A Model of Cerebral Arterial Vasospasm in Rabbits

ABSTRACT

OBJECTIVES: The present study aimed at confirming whether the previously reported rabbit vasospasm models are suitable to investigate the mechanisms of vasospasm after subarachnoid hemorrhage(SAH) in human. MATERIALS AND METHODS: Twenty rabbits were divided into 3 groups. The first one was the control group receiving no operation, and the second was the sham operation group, which received injection of 0.5ml/kg normal saline into cisterna magna, and the third was the SAH group, which received injection of 0.5ml/kg autologous arterial blood into the cisterna magna. Vertebrobasilar angiographies were followed up in the 12 rabbits that survived on the 2nd, 9th, and 16th days following the operation(9 rabbits in the SAH group, and 3 rabbits in the sham operation group). Baseline angiograms were obtained two days before the operation. The diameters of basilar artery on each days following the operation were measured and expressed as the percentage reduction compared with the initial basilar artery diameter. In 3 rabbits of the control group, vertebrobasilar angiographies were followed up on the same days as in the operation groups. RESULTS: There was a statistically significant differences in the size of the basilar artery among groups at sixteen days after cisternal injection(p=0.0450). On the second and ninth day after the operations, there was only the trend of the vasospasm of basilar artery(p=0.0687 and p=0.0812). The patterns of vasospasms were quite variable among rabbits. CONCLUSIONS: This study showed that vasospasm developed with the injection of 0.5ml/kg autologous blood injection into the cisterna magna but the pattern of vasospasm did not follow those demonstrated in the previous reports of vasospasm in rabbit models. The mortality rate was lower than previously reported results of other experimental SAH models. These results suggested that studies of the rabbit model should be conducted individually. In order to improve the model for the application to human, the functional study of the spasmodic basilar artery after the injection of autologous blood into the cisterna magna seems mandatory in the rabbits.