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 thus far to comparatively reproduce the ischemic state of the brain that may occur in patients after subarachnoid hemorrhage. METHODS In the present study, we attempted to induce severe vasospasm in rabbits by using an oxyhemoglobin-rich blood product prepared from hemolyzed arterial blood and evaluate neurological symptoms, cerebral angiogram, cerebral blood flow, and histology. RESULTS Clinically significant neurological symptoms were observed in about half of the rabbits. There was no significant correlation between angiographic results of the vasospastic state of the main artery and the severity of neurological symptoms observed. However, the cerebral blood flow was significantly lower than in the control group and significantly correlated with the severity of neurological symptoms. On histological examination, lesions were found in about half of the rabbits. Development of obvious infarction was found more frequently than in other reported models. CONCLUSIONS These results suggest that this model is appropriate as an experimental model of vasospasm occurring after subarachnoid hemorrhage and is especially useful in that it induces vasospasm intense enough to cause obvious infarction.