缺血后适应对心肌缺血再灌注损伤大鼠p38丝裂原活化蛋白激酶和血小板-白细胞聚集体表达的影响

Effects of Ischemic Postconditioning on p38MAPK and PLA Expression in Rats With Myocardial Ischemia Reperfusion Injury

目的:从炎症-血栓机制角度初步探讨缺血后适应减轻心肌缺血再灌注损伤的可能机制。方法:60只SD大鼠随机分为六组:假手术组(n=10)、缺血再灌注(I/R)组(n=10)、缺血后适应组(n=10)、SB203580组(n=10)、Anisomycin+缺血后适应(Ani+缺血后适应)组(n=10)和Ani组(n=10)。建立大鼠心肌缺血再灌注模型,检测心肌损伤标志物血清肌酸激酶同工酶(CK-MB)和肌钙蛋白I(Tn I)水平,采用流式细胞仪在不同时间点检测血小板-白细胞聚集体(PLA)表达水平,使用2,3,5-氯化三苯基四氮唑(TTC)染色检测心肌梗死面积以及利用免疫蛋白印迹法测定磷酸化p38丝裂原活化蛋白激酶(p38MAPK)表达水平。结果:与I/R组相比,缺血后适应组和SB203580组的CK-MB和Tn I水平、梗死面积和再灌注60 min和3 h时PLA表达水平明显降低(P<0.05)。与缺血后适应组相比,SB203580组、Ani+缺血后适应组和Ani组的上述指标明显升高(P<0.05),Ani组和I/R组之间没有差异(P>0.05)。与I/R组相比,缺血后适应组、SB203580组和Ani+缺血后适应组明显抑制了磷酸化p38MAPK的表达(P<0.05),Ani组的磷酸化p38MAPK表达水平明显升高(P<0.05)。与缺血后适应组相比,Ani+缺血后适应组和Ani组磷酸化p38MAPK表达水平明显升高(P<0.05)。SB203580组具有与缺血后适应组类似的心脏保护作用。在Tn I、CK-MB、梗死面积和PLA水平方面,Ani+缺血后适应的保护作用减弱。结论:缺血后适应通过抑制p38MAPK的磷酸化而减少再灌注过程中PLA的表达,从而减轻缺血再灌注损伤。

Objectives： To explore the possible mechanisms of ischemic postconditioning on alleviating myocardial ischemia-reperfusion injury, focusing on the inflammatory-thrombus related mechanisms.Methods： Rats were randomly divided into six groups（n =10 each）： sham group, ischemia-reperfusion injury group, postconditioning group, SB203580 group, anisomycin＋postconditioning（Ani＋postconditioning） group and anisomycin（Ani） group. After establising the model of myocardial ischemia reperfusion in rats, the levels of myocardial injury markers troponin I（Tn I） and creatine kinase isoenzyme（CK-MB）, level of leukocyte-platelet aggregation（PLA） were detected by flow cytometry at different time points, myocardial infarction area was measured by using TTC staining and the level of phosphorylation of p38 MAPK（P-p38 MAPK） was determined by Western blot. Results： Compared with the I/R group, the levels of CK-MB, Tn I, the infarct size and the expression of PLA at 60 min and 3 h reperfusion were significantly reduced in the postconditioning group and SB203580 group（P〈0.05）. Compared with the postconditioning group, the levels of above parameters were significantly higher in the SB203580 group, Ani＋postconditioninggroup and Ani group（P〈0.05）. Compared with the I/R group, the expression of P-p38 MAPK in the postconditioning group, SB203580 group, Ani＋postconditioning group was significantly reduced（P〈0.05）, while it was significantly upregulated in the Ani group（P〈0.05）. Furthermore, compared with the postconditioning group, the expression of P-p38 MAPK in the Ani＋postconditioning group and Ani group was significantly upregulated（P〈0.05）. SB203580 group presented the similar protection effect as the postconditioning group. Cardioprotective effects of postconditioning was partially reduced in the Ani＋postconditioning group. Conclusions： Ischemia postconditioning can reduce the expression of PLA during reperfusion by inhibiting the phosphorylation of p38 MAPK, thereby attenuating myocardial ischemia-reperfusion injury.