动脉粥样硬化对大鼠心肌缺血/再灌注损伤及缺血预处理保护作用的影响

目的探讨心肌缺血／再灌注（I／R）损伤及缺血预处理（IP）的保护作用是否受动脉粥样硬化的影响。方法48只健康Wistar大鼠随机分为2大组：正常大鼠组（NC rats）及动脉粥样硬化大鼠组（ASrats）。正常大鼠饲以标准实验室饲料，动脉粥样硬化大鼠连续3d腹腔注射维生素D3后给以致动脉粥样硬化饲料。每大组动物又随机分为2小组：缺血／再灌注损伤组（I／R group）及缺血预处理组（IP group），NC-I/R和AS-I／R组大鼠给予45min左室前壁缺血及180min再灌注；NC-IP和AS-IP组大鼠在2次5min缺血10min再灌后给予45min缺血及180min再灌。检测指标为：心功能、心梗面积、心肌MPO活性、心肌MDA含量、心肌NO含量及iNOS活性。结果I／R使两组大鼠心肌均受到严重损伤，但AS大鼠损伤更重。IP可以明显减轻两组大鼠心肌I／R损伤，且两组大鼠IP的保护作用相似。结论动脉粥样硬化心脏更易受到I／R损伤，但是IP对动脉粥样硬化心脏仍然具有保护作用，且该作用和IP对正常大鼠的保护作用相似。

Effects of hyperlipoidemic atherosclerosis on myocardial ischemia/reperfusion injury and protective role of ischemic preconditioning in rats

Objective To study whether the myocardial ischemia/reperfusion injury and the protective role of ischemic preconditioning(IP) are affected by atherosclerosis. Methods Fortyeight healthy Wistar rats were randomly divided into 2 groups: normal control rats(NC rats) and atherosclerotic rats(AS rats).NC rats were fed with standard laboratory chow,while AS rats were celiac injected for 3 days with vitamine D_3 and then fed with an atherogenic diet.Each group was further randomly divided into 2 subgroups: ischemia/reperfusion(I/R) group and ischemic preconditioning(IP) group.NC-I/R and AS-I/R groups were subjected to 45 min regional ischemia followed by 180 min reperfusion;while NC-IP and AS-IP groups were subjected to two cycles of preconditioning,comprising 5 min regional ischemia plus 10 min reperfusion,prior to 45 min ischemia followed by 180 min reperfusion.Cardiac function,infarct size,myocardial MPO activity,MDA content,NO level and iNOS activity were measured. Results I/R caused pronounced myocardial injuries in both groups with,however,AS rats being more severely impaired than did NC rats.IP could significantly relieve the I/R-induced injuries to approximately the same extent in both NC rats and AS rats. Conclusion Atherosclerotic heart is more susceptible to I/R injury.However,the protective role of IP is still existed in the atherosclerotic heart to the same extent as in the normal heart.