急性长时间运动对大鼠心肌线粒体NOS/NO,COX和HIF-1 mRNA表达的影响

Effects of a Bout of Strenuous Exercise on the Expression of Mitochondrial NOS/NO, COX and HIF-1 mRNA in Myocardial of Rats

目的:探讨急性长时间运动对大鼠心肌线粒体一氧化氮合酶/一氧化氮(NOS/NO)、细胞色素c氧化酶(COX)活性、COXⅣ亚基和低氧诱导因子(HIF-1)α亚基mRNA表达的影响。方法:23只8周龄的雌性SD大鼠,体重215±23g,随机分为对照组(7只)、运动即刻组(8只)和运动后4小时组(8只)。游泳时间平均为249±54min。运动后分别测定大鼠心肌线粒体NOS活力和NO含量、COX活性、COXⅣ和HIF-1αmRNA的表达。结果:对照组、运动即刻组和运动后4小时组NOS活力无显著差异(P>0.05);运动即刻组和运动后4小时组心肌线粒体NO含量低于对照组,有显著性差异(P<0.01);运动即刻组COX活性高于对照组,有显著性差异(P<0.01),运动后4小时略有下降,但仍高于对照组(P<0.05)。COXⅣ和HIF-1αmRNA表达3组之间无显著性差异。结果表明,急性长时间游泳运动大鼠心肌线粒体NOS活力相对稳定,但运动后即刻线粒体NO含量明显降低,COX活性明显增高,COXⅣ和HIF-1αmRNA表达无明显变化。结果提示,一次长时间运动后大鼠心肌线粒体呼吸链功能相对完好,该运动模型对COXⅣ和HIF-1αmRNA表达诱导作用不明显。

Objective To investigate the effect of a bout of strenuous swimming on mitochondrial NOS/NO,COX activities, mRNA expression of COXⅣ subunit and HIF-1α subunit in myocardium of rats. Methods Twenty-three eight-week old female SD rats, weighed averagely 215±23g, were randomly divided into three groups:control group, immediate group(tested immediately after prolonged burdening swimming),and 4-hour group(tested after 4-hour prolonged burdening swimming). The average swimming time was 249±54min. After swimming, myocardium was isolated from all three groups and then mtNOS activity and NO concentration in the mitochondria, COX activity and the change of COXⅣ and HIF-1α mRNA expression were determined. Results Statistic analysis showed that there was no significant discrepancy among control group, immediate group and 4-hour group in the activity of NOS (P>0.05). However, NO concentration decreased significantly immediately after exercise (P< 0.01), and increased in some extent four hours after exercise, while still lower than that in the control group. COX activity increased significantly immediately after exercise (P<0.01), and decreased four hours after exercise, while still higher than that in the control group (P>0.05). COXⅣ mRNA and HIF-1α mRNA expression remained unchanged among three groups. Conclusions The result indicates that after a bout of strenuous swimming, the function of mitochondrial respiratory chain in rat was comparatively in good condition, COXⅣ mRNA and HIF-1α mRNA expression in this animal model was not obvious. The biological significance of the obvious decrease in mitochondrial NO concentration after exercise needed further investigation.