Cerebral vasospasm and ultrastructural changes in cerebral arterial wall

Abstract

Subarachnoid hemorrhage (SAH) was produced experimentally by injecting normal dog''s blood and reserpinized dog''s blood into the chiasmal cistern of the dog. After SAH with normal dog''s blood, the intima of the basal truncal arterial wall showed some or all of such ultrastructural changes as appearance of vacuoles and dense bodies in endothelial cells, detachment of endothelial cells, appearance of intimal cells and intimal thickening. The changes first appeared 2 h after SAH, culminated at 3-7 days after SAH and persisted up to 1 mo. after SAH. After SAH with normal dog''s blood, the media of the basal truncal arterial wall showed some or all of such ultrastructural changes as moth-eaten contour of muscle cells, appearance of intracytoplasmic vacuoles and dense bodies, appearance of cell debris, enlargement of interstitial space and appearance of dense particles. These findings, expressed as myonecrosis and its repairing process, first appeared 2 h after SAH, culminated at 1-4 mo. after SAH and persisted up to 1 yr after SAH. Three and 5 days following SAH with reserpinized dog''s blood, ultrastructural findings of the intima and media of the basal truncal arterial wall were entirely normal. Ultrastructural changes in the cerebral arterial wall observed after SAH with normal dog''s blood occurred as a consequence of vasospasm. Late spasm may be facilitated by myonecrosis.