Is limb immobilization a model of muscle disuse?
Is limb immobilization a model of muscle disuse?
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肢体固定是肌肉废用的模型吗？
DOI：
10.1016/0014-4886(83)90011-0
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发表时间：
1983
影响因子：
5.3
通讯作者：
Edgerton,VR
中科院分区：
文献类型：
--
作者：
Fournier,M;Roy,RR;Perham,H;Simard,CP;Edgerton,VR
肢体固定常被用作骨骼肌废用性萎缩的模型。因为萎缩的程度在某种程度上取决于肌肉固定的长度，所以关于不同关节位置固定对慢速和快速肌肉电活动的影响的信息应该有助于更好地理解“使用-废弃”在确定萎缩程度方面的作用。采用双极记录电极长期植入成年雌性大鼠比目鱼肌（SOL）和腓肠肌内侧肌（MG）。后肢两侧用外部支架固定，使肌肉固定在缩短、中立或延长的位置。电极植入后3、9天，固定后7、17、28天，每小时15分钟，连续24小时同时记录SOL和MG的肌电图。28 d后，短位和中立位的肌肉重量显著下降（P< 0.05），而长位的肌肉重量则无显著下降。24 h综合肌电图（IEMG）显示，无约束大鼠的SOL比MG更活跃，刺激后活动下降幅度最大。短位固定28 d后，SOL和MG的IEMG分别显著降低了77%和50% （P< 0.05）。固定在中性位置的SOL的IEMG下降了50%，而MG则没有变化。SOL或MG固定在加长位置时，IEMG无明显变化。这些数据表明肌电图与肌肉类型和固定时间有关。此外，萎缩程度似乎与IEMG的变化没有密切关系，这表明肢体固定不一定是“废用”的模型。
Limb immobilization is often used as a model of disuse-atrophy of skeletal muscle. Because the degree of atrophy is somewhat dependent on the length at which the muscle is immobilized, information regarding the effect of immobilization at various joint positions on the electrical activity of slow and fast muscles should provide a better understanding of the role of “use-disuse” in determining the degree of atrophy. In this study, the soleus muscle (SOL) and medial gastrocnemius muscle (MG) of adult female rats were chronically implanted with bipolar recording electrodes. The hind limbs were immobilized bilaterally using an external brace such that the muscles were fixed in a shortened, neutral, or lengthened position. Electromyograms (EMGs) of the SOL and MG were recorded simultaneously during a 15-min period each hour for 24 consecutive hours 3 and 9 days after electrode implantation, and 7, 17, and 28 days after immobilization. The weights of both muscles decreased significantly (P< 0.05) when fixed in a shortened or neutral, but not in a lengthened position after 28 days. As indicated by the 24-h integrated EMG (IEMG), the SOL, which was more active than the MG in unrestrained rats, showed the greatest decrease in postimmobilization activity. After 28 days of immobilization in a shortened position, the IEMG of the SOL and MG was significantly reduced (P< 0.05) by 77 and 50%, respectively. The IEMG of the SOL immobilized in a neutral position decreased 50% whereas no change was seen in the MG. There was no significant change in the IEMG for the SOL or MG fixed in a lengthened position. These data suggest that the EMG was dependent on the type of muscle and the length of fixation. Furthermore, it appeared that the degree of atrophy was not related closely to changes in the IEMG suggesting that limb immobilization was not necessarily a model of “disuse”.