Shah S B, Peters D, Jordan K A, Milner D J, Fridén J, Capetanaki Y, Lieber R L
Department of Orthopaedics, Biomedical Sciences Graduate Group, Veterans Affairs and University of California Medical Centers, San Diego, CA 92161, USA.
J Exp Biol. 2001 May;204(Pt 10):1703-10. doi: 10.1242/jeb.204.10.1703.
The serial sarcomere number of skeletal muscle changes in response to chronic length perturbation. The role of the intermediate filament desmin in regulating these changes was investigated by comparing the architectural adaptations of the tibialis anterior, extensor digitorum longus (EDL) and soleus from wild-type mice with those of homozygous desmin knockout mice after hindlimb immobilization. After 28 days, serial sarcomere number increased significantly in the lengthened wild-type tibialis anterior (by approximately 9%) and EDL (by approximately 17%). Surprisingly, muscles from desmin knockout mice also experienced significant serial remodeling, with the serial sarcomere number of the tibialis anterior increasing by approximately 10% and that of the EDL by approximately 27%. A consistent result was observed in the shortened soleus: a significant decrease in sarcomere number was observed in the muscles from both wild-type (approximately 26%) and knockout (approximately 12%) mice. Thus, although desmin is not essential for sarcomerogenesis or sarcomere subtraction in mouse hindlimb muscles, the results do suggest subtle differences in the nature of sarcomere number adaptation. We speculate that desmin may play a role in regulating the optimal arrangement of sarcomeres within the muscle or in sensing the magnitude of the immobilization effect itself.
骨骼肌的连续肌节数量会因慢性长度扰动而发生变化。通过比较野生型小鼠和纯合结蛋白基因敲除小鼠后肢固定后胫骨前肌、趾长伸肌（EDL）和比目鱼肌的结构适应性，研究了中间丝结蛋白在调节这些变化中的作用。28天后，野生型小鼠拉长的胫骨前肌（增加约9%）和EDL（增加约17%）的连续肌节数量显著增加。令人惊讶的是，结蛋白基因敲除小鼠的肌肉也经历了显著的连续重塑，胫骨前肌的连续肌节数量增加了约10%，EDL增加了约27%。在缩短的比目鱼肌中观察到了一致的结果：野生型（约26%）和基因敲除（约12%）小鼠的肌肉中肌节数量均显著减少。因此，尽管结蛋白对于小鼠后肢肌肉的肌节生成或肌节减少并非必不可少，但结果确实表明在肌节数量适应的性质上存在细微差异。我们推测，结蛋白可能在调节肌节在肌肉内的最佳排列或感知固定效应本身的大小方面发挥作用。
