A rabbit model of abdominal aortic aneurysm associated with intimal thickening

A model of abdominal aortic aneurysm with intimal thickening was developed in the rabbit. A segment of the abdominal aorta just proximal to the bifurc ation (1 or 2 cm in length) was dissected and isolated with clamps. This se gment was perfused by injecting physiologic saline or 100 U/ml of hog pancr eatic elastase from the lumen. Perfusion was performed manually for 5 min a nd the peak pressure in the segment was between 300 and 400 mm Hg in order to cause aortic wall injury. After 4 weeks, animals that had received perfu sion with elastase had aneurysms in the perfused segment on arteriography. None of the other animals developed aortic aneurysms. Histologically, the s egments of aorta perfused with saline exhibited intimal hyperplasia. In add ition to the intimal hyperplasia, the segments of aorta perfused with elast ase solution showed lysis of the elastic lamellae in the media that resulte d in aneurysm formation.