The cognitive and histopathological effects of chronic 4-vessel occlusion in rats depend on the set of vessels occluded and the age of the animals.

Continuing previous efforts to develop the 4-vessel occlusion (4-VO) model of chronic cerebral hypoperfusion (CCH), here we evaluated whether permanent, stepwise 4-VO causes both learning deficits, hippocampal neurodegeneration and retinal lesion in young, middle-aged or aged rats. Chronic 4-VO was induced by ligation of different sets of vessels, i.e.