Susceptibility to sarcomere injury induced by single stretches of maximally activated muscles of mdx mice
Susceptibility to sarcomere injury induced by single stretches of maximally activated muscles of mdx mice
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DOI：
10.1152/japplphysiol.00587.2003
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发表时间：
2004-02-01
影响因子：
3.3
通讯作者：
Brooks, SV
中科院分区：
文献类型：
--
作者：
Consolino, CM;Brooks, SV
目的是研究肌节的机械损伤对营养不良的肌纤维对收缩诱导的损伤的更大易感性的贡献。单次牵张为研究引起收缩性损伤的力学因素提供了一种有效的方法。我们假设，在单次拉伸后，mdx小鼠肌肉的等长收缩力的缺陷将大于C57 BL/10小鼠，而所有肌肉的膜损伤将是最小的。在用Avertin（三溴乙醇）麻醉下去除小鼠的趾长伸肌（EDL）和比目鱼肌。在体外最大等长收缩的平台期间，通过20 - 60%纤维长度的单应变拉伸肌肉。1分钟后重新测量等长力，然后将肌肉在Procion橙子染料中孵育以鉴定具有膜损伤的纤维。与C57 BL/10小鼠相比，mdx的EDL肌肉在1分钟时的力缺陷大2至3倍，而mdx和C57 BL/10小鼠的比目鱼肌之间没有观察到显著差异。对于所有的肌肉，膜损伤是最小的，并且对于任一品系的小鼠，单次拉伸都没有显著增加。这些数据支持肌营养不良蛋白维持肌节稳定性在EDL肌肉中的关键作用，而比目鱼肌保留能力，在肌营养不良蛋白的情况下，与对照肌肉没有不同，以抵抗肌节损伤。
The purpose was to investigate the contribution of mechanical damage to sarcomeres to the greater susceptibility of dystrophic muscle fibers to contraction- induced injury. Single stretches provide an effective method for studying mechanical factors that contribute to the initiation of contraction- induced injury. We hypothesized that, after single stretches, the deficits in isometric force would be greater for muscles of mdx than C57BL/10 mice, whereas membrane damage would be minimal for all muscles. Extensor digitorum longus (EDL) and soleus muscles of mice were removed under anesthesia with Avertin ( tribromoethanol). During the plateau of a maximum isometric contraction in vitro, muscles were stretched through single strains of 20 - 60% fiber length. Isometric force was remeasured 1 min later, and muscles were then incubated in procion orange dye to identify fibers with membrane damage. Force deficits at 1 min were two- to threefold greater for EDL muscles of mdx compared with C57BL/10 mice, whereas no significant differences were observed between soleus muscles of mdx and C57BL/10 mice. For all muscles, membrane damage was minimal and not significantly increased by single stretches for either strain of mice. These data support a critical role of dystrophin maintaining sarcomere stability in EDL muscles, whereas soleus muscles retain abilities, in the absence of dystrophin, not different from control muscles to resist sarcomere damage.