Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.
Muscle Nerve. 2011 Jan;43(1):65-75. doi: 10.1002/mus.21831.
In humans, spinal cord injury (SCI) induces deleterious changes in skeletal muscle that may be prevented or reversed by electrical stimulation muscle training. The molecular mechanisms underlying muscle stimulation training remain unknown. We studied two unique SCI subjects whose right soleus received >6 years of training (30 minutes/day, 5 days/week). Training preserved torque, fatigue index, contractile speed, and cross-sectional area in the trained leg, but not the untrained leg. Training decreased 10 mRNAs required for fast-twitch contractions and mRNA that encodes for myostatin, an autocrine/paracrine hormone that inhibits muscle growth. Conversely, training increased 69 mRNAs that mediate the slow-twitch, oxidative phenotype, including PGC-1α, a transcriptional coactivator that inhibits muscle atrophy. When we discontinued right soleus training, training-induced effects diminished slowly, with some persisting for >6 months. Training of paralyzed muscle induces localized and long-lasting changes in skeletal muscle mRNA expression that improve muscle mass and function.
在人类中，脊髓损伤 (SCI) 会导致骨骼肌产生有害变化，这些变化可以通过电刺激肌肉训练来预防或逆转。肌肉刺激训练的分子机制尚不清楚。我们研究了两名独特的 SCI 受试者，他们的右腿比目鱼肌接受了超过 6 年的训练（每天 30 分钟，每周 5 天）。训练保留了训练腿的扭矩、疲劳指数、收缩速度和横截面积，但对未训练腿没有影响。训练降低了 10 种快速收缩所需的 mRNA 和编码肌肉生长抑制素的 mRNA，肌肉生长抑制素是一种自分泌/旁分泌激素，可抑制肌肉生长。相反，训练增加了 69 种调节慢收缩、氧化表型的 mRNA，包括 PGC-1α，一种转录共激活因子，可抑制肌肉萎缩。当我们停止右腿比目鱼肌训练时，训练引起的效应缓慢减弱，其中一些持续超过 6 个月。瘫痪肌肉的训练会导致骨骼肌 mRNA 表达产生局部和持久的变化，从而改善肌肉质量和功能。
