Temporal and spatial profile of apoptotic cells after focal cerebral ischemia in rats.

The significance of apoptosis in focal ischemia was investigated in the spatial and temporal profiles of apoptotic cells caused by permanent and transient focal ischemia induced in male Wistar rats by intraluminal vascular occlusion. Animals were sacrificed at various times and coronal sections of the brain at the level of the optic chiasm were examined histologically by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling. Animals in both groups showed apoptotic cells in the infarcted area, particularly in the border zone. Animals with permanent ischemia showed more extensive infarct and more rapid appearance of apoptotic cells. Activation of apoptosis might depend on the severity of the ischemic insult. Apoptotic cells were observed at 7 days after the ischemic insult in animals with transient ischemia, suggesting apoptosis is involved in the developments of delayed infarct.