Effects Of Acute Ischemia/Reperfusion Injury On Coronary Artery Function In Porcine Hearts

Background and objectiveMyocardial revascularization therapy is an effective method of treating ischemic heart disease, such as thrombolysis, coronary artery bypass grafting (CABG), percutaneous transluminal coronary angioplasty (PTCA), percutaneous coronary intervention (PCI), and so on. However, many studies have shown that reperfusion has two sides, which can result in more severe myocardial damage. In recent years, studies of ischemia/reperfusion injury are mainly concentrated on myocardial tissue, and less on coronary artery, especially endothelial cells. Study of the function of coronary vascular endothelial cells in ischemia/reperfusion injury is very important to reduce reperfusion injury. Therefore, the objective of this study was to investigate the effects of acute ischemia/reperfusion injury on coronary artery function in porcine hearts.Materials and methodsTwenty Four Swedish domestic pigs were randomly divided into three groups: control group, ischemia group,ischemia/reperfusion group, eight in each group.The hearts in control group were observed1h after thoracotomy and then were removed directly;The hearts in ischemia group were removed after1h occlusion of left anterior descending coronary artery (LAD) distal coronary artery;The hearts in ischemia/reperfusion group were removed after30min of occlusion and30min of reperfusion of LAD distal coronary artery. Then the function of the smooth muscle and endothelial cells of LAD distal coronary artery in the three groups was evaluated in organ baths.ResultsThere are no significant differences in the maximal contraction (Cmax) of smooth muscle, which are16.94mN (10.22mN-24.24mN)、13.03mN (8.92mN-16.94mN)、8.76mN (5.97mN-14.91mN) respectively, and the maximal relaxation percentage (Rmax) of smooth muscle, which are all100%, in the control group, ischemia group and ischemia/reperfusion group (P>0.05). The maximal endothelium dependent relaxation (EDRmax) are (96.88±5.11)%、(90.88±13.90)%,(82.75±14.12)%, and the negative logarithm of the concentration of P substance (pEC50) are9.51±0.80、8.19±0.35、7.64±0.24respectively in the three groups. Compared with control group, both EDRmax and pEC50declined in ischemia group and ischemia/reperfusion group (P<0.05). Both EDRmax and pEC50declined in ischemia/reperfusion group in comparison with ischemia group, there are significant differences in pEC50and EDRmax between the two groups (P<0.05)ConclusionAlthough acute ischemia and acute ischemia/reperfusion do not result in significant injury to the function of smooth muscle of coronary artery in the porcine hearts, they can result in significant injury to the function of endothelial cells, and more injury exists in acute ischemia/reperfusion than actue ischemia group.