EPO预处理对心肌缺氧复氧损伤保护作用的研究

Protective effects of EPO pretreatment on myocardium with hypoxia/reoxygenation injury in rats

目的建立大鼠心肌缺氧复氧损伤模型,观察促红细胞生成素(erythropoietin,EPO)预处理是否具有心肌保护作用。方法Wistar成年雄性大鼠60只分为3组,分别为对照组,缺氧复氧损伤组(H/R组)、EPO预处理组(EPO组),每组20只,EPO组大鼠经腹腔注射5000u/kg的重组人促红细胞生成素(recombinanthumanerythropoietin,RHuEPO),对照组和H/R组则注射同体积的生理盐水。给药24h后,将EPO组和H/R组大鼠置于常压缺氧环境中(O27%,N293%)12h后,移至常压常氧环境中2h,采取血及心肌标本,检测血清心肌酶活性、心肌细胞凋亡、心肌超微结构、心肌细胞MDA等指标,分别于复氧30、60、120min观察心脏血流动力学指标。免疫组化染色检测心肌细胞EPO受体(EPOR)蛋白表达及分布。结果成年大鼠心肌细胞EPOR蛋白呈弱阳性表达,分布于心肌细胞和血管内皮细胞的胞浆和胞膜;与H/R组大鼠比较,EPO预处理减轻大鼠心肌缺氧复氧后细胞超微结构的损伤,降低血清心肌酶活性,抑制心肌细胞凋亡,减轻心肌过氧化损伤,并促进复氧后心功能的恢复。结论成年大鼠心肌细胞能够表达EPOR蛋白;EPO预处理对大鼠心肌缺氧复氧损伤具有保护作用。

Objective To establish the rat model with myocardial hypoxia/reoxygenation (H/R) injury, and to investigate the cardiac protective effects of EPO pretreatment.Methods Sixty male adult Wistar rats were randomly divided into 3 groups: control group, H/R group, and EPO group. There were 20 rats in each group. The rats in EPO group accepted peritoneal injection of 5000U/kg RHuEPO, and the other rats accepted the peritoneal injection of the same volume of saline. 24h after the injection, rats in the EPO and H/R group were placed into the hypoxia environment for 12h and then returned to the normoxic environment for 2h,when the samples of blood and myocardium were collected. Serum myocardial enzyme activity, apoptosis, myocardial ultrostructure, myocardial MDA content, expression of EPOR protein in cardiac myocyte and cardiac function were detected.Results Adult rat cardiac myocyte and vascular endothelial cell expressed EPOR protein. Compared to rats in H/R group, rats in EPO group presented lighter injury of myocardial ultrastructure, the reduction of serum myocardial enzyme activity, inhibition of apoptosis, the better recovery of cardiac functions, and the less production of oxygen-derived free radicals.Conclusion Adult rat cardiac myocytes could express EPOR protein; EPO pretreatment produced protective effect on myocardium with H/R injury.