Objective To observe the effects of ischemic postconditioning (IPTC) on myocardial infarction sizes (IS) and protein kinase Cα (PKCα) expression in aged rats with post-ischemia reperfusion injury,and to explore the mechanism.Methods A total of 120 male Wistar rats were divided into aged group and adult group.The aged group was randomly divided into control group (n=12,30-min ischemia and 3-h reperfusion),5 s,10 s,30 s and 60 s IPTC groups [n= 12,each;after 30 min occlusion of left coronary artery (LCA),three cycles of 5 s,10 s,30 s,60 s reperfusion respectively followed by the same interval LCA re-occlusion were applied at the beginning of reperfusion].The IS was measured with TTC dye,and PKC expression was investigated by immunohistochemistry.Results Different IPTC intervals had different effects on IS and PKC expression,10 s and 30 s IPTC could reduce IS both in aged rats and adult rats [(55.9±6.0)% and (47.4±5.5)%],IS in 10 s IPTC group in aged rats was (48.1±5.3)%,in adult rats was (39.2±5.7) %;IS in 30 s IPTC group in aged rats was (48.8 ± 6.8) %,in adult rats was (40.2 ± 6.1 ) %.PKCα expression increased in aged and adult rats (all P<0.05).5 s IPTC could increase IS [IS in 5 s IPTC group in aged rats was (63.5±5.4)%,and PKCα expression reduced in aged rats (all P<0.05)].Conclusions IPTC has cardio-protective effect in aged rats suffering from acute myocardial injury during reperfusion,the effect of IPTC is related to reperfusion-reocclusion interval.%目的 研究心肌缺血后处理对老年大鼠急性心肌缺血再灌注损伤后心肌梗死面积、心肌细胞蛋白激酶Cα(PKCα)表达的影响,并探讨其可能机制.方法 120只健康雄性Wistar大鼠,根据鼠龄分为老年和成年组,每组再分为对照组(缺血30 min再灌注3 h,12只)和5 s、10 s、30 s、60 s组(缺血30 min,再灌注开始时分别给予5 s、10 s、30 s、60 s再通-闭塞冠状动脉处理后再灌注共3 h,每组12只).2,3,5-三苯基氯化四氮唑染色测定心肌梗死面积,免疫组化技术检测心肌细胞PKCα表达.结果 不同时间缺血处理心肌梗死面积和PKCα表达不同,对照组、10 s和30 s再通-闭塞处理均可缩小老年和成年大鼠心肌梗死面积[分别为(55.9±6.0)%和(47.4±5.5)%、(48.1±5.3)%、和(39.2±5.7)%、(48.8±6.8)%和(40.2±6.1)%],PKCα表达增加(均P<0.05);老年5 s组再通-闭塞处理可增加大鼠心肌梗死面积,老年5 s组梗死面积为(63.5±5.4)%,PKCα表达降低(均P<0.05).结论 缺血后处理对老年大鼠急性心肌缺血再灌注损伤具有保护作用;缺血后处理效果与再通-闭塞时间有关.
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