Herbert K J, Hickey M J, Lepore D A, Knight K R, Morrison W A, Stewart A G
Bernard O'Brien Institute of Microsurgery, St Vincent's Hospital Melbourne, 42 Fitzroy Street, Fitzroy, Victoria 3065, Australia.
Eur J Pharmacol. 2001 Jul 13;424(1):59-67. doi: 10.1016/s0014-2999(01)01133-5.
We examined the role of endothelin in ischaemia/reperfusion injury in skeletal muscle, using the endothelin receptor antagonist Bosentan. In the rat hindlimb tourniquet ischaemia model, one hindlimb was rendered ischaemic for 2 h at 36 degrees C, then blood flow was re-established for either 24 h to assess muscle survival or 1.5 h for a study of capillary perfusion. In the first set of rats, the gastrocnemius muscle was removed from the postischaemic limb and assessed for viability histochemically using the nitro blue tetrazolium stain. Tissue water content (a measure of oedema) and myeloperoxidase activity (a measure of neutrophil accumulation) were also assessed in the ischaemic muscle, the contralateral non-ischaemic muscle and the lungs. In the second set of rats, the hind limb was infused with India ink after 2-h ischaemia and 1.5-h reperfusion and the muscle was harvested, fixed and cleared. In control rats, muscle viability was 17+/-2% (S.E.M.). In rats treated with Bosentan (10 mg/kg, i.p.) 30 min before release of the tourniquet, muscle viability (48+/-7%) was significantly increased compared to the control group (P<0.01). Bosentan treatment had no significant effect on tissue water content or myeloperoxidase activity in the ischaemic muscle, the contralateral non-ischaemic muscle or the lung. Immunoreactive endothelin levels in serum increased to a peak at 90 min of reperfusion and returned to control levels by 24-h reperfusion. India ink studies demonstrated a significantly increased functional capillary density in postischaemic Bosentan-treated muscles compared with postischaemic control muscles (P<0.05). These results suggest that endothelin plays an important role in the necrosis which results from a period of ischaemia and reperfusion in skeletal muscle, by mediating a decrease in postischaemic microvascular perfusion.
我们使用内皮素受体拮抗剂波生坦，研究了内皮素在骨骼肌缺血/再灌注损伤中的作用。在大鼠后肢止血带缺血模型中，一侧后肢在36℃下缺血2小时，然后恢复血流24小时以评估肌肉存活情况，或恢复1.5小时以研究毛细血管灌注。在第一组大鼠中，从缺血后的肢体取下腓肠肌，使用硝基蓝四氮唑染色进行组织化学评估其活力。还在缺血肌肉、对侧非缺血肌肉和肺中评估组织含水量（水肿指标）和髓过氧化物酶活性（中性粒细胞聚集指标）。在第二组大鼠中，缺血2小时和再灌注1.5小时后，向后肢注入印度墨水，然后收获肌肉，固定并清除。在对照大鼠中，肌肉活力为17±2%（标准误）。在松开止血带前30分钟用波生坦（10毫克/千克，腹腔注射）治疗的大鼠中，肌肉活力（48±7%）与对照组相比显著增加（P<0.01）。波生坦治疗对缺血肌肉、对侧非缺血肌肉或肺中的组织含水量或髓过氧化物酶活性没有显著影响。血清中免疫反应性内皮素水平在再灌注90分钟时升至峰值，并在再灌注24小时时恢复到对照水平。印度墨水研究表明，与缺血后对照肌肉相比，缺血后用波生坦治疗的肌肉中功能性毛细血管密度显著增加（P<0.05）。这些结果表明，内皮素通过介导缺血后微血管灌注减少，在骨骼肌缺血和再灌注所致的坏死中起重要作用。
