Institute of Sports Medicine Copenhagen, Bispebjerg Hospital, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark.
Scand J Med Sci Sports. 2011 Apr;21(2):215-23. doi: 10.1111/j.1600-0838.2009.01044.x.
Myostatin is a potent negative regulator of skeletal muscle mass, but its role in human skeletal muscle hypertrophy and atrophy is sparsely described. Muscle biopsies were obtained from young male subjects before and after 30 and 90 days of resistance training as well as after 3, 10, 30, 60 and 90 days of subsequent detraining. Myostatin mRNA increased significantly with detraining. We observed a 28 kDa myostatin immunoreactive protein, which, however, was also present in myostatin knock out mice skeletal muscle. As a novel finding we consistently detected a 10 kDa band, which may represent a mature myostatin monomer under reducing conditions or a novel, unknown myostatin form. Further, we observed a significant increase in this 10 kDa band after 3 days of detraining preceding the rapid type II fiber atrophy, in which almost half of the acquired fiber area was lost after only 10 days of detraining. Accordingly, an increase in the level of the 10 kDa protein is associated with rapid type II fiber atrophy, suggesting myostatin-mediated specific type II fiber atrophy, which in combination with our mRNA data support a role for myostatin in the negative regulation of adult human skeletal muscle mass.
肌肉生长抑制素是一种强有力的负调控骨骼肌质量的因子，但它在人类骨骼肌肥大和萎缩中的作用描述甚少。我们在年轻男性受试者进行 30 天和 90 天的抗阻训练前后以及随后的 3 天、10 天、30 天、60 天和 90 天的停训后获得了肌肉活检。肌肉生长抑制素 mRNA 在停训后显著增加。我们观察到了一种 28 kDa 的肌肉生长抑制素免疫反应性蛋白，但它也存在于肌肉生长抑制素敲除小鼠的骨骼肌中。作为一个新的发现，我们一致检测到一种 10 kDa 的条带，它可能代表还原条件下成熟的肌肉生长抑制素单体或一种新的、未知的肌肉生长抑制素形式。此外，我们观察到在停训后 3 天，即快速 II 型纤维萎缩之前，这种 10 kDa 条带显著增加，而在仅仅 10 天的停训后，几乎一半的获得的纤维面积丢失。因此，10 kDa 蛋白水平的增加与快速 II 型纤维萎缩有关，提示肌肉生长抑制素介导的特异性 II 型纤维萎缩，这与我们的 mRNA 数据一起支持肌肉生长抑制素在负调控成人骨骼肌质量中的作用。
