重组人促红细胞生成素预先给药对心肌缺血再灌注损伤大鼠心肌炎性反应的影响

Effect of recombinant human erythropoietin pretreatment on the myocardial inflammatory response induced by ischemia-reperfusion injury in rats

目的探讨重组人促红细胞生成素（rhEPO）预先给药对心肌缺血再灌注损伤大鼠心肌炎性反应的影响及其机制。方法健康雄性SD大鼠138只,体重350～450g,随机分为3组：假手术组（Sham组,n=42）、缺血再灌注组（I/R组,n=48）和rhEPO预先给药组（n=48）。缺血前24h,Sham组和I/R组腹腔注射0．9%NaCl溶液4ml/kg,rhEPO预先给药组腹腔注射rhEPO 5 000IU/kg（溶于0．9% NaCl溶液4ml/kg）。采用阻断左前降支冠状动脉30min、再灌注180min制备心肌缺血再灌注损伤模型,分别于结扎冠状动脉前即刻、缺血即刻、再灌注30、60、120、180min 3组各随机处死6只大鼠,取左心室心肌组织,测定肿瘤坏死因子-α（TNF-α）、自细胞介素（IL）-6和IL-10的含量,检测心肌细胞核NF-kB和活化蛋白-1（AP-1）的表达；3组随机另取6只大鼠,再灌注结束时观察心肌中性粒细胞浸润情况。I/R组和rhEPO预先给药组再随机取6只大鼠,再灌注结束时测定心肌梗死面积。结果与Sham组比较,I/R组和rhEPO预先给药组NF-kB、AP-1表达及TNF-α、IL-6、IL-10含量升高（P＜0．01）；与I/R组比较,rhEPO预先给药组NF-kB和AP-1表达及TNF-α、IL-6含量降低,IL-10含量升高（P＜0．05或0．01）；rhEPO预先给药组较I/R组心肌梗死面积减小,中性粒细胞浸润程度减轻。结论预先腹腔注射rhEPO 5 000 IU/kg可减轻大鼠心肌缺血再灌注损伤,其机制与下调NF-kB和AP-1表达,抑制心肌炎性反应有关。

Objective To study the anti-inflammatory effects of recombinant human erythropoietin （rhEPO） and possible mechanism in a rat model of myocardial ischemia-reperfusion （I/R） injury. Methods One hundred and thirty-eight male SD rats weighing 350-450 g were randomly divided into 3 groups： group Ⅰ sham operation （S） （n =42） ; groupⅡ I/R （n =48） and group Ⅲ rhEPO pretreatment （n =48）. Myocardial I/R was produced by reversible occlusion of left anterior descending artery for 30 min followed by 180 min reperfusion. In group Ⅲ rhEPO 5 000 IU/kg was injected intraperitoneally 24 h before I/R. Infarct size was measured by triphenyl tetrazolium chloride Evans blue technique. Tissue neutrophil infiltration was also studied. TNF-α, IL-6 and IL-10 content in left ventricle myocardium were determined by enzyme-linked immunosorbance assay and the expression of NF-κB and activator protein-1 （AP-1） by electrophoretic mobility shift assay. Results A single bolus injection of 5 000 IU/kg of rhEPO 24 h before I/R significantly reduced infarct size and neutrophil infiltration and attenuated I/R-induced NF-κB and AP-1 activation and TNF-α and IL-6 production but enhanced IL-10 production. Conclusion The cardioprotective effect of rhEPO pretreatment may be due in part to suppression of the myocardial inflammatory response by down-regulating NF-κB and AP-1 expression induced by myocardial I/R in rats.