Gross G J, O'Rourke S T, Pelc L R, Warltier D C
Department of Anesthesiology, Medical College of Wisconsin, Milwaukee 53226.
Am J Physiol. 1992 Dec;263(6 Pt 2):H1703-9. doi: 10.1152/ajpheart.1992.263.6.H1703.
The major objective of the present study was to determine the effect of multiple, brief periods of coronary artery occlusion and reperfusion on postischemic contractile function (sonomicrometry) and endothelium-dependent vasodilator responses in isolated conduit coronary artery rings obtained from anesthetized dogs. The role of oxygen-derived free radicals was also investigated. Dogs were subjected to four 5-min episodes of left anterior descending coronary occlusion interspersed with 5 min of reperfusion followed by a final 60-min reperfusion period. The multiple occlusion-reperfusion protocol resulted in regional segment dysfunction (37 +/- 15% of preocclusion values at 60 min of reperfusion) and attenuated endothelium-dependent responses to acetylcholine, bradykinin, and the calcium ionophore, A23187. Responses to the endothelium-independent vasodilator, sodium nitroprusside, were unaffected. Infusion of superoxide dismutase (5,000 U/kg) and catalase (55,000 U/kg) markedly improved the recovery of myocardial function at 30 and 60 min of reperfusion and completely protected against vascular endothelial damage. These results suggest an important role for oxygen-derived free radicals in the myocardial and endothelial injury that occurs in this model of multiple stunned myocardium.
本研究的主要目的是确定多次短暂冠状动脉闭塞和再灌注对从麻醉犬获取的离体冠状动脉环缺血后收缩功能（超声心动图）和内皮依赖性血管舒张反应的影响。还研究了氧自由基的作用。对犬进行4次每次5分钟的左前降支冠状动脉闭塞，期间穿插5分钟的再灌注，随后是最终60分钟的再灌注期。多次闭塞-再灌注方案导致局部节段功能障碍（再灌注60分钟时为闭塞前值的37±15%），并减弱了对乙酰胆碱、缓激肽和钙离子载体A23187的内皮依赖性反应。对非内皮依赖性血管舒张剂硝普钠的反应未受影响。输注超氧化物歧化酶（5000 U/kg）和过氧化氢酶（55000 U/kg）可显著改善再灌注30分钟和60分钟时心肌功能的恢复，并完全防止血管内皮损伤。这些结果表明氧自由基在这种多次心肌顿抑模型中发生的心肌和内皮损伤中起重要作用。
