Miki T, Swafford A N, Cohen M V, Downey J M
Department of Physiology, University of South Alabama, College of Medicine, Mobile, Alabama 36688, USA.
J Mol Cell Cardiol. 1999 Apr;31(4):809-16. doi: 10.1006/jmcc.1998.0917.
To date, most studies of the second window of protection against infarction (SWOP) have evaluated infarct size by staining with triphenyltetrazolium chloride (TTC) soon after reperfusion. However, early TTC staining has been found to be an unreliable indicator of the ultimate infarct size following some interventions. Therefore, we tested whether SWOP could induce a sustained limitation of infarct size. Instrumented, conscious rabbits underwent 30 min of coronary occlusion. Infarct size was determined by either TTC staining after 3 h of reperfusion or conventional histology after 72 h of reperfusion. In the TTC study, 43.5+/-3.1% of the risk zone infarcted in the control group. Four cycles of 5 min ischemia/10 min reperfusion 24 h prior to 30 min ischemia significantly reduced infarct size measured by TTC to 32.5+/-2.3% (P<0.05 v control). In the histological study 57.8+/-3.6% of the risk zone infarcted in the control group. However, ischemic preconditioning 24 h prior to the 30 min ischemia did not protect the heart (59.3+/-4.4% infarction). Thus the infarct-limiting effect of SWOP evaluated with early TTC staining could not be demonstrated when infarction was assessed by histology after 3 days of reperfusion. These data suggest that SWOP may not have a sustained anti-infarct effect, but rather may simply delay the progression to infarction.
迄今为止，大多数关于梗死保护第二窗口（SWOP）的研究都是在再灌注后不久通过用氯化三苯基四氮唑（TTC）染色来评估梗死面积。然而，人们发现早期TTC染色在某些干预后并不能可靠地指示最终的梗死面积。因此，我们测试了SWOP是否能持续限制梗死面积。对植入仪器的清醒家兔进行30分钟的冠状动脉闭塞。梗死面积通过再灌注3小时后的TTC染色或再灌注72小时后的传统组织学方法来确定。在TTC研究中，对照组有43.5±3.1%的危险区发生梗死。在30分钟缺血前24小时进行四个周期的5分钟缺血/10分钟再灌注，通过TTC测量发现梗死面积显著减少至32.5±2.3%（与对照组相比P<0.05）。在组织学研究中，对照组有57.8±3.6%的危险区发生梗死。然而，在30分钟缺血前24小时进行的缺血预处理并不能保护心脏（梗死率为59.3±4.4%）。因此，当在再灌注3天后通过组织学评估梗死时，用早期TTC染色评估的SWOP的梗死限制作用无法得到证实。这些数据表明，SWOP可能没有持续的抗梗死作用，而可能只是简单地延迟了梗死的进展。
