Semb A G, Ytrehus K, Vaage J, Myklebust R
Department of Medical Physiology, University of Tromsø, Oslo, Norway.
J Mol Cell Cardiol. 1996 Feb;28(2):311-20. doi: 10.1006/jmcc.1996.0029.
Leukocytes can take part in an inflammatory response in the heart after myocardial infarction or cardio-thoracic surgery. To investigate the injurious mechanism of activated polymorphonuclear leukocytes (PMN), isolated rat hearts were perfused with phorbol 12-myristate 13-acetate (PMA) activated PMN (3 x 10(6)/ml) alone for 10 min, in combination with a mixture of oxygen free radical scavengers (superoxide dismutase+catalase+thiourea) or in combination with ibuprofen (IBU), a cyclooxygenase inhibitor or diethylcarbamazine (DCM), a lipoxygenase inhibitor or BW 755C, a dual inhibitor of cyclooxygenase and lipoxygenase and an oxygen free radical scavenger. After 30 min of recovery, the hearts were perfusion-fixed with glutaraldehyde for electron microscopical examination. Based on examination of 25 micrographs per heart obtained by a random sampling procedure and on morphometric methods, volume fractions (Vv) of mitochondria (mito), altered mitochondria (alt mito), myofilament, and cellular edema were measured as fractions of myocyte volume. The most important finding was that Vv(alt mito/myocyte) was 0.09 +/- 0.16 and 0.02 +/- 0.04 in the hearts receiving PMN+PMA alone and when scavengers were added, respectively, whilst no changes in mitochondrial ultrastructure was observed after addition of IBU, BW 755C or DCM. Vv(mito/myocyte) was for PMN+PMA alone: 0.33 +/- 0.04, +scavengers: 0.29 +/- 0.02 +IBU:0.29 +/- 0.02, +BW 755C: 0.23 +/- 0.03*, +DCM: 0.28 +/- 0.02 (mean +/- S.D., P < 0.05 compared to PMN+PMA). Capillary wall volume (cap wall) as a fraction of the whole capillary was also quantified. Vv(cap wall/cap) was for PMN+PMA alone: 0.26 +/- 0.06, +scavengers: 0.22 +/- 0.03, +IBU: 0.19 +/- 0.04, +BW755C: 0.21 +/- 0.03, +DCM: 0.15 +/- 0.04* (*P < 0.05). These results further strengthen the notion that activated PMN are intravascularly active. In addition to exerting a cardiodepressive effect the present study shows that activated PMN can induce structural changes in the heart through the combined action of oxygen free radicals and arachidonic acid metabolites.
白细胞可在心肌梗死或心胸外科手术后参与心脏的炎症反应。为研究活化多形核白细胞（PMN）的损伤机制，将离体大鼠心脏单独用佛波酯12 -肉豆蔻酸酯13 -乙酸酯（PMA）活化的PMN（3×10⁶/ml）灌注10分钟，或与氧自由基清除剂混合物（超氧化物歧化酶+过氧化氢酶+硫脲）联合灌注，或与环氧化酶抑制剂布洛芬（IBU）、脂氧化酶抑制剂二乙氨基甲嗪（DCM）、环氧化酶和脂氧化酶双重抑制剂及氧自由基清除剂BW 755C联合灌注。恢复30分钟后，用戊二醛对心脏进行灌注固定以进行电子显微镜检查。基于通过随机抽样程序获得的每颗心脏25张显微照片的检查以及形态计量学方法，测量线粒体（mito）、改变的线粒体（alt mito）、肌丝和细胞水肿的体积分数（Vv）作为心肌细胞体积的分数。最重要的发现是，单独接受PMN + PMA灌注的心脏和添加清除剂的心脏中，Vv（alt mito/心肌细胞）分别为0.09±0.16和0.02±0.04，而添加IBU、BW 755C或DCM后未观察到线粒体超微结构的变化。单独PMN + PMA灌注时Vv（mito/心肌细胞）为：0.33±0.04，+清除剂：0.29±0.02，+IBU：0.29±0.02，+BW 755C：0.23±0.03*，+DCM：0.28±0.02（平均值±标准差，与PMN + PMA相比P < 0.05）。还对作为整个毛细血管一部分的毛细血管壁体积（cap wall）进行了定量。单独PMN + PMA灌注时Vv（cap wall/毛细血管）为：0.26±0.06，+清除剂：0.22±0.03，+IBU：0.19±0.04，+BW755C：0.21±0.03，+DCM：0.15±0.04*（*P < 0.05）。这些结果进一步强化了活化的PMN在血管内具有活性的观点。除了发挥心脏抑制作用外，本研究还表明活化的PMN可通过氧自由基和花生四烯酸代谢产物的联合作用诱导心脏结构改变。
