Heat stress facilitates the recovery of atrophied soleus muscle in rat
Heat stress facilitates the recovery of atrophied soleus muscle in rat
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DOI：
10.2170/jjphysiol.54.285
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发表时间：
2004-06-01
期刊：
影响因子：
--
通讯作者：
Yoshioka, T
中科院分区：
文献类型：
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作者：
Goto, K;Honda, M;Yoshioka, T
本文研究了热应激对大鼠比目鱼肌萎缩后恢复的影响。10周龄雄性Wistar大鼠随机分为笼内对照组（CC）和后肢悬吊5 d组（HS）。HS组中的一半大鼠在后肢悬吊后立即在恒温箱中暴露于热应激（41 ℃ 60 min）（HS-H），另一组大鼠在10天的截肢恢复之前不热应激（HS-C）。一组笼内对照大鼠（CH）也暴露于类似的热。在四个时间点解剖比目鱼肌，即，在悬浮（或热应激）后立即和恢复后3、5和10天（每组在每个时间点n = 8）。HS-C组比目鱼肌全肌绝对湿重、水分和蛋白质含量与CC组相近，分别比CC组低36、27和8 mg（p < 0.05）。因此，水和蛋白质损失对肌肉重量下降的贡献百分比分别为75%和22%。虽然水含量以及肌肉重量在3天内升高，但蛋白质的增加被延迟。即使在对照组中，恢复前的热暴露也加速了蛋白质含量的增加。这些现象与72 kD热休克蛋白（HSP 72）含量密切相关。提示后肢去负荷后热应激促进了大鼠比目鱼肌萎缩的恢复，其机制可能与HSP 72蛋白代谢有关。数据还表明，热和机械应力的组合比单独的热或机械应力诱发更大和持久的HSP 72反应。
Effects of heat stress on the recovery of atrophied soleus muscle were studied in rats. Ten-week-old male Wistar rats were randomly divided into cage control (CC) and 5-day hindlimb suspension group (HS). The half of the rats in group HS was exposed to heat stress (41 degreesC for 60 min) in an incubator immediately after the hindlimb suspension (HS-H) and the other group of rats was not heat stressed (HS-C) prior to 10 days of ambulation recovery. One group of cage control rats (CH) was also exposed to heat similarly. The soleus muscles were dissected at four time points, i.e., immediately after the suspension (or heat stress), and 3, 5, and 10 days after the recovery (n = 8 per group at each time point). The absolute wet weight and water and protein content of whole soleus muscle in group HS-C were similar to36, 27, and 8 mg less than CC (p < 0.05). Thus, the percentage contribution of water and protein loss to the decrease in muscle weight was 75 and 22%, respectively. Although water content, as well as muscle weight, was elevated within 3 days, the increase of protein was delayed. Heat exposure prior to recovery accelerated the increase in protein content even in the control group. These phenomena were closely associated with 72-kD heat shock protein (HSP72) content. It is suggested that heat stress applied at the end of hindlimb unloading facilitated the recovery of atrophied soleus muscle of rat, through possibly HSP72-related events of protein metabolism. The data also indicated that the combination of heat and mechanical stress evoked larger and long lasting HSP72 response than does heat or mechanical stress alone.