Neutrophil accumulation in experimental myocardial infarcts: relation with extent of injury and effect of reperfusion.

Abstract
The effects of reperfusion on the myocardial accumulation of neutrophils and their role in the extent of injury were investigated in a canine preparation with a 3 hr coronary occlusion followed by 21 hr of reperfusion. The left anterior descending coronary artery (LAD) was permanently occluded in group 1 and reperfused after 3 hr in four others (groups 2 to 5). All but group 5 received lidocaine (1 mg/min over 8 hr). A critical stenosis was produced and left in place at reperfusion only in group 2. In groups 1 and 2, 111In-labeled autologous neutrophils were injected at the time of coronary occlusion. Group 4 animals were rendered leukopenic 2 hr before the coronary ligature and throughout the experiment by injection of an antineutrophil rabbit serum. Quantification of the radioactivity by digitized scintigraphy of the heart slices revealed an 80% (p less than .05) increase in neutrophil accumulation in the infarct region after reperfusion (group 2) as compared with permanent occlusion (group 1). Gamma co...