电刺激对失用性肌萎缩肌肉肌力与肌电影响的生物学效应

Biological effects of electrical stimulation on muscle strength and electromyogram in rats with muscle disuse atrophy

目的:建立大鼠失用性肌萎缩的动物模型,观察固定后不同时间电刺激治疗对模型鼠股四头肌肌力和诱导肌电图的影响。方法:实验于2003-09/2004-03在华南师范大学运动人体科学实验室进行。在预备性动物建模成功的基础上,将125只SD大鼠单纯随机分为5组(n=25):①正常对照组:不干预。②24h,1,2,3周电刺激组:均采用长腿石膏固定法,使大鼠膝关节固定,各组分别在固定后24h内,1,2,3周时进行电刺激治疗。电刺激采用T90-Ⅱ电脑电刺激肌肉力量训练器,波形为方波,电流强度为5mA,刺激时间为10min/d,隔天进行。分别于实验前和固定后1,2,3,4周各周末采集股四头肌肌力、诱导肌电图放电水平。结果:125只大鼠全部进入结果分析。①肌电图放电水平:正常对照组的在4周期间并无明显变化;其他各组均从第2周发生显著下降,至第4周,24h,1,2,3周电刺激组较正常对照组分别下降了21.26%,34.65%,45.67%,和55.12%,实施电刺激越早,降低幅度越小。②肌力:正常对照组的在4周期间并无明显变化;其他各组均从第2周发生显著下降,至第4周,24h,1,2,3周电刺激组较正常对照组分别下降了28.97%,53.10%,61.38%,和达66.90%,实施电刺激越早,降低幅度越小。结论:①大鼠的肌力和肌电图放电水平会随固定时间延长呈现逐步下降趋势,且下降的幅度随固定时间延长而加大。②电刺激并不能完全防止肌力和肌电图放电水平的下降,但可以有效缓解下降的速率。③在固定后电刺激治疗实施得越早,肌肉功能降低的速率越慢,降低的幅度越小。

AIM： To set up muscle disuse atrophy rat models and observe the effect of electrical stimulation （ES） on muscular strength of quadriceps femoris and electromyogram （EMG）. METHODS： The experiment was performed at the Sports Body Science Laboratory, South China Normal University from September 2003 to March 2004. On the basis of successful establishing model, totally 125 SD rats were randomly selected into five group （n=25）： ①normal control group： no intervention, ②4 experiment groups （hour 24, weeks 1, 2, 3 ES groups）： with disuse muscle atrophy （DMA） was modeled by the gypsum fixation of knee in rats. ES was performed after immobilization within 24 hours, 1, 2, 3 weeks, respectively in each group with T90-Ⅱ computer ES muscle strength training, square wave, 5 mA for 10 minutes in a day, once another day. Data of EMG and strength of quadriceps femoris were collected before experiment and every weekend after fixation, respectively. RESULTS： A total of 125 rats entered result analysis. ①Discharge level of EMG： There was no obvious change during the 4 weeks in the normal control group. It decreased markedly from the 2^nd week in other groups, till the 4^th week, it decreased by 21.26%, 34.65%, 45.67% and 55.12% in the hour 24, weeks 1, 2, 3 ES groups as compared with the normal control group, respectively. The earlier the ES, the small the decreased range was. ②Muscle strength： There was no obvious change during the 4 weeks in normal control group. It decreased markedly from the 2^nd week in other groups, till the 4s week, it decreased by 28.97%, 53.10%, 61.38% and 66.90% in the hour 24, weeks 1, 2, 3 ES groups as compared with the normal control group, respectively. The earlier the ES, the small the decreased range was. CONCLUSION： ①The muscle strength and EMG discharge decrease with the prolongation of immobilization duration, and the reduction becomes fast with the prolongation of immobilization duration. ②ES cannot fully prevent the decrease of muscle strength and EMG discharge, but can significantly delay the descendent speed. ③The earlier the ES performs, the slower the descendent speed of muscle function is and the smaller the decreased range is.