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目的:探讨不同运动方式对后肢固定大鼠腓肠肌湿重比、单收缩最大张力、肌肉生长抑制素(GDF-8)mRNA表达的影响。方法:2月龄雄性SD大鼠随机分为对照组、模型组、游泳组、跑台组和自然恢复组,除对照组外,其他各组大鼠右后肢用可塑性石膏固定4周,模型组大鼠于右后肢固定4周后处死、取材;游泳组、跑台组、自然恢复组解除固定后分别再进行3周小强度运动或笼养后处死、取材。测定腓肠肌单收缩最大张力,荧光定量PCR方法测定腓肠肌GDF-8mRNA表达。结果:4周后肢固定大鼠的体重、腓肠肌固定侧肌湿重/对侧肌湿重、腓肠肌单收缩最大张力显著降低,腓肠肌GDF-8mRNA表达显著升高;经过3周小强度游泳、跑台运动和自然恢复,游泳组、跑台组的固定侧肌湿重/对侧肌湿重、腓肠肌单收缩最大张力高于自然恢复组,但无统计学意义;跑台组腓肠肌GDF-8mRNA表达显著低于自然恢复组。结果提示:4周后肢固定可造成大鼠废用性肌萎缩,3周小强度游泳、跑台运动对废用性肌萎缩的恢复作用有略优于自然恢复的趋势。
OBJECTIVE: To investigate the effects of different exercise modes on the ratio of wet weight to muscle weight, maximum systolic pressure and the expression of myostatin (GDF-8) in the fixed hindlimb of rats. Methods: Two-month-old male Sprague-Dawley rats were randomly divided into control group, model group, swimming group, treadmill group and spontaneous recovery group. Except the control group, the right hind limbs of rats in each group were fixed for 4 weeks with plastic plaster. The rats were sacrificed in the right hind limb for 4 weeks and then sacrificed. The swimming group, treadmill group and spontaneous recovery group were sacrificed after 3 weeks of low-intensity exercise or cage catching. The maximal unidirectional systolic pressure of the gastrocnemius muscle was measured. The expression of GDF-8 mRNA in the gastrocnemius muscle was detected by fluorescence quantitative PCR. Results: After 4 weeks, the weight of the fixed limbs, the wet weight of the fixed side of the gastrocnemius muscle and the wet weight of the contralateral muscle and the maximum tension of gastrocnemius were significantly decreased, and the expression of GDF-8 mRNA in the gastrocnemius muscle increased significantly. After 3 weeks of low intensity swimming, Exercise and spontaneous recovery, swimming group, treadmill wet weight of fixed side / contralateral muscle wet weight, gastrocnemius single contraction maximum tension higher than the natural recovery group, but not statistically significant; treadmill gastrocnemius muscle GDF-8mRNA expression was significant Lower than the natural recovery group. The results suggest that 4-week hindlimb fixation can cause atrophy in rats and small-intensity swimming for 3 weeks. Treadmill exercise has a slightly better recovery from disuse atrophy than natural recovery.