Kukielka G L, Smith C W, LaRosa G J, Manning A M, Mendoza L H, Daly T J, Hughes B J, Youker K A, Hawkins H K, Michael L H, Rot A, Entman M L
Section of Cardiovascular Sciences, Methodist Hospital, DeBakey Heart Center, Houston, Texas.
J Clin Invest. 1995 Jan;95(1):89-103. doi: 10.1172/JCI117680.
Neutrophil adhesion and direct cytotoxicity for cardiac myocytes require chemotactic stimulation and are dependent upon CD18-ICAM-1 binding. To characterize the potential role of IL-8 in this interaction, canine IL-8 cDNA was cloned and the mature recombinant protein expressed in Escherichia coli BL21 cells. Recombinant canine IL-8 markedly increased adhesion of neutrophils to isolated canine cardiac myocytes. This adhesion resulted in direct cytotoxicity for cardiac myocytes. Both processes were specifically blocked by antibodies directed against CD18 and IL-8. In vivo, after 1 h of coronary occlusion, IL-8 mRNA was markedly and consistently induced in reperfused segments of myocardium. IL-8 mRNA was not induced in control (normally perfused) myocardial segments. Minimal amounts of IL-8 mRNA were detected after 3 or 4 h of ischemia without reperfusion. Highest levels of induction were evident in the most ischemic myocardial segments. IL-8 mRNA peaked in the first 3 h of reperfusion and persisted at high levels beyond 24 h. IL-8 staining was present in the inflammatory infiltrate near the border between necrotic and viable myocardium, as well as in small veins in the same area. These findings provide the first direct evidence for regulation of IL-8 in ischemic and reperfused canine myocardium and support the hypothesis that IL-8 participates in neutrophil-mediated myocardial injury.
中性粒细胞对心肌细胞的黏附及直接细胞毒性作用需要趋化刺激，且依赖于CD18-细胞间黏附分子-1（ICAM-1）的结合。为了阐明白细胞介素-8（IL-8）在此相互作用中的潜在作用，克隆了犬IL-8 cDNA，并在大肠杆菌BL21细胞中表达了成熟的重组蛋白。重组犬IL-8显著增加了中性粒细胞对分离的犬心肌细胞的黏附。这种黏附导致了对心肌细胞的直接细胞毒性。这两个过程均被针对CD18和IL-8的抗体特异性阻断。在体内，冠状动脉闭塞1小时后，再灌注的心肌节段中IL-8 mRNA显著且持续诱导表达。对照（正常灌注）心肌节段未诱导出IL-8 mRNA。缺血3或4小时且未再灌注后，检测到极少量的IL-8 mRNA。诱导水平最高的是最缺血的心肌节段。IL-8 mRNA在再灌注的最初3小时达到峰值，并在24小时后持续高水平表达。IL-8染色存在于坏死心肌与存活心肌交界处附近的炎性浸润中，以及同一区域的小静脉中。这些发现为缺血和再灌注犬心肌中IL-8的调控提供了首个直接证据，并支持IL-8参与中性粒细胞介导的心肌损伤这一假说。
