A modified technique improved histology similarity to human intracranial aneurysm in rabbit aneurysm model

Persistent undigested elastic membranes and collagen in the tunic media of rabbit elastase-induced aneurysm models lowered their histology similarity to human intracranial aneurysm. Our purpose was to make good the deficiency. Ten New Zealand white rabbits were divided into three groups: six rabbit in two groups for evaluating the difference in various treatments, and four rabbits for long-term observation. We inflated and occluded the right common carotid artery (CCA) by an endovascular technique. The first group of three rabbits was only given 200u elastase in the proximal segment of right CCA; the second group was given 100u elastase and 1.5mg collagenase, then the right CCA was ligated. The first and second groups were studied by magnetic resonance angiography (MRA), sacrificed at three weeks after aneurysm creation, their histology results were obtained and compared with human aneurysm. The third group underwent the same procedure as the second group only for three months of observation with enhanced MRA. Saccular aneurysms formed in all rabbits. Degeneration of the extracellular matrix and atrophy of smooth muscular cells in tunic media were more apparent in the second group. The third group remained stable for more three months. Two modifications included inflating the right CCA with a balloon and adding collagenase incubation can promote an aneurysm model more histologically similar to human aneurysm. In addition the improved aneurysm model remains stability for a long time.