Baker J H, Matsumoto D E
Department of Anatomy, Howard University College of Medicine 20059.
Muscle Nerve. 1988 Mar;11(3):231-44. doi: 10.1002/mus.880110308.
This study determined the morphological changes and adaptations that occur following immobilization of rat soleus and gastrocnemius muscles when the ankle joint is placed in complete plantar flexion for 2, 5, 7, 14, 21, and 28 days by means of plaster casts. Previous studies of such shortened muscles have shown that the number of sarcomeres in series is reduced, but how the sarcomeres are reduced has not been determined. We observed that the fibers in the mid-belly region of the muscles demonstrated a progressive degenerative process over the first few weeks. Myofibrils across the entire width of the affected fibers underwent dissolution. However, by 4 weeks new myofibrils were being formed, and sarcomere lengths appeared normal. Portions of the fibers near the tendon underwent segmental necrosis. These findings are similar to the response of the soleus and gastrocnemius muscles to tenotomy and are clinically relevant to orthopedic procedures that maintain muscles in shortened conditions for prolonged periods.
本研究通过石膏固定，将大鼠比目鱼肌和腓肠肌的踝关节完全跖屈2、5、7、14、21和28天，以确定固定后发生的形态学变化和适应性。此前对这种缩短肌肉的研究表明，串联肌节的数量减少了，但肌节是如何减少的尚未确定。我们观察到，在最初几周，肌肉中腹部区域的纤维呈现出进行性退化过程。受影响纤维整个宽度上的肌原纤维发生溶解。然而，到4周时，新的肌原纤维开始形成，肌节长度看起来正常。靠近肌腱的部分纤维发生节段性坏死。这些发现与比目鱼肌和腓肠肌对肌腱切断术的反应相似，并且在临床上与长时间使肌肉处于缩短状态的骨科手术相关。
