Elastase & Collagenase-Induced Saccular Aneurysms In Rabbits And Biomechanical Experiment

Elastase & Collagenase-Induced Saccular Aneurysms in Rabbits and biomechanical experimentObjective: 1.To construct a new saccular aneurysm model in Rabbit's common carotid arteries with Artial segments digested by both elastase and collagenase. 2.Evaluation of the model by in vitro modeling experiment and to investigate the exponential relationless equation, material constant and the curve of the stress and straining of aneurysm models.Methods: 1. Rabbits were manipulated under general anesthesia and snipped a segmen about 2cm long from the animal's common carotid arteries. Artial segments were digested by both elastase(0.1ml,6units) and collagenase(1mg/ml)20 min . Then anastomosing Artial segments onto lateral sides of arteries constructed lateral aneurysm models.The animals were fed in coops. 2. Four days later, full aneurysms and parent arterys were took from rabbit's common carotid arteries.Models were placed in a circuit of pulsatile 0.9%brine that mimics the rheologic properties of blood. Images were recorded on computer and on a super VHS video at shutter speeds of 1/500 second. Analysis of the images were accomplished by softwire in computer. Indexs were dealt with biomechanical method .In the end, we gained the exponential relationless equation, material constant and the curve of the stress and straining of aneurysm models. 3.The same amount nomal arteries were experimented on the same way and compared by the models.Results: 1. Successful 7 lateral aneurysms,but 2 models occluded spontaneously. We gained 5 effective models in the end.2.The results and the theoretical tentative was similar.The exponential equation constituted is suitable to match their relationship.We obtained the exponential relationless equation, material constant and the curve of the stress and straining of the experiment group and the nomal group successfully.3.There are much difference between two groups in Results of biomechanical property.We found the material constant X1 ,X2 have statistic difference(P<0.05).In nomal group,the curves of the stress and strain were not linear ,but similar to the exponential function in the nomal pressure of the arteries.The curves in experiment group were not linear, either ,and the curves shifted to the left evidently. The mechanical properties of both the normal arteries and the aneurysms can be defined by the equations of the exponential function. Conclution: 1. The strength of aneurismal wall was destroyed as well as the elastic membrane disappeared in our new aneurysm model constructed by elastase & collagenase digested artial segment, which made this kind of experimental aneurysm similar to authentic aneurysms in both gross appearance and histological architectures and have the tendancy to rupture spontaneously. 2.We prove this new experiment method was feasible and obtained lots of biomechanical parameters which we want to kown. We first reported this experiment method in publication. 3. At present sugery and embolism was the primary treatment of intracranial aneurysms.But the curative effect by these treatment were not very satisfaction.The pathogeny of the aneurysms wound be shown by anatomy,pathology,biomechamics,molecular biology and gene study.They will help us find the most effective treatments of this disease.