心脏缺血再灌注损伤后一氧化氮合酶的变化

目的:研究大鼠心脏缺血再灌注损伤(IRI)过程中一氧化氮合酶(NOS)的变化规律及其作用.方法:制作SD大鼠心脏IRI动物模型,用同位素法测定正常及IRI心组织的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:心脏eNOS活性、蛋白和mRNA表达水平,在缺血再灌注2～6 h后均增高,3天后降低,21天后逐渐恢复到正常水平.心脏iNOS活性、蛋白和mRNA表达水平,在缺血再灌注12 h后开始表达,3天达高峰,然后逐渐降至正常水平.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.

Changes of nitric oxide synthesis in cardiac ischemia reperfusion injury

AIM: To investigate the expression and function of endothelial nitric oxide synthase (eNOS) and inducible NOS (iNOS) during ischemia-reperfusion injury (IRI) in rat hearts. METHODS: IRI was induced by clamping the left anterior descending (LAD) of coronary artery for 1h, followed by reperfusion. Nitric oxide synthase (NOS) activities of hearts was assayed at various time points and 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 all increased after 2-6 h of IRI and decreased after 3 d of IRI and then gradually returned to basal level after 21 d. iNOS was expressed after 12 h of IRI and reached the peak level at day 3 after IRI and then decreased to basal level. CONCLUSION: The expression of iNOS is high while that of eNOS is low during cardiac ischemia-reperfusion injury. Proper regulation of eNOS and iNOS expression may be therapeutically helpful in treating patients with cardiac ischemia-reperfusion injury.