目的 探讨缺血后处理对大鼠骨骼肌缺血再灌注损伤的影响以及应用缺血后处理的时机.方法 将32只大鼠随机分成四组,采用切断患肢全部皮肤、肌肉和神经,保留患肢股动静脉的动物模型,通过夹闭和开放股动静脉造成骨骼肌缺血和再灌注损伤.采用测定骨骼肌缺血4 h.再灌注1 h后血清丙二醛(MDA)、骨骼肌髓过氧化物酶(MPO),再灌注6 h后骨骼肌的死亡程度来观察缺血后处理对大鼠骨骼肌缺血再灌注损伤的影响,以及再灌注5 min后应用缺血后处理是否对骨骼肌缺血再灌注损伤有保护作用.结果 对骨骼肌缺血4 h再灌注6 h的损伤,再灌注开始后即刻应用30 s缺血、30 s再通,三次循环的缺血后处理对骨骼肌的缺血再灌注损伤即有保护作用,不仅减少了骨骼肌再灌注区域中性粒细胞浸润(MPO)和血清氧自由基水平(MDA)水平,而且减少了骨骼肌的死亡程度;再灌注5 min后应用缺血后处理并没有降低骨骼肌缺血再灌注区域的MPO和血清MDA水平,也没有降低骨骼肌缺血再灌注后的死亡程度,与直接缺血再灌注组相同,对骨骼肌缺血再灌注损伤并没有保护作用.结论 骨骼肌缺血后再灌注开始前立刻应用缺血后处理对大鼠骨骼肌缺血再灌注损伤有一定的保护效果,可以减少骨骼肌缺血再灌注损伤后的死亡程度;缺血后处理应用时机非常重要,再灌注5 min后应用缺血后处理则失去对骨骼肌缺血再灌注损伤的保护作用.“,”Objective To investigate the effects of ischemic posteondifioning on ischemic repeffusion injury of rat skeletal muscle and the timing of applying isehemie posteondifioning. Methods 32 Wistar rats were randomly divided into 4 groups. To create a skeletal muscle ischemia reperfusion injury model, the skin,muscles and nerves of the hind limb were severed while the femoral vessels were left intact and damped and released at designated time. By measuring serum malondialdehyde (MDA) level and skeletal muscle myeloperoxidase (MPO) level after 4 hours of isehemia and 1 hour of teperfusion and observing the exteny of skeletal muscle death 6 hours following repeffusion, the effects of posteonditioning on skeletal muscle isehemia repeffusion injury were evaluated. The effect of ischemia postconditioning applied 5 minutes following repeffusion on the ischemia repeffusion injury of skeletal muscles were also studied. Results Skeletal muscles that sustained 4 hours of isehemia and 6 hours of reperfusion could be protected by immediate isehemie postconditioning with three cycles of alternating 30 seconds of ischemia and 30 seconds of reperfusion. The extent of skeletal muscle isehaemie reperfusion injury was reduced as shown by the decreased level of neutrophil infiltration (MDA) in the repeffused areas, the decreased level of serum free radicals (MPO) and the reduced extent of muscle death. Posteonditioning applied 5 minutes after repeffusion did not reduce MDA level in the repeffused areas and serum MPO level, neither did it reduce the extent of muscle death. It therefore did not protect skeletal muscles from isehemia repeffusion injury. Conehtsion Isehemie posteanditioning at the beginning of reperfusion can protect skeletal muscle against isehemie reperfusion injury. Timing of applying posteonditioning is critical. If applied 5 minute after reperfusion, posteonditioning lost its protective effects.