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长期有氧运动对骨骼肌AR及mTOR下游信号表达的影响

发表时间:2014-09-15  浏览量:1827  下载量:698
全部作者: 汤春雪,曾凡星,楚璐雅
作者单位: 北京体育大学运动人体科学学院
摘 要: 目的:通过观察长期有氧运动干预后骨骼肌雄激素受体(androgen receptor,AR)、70 ku核糖体蛋白S6激酶(p70S6K)及真核翻译起始因子4E结合蛋白1(eIF4E-binding protein 1,4EBP1)信号表达在运动恢复期不同时程的变化特点,以期探讨在蛋白合成过程中AR与哺乳动物雷帕霉素靶蛋白(mammalian target of rapamycin,mTOR)信号通路之间发挥作用的联系,为运动促骨骼肌蛋白合成的内在分子机制提供更多的实验依据。方法:7周龄雄性SD大鼠30只,随机分为安静对照组和有氧运动组,其中有氧运动组又分为4个取材点组,每组6只。运动干预采用终强度为28 m/min,60 min的递增负荷跑台训练方案,每周训练5 d,休息2 d,共持续7周。采用Western blotting方法测定各组腓肠肌肌球蛋白重链(myosin heavy chain,MHC)蛋白表达,AR, p70S6K和4EBP1的磷酸化及蛋白表达。结果:运动组腓肠肌MHC呈现增长趋势,但与对照组相比无显著性差异(P>0.05);腓肠肌AR(Ser210)磷酸化表达在运动后6 h显著增加并达到峰值(P<0.05),而AR蛋白表达则在运动后12 h出现峰值(P<0.05);与对照组相比,运动组腓肠肌S6K(Thr389)磷酸化表达在运动后6 h显著增加(P<0.05),4EBP1(Thr37/46)磷酸化则在运动后即刻、6 h和12 h均出现非常显著的增加(P<0.01),且峰值点出现在运动后6 h;运动组S6K蛋白表达在运动后24 h显著下降(P<0.05),其余时间表达与对照组相比并无显著性差异(P>0.05),而4EBP1蛋白表达与对照组相比均无显著性差异(P>0.05)。结论:长期有氧运动可显著激活骨骼肌AR, p70S6K及4EBP1信号表达,且三者变化呈现平行趋势,提示AR与mTOR下游信号在骨骼肌蛋白合成过程中发挥了协同作用。
关 键 词: 运动生理学;哺乳动物雷帕霉素靶蛋白信号通路;Western blotting;雄激素受体;有氧运动
Title: Effects of long-term aerobic exercises on the expressions of AR and the downstream signals of mTOR in rat skeletal muscle
Author: TANG Chunxue, ZENG Fanxing, CHU Luya
Organization: Sport Science College, Beijing Sport University
Abstract: Objective: In this research, we built up an exercise protocol of long-term aerobic exercise, in order to observe the changing characteristics of androgen receptor (AR), ribosomal protein S6 kinase, 70 ku (p70S6K) and eIF4E-binding protein 1(4EBP1) signals and explore the interaction between AR and mammalian target of rapamycin (mTOR) signaling pathway during the process of protein synthesis, and to provide more experimental basis for the molecular mechanism of sports promoting protein synthesis in skeletal muscle. Methods: 30 male SD rats aged 7 weeks were randomly divided into 5 groups, 6 for each: group control and aerobic exercise groups with muscle being isolated at 4 different time points after the last exercise training. The rats were trained with increasing load of treadmill running which the final intensity was 28 m/min, 60 min. The training program lasted for 7 weeks with 2 days break each week. The protein levels of myosin heavy chain (MHC) expressions and both the total and the phosphorylated forms of AR, p70S6K and 4EBP1 were determined by Western blotting. Results: MHC in group exercise increased compared with the group control (P>0.05). The phosphorylation expression of AR(Ser210) increased significantly at 6 hours after exercise in the gastrocnemius (P<0.05), while the total amount of AR reached the peak of expressions at 12 hours after exercise (P<0.05). Compared to the group control, the long-term aerobic exercise significantly increased the phosphorylation expressions of both S6K(Thr389) at 6 hours (P<0.05) and 4EBP1(Thr37/46) at 0, 6, 12 hours after exercise (P<0.01) in gastrocnemius, and the peak of 4EBP1 phosphorylation expression was also at 6 hours after the last training. Also, the expressions of total S6K declined significantly at 24 hours after exercise (P<0.05), while the total 4EBP1 had no significant changing compared to control (P>0.05). Conclusion: Long-term aerobic exercise can significantly activate AR, p70S6K and 4EBP1 signals in skeletal muscle, and the parallel trend of these changes prompts that AR and mTOR downstream signals have played a synergy in the process of protein synthesis in the skeletal muscle.
Key words: sport physiology; mammalian target of rapamycin signaling pathway; Western blotting; androgen receptor; aerobic exercise
发表期数: 2014年9月第17期
引用格式: 汤春雪,曾凡星,楚璐雅. 长期有氧运动对骨骼肌AR及mTOR下游信号表达的影响[J]. 中国科技论文在线精品论文,2014,7(17):1772-1781.
 
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