采用自旋捕捉ＥＳＲ方法研究了大白鼠和豚鼠在心肌缺血再灌注中自由基产生的动力学过程，首次测出复氧过程中羟基自由基变化的动力学曲线．同时结果还表明，在缺血后的复氧过程中除羟基·ＯＨ之外，还有碳中心自由基Ｒ·和可能的烷氧基ＲＯ·的生成，但其中·ＯＨ基生成的量经常是最大的．由于·ＯＨ基具有很高的反应活性，因而不可避免地就会通过它的夺氢作用导致碳中心自由基Ｒ的生成．特别有趣的是，羟基产生过程中其ＥＳＲ信号的强度总是随着时间不断地增强而达到一最大值，然后又逐步地缓慢衰减到趋于几乎消失，此现象迄今尚未见有文献报道．我们建立了可近似表征羟基自由基生成速度的上升和下降过程的动力学方程．自由基生成与变化过程亦可近似地用退化分支链反应图式来予以描述．在所提出的链反应过程图式中，可对于通常所谓脂质体过氧化的过程，给予以合理的解释 Spin-capture-ESR method was used to study the kinetics of free radical generation in myocardial ischemia-reperfusion in rats and guinea pigs. The kinetic curve of hydroxyl radical changes during reoxygenation was first detected. At the same time, the results also show that in addition to hydroxy · OH, there is the generation of carbon center radicals R · and possibly alkoxy RO · during the post-ischemic reoxygenation process, but the amount of OH radicals generated is often biggest. Due to the high reactivity of · OH group, it inevitably leads to the generation of carbon center radical R through its hydrogen abstraction. What is particularly interesting is that the intensity of ESR signal in hydroxyl production always increases to a maximum value with time, then slowly decays gradually to almost disappear. This phenomenon has not been reported in the literature so far. We have established a kinetic equation that approximates the processes of rising and falling of the hydroxyl radical production rate. The formation and evolution of free radicals can also be approximated by degenerate branching chain reactions. In the proposed scheme of the chain reaction process, a reasonable explanation can be given to what is generally referred to as lipoperoxidation