Creation Of Saccular Aneurysms In The Rabbits Using Endovascular Technique And Elastase

Objective:we evaluated the feasible of intra-venous digital subtraction angiography in rabbits imaging, to search for the dosage of administer and X-ray delay time. Then we contrasted the image between the arteriography and phlebography. We established saccular aneurysms in the rabbits using endovascular technique and elastase. Then we observed long-term patency in angiography and changes in pathology and research for the easy method to digital subtraction angiography for experimental aneurysms imaging.Methods:(1)contrast intra-arterial digital subtraction angiography and intra-venous digital subtraction angiography: 3 New Zealand white rabbits(2.6～2.7kg) were involved in this study.The angiography of first time was intra-venous digital subtraction angiography, while the second was intra-arterial digital subtraction angiography. When we took intra-venous digital subtraction angiography, we chosed pressure 300, X-ray 5s,4s,3s, the dosage of administer:the speed of injection was 10ml:8ml/s, 8ml:6ml/s, 6ml:4ml/s, 4ml:3ml/s, 2ml:1ml/s. When we took intra-arterial digital subtraction angiography, we used surgical intervention to separate femoral artery, puncted it with 18G dynamic and static needle, then we inserted 4F sheath, infused heparin 100u/kg, took the pipe to the aortic arch. We attenuated constrast medium(ultravist:PS is 1:2). When we took arteriography, we chosed pressure 300, inject delay 1s, the dosage of administer:the speed of injection was 4ml:3ml/s. Then we contrasted the imaging in the same rabbit. (2) The establishment of aneurysm model: 12 New Zealand white rabbits(2.5～3.0kg) were involved in this study.This experiment included two groups: test group included 9 animals and control group included 3 animals. We took anaesthesia with intramuscular injection. We puncted ear edge vein with 20G dynamic and static needle, detained the sheath to provide phlebography. we used surgical intervention to separate right common carotid artery, puncted it with 18G dynamic and static needle, then we inserted 4F sheath, made route through 4F sheath, under the route we inserted Hyper Glide ball at the origin of right common carotid artery. We turged ball to bung the right common carotid artery. Elastase was incubated endoluminally in the proximal common carotid artery above the ball in the test group, while the control group was PBS liquor. The common carotid artery was ligated distally. Animals were studied angiographically and sacrificed at 1 weeks (n = 3), 2 weeks (n = 3), and 4 weeks (n = 3) after aneurysm creation. (3) Pathematology Checked: We executed 3 rabbits in test group and 1 rabbit in control group with injecting overdose narcotis after phlebography. Then we cut both carotid and its branch, put it into 10% formaldehyde solution. 48 hours later, we used 0.01M PBS to wash it 3 times, each time is 5 minute, fixed it in neutral formalin solution 1 week. Then we used alcohol dehydrate it, embedment, slender, semithin section. We observed it with light microscope after dye.Results:(1)We contrasted the image of between the arteriography and phlebography. It can display aorta and other great vessels clearly ,when we chosed pressure 300, X-ray delay 4s, volume dose of contrast : inject speed is 10ml : 8ml/s, 8ml:6ml/s, 6ml:4ml/s, 4ml:3ml/s. For prevention of the constrast medium overdose, we think that pressure 300, X-ray delay 4s, volume dose of contrast : inject speed is 4ml : 3ml/s is most better in intra-venous digital subtraction angiography.(2)Saccular aneurysms formed in eight of the nine rabbits in test group(88.9%).1 rabbit was failed to form the aneurysm model. At the point of 1 weeks, 2weeks, 4weeks after surgery, The width, height and parent vessel diameter of aneurysms was been measured. There were no significant difference(P>0.05). 1 rabbit was accidental dead in control group, others did not form aneurysm model. (3)HE dyeing shown that thrombosis formed at the top of the aneurysms cavea,nascent endomembrane formed,the wall of the aneurysms hyperplasy, inflammatory cell infiltrated,4 weeks later thrombus organization. We can see that the right carotid artery stump was bung with thrombosis.Conclusion:1.we can establish stable saccular aneurysms in the rabbits using endovascular technique and elastase. 2.Intra-Venous Digital Subtraction Angiography can clearly shown the large arteries on aortic arch in rabbit imaging, and it is a well complementary method to IADSA especially for the long-term follow up. 3.The aneurysm model is similar with human intracranial aneurysms, which was confirmed by angiography. 4,This aneurysm model can be used for the research of endovascular treatment.