Significant Levels of Oxidants Are Generated by Isolated Cardiomyocytes During Ischemia Prior to Reperfusion

摘要: Oxidants such as reactive oxygen species (ROS) have been shown to participate in myocardial ischemia/reperfusion injury. While many studies report a burst of ROS at reperfusion, few reports presented evidence significant generation during ischemia. Our previous cultured cardiomyocytes indicated that antioxidants are most effective when given prior reperfusion Therefore, we hypothesized may occur ischemia reperfusion. We tested this perfused isolated cardiomyocyte system (i.e. without neutrophils, endothelial cells, or xanthine/xanthine oxidase) simulated while measuring oxidant using intracellular fluorescent probes. During ischemia, the probes dihydroethidium and 2',7'-dichlorofluorescin were significantly oxidized, suggesting superoxide H2O2 generation. At following 1 h these suggested further hydroxyl radicals. The 2-mercaptopropionyl glycine 1,10-phenanthroline used attenuated generation, increased cell viability, improved return contraction after To evaluate relationship between residual O2 administered scavengers measured corresponding changes viability Enzymatic scavenging (reducing PO2 from 3.5 2.5 tau) paradoxically subsequent contraction. These results indicate generate This is related present contributes cellular injury seen