心肌缺血再灌过程中自由基生成动力学的ESR研究

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.

ESR STUDY ON THE KINETICS OF FREE RADICAL GENERATION IN MYOCARDIAL ISCHEMIA-REPERFUSION PROCESSES

The kinetic changes of free radical generation in myocardial ischemia reperfusion of rat and guinea pig were studied by means of spin trapping ESR technique. The results indicated that not only the hydroxyl radical \5OH, but also the carbon centered radical R \5, as well as the alkyloxyl radical RO \5 were formed in reoxygenation processes, and the \5OH radicals always were in majority. An interesting fact was first discovered in our experiments that the signal intensity of \5OH radicals in reoxygenation processes increased constantly with time to a maximum and then slowly decayed almost to zero, a kinetics curve of change processes in test samples at different time points was drawn. Up to date, this kinetic phenomena has not been reported yet in literatures. The kinetics equations for increasing and decreasing processes of hydroxyl free radicals were established respectively. The formation and change of free radicals might be described approximately by degenerate branching chain reaction scheme.