A Novel Animal Model Of Abdominal Aortic Aneurysm Complicated With Outflow Tract Stenosis

Objective:To establish a novel rabbit model of abdominal aortic aneurysm complicated with outflow tract stenosis(OTS-AAA)and make a preliminary discussion about characteristics of the model,the Risk factors of abdominal aortic aneurysm(AAA)and the impact of outflow tract stenosis(OTS)on the rupture of AAA.To provideanimal model for the further research and treatment of AAA.Method:24 healthy male New Zealand rabbits were randomly divided into AAA(group A),AAA complicated with outflow tract stenosis(group B)and sham(group C)group.Rabbits in group A,the infrarenal aorta was freed for a segment and then infiltrated with porcine trypsin on the adventitia of this aortic segment for 30 minutes.Rabbits in group B was initially intervened the same with those in group A and then make a stenosis at the distal of aortic segment.Rabbits in group C had sham operation which saline was used for infiltration.We used digital subtraction angiography to measures the aortic diameter and then euthanize the rabbits to get the aortic tissues for HE,WVG staining for histologic analysis.Results:No rupture was observed in group A,and AAA was induced in 7 rabbits after 2 weeks,the average diameter of the artery was 3.53±0.03 mm.In group B,AAA was induced in 6rabbits after 2 weeks,3 rabbits(3 of 8)died of AAA rupture on the 18 th hour,29 th hour,and 68 th hour after operation,as group Br(B rupture).The average diameter of the artery was 3.57±0.07 mm,all of them were longitudinal ligature rupture.Other 3 rabbits in groupB were called group Bu(B unrupture),and the average diameter of the artery was3.49±0.08 mm on the 14 th days after operation.There is no ststistical differences betweem group A,Bu and Br.(p>0.05)No significant dilation was observed in group C.Compared with group C,arterial wall lesion,inflammatory cells infiltration and elastic fibers rupture were more serious in group A and B.Conclusions:All of the two methods can induce AAA model steadily.Compared with the classical model,the rabbit model of OTS-AAA is more likely to induce the rupture of aneurysm,which could better facilitate the study of the risk facts of ruptured AAA.