Mrak R E, Carry M M, Murphy M L, Peng C F, Straub K D
Division of Pathology, John L. McClellan Memorial Veterans Hospital, Little Rock, AR.
Am J Cardiovasc Pathol. 1990;3(3):217-24.
Restoration of coronary artery flow following a period of ischemia often results in further ultrastructural damage to cardiac fibers, a phenomenon known as reperfusion injury. We have compared the ultrastructural effects of uncontrolled reperfusion in vivo of ischemic pig myocardium with the ultrastructural effects of reperfusion controlled at flow rates comparable to preischemia levels. Myocardial ischemia was produced for 60 minutes in 9 pigs by means of a reversible coronary artery occlusion, after which coronary artery flow was restored for 120 minutes. This restoration of flow was complete in four pigs (resulting in uncontrolled reperfusion) and partial in five pigs, with constant monitoring and adjustment of flow to maintain rates near preischemia values (controlled reperfusion). Myocardial samples from the ischemic, reperfused region were examined by electron microscopy. Ischemic damage to nuclei, mitochondria, and myofibrils and ischemic depletion of glycogen were graded independently and blindly by two investigators using a simple, nonparametric three-point scale. Ischemic damage was greater in pigs receiving uncontrolled reperfusion than in animals receiving controlled reperfusion, and these differences were significant for ischemic effects on nuclei (p less than 0.01), glycogen (p less than 0.02), and myofibrils (p less than 0.05) but not for ischemic effects on mitochondria (p = 0.095). We conclude that uncontrolled, hyperemic flow during reperfusion of ischemic myocardium is responsible, in part, for the phenomenon of reperfusion injury.
一段时间的缺血后冠状动脉血流的恢复常常导致心肌纤维进一步的超微结构损伤，这一现象被称为再灌注损伤。我们比较了缺血猪心肌在体内不受控制的再灌注的超微结构效应与以与缺血前水平相当的流速控制再灌注的超微结构效应。通过可逆性冠状动脉闭塞在9头猪中造成心肌缺血60分钟，之后恢复冠状动脉血流120分钟。血流恢复在4头猪中是完全的（导致不受控制的再灌注），在5头猪中是部分的，通过持续监测和调整血流以维持接近缺血前值的流速（控制性再灌注）。对缺血再灌注区域的心肌样本进行电子显微镜检查。两位研究者使用简单的非参数三点量表对细胞核、线粒体和肌原纤维的缺血损伤以及糖原的缺血耗竭进行独立且盲法分级。接受不受控制再灌注的猪的缺血损伤比接受控制性再灌注的动物更严重，并且这些差异在缺血对细胞核的影响（p<0.01）、糖原（p<0.02）和肌原纤维（p<0.05）方面具有统计学意义，但在缺血对线粒体的影响方面无统计学意义（p = 0.095）。我们得出结论，缺血心肌再灌注期间不受控制的充血性血流部分导致了再灌注损伤现象。
