Maupoil V, Rochette L, Tabard A, Clauser P, Harpey C
Laboratoire de Pharmacodynamie, Faculté de Pharmacie, Dijon, France.
Cardiovasc Drugs Ther. 1990 Aug;4 Suppl 4:791-5. doi: 10.1007/BF00051276.
Free radicals have been implicated in several aspects of cellular injury, both during ischemia and reperfusion of the myocardium. In this study, formation of free radicals in the isolated rat heart was measured a) directly using electron paramagnetic resonance (EPR) spectroscopy and b) indirectly using the generation of thiobarbituric acid reactants as an index of lipid peroxidation. EPR spectra of frozen heart powder recorded at 100 degrees K show several lines and consist of different components separated by temperature studies: signal C disappears after warming the sample 1 minute at 190 degrees K and is suggestive of a triplet signal g = 2.001, aN = 25 Gauss; signal B g parallel = 2.034, g perpendicular = 2.007, disappears after 1 min at 240 degrees K, and is similar to those previously reported for oxygen alkylperoxyl free radical; the remaining signal, signal A with g = 2.004 is identical to that of a carbon-centered ubiquinone free radical. The total free radical concentration in isolated rat heart perfused at a constant flow rate of 12 ml/min was increased by 44% compared with control (p less than 0.05) after 10 minutes of normothermic global ischemia with a 10% residual flow, and by only 31% compared with control after 20 seconds of reflow with oxygenated perfusate (p less than 0.05). Compared with the reperfused group, trimetazidine 10(-5) M administered 15 minutes before the ischemic period decreased the free radical concentration (-20%). However, this free radical generation in heart was not associated with a concomitant increase of lipid peroxides.
自由基与心肌缺血及再灌注期间细胞损伤的多个方面有关。在本研究中，采用以下两种方法测定离体大鼠心脏中自由基的形成：a）直接使用电子顺磁共振（EPR）光谱法；b）间接使用硫代巴比妥酸反应物的生成作为脂质过氧化的指标。在100°K下记录的冷冻心脏粉末的EPR光谱显示出几条谱线，通过温度研究可分为不同成分：信号C在190°K将样品加热1分钟后消失，提示为三重态信号g = 2.001，aN = 25高斯；信号B的g平行 = 2.034，g垂直 = 2.007，在240°K 1分钟后消失，与先前报道的氧烷基过氧自由基的信号相似；其余信号，即g = 2.004的信号A与以碳为中心的泛醌自由基的信号相同。在以12 ml/min的恒定流速灌注的离体大鼠心脏中，在具有10%残余血流的常温全心缺血10分钟后，总自由基浓度比对照组增加了44%（p < 0.05），而在使用含氧灌注液再灌注20秒后，仅比对照组增加了31%（p < 0.05）。与再灌注组相比，在缺血期前15分钟给予10⁻⁵ M的曲美他嗪可使自由基浓度降低（-20%）。然而，心脏中这种自由基的产生与脂质过氧化物的相应增加无关。
