Polymorphonuclear Leukocyte Accumulation in Brain Regions with Low Blood Flow during the Early Postischemic Period

摘要

In an anesthetized canine model in which ischemia was induced by incremental air embolism, 16 animals were exposed to 1 hr of ischemia and monitored for 10 min (n = 4), 60 min(n = 6), or 240 min (n = 6). Fourteen animals were observed for corresponding periods without being subjected to ischemia 70 min (n = 4), 120 min(n = 4), or 300 min(n = 6). Autologous granulocytes were labeled with Indium III and reinfused just before ischemia. At the conclusion of each experiment, a Carbon 14 -iodoantipyrine autoradiographic blood flow study was performed. Granulocyte accumulation measured by gamma scintigraphy (cpm/gm) occurred in the injured hemisophere of ischemic animals at 60 min in anterior brain segments and at 240 min in anterior, middle, and posterior segments. By means of a double label autoradiography technique, clustering of punctate granulocyte image was detected in regions of low flow or heterogeneous flow in half of the animals at both 60 min and 240 min postischemia. Granulocyte clustering did not occur in the autoradiograms of nonischemic animals. The results implicate granulocyte participation in the acute phase of ischemic brain injury and signal a convergence of hemostatic and inflammatory process during the immediate post is chemic period. Keywords: Strokes.