Significant levels of oxidants are generated by isolated cardiomyocytes during ischemia prior to reperfusion
Significant levels of oxidants are generated by isolated cardiomyocytes during ischemia prior to reperfusion
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DOI：
10.1006/jmcc.1997.0497
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发表时间：
1997-09-01
影响因子：
5
通讯作者：
Becker, LB
中科院分区：
文献类型：
--
作者：
VandenHoek, TL;Li, CQ;Becker, LB
活性氧（ROS）等氧化剂已被证明参与心肌缺血/再灌注损伤。虽然许多研究报告再灌注时 ROS 激增，但很少有报告提供缺血期间大量 ROS 生成的证据。我们之前对培养心肌细胞的研究表明，在缺血期间再灌注前给予抗氧化剂最有效。因此，我们假设在再灌注之前的缺血期间可能会产生大量的 ROS。我们在模拟缺血/再灌注期间在灌注的分离心肌细胞系统（即没有中性粒细胞、内皮细胞或黄嘌呤/黄嘌呤氧化酶）中对此进行了测试，同时使用细胞内荧光探针测量氧化剂的产生。缺血期间，ROS 探针二氢乙锭和 2', 7'-二氯荧光素显着氧化，表明产生了超氧化物和 H2O2。在缺血1小时后的再灌注时，这些探针表明H 2 O 2 和羟自由基的进一步爆发。缺血期间使用的抗氧化剂 2-巯基丙酰甘氨酸和 1,10-菲咯啉可减弱氧化剂的产生，增加细胞活力，并改善缺血后收缩的恢复。为了进一步评估残余 O-2 和 ROS 生成之间的关系，我们在缺血期间施用 O-2 清除剂，并测量再灌注期间氧化剂生成、细胞活力和收缩的相应变化。缺血期间残余 O-2 的酶促清除（将 PO2 从 3.5 tau 降低至 2.5 tau）反而改善了随后的活力和收缩。这些结果表明，培养的心肌细胞在缺血期间产生显着的 ROS。这种 ROS 的产生与缺血期间存在的残留 O-2 有关，并且对再灌注时出现的细胞损伤有显着贡献。 (C) 1997 学术出版社有限公司。
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 have presented evidence of significant ROS generation during ischemia. Our previous studies of cultured cardiomyocytes indicated that antioxidants are most effective when given prior to reperfusion during ischemia. Therefore, we hypothesized that significant ROS generation may occur during ischemia prior to reperfusion. We tested this in a perfused isolated cardiomyocyte system (i.e. without neutrophils, endothelial cells, or xanthine/xanthine oxidase) during simulated ischemia/reperfusion while measuring oxidant generation using intracellular fluorescent probes. During ischemia, the ROS probes dihydroethidium and 2', 7'-dichlorofluorescin were significantly oxidized, suggesting superoxide and H2O2 generation. At reperfusion following Ih ischemia, these probes suggested a further burst of H2O2 and hydroxyl radicals. The antioxidants 2-mercaptopropionyl glycine and 1,10-phenanthroline used during ischemia attenuated oxidant generation, increased cell viability, and improved return of contraction after ischemia. To further evaluate the relationship between residual O-2 and ROS generation, we administered O-2 scavengers during ischemia and measured corresponding changes in oxidant generation, cell viability and contraction during reperfusion. Enzymatic scavenging of residual O-2 during ischemia (reducing PO2 from 3.5 to 2.5 tau) paradoxically improved subsequent viability and contraction, These results indicate that cultured cardiomyocytes generate significant ROS during ischemia. This ROS generation is related to residual O-2 present during ischemia and contributes significantly to the cellular injury seen at reperfusion. (C) 1997 Academic Press Limited.