An improved elastase-based method to create a saccular aneurysm rabbit model

Purpose. To find a safe, effective, and simple method to create a rabbit aneurysm model. Methods. Twelve adult New Zealand rabbits were divided into two groups: experimental (n = 9) and control (n = 3). The origin of the right external carotid artery was occluded with a temporary aneurysm clip, after which the right external carotid artery was ligated distally. The resulting stump was infused with elastase (experimental group) or saline (control group) for 20 minutes, and the clip was removed. The animals were studied angiographically and sacrificed 3 weeks after the procedure to harvest the aneurysms for histological analysis. Results. All nine rabbits in the experimental group successfully developed aneurysm after 3 weeks. Aneurysms had an average height of 5.2 +/- 1.1 mm and width of 3.5 +/- 0.8 mm. Histological analysis showed that the tunica media of the aneurysmal wall was barely identifiable. None of the three rabbits in the control group developed an aneurysm, and instead had achieved closure of the right external carotid artery stump. Conclusions. We have established an effective and a simple elastase-based method to create a rabbit aneurysm model. The procedure is easy to perform and does not require an interventional technique and or ligation of the internal carotid artery, which would otherwise reduce the blood supply to the brain.