Mokrusch T, Engelhardt A, Eichhorn K F, Prischenk G, Prischenk H, Sack G, Neundörfer B
Neurological Clinic, University of Erlangen-Nürnberg, Federal Republic of Germany.
J Neurol. 1990 Feb;237(1):29-34. doi: 10.1007/BF00319664.
The efficacy of electrical stimulation on a chronically denervated muscle depends on stimulus parameters, which have an important influence on the development of atrophy. Stimulus frequency and/or total activity are particularly responsible for the development of some histological, biochemical and contractile features. The present study in 18 rabbits deals with a recently developed electrical stimulus, which had proved effective in maintaining muscle force following denervation. This current has (1) unusual long bidirectional rectangular impulses (20 ms) and (2) a frequency of 25 Hz, which is between the frequencies of fast- and slow-firing motor units. Electrical stimulation began 28 (in one animal 53) days after total motor and sensory denervation of the right hindleg, and was continued until the end of the experiment, up to 205 days. To mimic a therapeutic regimen, which should be agreeable to patients, daily treatment times were kept to a minimum (2 x 6 min), and surface electrodes were used. Morphometric evaluation of the fast flexor digitorum sublimis muscle showed that such electrical stimulation was able to preserve fibre diameter at a level of 72-86% of the initial values for several months, while unstimulated fibres showed the usual atrophy with a decrease of diameters below 40% of normal. The stimulation induced a "hybrid" fibre type with properties of a slow muscle (rich in mitochondria in NADH-dependent tetrazolium reductase staining and electron microscopy) as well as of a fast-twitch muscle (fibre type IIb in myofibrillar ATPase stainings).
电刺激对长期失神经支配肌肉的疗效取决于刺激参数，这些参数对萎缩的发展有重要影响。刺激频率和/或总活动量尤其决定了一些组织学、生化和收缩特性的发展。本研究以18只兔子为对象，探讨一种新开发的电刺激，该刺激已被证明在失神经支配后维持肌肉力量方面有效。这种电流具有：（1）异常长的双向矩形脉冲（20毫秒）；（2）25赫兹的频率，该频率介于快速和慢速发放运动单位的频率之间。电刺激在右侧后肢运动和感觉完全去神经支配28天（1只动物为53天）后开始，并持续到实验结束，长达205天。为模拟一种患者能够接受的治疗方案，每日治疗时间保持在最短（2×6分钟），并使用表面电极。对趾浅屈肌的形态计量学评估表明，这种电刺激能够在数月内将纤维直径维持在初始值的72%至86%水平，而未受刺激的纤维则出现了常见的萎缩，直径下降至正常的40%以下。刺激诱导出一种“混合型”纤维类型，具有慢肌的特性（在依赖NADH的四唑还原酶染色和电子显微镜下富含线粒体）以及快肌的特性（在肌原纤维ATP酶染色中为IIb型纤维）。
