Cardioprotective effect of remote preconditioning of trauma and remote ischemia preconditioning in a rat model of myocardial ischemia/reperfusion injury.

Remote ischemia preconditioning (RIPC) and remote preconditioning of trauma (RPCT) are two methods used to induce a cardioprotective function against ischemia/reperfusion injury (IRI). However, the underlying mechanisms of these two methods differ. The aim of the present study was to investigate the cardioprotective function of the two methods, and also observe whether combining RIPC with RPCT enhanced the protective effect. In total, 70 male Sprague Dawley rats were randomly divided into five groups, which included the sham, control, RIPC + RPCT, RPCT and RIPC groups. With the exception of the sham group, all the rats were subjected to myocardial IRI through the application of 30 min occlusion of the left coronary artery and 180 min reperfusion. Serum cardiac troponin I (cTnI) levels, myocardial infarct size (IS) and the cardiomyocyte apoptotic index (AI) were assessed. The levels of serum cTnI were lower in the experimental groups when compared with the control group (control, 58.59±12.50 pg/ml; RIPC + RPCT, 46.05±8.62 pg/ml; RPCT, 45.98±11.24 pg/ml; RIPC, 43.46±5.05 pg/ml; P<0.05, vs. control), and similar results were observed for the myocardial IS (control, 48.34±6.79%; RIPC + RPCT, 29.64±4.51%; RPCT, 29.05±8.51%; RIPC, 27.72±6.27%; P<0.05, vs. control) and the AI (control, 31.75±10.65%; RIPC + RPCT, 18.32±9.30%; RPCT, 18.51±9.26%; RIPC, 20.41±3.86%; P<0.05, vs. control). However, no statistically significant differences were observed among the three experimental groups (P>0.05). Therefore, RIPC and RPCT exhibit cardioprotective effects when used alone or in combination. However, a combination of RIPC and RPCT does not enhance the cardioprotective effect observed with the application of either single method. Therefore, for patients undergoing major abdominal surgery, RIPC was considered to be unnecessary, while for patients undergoing other types of non-cardiac major surgery and minimally invasive interventional surgery, RIPC may be useful. In addition, patients with embolism diseases are also liable to IRI when reperfusion treatment such as thrombolysis is conducted. Thus RIPC may also be beneficial for these patients.