Brown M, Hasser E M
School of Medicine, Washington University, St. Louis, MO, USA.
Arch Phys Med Rehabil. 1995 Jun;76(6):541-6. doi: 10.1016/s0003-9993(95)80508-7.
The detrimental consequences of bed rest include a rapid loss of muscle mass and strength. Yet, the utility of treatment to offset the effects of bed rest has not been well established. It was the purpose of this study to examine the effects of therapeutic intervention on simulated bed rest in rats. Simulated bed rest was accomplished by unweighting the hindlimbs of rats for 2 weeks via a suspension apparatus attached to the tail and midriff. Weight-bearing (eg, standing, walking) effects on hindlimb unweighting (HLU) were investigated under three conditions: (1) 1 hour of weight bearing per day during HLU; (2) a week of natural cage recovery after HLU; and (3) a combination of 1 hour of weight bearing per day during HLU and a week of recovery after HLU. Muscle contractile function and fiber atrophy were examined in the soleus (SOL), a postural muscle, and the extensor digitorum longus (EDL), a nonpostural muscle. The unweighted SOL showed a 37% loss in wet weight and a 61% decline in peak tetanic tension (P0). The SOL in rats allowed 1 hour of weight bearing per day lost 22% of its mass and 38% of its P0, a 38% attenuation. One week of cage recovery after HLU resulted in a SOL wet weight that was 26% less and P0 that was 42% less than controls. Animals that received the combination of 1 hour of weight bearing per day and 1 week of cage activity nearly recovered muscle mass, but P0 still was 19% less than controls. The EDL was much less affected by HLU than the SOL.(ABSTRACT TRUNCATED AT 250 WORDS)
卧床休息的有害后果包括肌肉质量和力量迅速丧失。然而，抵消卧床休息影响的治疗方法的效用尚未得到充分证实。本研究的目的是检验治疗性干预对大鼠模拟卧床休息的影响。通过将连接在大鼠尾巴和腹部的悬吊装置使大鼠后肢失重2周来实现模拟卧床休息。在三种条件下研究负重（如站立、行走）对后肢失重（HLU）的影响：（1）在HLU期间每天负重1小时；（2）HLU后进行一周的自然笼内恢复；（3）HLU期间每天负重1小时与HLU后一周恢复相结合。在比目鱼肌（SOL，一种姿势肌）和趾长伸肌（EDL，一种非姿势肌）中检测肌肉收缩功能和纤维萎缩情况。失重的SOL湿重减少37%，强直收缩峰值张力（P0）下降61%。每天允许负重1小时的大鼠的SOL质量损失22%，P0损失38%，衰减38%。HLU后一周的笼内恢复导致SOL湿重比对照组少26%，P0比对照组少42%。每天接受1小时负重和1周笼内活动相结合的动物的肌肉质量几乎恢复，但P0仍比对照组少19%。EDL受HLU的影响比SOL小得多。（摘要截断于250字）
