Pérez Margarita, Lucia A, Rivero J-l L, Serrano A L, Calbet J-A L, Delgado M A, Chicharro J L
Departamento de Ciencias Morfológicas y Fisiología, Universidad Europea de Madrid, 28670 Villaviciosa de Odón, Madrid, Spain.
Pflugers Arch. 2002 Mar;443(5-6):866-74. doi: 10.1007/s00424-001-0769-6. Epub 2002 Jan 22.
Fifteen healthy, untrained male subjects (mean age +/- SD, 22 +/- 5 years) were used to examine the plasticity of myosin heavy chain phenotype, size, oxidative capacity and capillarization of skeletal muscle fibre types with short-term electrical stimulation (ES). Ten subjects were electro-stimulated on both quadriceps muscles with a frequency of 45-60 Hz, with 12 s of stimulation followed by 8 s of recovery for a total of 30 min per day, 3 days per week for 6 weeks. The remaining five subjects served as controls. Two vastus lateralis muscle biopsy samples were removed from each subject before (week 0) and after (week 6) ES training. A standardized exercise test on a cycle ergometer was performed by each subject before and after the experimental period and several indicators of whole-body aerobic capacity were estimated. The so-called electromyographic threshold was also determined during the tests. Muscle biopsy samples were analysed by electrophoresis, immunohistochemistry and quantitative histochemistry. Myosin heavy chain (MHC) composition, muscle fibre type distribution, fibre areas, oxidative capacity and capillaries of each fibre type were estimated. Muscular changes with ES revealed an increase of fibres expressing MHC-IIA, and a decrease of fibres expressing MHC-IIX and MHC-I, as well as an increase of the oxidative capacity and mean number of capillaries of fast-twitch (type II) fibres with minimal muscle fibre hypertrophy. These adaptations seem related to a bi-directional transformation from both MHC isoforms I and IIX towards the MHC-IIA isoform. The aerobic performance and electromyographic variables at the whole-body level were not altered by ES. These results indicate that the particular short-term ES training protocol tested in the present study induces significant adaptations in histochemical and metabolic machineries of human skeletal muscle. The results also offer new perspectives for realistic applications of ES in various clinical situations and sport training.
选取15名健康、未经训练的男性受试者（平均年龄±标准差，22±5岁），通过短期电刺激（ES）来研究骨骼肌纤维类型的肌球蛋白重链表型、大小、氧化能力和毛细血管化的可塑性。10名受试者的双侧股四头肌接受频率为45 - 60Hz的电刺激，每次刺激12秒，随后恢复8秒，每天共刺激30分钟，每周3天，持续6周。其余5名受试者作为对照。在ES训练前（第0周）和训练后（第6周），从每个受试者身上采集两块股外侧肌活检样本。在实验期前后，每位受试者在自行车测力计上进行标准化运动测试，并评估全身有氧能力的几个指标。测试过程中还测定了所谓的肌电图阈值。通过电泳、免疫组织化学和定量组织化学分析肌肉活检样本。估计各纤维类型的肌球蛋白重链（MHC）组成、肌纤维类型分布、纤维面积、氧化能力和毛细血管数量。ES引起的肌肉变化表现为表达MHC-IIA的纤维增加，表达MHC-IIX和MHC-I的纤维减少，以及快肌纤维（II型）的氧化能力和平均毛细血管数量增加，同时肌纤维肥大程度最小。这些适应性变化似乎与从MHC同工型I和IIX向MHC-IIA同工型的双向转变有关。ES并未改变全身水平的有氧性能和肌电图变量。这些结果表明，本研究中测试的特定短期ES训练方案可诱导人类骨骼肌在组织化学和代谢机制方面产生显著适应性变化。这些结果还为ES在各种临床情况和运动训练中的实际应用提供了新的视角。
