| Background: As a new type of biodegradable materials, chitosan has a good histocompatibility and after sulfating the silk fibroin has good anticoagulant and mechanical stability. The present experimental study used the new type of biodegradable small diameter artificial blood vessels that fabricated with chitosan and sulfated silk fibroin for replacing canine common carotid artery, and evaluated the effect of the small diameter artificial vessels bypass transplantation. To evaluate the patency of artificial blood vessel, the carotid artery angiography was performed; And pathological light microscope and electron microscope observation were used to test the degree of biodegradation and endothelialization. If the performance index of this artificial material blood vessel was good, it will be expected to solve the current shortage of small diameter artificial blood vessels.The artificial blood vessel that made by new materials is closer to human body’s vessel, and its autologous level was high after vessels transplantation. However, it has many shortcomings including the histocompatibility of blood and tissue was not good after transplanting the artificial blood vessel to human body, acute thrombosis and chronic excessive hyperplasia endometrium, which may lead to the anastomosis stenosis and occlusion.Objective: Investigating the patency and pathological change of histocompatibility and endothelial cells’ growth in different stages after the transplanting of the small diameter artificial blood vessels.Methods: We duplicated the canine model of artificial blood vessels graft replaced the common carotid artery, and anticoagulation and antiplatelet drugs were administrated during the perioperative period. Canines’ common carotid artery angiographies were performed after one month, three months and six months respectively. The materials of artificial blood vessels were observed by the light and electron microscope to determine their pathological changes.Results and conclusion:(1) Angiography: the artificial blood vessels were unobstructed after one month transplantation, and mild stenosis not occlusion of anastomositis was observed. The artificial blood vessel anastomotic was severe stenosis or almost occlusion after three months transplantation. Six months later, the anastomotic of artificial blood vessel was totally occlusion.(2)Light microscope: After one month transplantation, there was no capillary in the artificial blood vessel cavity, but we could find a small amount of lymphatic cells, neutrophils and monocytes infiltration, fibroblasts in surrounding. Three months and six months after transplantation, the anastomotic was occlusion, as well there was a large amount of fibrous tissue hyperplasia and inflammatory changes around the anastomotic. However, new capillaries could be found, which were increased significantly in the six months group than the three months group.(3)Electron microscope: One month group endothelial cells were not found. In the three months group, we found a small quantity of dispersive endothelial cells in the gridding of the artificial blood vessel. In the six months group, we found a large of consecutive endothelial cells, which grew from the anastomositis to the middle of the artificial blood vessel.(4)All the artificial vessels were not fractured, and aneurysms were not happened when we got out them from canine’s body. The old thrombosis was not seen in artificial blood vessel, but a large amount of fibrous tissue hyperplasia chronic inflammation happening around the anastomositis. These results suggest that the novel small diameter artificial blood vessel has many advances, such as the stable mechanical performance, the earlier formation of endothelial cells, the perfect blood histocompatibility. But the inflammation of tissue is so severe that the fibrous tissue was hyperplasia, leading to the anastomositis stenosis and occlusion finally, the long-term patency rate of the vascular was low,and need further study to improve. |
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