【摘要】 背景:耐力运动对骨骼肌线粒体生成影响的研究多采用中小强度,长期大强度对其有何影响还不清楚,这种影响是否涉及5’-一磷酸腺苷激活的蛋白激酶(AMPK)、沉默信息调节因子2相关酶1(SIRT1)等调节线粒体生成的信号分子也未见报道。目的:观察AMPK/SIRT1信号级联在7周不同强度耐力运动中对骨骼肌线粒体生物合成的影响。方法:42只雄性SD大鼠分为安静组、中等强度运动组和大强度运动组。运动负荷为中等强度组28 m/min,60 min/d、大强度组38 m/min,60 min/d,每周运动5 d,休息2 d,共7周。运动组动物分别在运动后即刻、6 h和24 h取材。荧光定量PCR检测骨骼肌PGC-1α、SIRT1基因表达,Western blot测定P-AMPK、SIRT1蛋白表达。结果与结论:①中等强度运动后即刻、6 h、24 h,骨骼肌PGC-1αmR NA表达分别为安静组的362%(P<0.01)、657%(P<0.01)、116%,P-AMPK蛋白表达分别为安静组的112%、163%(P<0.05)、129%(P<0.05),SIRT1蛋白和mR NA表达分别为安静组的55%(P<0.05)、86%、103%和109%、155%(P<0.05)、132%(P<0.05)。②大强度运动后即刻、6 h、24 h,骨骼肌PGC-1αmR NA表达分别为安静组的274%(P<0.01)、130%(P<0.05)、68%(P<0.05),P-AMPK蛋白表达分别为安静组的235%(P<0.01)、166%(P<0.05)、160%(P<0.05),SIRT1蛋白和mR NA表达分别为安静组的199%(P<0.01)、166%(P<0.05)、164%(P<0.05)和255%(P<0.01)、292%(P<0.01)、122%。结果表明:①7周中等强度耐力运动显著增加骨骼肌PGC-1α基因表达,其机制可能涉及AMPK/SIRT1信号级联。②7周大强度耐力运动造成骨骼肌PGC-1α基因表达在运动后24 h时被抑制,这一过程是以非AMPK/SIRT1信号级联依赖性方式进行的。更多还原

【Abstract】 BACKGROUND: There are many reports on the effects of low-to-moderate intensity endurance exercise on mitochondrial biogenesis in the skeletal muscle,but there is no understanding about the high-intensity endurance exercise. It has not been reported whether the high-intensity endurance exercise influence the mitochondrial biogenesis in the skeletal muscle through 5′-adenosine monophosphate-activated protein kinase(AMPK)/silent information regulator factor 2 related enzyme 1(SIRT1) signal molecules. OBJECTIVE: To investigate the effect of AMPK/SIRT1 signaling cascade on the mitochondrial biogenesis in the skeletal muscle during different intensities of endurance exercises. METHODS: Forty-two male Sprague-Dawley rats were randomly divided into sedentary group,moderate-intensity exercise group and high-intensity exercise group. Moderate-intensity exercise load was 28 m/min,60 min/d;high-intensity exercise load was 38 m/min,60 min/d. In both exercise groups,the rats had 5 days of exercise and 2 days of rest within 1 week,and the exercise lasted for totally 7 weeks. The animals of exercise groups were killed immediately,6 hours and 24 hours after exercise. Quantitative PCR was used to detect peroxisome proliferators γ activated receptor coativator-1α(PGC-1α) and SIRT1 gene expression,and western blot to detect phosphorylated-AMPK(P-AMPK) and SIRT1 protein expression. RESULTS AND CONCLUSION:(1) Immediately,6 hours,24 hours after moderate-intensity exercise,PGC-1α m RNA expression in the skeletal muscle was 362%(P < 0.01),675%(P < 0.01) and 116% of that in the sedentary group,P-AMPK protein expression was 112%,165%(P < 0.05),129%(P < 0.05) of that in the sedentary group,the expressions of SIRT1 protein and m RNA were 55%(P < 0.05),86%,103% and 109%(P < 0.05),155%,132%(P < 0.05) of those in the the sedentary group,respectively.(2) Immediately,6 hours,24 hours after high-intensity exercise,PGC-1α m RNA expression in the skeletal muscle was 274%(P < 0.01),130%(P < 0.05),68%(P < 0.05) of that in the sedentary group,the expression of P-AMPK protein was 235%(P < 0.01),166%(P < 0.05),160%(P < 0.05) of that in the sedentary group,the expressions of SIRT1 protein and m RNA were 199%(P < 0.01),166%(P < 0.05),164%(P < 0.05) and 255%(P < 0.01),292%(P < 0.01),122% of those in the sedentary group,respectively. These findings indicate that(1) 7 weeks of moderate-intensity endurance exercise significantly increased PGC-1α gene expression in the skeletal muscle,and its mechanism may involve AMPK/SIRT1 signaling cascade;(2) 7 weeks of high-intensity endurance exercise significantly inhibited PGC-1α gene expression at 24 hours after exercise,and this process was carried out in an AMPK/SIRT1 signal cascade independent manner.更多还原