Ko W, Hawes A S, Lazenby W D, Calvano S E, Shin Y T, Zelano J A, Antonacci A C, Isom O W, Krieger K H
Department of Surgery, New York Hospital-Cornell University Medical College, NY 10021.
J Thorac Cardiovasc Surg. 1991 Aug;102(2):297-308.
To study the roles of platelet-activating factor, polymorphonuclear leukocytes, and oxygen free radicals in myocardial reperfusion injury, we subjected 10 sheep to 90 minutes of mid-left anterior descending coronary artery followed by 6 hours of reperfusion. Stainings with gentian violet and tetratriphenyl ammonium chloride demonstrated 20% +/- 3% of the left ventricular mass at risk for ischemia, of which 75% +/- 10% underwent infarction. Coronary sinus blood was assayed for platelet-activating factor and neutrophil hydrogen peroxide production before and during coronary occlusion and during reperfusion. Platelet-activating factor was isolated by column chromatography and lipid extraction and quantified by radioimmunoassay. Neutrophil hydrogen peroxide production was measured by a 2',7'-dichlorofluorescein flow-cytometric assay. Platelet-activating factor was elevated to 899 +/- 210 pg/ml at 15 minutes of reperfusion, compared with the preocclusion level of 271 +/- 55 pg/ml and coronary occlusion level of 359 +/- 64 pg/ml (p less than 0.05; analysis of variance). Neutrophil hydrogen peroxide production, measured on a relative fluorescence scale, was also elevated to a level of 141 +/- 27 at 1 hour of reperfusion, compared with the preocclusion level of 103 +/- 6 and the coronary occlusion level of 114 +/- 13 (p less than 0.01; analysis of variance). Both of these parameters returned toward baselines at the end of 6 hours of reperfusion. Histologic examination revealed infiltration of polymorphonuclear leukocytes into the interstitium of the reperfused myocardium. Neutrophils isolated from unoperated and healthy sheep demonstrated a graded dose response in hydrogen peroxide production when stimulated by purified platelet-activating factor in vitro. These findings suggest that platelet-activating factor is released in the coronary circulation and is a mediator of oxygen free radical production in polymorphonuclear leukocytes during myocardial reperfusion.
为研究血小板活化因子、多形核白细胞及氧自由基在心肌再灌注损伤中的作用，我们对10只绵羊进行实验，使左冠状动脉前降支中段闭塞90分钟，随后再灌注6小时。用结晶紫和四苯基氯化铵染色显示，左心室有20%±3%的心肌存在缺血风险，其中75%±10%发生梗死。在冠状动脉闭塞前、闭塞期间及再灌注期间，对冠状窦血液进行血小板活化因子和中性粒细胞过氧化氢生成量的检测。血小板活化因子通过柱色谱法和脂质提取法分离，并通过放射免疫测定法定量。中性粒细胞过氧化氢生成量通过2',7'-二氯荧光素流式细胞术测定。再灌注15分钟时，血小板活化因子升高至899±210 pg/ml，而闭塞前水平为271±55 pg/ml，冠状动脉闭塞时水平为359±64 pg/ml（p<0.05；方差分析）。以相对荧光量度衡量，中性粒细胞过氧化氢生成量在再灌注1小时时也升高至141±27，而闭塞前水平为103±6，冠状动脉闭塞时水平为114±13（p<0.01；方差分析）。这两个参数在再灌注6小时结束时均恢复至基线水平。组织学检查显示多形核白细胞浸润至再灌注心肌的间质中。从未手术的健康绵羊分离出的中性粒细胞在体外受纯化的血小板活化因子刺激时，过氧化氢生成呈现剂量依赖性反应。这些发现表明，血小板活化因子在冠状动脉循环中释放，并且是心肌再灌注期间多形核白细胞中氧自由基生成的介质。
