血小板-白细胞聚集体促进大鼠心肌缺血再灌注损伤及缺血后适应的保护作用

摘要： 目的 观察缺血后适应 （PostC） 对大鼠心肌缺血再灌注过程中血小板-白细胞聚集体 （PLA） 表达的影响，探讨缺血后适应PostC减轻心肌缺血再灌注损伤 （MIRI） 的机制。方法 将60只SD大鼠随机分为假手术 （Sham） 组、缺血再灌注 （I/R） 组、 缺血后适应 （PostC） 组、 c-Jun氨基末端激酶 （JNK） 抑制剂 （I-JNK） 组、 JNK激活剂+缺血后适应（Ani+ PostC） 组和JNK激活剂 （Ani） 组6组。构建大鼠心肌缺血再灌注模型， 利用肌酸激酶同工酶 （CK-MB） 和肌钙蛋白I （TnI） 试剂盒检测心肌损伤标志物水平； 采用流式细胞仪在基础状态、 缺血30 min、 再灌注30 min、 再灌注60 min 及再灌注3 h检测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； 利用Western blot方法测定磷酸化JNK （P-JNK） 表达水平。结果 （1） I/R组CK-MB、 TnI水平及心肌梗死面积高于Sham组 （P＜0.05）； PostC组和I-JNK组CK-MB、 TnI水平和梗死面积低于I/R组 （P＜0.05）； 与PostC组相比， Ani+PostC组和Ani组CK- MB、 TnI水平和梗死面积明显升高 （P＜0.05）。（2） 与Sham组相比， I/R组缺血后各时间点PLA表达水平升高 （P＜ 0.05）。在MIRI不同时间点， I/R组、 Ani+PostC组及Ani组PLA表达水平逐渐上升 （P＜0.05）； 在再灌注60 min和3 h，与I/R组相比， PostC组和I-JNK组PLA表达水平明显降低 （P＜0.05）。与PostC组相比， Ani+PostC组和Ani组PLA表达水平明显升高 （P＜0.05）。（3） I/R组P-JNK水平高于Sham组 （P＜0.05）。PostC和I-JNK抑制了P-JNK的生成 （P＜ 0.05）， 而Ani促进P-JNK水平升高 （P＜0.05）； 与PostC组相比， Ani+PostC组和Ani组P-JNK水平明显升高 （P＜0.05）。结论 PostC通过抑制JNK MAPK的磷酸化而减少再灌注过程中PLA的表达， 从而减轻MIRI。

Study on protective effects of platelet-leukocyte aggregation on myocardial ischemia reperfusion injury and postischemic recovery in rats

Abstract: Objective To observe the effect of postconditioning (PostC) on the expression of platelet-leukocyte aggregation (PLA) during the process of myocardial ischemia and reperfusion in rats, and to explore the mechanisms of ischemic postconditioning (PostC) alleviating myocardial ischemia-reperfusion injury (MIRI). Methods Sixty rats were randomly divided into six groups: sham, reperfusion injury (I/R), postconditioning (PostC), SP600125 (inhibition of c-Jun N-terminal kinase, I-JNK), anisomycin and postconditioning (Ani+ PostC) and anisomycin (Ani) groups. After constructing the model of myocardial ischemia reperfusion in rats, the levels of myocardial injury markers were detected by using the CK-MB kits and TnI kits. The levels of PLA at different time points were detected by using flow cytometry. The myocardial infarction area were measured by using 2.3.5-Triphenyte-trazoliumchloride (TTC) staining, and the level of phosphorylation of JNK (P- JNK) was determined by using Western blot method. Results (1) The levels of CK-MB, TnI and the infarct size were significantly higher in the I/R group than those in the Sham group (P＜0.05). The levels of CK-MB, TnI and the infarct size were significantly lower in the PostC group and I-JNK group than those in the I/R group (P＜0.05). Compared with the PostC group, the levels of CK-MB, TnI and the infarct size were significantly higher in the Ani+PostC group and Ani group (P＜ 0.05). (2) Compared with the Sham group, the expression levels of PLA significantly increased in the I/R group at different time points after ischemia (P＜0.05). At different time points of MIRI, the expressions of PLA increased gradually in I /R group, Ani+PostC group and Ani group (P＜0.05). At the time point of reperfusion for 60 minutes and reperfusion for 3 hours, the expressions of PLA were significantly lower in the PostC group and I-JNK group compared with those of I/R group (P＜0.05). Compared with the PostC group, the expressions of PLA were significantly higher in the Ani+PostC group and Ani group (P＜0.05). (3) Compared with the Sham group, the expression levels of P-JNK were significantly higher in the I /R group (P＜0.05). PostC and I-JNK inhibited the production of P-JNK (P＜0.05), while Ani promoted the increase of P-JNK (P＜0.05). Compared with the PostC group, the expression levels of P-JNK were significantly higher in the Ani+PostC group and Ani group (P＜0.05). Conclusion PostC can reduce the expression of PLA during reperfusion by inhibiting the phosphorylation of JNK, thereby reducing myocardial ischemia-reperfusion injury.