Ganote C E, Humphrey S M
Am J Pathol. 1985 Jul;120(1):129-45.
It has not previously been possible to study the in vitro effects of reperfusion on severely injured isolated perfused hearts because of the development of the no-reflow phenomenon, concomitant with the onset of irreversible myocardial cell injury. A new model of ischemic injury which utilizes an intraventricular balloon to allow uniform reperfusion of irreversibly damaged hearts is described. The effects of reperfusion were studied in Langendorff perfused rat hearts after no-flow ischemia for 60 and 150 minutes at 37 C. Uniform reflow was facilitated by maintaining the left ventricle at an isovolumic diastolic volume with a balloon during ischemia and removal of the balloon prior to reflow. Reperfusion was with 1) anoxic media, 2) oxygenated media, 3) oxygenated media in the presence of the mitochondrial inhibitor Amytal, or 4) an initial anoxic reperfusion followed by oxygenated media. Injury was monitored by the assay of released creatine kinase (CK) and myoglobin (Myo), by light-microscopic estimates of the percent of cells containing contraction bands, and by ultrastructural changes. CK and Myo were released with anoxic reperfusion, but larger releases occurred with oxygenated reperfusion. Amytal inhibited the oxygen but not the nitrogen component of release. Contraction bands occurred following oxygenated, but not anoxic, reperfusions and were inhibited by Amytal. Following an initial anoxic reperfusion, oxygen caused additional CK and Myo release and produced an increase in the percent of cells with contraction bands, compared with that with oxygen alone. The response of cells to injury was heterogeneous, and the hearts contained cells with a spectrum of ultrastructural changes. Anoxic reperfusion was associated with cellular swelling and oxygenated reperfusion with contraction band necrosis.
由于无复流现象的出现，同时伴随着不可逆心肌细胞损伤的发生，以前一直无法研究再灌注对严重损伤的离体灌注心脏的体外影响。本文描述了一种新的缺血损伤模型，该模型利用心室内球囊使不可逆损伤的心脏实现均匀再灌注。在37℃下无血流缺血60分钟和150分钟后，在Langendorff灌注的大鼠心脏中研究再灌注的影响。在缺血期间用球囊将左心室维持在等容舒张容积，并在再灌注前移除球囊，以促进均匀复流。再灌注采用以下方式：1）缺氧介质；2）氧合介质；3）在线粒体抑制剂阿米妥存在下的氧合介质；或4）初始缺氧再灌注后接氧合介质。通过测定释放的肌酸激酶（CK）和肌红蛋白（Myo）、通过光学显微镜估计含有收缩带的细胞百分比以及通过超微结构变化来监测损伤。CK和Myo在缺氧再灌注时释放，但在氧合再灌注时释放量更大。阿米妥抑制了释放的氧成分，但不抑制氮成分。收缩带出现在氧合再灌注后，而不是缺氧再灌注后，并且被阿米妥抑制。与单独使用氧相比，在初始缺氧再灌注后，氧导致额外的CK和Myo释放，并使含有收缩带的细胞百分比增加。细胞对损伤的反应是异质性的，心脏中含有具有一系列超微结构变化的细胞。缺氧再灌注与细胞肿胀有关，氧合再灌注与收缩带坏死有关。
