The effects of peripheral leukocytes on the hippocampal neuronal changes in transient global ischemia and unilateral cerebral hemispheric infarction

The participation of activated leukocytes and subsequent production of chem ical mediators has been well accepted in the pathophysiology of hypoxic-isc hemic injury. This study was performed to see the effects of leukocytes on hippocampal neuronal damage in transient global ischemia induced by 10-min occlusion of bilateral common carotid arteries (CCAs) with reperfusion for various times, and in complete unilateral ischemia induced by 24-hr ligatio n of left CCA, Leukopenia was induced by intraperitoneal injection of cyclo phosphamide for 4 days. The results showed that hippocampal neuronal damage s were worse at 6-hr reperfusion in leukopenic experimental group than in t he control group. In comparison, 24-hr and 3-day reperfusion leukopenic gro ups showed less numbers of damaged neurons and milder changes. The 5-day re perfusion group showed inconsistent changes, Unilateral CGA occlusion showe d extensive infarction in 83.3% of gerbils in the control group, compared t o 25% of gerbils in the experimental group (p<0.05). These results strongly suggest that the number of peripheral leukocytes were closely related to t he development of delayed neuronal damage of hippocampus in transient globa l ischemia and the incidence of infarction induced by 24-hr unilateral CCA ligation.