Aboudrar S, Sempore B, Koubi H, Dechaud H, Desplanches D
Unité de Recherche Associée 1341, Centre National de la Recherche Scientifique, Laboratoire de Physiologie, Faculté de Médecine de Lyon Grange Blanche, France.
J Appl Physiol (1985). 1993 Dec;75(6):2767-73. doi: 10.1152/jappl.1993.75.6.2767.
The purpose of this study was to investigate the effects of a glucocorticoid antagonist, RU-486, and of adrenalectomy (ADX) on rat skeletal muscle structural properties after 3, 7, and 14 days of hindlimb suspension (H). After H, a significant loss in muscle weight was observed as early as 3 days in soleus (SOL; -10%) and adductor longus (AL; -14%) muscles. In SOL, after only 7 days, a reduction (-14%) in type I fiber percent distribution occurred, accompanied by an increase (+129%) in intermediate type I fibers. Fiber type changes increased depending on the duration of H. In AL muscle, no change occurred after H in the fiber type composition despite a similar degree of muscle atrophy. Treatment with RU-486 or ADX significantly reduced the loss of SOL weight observed after 14 days (-42 and -44%, respectively, vs. -50% for H rats), delayed the SOL atrophy (from 3 to 7 days), and normalized the shift in fiber type distribution induced by H. In SOL, administration of RU-486 (but not ADX) partly prevented the reduction in size induced by H of all the fibers. In AL, neither treatment affected the extent of muscle atrophy, even though the reduction in type IIa fiber size was prevented by RU-486 but not by ADX after 14 days of suspension. ADX or RU-486 administration did not prevent the extensor digitorum longus weight loss observed after 14 days of suspension but allowed a recovery of its normal fiber type composition.(ABSTRACT TRUNCATED AT 250 WORDS)
本研究旨在探讨糖皮质激素拮抗剂RU - 486以及肾上腺切除术（ADX）对后肢悬吊（H）3天、7天和14天后大鼠骨骼肌结构特性的影响。H后，早在3天时，比目鱼肌（SOL；-10%）和长收肌（AL；-14%）就出现了显著的肌肉重量损失。在SOL中，仅7天后，I型纤维百分比分布就减少了（-14%），同时中间型I型纤维增加（+129%）。纤维类型变化随H持续时间增加。在AL肌肉中，尽管肌肉萎缩程度相似，但H后纤维类型组成未发生变化。用RU - 486或ADX治疗可显著减少14天后观察到的SOL重量损失（分别为-42%和-44%，而H组大鼠为-50%），延迟SOL萎缩（从3天延迟到7天），并使H诱导的纤维类型分布转变恢复正常。在SOL中，给予RU - 486（而非ADX）部分阻止了H引起的所有纤维大小减小。在AL中，两种治疗均未影响肌肉萎缩程度，尽管在悬吊14天后，RU - 486可防止IIa型纤维大小减小，而ADX则不能。给予ADX或RU - 486不能阻止悬吊14天后观察到的趾长伸肌重量减轻，但可使其恢复正常的纤维类型组成。（摘要截断于250字）
