Endurance training affects myosin heavy chain phenotype in regenerating fast-twitch muscle
Endurance training affects myosin heavy chain phenotype in regenerating fast-twitch muscle
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DOI：
10.1152/jappl.1996.81.6.2658
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发表时间：
1996-12-01
影响因子：
3.3
通讯作者：
DAlbis, A
中科院分区：
文献类型：
--
作者：
Bigard, XA;Janmot, C;DAlbis, A
本研究的目的是分析跑台训练（2小时/天，5天/周，30米/分钟，7%级，5周）的肌球蛋白重链（MHC）亚型的表达过程中和再生后的快速收缩白色肌肉[趾长伸肌（EDL）]的影响。将雄性Wistar大鼠随机分为久坐组（n = 10）和耐力训练组（ET; n = 10）。通过两次皮下注射蛇毒素诱导EDL肌肉变性和再生。诱导肌肉损伤后5天，动物进行为期5周的训练。证实了类似于毒液处理后40天，在来自久坐和ET大鼠的经处理的EDL肌肉中存在中央核。采用生物化学和免疫细胞化学相结合的方法检测了趾长伸肌中MHC表达的变化。与对侧非变性肌肉相比，ET大鼠再生趾长伸肌中I、IIa和IIx型MHC亚型的相对含量均显著升高（分别为146%，P < 0.05; 76%，P < 0.01; 87%，P < 0.01）。其升高对应于IIb型MHc相对浓度的降低（-36%，P < 0.01）。虽然I型肌球蛋白只占总肌球蛋白的3.2%，从ET组的再生肌肉的细胞化学分析表明，与慢MHC抗体的阳性染色的比例显着大于在对侧的再生肌肉。总的来说，这些结果表明，再生的EDL肌肉是敏感的耐力训练，并表明，在这些肌肉中观察到的MHC亚型的训练诱导的转变，从再生和重复运动的累加效应。
The aim of this study was to analyze the effects of treadmill training (2 h/day, 5 days/wk, 30 m/min, 7% grade for 5 wk) on the expression of myosin heavy chain (MHC) isoforms during and after regeneration of a fast-twitch white muscle [extensor digitorum longus (EDL)]. Male Wistar rats were randomly assigned to a sedentary (n = 10) or an endurance-trained (ET; n = 10) group. EDL muscle degeneration and regeneration were induced by two subcutaneous injections of a snake toxin. Five days after induction of muscle injury, animals were trained over a 5-wk period. It was verified that similar to 40 days after venom treatment, central nuclei were present in the treated EDL muscles from sedentary and ET rats. The changes in the expression of MHCs in EDL muscles were detected by using a combination of biochemical and immunocytochemical approaches. Compared with contralateral nondegenerated muscles, relative concentrations of types I, IIa, and IIx MHC isoforms in ET rats were greater in regenerated EDL muscles (146%, P < 0.05; 76%, P < 0.01; 87%, P < 0.01, respectively). Their elevation corresponded to a decrease in the relative concentration of type IIb MHc (-36%, P < 0.01). Although type I accounted for only 3.2% of total myosin in regenerated muscles from the ET group, the cytochemical analysis showed that the proportion of positive staining with the slow MHC antibody was markedly greater in regenerated muscles than in contralateral ones. Collectively, these results demonstrate that the regenerated EDL muscle is sensitive to endurance training and suggest that the training-induced shift in MHC isoforms observed in these muscles resulted from an additive effect of regeneration and repeated exercise.