Gardner T J
Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205.
Free Radic Biol Med. 1988;4(1):45-50. doi: 10.1016/0891-5849(88)90010-x.
Most cardiac surgical procedures require the use of prolonged induced myocardial ischemia. Experimental models of global myocardial ischemia which mimic cardiac surgical techniques have been developed to investigate the possibility of oxygen free radical development during prolonged myocardial ischemia or upon reperfusion. In such experiments, various free radical scavenging agents, including superoxide dismutase, catalase, and mannitol, have been shown to improve the tolerance of the heart to protracted global ischemia. Use of these agents has improved cardiac functional recovery and has attenuated the biochemical and structural changes which occur due to prolonged ischemia and reflow. In a recently developed porcine experimental model, the effects of preexisting regional myocardial ischemia with superimposed global ischemia and reperfusion have been studied, with free radical scavenging agents administered in an attempt to reduce myocardial infarction and improve regional functional recovery. In most such studies completed to date, free radical scavenging agents have resulted in better myocardial preservation, suggesting, at least indirectly, that there may be an oxygen free radical-mediated component of the ischemia-reperfusion injury seen in such models. Techniques for directly measuring myocardial oxygen free radical levels may allow for early clarification of the development of such toxic species in the clinical cardiac surgical setting.
大多数心脏外科手术需要使用延长的诱导性心肌缺血。已经开发出模拟心脏手术技术的全心肌缺血实验模型，以研究在延长的心肌缺血期间或再灌注时产生氧自由基的可能性。在这类实验中，包括超氧化物歧化酶、过氧化氢酶和甘露醇在内的各种自由基清除剂已被证明可提高心脏对长时间全心缺血的耐受性。使用这些药物可改善心脏功能恢复，并减轻因长时间缺血和再灌注而发生的生化和结构变化。在最近开发的猪实验模型中，研究了预先存在的局部心肌缺血叠加全心缺血和再灌注的影响，并给予自由基清除剂以试图减少心肌梗死并改善局部功能恢复。在迄今为止完成的大多数此类研究中，自由基清除剂可更好地保存心肌，这至少间接表明，在此类模型中看到的缺血再灌注损伤可能存在氧自由基介导的成分。直接测量心肌氧自由基水平的技术可能有助于早期阐明临床心脏手术环境中此类毒性物质的产生情况。
