缺血预处理对兔骨骼肌再灌注损伤延迟保护作用的实验研究

Study on delayed protection of ischemia preconditioning for reperfusion injury of skeletal muscle in limbs of rabbits

目的探讨缺血预处理对兔骨骼肌再灌注损伤是否存在早期、延迟保护作用及保护程度。方法选择30只新西兰大白兔随机等分为对照组、早期保护组(EP)和延迟保护组(DP)。对照组直接用气囊止血带阻断兔后肢血流4h,造成骨骼肌缺血再灌注损伤模型。EP和DP组先进行缺血预处理,分别在预处理后立即和24h后用气囊止血带阻断兔后肢血流4h造成缺血再灌注模型。测定再灌注期血清中肌酸磷酸激酶(CPK)、天门冬酰胺氨基转移酶(AST)和超氧化物歧化酶(SOD)含量,光、电镜下观察骨骼肌结构变化。结果再灌注后1、2、4、8h,EP与DP组血清中CPK和AST的含量均明显低于对照组(P<0.01);SOD含量明显高于对照组(P<0.01),而EP与DP组之间差异无显著性意义(P>0.05)。骨骼肌线粒体空泡变性和肌原纤维溶解均延迟出现,其病变程度明显轻于对照组。结论缺血预处理不仅存在早期、延迟保护作用,且均能提高骨骼肌对长时间缺血的耐受能力,减轻骨骼肌缺血再灌注损伤程度,这两种保护作用的程度无明显差异。

Objective To study the early protection (EP) and delayed protection (DP) of ischemia preconditioning for reperfusion injury of skeletal muscle of rabbits. Methods Thirty healthy rabbits were used in the experiment. The animals were divided into an EP group,a DP group and a control group with 10 rabbits in each. The blood flows of the rabbitslimbs were stopped with a special pneumatic tourniquet. The control group underwent a 4 hour ischemia directly. The EP group was subjected to 4 hour ischemia immediately after preconditioning treatment while the DP group was subjected to 4 hour ischemia 24 hours after preconditioning ischemia,a 10 minute intervening reperfusion period,and another 10 minute ischemia followed by 10 minute reperfusion treatment. The contents of CPK,AST and SOD in the serum before and 1,2,4,8 hours after reperfusion were measured respectively. Histological examination of the skeletal muscle was studied under both a light and an electron microscope. Results Experimental study on rabbits indicated: CPK,AST,SOD in control group at 1 hour,2 hour,4 hour,8 hour time points after reperfusion were superior to those in EP group and in DP group at the same time points (P< 0.01). There were no significant differences between EP group and DP group at the same time points (P >0.05). Vacuolation of mitochondria and lysis of myofibrillae in EP and DP groups were observed later and obviously lighter than those in the control group. Conclusions Both EP and DP of ischemia preconditioning may improve the tolerance of skeletal muscle to reperfusion injury. There is no significant difference between EP and DP. This study suggests that ischemia preconditioning is one of the effective methods of preventing skeletal muscle from ischemia/reperfusion injury.