Apoptosis in the Penumbra of Vein Occlusion

Abstract

Two cortical veins occlusion in rats is less invasive, clinically relevant and reproducible model which is suitable forthe pathophysiology of penumbra-like tissue. We here examined sequential changes of Bcl-2 family proteins and TUNEL staining in this model.

Twenty-seven male Wister rats were used. Two adjacent cortical veins were occluded photochemically by using rose bengal dye. The rats were submitted to perfusion fixation at 4, 12 hours and 1,2,4,7 days after the vein occlusion(each=4). Immunohistochemical analysis of Bcl-2 family protein and TUNEL staining were performed to examine the relation with the process of cell death in the penumbra-like condition in venous circulation disorders. Three animals served as sham-operated control.

TUNEL positive cells began to appear at 1 day after the vein occlusion with the peak at 2～4 days and localized in the center and around infarction. Bax protein began to appear immunohistochemically at 4 hours around the ischemic lesion. Its peak was 1 day, and they were scattered around the infarction. On the other side, Bcl-2 protein was negative from the early phase to 4 days.

Based on the results of this study, apoptosis is related to the pathological development of venous infarction.