Comparison between one- and two-hemorrhage models of cerebral vasospasm in rabbits

Injection of blood into the cisterna magna is one of the most frequently used methods to produce subarachnoid hemorrhage (SAH) models in animals. Although the two-hemorrhage model of vasospasm is frequently used in canine and rat models, most studies with rabbits only use the one-hemorrhage model. In the present study, we accomplished a side-by-side comparison between one- and two-hemorrhage models in rabbits. A total of 38 rabbits were randomly divided into three groups, i.e. control group (n = 5), one (n = 15)- and two (n = 18)-hemorrhage model groups. The degree of cerebral vasospasm, the time course of cerebral vasospasm, the clinical behavior, and the residual amount of subarachnoid blood clots were measured on days 3, 5 and 7 after the establishment of the models. Compared with one-hemorrhage model, the time course of vasospasm in the two-hemorrhage model was more coincident with that observed in humans, produced more severe vasospasm after SAH, and had an acceptable low mortality. In conclusion, the two-hemorrhage model in rabbits is more appropriate than the one-hemorrhage model for the research on SAH or cerebral vasospasm, and thus can be used for the investigation of the mechanisms of and therapeutic approaches for cerebral vasospasm.