重组人促红细胞生成素对缺血后处理大鼠心脏保护作用及对PI3K/Akt信号通路的影响

Preffects of intervention of rhEPO on myocardial function in rats with myocardial ischemic postconditioning and PI3k/Akt pathway

目的:研究重组人促红细胞生成素(Erythropoietin,rhEPO)对大鼠心肌再灌注损伤心脏功能的影响及对PI3K/Akt信号通路影响。方法:将42只SD雄性大鼠随机分为7组:①假手术组(Sham组);②缺血/再灌注组(I/R组);③缺血后处理组I-PostC组;④渥曼青霉素+缺血后处理组(Wort+I-PostC)组;⑤rhEPO组;⑥Wort+rhEPO组;⑦rhEPO+I-PostC组。术中监测心电变化,于再灌注结束后采用"伊文氏蓝-TTC"法测定心肌梗塞面积,逆转录聚合酶链反应(RT-PCR)和免疫组织化学法检测各组心肌组织中Akt mRNA、p70s6k mRNA水平,Akt、p70s6k蛋白表达水平。结果:(1)心肌梗塞面积:I-PostC组、rhEPO组和rhEPO+I-PostC组心肌梗塞面积较I/R组明显减少(P<0.05),组间无统计差别;I-PostC+Wort组和rhEPO+Wort组较I-PostC组和rhEPO组心肌梗塞面积显著增大(P<0.05)。(2)心肌组织中Akt mRNA、p70s6k mRNA、Akt、p70s6k蛋白表达:各组大鼠心肌组织均有Akt mRNA、p70s6k mRNA,Akt、p70s6k蛋白的表达,以Sham组表达最低。I-PostC组、rhEPO组、rhEPO+I-PostC组较I/R组显著增高(P<0.05);I-PostC+Wort组、rhEPO+Wort组较I-PostC组、rhEPO组明显降低(P<0.05);而I-PostC组、rhEPO组、I-PostC+rhEPO组组间、I/R组、I-PostC+Wort组、rhEPO+Wort组组间差异均无统计学意义。结论:rhEPO能明显改善缺血再灌注所致的心肌组织损伤,发挥与I-PostC相似的心脏保护作用。保护作用与激活PI3K-Akt信号通路及其下游的靶点p70s6k有关。

Objective：To investigate the influence of rhEPO on myocardial function in rats with myocardial ischemia/Reperfusion and PI3K/Akt pathway.Methods：42 rats were randomly divided into①Sham operation group（Sham grou）,②Ischemia/Reperfusion group（I/R group）,③Ischemia-Postconditioning group（I-postC group）,④I-postC＋Wortmannin group（I-postC＋Wort group）,⑤rhErythropoietin group（rhEPO group）,⑥rhEPO＋Wort group,⑦rhEPO＋I-postC group.ECG changes were monitored during the procedure.Ischemic and infarct areas were measured by Evans blue and TTC staining respectively.The mRNA and protein expression of Akt and p70S6K in myocardium were tested by RT-PCR and immunohistochemistry.Results：（1）Areas of myocardial infarction：I-PostC group,rhEPO group and rhEPO＋I-PostC group had smaller areas of myocardial infarction compared with I/R group（P0.05）,while I-PostC＋Wort group and rhEPO＋Wort group had bigger areas of myocardial infarction than I-PostC group and rhEPO group（P0.05）.There were no significant differences among I-PostC group,rhEPO group and rhEPO＋I-Post group.（2）The expressions of Akt mRNA,p70s6k mRNA,Akt,p70s6k protein in myocardium：Akt mRNA,p70s6k mRNA and Akt,p70s6k protein expressed in myocardium in each group,with the lowest expression in Sham group.I-PostC group,rhEPO group and rhEPO ＋ I-PostC group had higher expression than I/R group（P0.05）;the expressions in I-PostC＋Wort group and rhEPO＋Wort ground were lower than rhEPO group the expressions in rhEPO group,I-PostC group and rhEPO＋I-PostC group（P0.05）.There were no significant differences among I-PostC group,rhEPO group and rhEPO＋I-Post group.Conclusion：rhEPO can significantly protect the myocardial tissues,and exert similar protective effects on myocardial tissues to I-Post.the protective effects of rhEPO on myocardial tissues may be related to the activation of PI3-Akt signaling pathways and its downstream target p70s6k.