Hudlicka O, Brown M D, Egginton S, Dawson J M
Department of Physiology, Medical School, University of Birmingham, United Kingdom.
J Appl Physiol (1985). 1994 Sep;77(3):1317-24. doi: 10.1152/jappl.1994.77.3.1317.
Fast skeletal muscles of Sprague-Dawley rats [tibialis anterior (TA) and extensor digitorum longus (EDL)] were subjected to ischemia by unilateral ligation of the common iliac artery. In some animals, ischemia was combined with indirect electrical stimulation at 10 Hz either for 3 x 2 h (strenuous activity) or for 7 x 10-min bouts/day (mild activity). After 2 wk, muscle blood flow and fatigue were measured during 5-min isometric supramaximal twitch contractions at 4 Hz. Terminal arteriole diameters were assessed in TA by intravital microscopy at rest and during contractions. Vascular perfusion pressure in the muscles was estimated from measurements in the carotid and saphenous arteries below the site of ligation. Capillary supply was expressed in TA and EDL as capillary-to-fiber ratio on the basis of histochemical staining for capillaries. Strenuous stimulation of ischemic muscles increased their atrophy, failed to restore blood flow, and actually worsened fatigue. In contrast, mild stimulation improved perfusion pressure, increased capillary-to-fiber ratio in the glycolytic part of TA, restored dilatation of terminal arterioles during muscle contractions, and improved blood flow and muscle fatigue so that they were no longer significantly different from control muscles. Thus, an attenuated intermittent protocol may be indicated in the treatment of muscle ischemia.
对Sprague-Dawley大鼠的快速骨骼肌[胫前肌（TA）和趾长伸肌（EDL）]进行单侧髂总动脉结扎以造成局部缺血。在一些动物中，局部缺血与10Hz的间接电刺激相结合，刺激时间为3×2小时（剧烈活动）或每天7×10分钟（轻度活动）。2周后，在4Hz下进行5分钟的等长最大强直收缩期间测量肌肉血流量和疲劳程度。通过活体显微镜检查评估静息和收缩期间TA的终末小动脉直径。根据结扎部位下方颈动脉和隐静脉的测量结果估算肌肉中的血管灌注压。基于毛细血管的组织化学染色，以TA和EDL中的毛细血管与纤维比例表示毛细血管供应情况。对缺血肌肉的剧烈刺激会加剧其萎缩，无法恢复血流量，实际上还会加重疲劳。相比之下，轻度刺激可改善灌注压，增加TA糖酵解部分的毛细血管与纤维比例，恢复肌肉收缩期间终末小动脉的扩张，并改善血流量和肌肉疲劳，使其与对照肌肉不再有显著差异。因此，在肌肉缺血的治疗中可能需要采用减弱的间歇性方案。
