目的 本研究旨在观察经皮电刺激对废用状态下肌肉的肌电及酶组织化学的影响.方法 用大鼠尾部悬吊法使大鼠下肢去负荷,以建立废用性肌萎缩模型.大鼠随机分为三组:下肢去负荷14 d组(Hu)、电刺激组(Hu+St)及正常对照组(Control).吊尾期间给予大鼠左侧下肢皮肤低频电刺激(2 Hz,20-25 V).采用电生理和酶组织化学技术观察腓肠肌肌电图,肌重及肌肉Na+-K+-ATP酶及Ca2+-ATP酶活性.结果 下肢去负荷14 d后大鼠腓肠肌肌重,Mmax,Hmax/Mmax,Na+-K+-ATP酶及Ca2+-ATP酶活性均明显降低(P<0.05).而在下肢去负荷期间给予大鼠左侧下肢电刺激后,以上指标与正常对照组比较均没有统计学差异(P>0.05).结论 以上结果 提示,经皮电刺激不仅可对抗废用肌肉的肌重下降,还对肌肉肌电、Na+-K+-ATP酶及Ca2+-ATP酶活性具有保护作用.%Objective To explore the effects of transcutaneous electric stimulation ( St ) on the electromyogram and enzymatic histochemistry of the disused muscle. Methods The disused muscle atrophy model was estahlished by the hindlimb unloading ( Hu ). Rats were randomly assigned to 14 d hindlimb unloading group ( Hu ) . electric stimulation group ( Hu + St ) and normal control group. The left hindlimh was transcutaneously given electric stimulation at a low frequency of 2 Hz with voltage of 20 - 25 V during the period of hindlimb unloading in Hu + St rats. Using electrophysiological and histochemical techniques, the electromyogram , muscular weight , Na+ -K+ -ATPase and Ca2+ -ATPase activities of gastrocnemius muscle were observed. Result.s After 14 d hindlimb unloading,wet weight,mean maximal motor response ( Mmax ), ratio of maximal Hoffmann reflex and Mmax ( Hmax/Mmax ) , Na+ -K+ -ATPase and Ca2 + -ATPase activities of gastrocnemius muscle were all significantly decreased ( P ＜0. 05 ). While all the above indices for Hu + St rats were not statistically different from those of the control rats ( P ＞0. 05 ). Conclusion The transcutaneous electric stimulation can not only counteract the decrease of muscle. wet weight,but also protect electrophysiology and enzymatic metabolism activities of disused muscle.
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