AN EXPERIMENTAL-MODEL OF SYMPTOMATIC VASOSPASM INDUCED BY OXYHEMOGLOBIN IN RABBITS

Background and Purpose There are many experimental models for studies of cerebral vasospasm. However, no ideal model has been established th us far to comparatively reproduce the ischemic state of the brain that may occur in patients after subarachnoid hemorrhage. Methods In the p resent study, we attempted to induce severe vasospasm in rabbits by us ing an oxyhemoglobin-rich blood product prepared from hemolyzed arteri al blood and evaluate neurological symptoms, cerebral angiogram, cereb ral blood flow, and histology. Results Clinically significant neurolog ical symptoms were observed in about half of the rabbits. There was no significant correlation between angiographic results of the vasospast ic state of the main artery and the severity of neurological symptoms observed. However, the cerebral blood flow was significantly lower tha n in the control group and significantly correlated with the severity of neurological symptoms. On histological examination, lesions were fo und in about half of the rabbits. Development of obvious infarction wa s found more frequently than in other reported models. Conclusions The se results suggest that this model is appropriate as an experimental m odel of vasospasm occurring after subarachnoid hemorrhage and is espec ially useful in that it induces vasospasm intense enough to cause obvi ous infarction.