Morphological changes of cerebral penetrating arteries in a canine double hemorrhage model

BACKGROUND Morphological presentations of cerebral vasospasm, such as dystrophy and de squamation of endothelial cells, corrugation of the internal elastic layer, and necrotic changes in smooth muscle cells, are well defined in large cer ebral arteries. This study was undertaken to examine pathological changes i n cerebral penetrating arteries in a canine double hemorrhage model. METHODS Eighteen mongrel dogs were subjected to an autologous arterial blood (0.4 m L/kg) injection into the cisterna magna on day 0 and day 2 after withdrawal of an equivalent amount of cerebrospinal fluid. Angiogram was performed on day 0 before the blood injection and on the day the dogs were sacrificed. The dogs were divided into four groups: control (day 0) (n = 4), hemorrhage and sacrificed on day 3 (n = 4), day 5 (n = 5), and day 7 (n = 5). The pen etrating arteries were removed and found to be spastic on days 3, 5, and 7, but not in the control group. RESULTS Endothelial dystrophy and partial desquamation were recorded in all dogs sa crificed on days 5 and 7. Condensation of chromatin, blebbing of the membra ne, and condensation of cytoplasm were identified in many endothelial cells , features that are consistent with apoptosis. The morphological changes in the penetrating arteries were more pronounced on days 5 and 7. CONCLUSIONS Vasospasm occurred in cerebral penetrating arteries in a canine double hemo rrhage model. The morphological change in penetrating arteries, especially apoptosis in endothelial cells, is consistent with an early phase of vasosp asm. Vasospasm in a penetrating artery may contribute to the cerebral ische mia that occurs during vasospasm. (C) 2000 by Elsevier Science Inc.