大运动量和减量训练对心肌mTOR和下游信号蛋白4E-BP1的影响

The Effects of Heavy Volume Training and Decremental Load Training on mTOR and 4E-BP1

目的:探讨大运动量和减量训练对心肌哺乳动物雷帕霉素靶蛋白(m TOR)和下游信号通路的影响。方法:72只雄性SD大鼠经过1周适应性训练后,随机分为8组:3周安静对照组、3周大运动量训练组、3天对照组、3天减量训练组、6天对照组、6天减量训练组、2周对照组和2周减量训练组。3周大运动量训练采用上坡跑,在跑台上以中等强度(20 m/min,坡度10%)和大强度(26 m/min,坡度10%)交替进行,运动时间逐渐延长,由60 min增加到120 min。大运动量训练期间,每周训练6天,周1休息,共训练3周。3周大运动量训练后进行减量训练,运动强度保持不变,仍然是中等强度和大强度交替进行,但运动时间逐渐减少,由60min减少到20 min。减量的速度为阶梯式的。减量训练分为3天、6天和2周的减量训练。安静对照组在安静饲养相应天数后,各运动训练组在末次运动后12小时,麻醉取血后取左心室肌。制备心肌组织匀浆后,用Western blotting方法测定m TOR、真核生物翻译起始因子4E结合蛋白1(4E-BP1)的蛋白表达和磷酸化。结果:3周大运动量训练后进行3天减量训练,心肌m TOR(Ser2448)磷酸化显著增加。3周大运动量训练后,心肌m TOR(Ser2448)磷酸化/m TOR显著降低(P<0.05)。而3天减量训练后,心肌m TOR(Ser2448)磷酸化/m TOR显著升高(P<0.05)。3周大运动量训练和减量训练后,心肌4E-BP1和4E-BP1(Thr37/46)磷酸化无显著变化(P>0.05)。结论:减量训练能引起心肌m TOR激活,对心脏有利。

Objectives To investigate mTOR and 4E-BPI. Methods 72 SD the effects of heavy volume training rats after adaptability training were and decremental load training on divided randomly into following groups：3-week heavy volume training group and its sedentary control group,3-day heavy volume training group and its sedentary control group, 3-day decremental load training group and its sedentary control group, 6-day decremental load training group and its sedentary control group,and 2-week decremental load training group and its sedentary control group. Moderate intensity （20 m/min, 10% grade）and high intensity （26 m/min, 10% grade）were adopted alternately for 3-week heavy volume training group,from 60 min per day increased to 120 min per day,6 day per week for 3 weeks. Thereafter,the training time decreased gradually from 60 min to 20min within 3 days,6 days and 2 weeks,respectively. Rats in each group 12 hours after the last training were scarified and their left ventricles were sampled for determination of mTOR and 4E-BP1 protein expression. Results mTOR （Ser2448） phosphorylation increased significantly after 3-day decrement of training time in 3-week heavy volume training group,while mTOR phosphorylation/mTOR decreased significantly （P 〈 0.05）. Conclusions 3-day decrement of training after heavy volume training resulted in mTOR activation in cardiac muscle.