研究大鼠肾脏缺血再灌注损伤 (IRI)过程中一氧化氮合酶 (NOS)的变化规律。方法　制作SD大鼠单侧肾脏IRI动物模型 ,用同位素法测定正常及IRI肾组织的NOS活性 ;用Western印迹和逆转录PCR法分析eNOS和iNOS在IRI过程中蛋白和基因表达的变化。结果　单纯热缺血 1h对肾脏NOS活性无明显影响 ,再灌注30min后NOS活性即开始升高 ,2～ 6h到达高峰 ,持续到 6h ,此后迅速下降 ,2 4h降低到正常以下 ,2 1d时恢复至正常水平。Western印迹显示IRI早期eNOS蛋白表达升高 ,12h后开始逐步降低 ,3d后明显低于正常对照组 ,以后逐步恢复正常。iNOS的变化与eNOS明显不同 ,正常肾脏iNOS表达微弱 ,IRI可诱导iNOS表达 ,12h开始表达 ,并逐渐升高 ,3d后达到高峰 ,以后逐步恢复正常。RT PCR分析发现eNOS及iNOSmRNA的变化与其蛋白变化相一致。结论　单纯缺血并不引起NOS活性的明显变化 ,再灌注损伤使NOS的mRNA表达增加 ,酶的合成增多 ,活性增高。正常肾脏iNOS的表达微弱 ,IRI可诱导iNOSmRNA表达 ,使iNOS合成增加

Differential Changes of Nitric Oxide Synthesis in Renal Ischemia Reperfusion Injury

Purpose Nitric oxide synthase (NOS) plays important roles in a variety of physiological and pathological processes in the kidney.In this study,we investigated the expression of endothelial NOS (eNOS) and inducible NOS (iNOS)during ischemia-reperfusion injury (IRI) in rat kidneys. Methods IRI was induced by clamping the left renal artery for 1 hour followed by 1 h reperfusion.NOS activities of kidneys was assayed at various time points,NOS protein levels as well as NOS mRNA expression were determined by Western blot and RT?PCR methods respectively. Results eNOS activity,protein level and mRNA expression were all increased in early stage of IRI (2-6 h after reperfusion),and decreased after 3 days of IRI,and then gradually returned to basal level after 21 days.During this period,there was a significantly elevation of iNOS expression,and reached its peak level at 3 days after IRI,and then decreased to basal level. Conclusions Our results clearly demonstrate that differential expression of eNOS and iNOS in kidney during ischemia-reperfusion injury.Therefore,selective regulation of eNOS and iNOS expression may be therapeutically relevant in treating patients with renal ischemia-reperfusion injury.