A modified rabbit model of stroke: evaluation using clinical MRI scanner.

Objective: Occluding the middle cerebral artery of small animals with an intraluminal filament to build a stroke model has gained increasing acceptance. In light of the growing demand for magnetic resonance imaging (MRI) studies using the clinical MRI scanner, large animal models can be superior to small animal models. In this work, we developed a modified rabbit model of stroke, which was assessed using clinical MRI scanner and compared with a most commonly silicone-coated filament model.

Methods: We presented a focal cerebral ischemia in rabbits. The key feature of this modified method is the use of a guide wire as a 'nylon suture'. At 3 days after ischemia, the percentage of brain infarct volume, neurobehavioral score, intracranial hemorrhagic incidence and dynamic changes of T(2) and apparent diffusion coefficient values were assessed respectively and compared between the focal cerebral models.

Results: Wire-induced models had more severe brain infarct size with less dispersion (32.7 +/- 6.5%, coefficient of variation=0.20) than that with filament models (25.4 +/- 8.9%, coefficient of variation=0.31; p<0.05). There were more significant MRI changes in the early stage, higher rate of technique success (wire, 20/20; filament, 17/20) and less intracranial hemorrhage (wire, 0/20; filament, 3/20) in wire-induced models than in filament-induced rabbits (p<0.05).

Conclusion: Our data suggest that wire-induced method can provide a useful tool for the earlier research of ischemia.