Biological And Practical Research Of The Chitosan Small-Diameter Biodegradable Artificial Vascular Prosthesis

Cardiovascular disease is a one kind of the common diseases that endanger thehealth of human. The most frequently used treatment is blood vessel transplantation.So the Source of the transplanted blood vessel has become an critical problem. Oneof the methods to resolve this problem is to prepare artificial vascular prothesis. Nowsome of the artificial vascular prosthesis have been applied in big-diameter artificialvascular prosthesis successfully. However, when they are used for arteriola,mediumsized artery and vein replacements (<6mm ID), they encounter muchlower flow scenarios and are more likely to promote thrombus formation and intimalhyperplasia. So the construction and modification of the artificial vascula prosthesishas been paid more and more attention in recent year.Chitosan is a kind of functional polysaccharide with polypositive ion。It showsa lot of interesting biological properties such as low cytotoxicity andbiodegradability. Therefore, it has been extensively used in tissue engineering andbiomedical material engineering. In this study, chitosan fiber, carboxymethylchitosan and hydroxyethyl chitosan were mixed with other polysaccharides andproteins to prepare a new biodegradable chitosan small-diameter artificial vascularprosthesis to ease some strains on the shortage of the small-diameter artificialvascular prosthesis. The studies develop four contents as below:1. To evaluate the physicochemical and mechanical properties of the artificialvascular prosthesis, aquiferous capacity, ash content and heavy metals content of theartificial vascular prostheses were measured respectively, and wall thickness, water absorbing rate, osmotic pressure, osmotic amount, longitudinal tensile strength, burstpressure and suture retention was measured respectively. aquiferous capacity, ashcontent and heavy metals content of the artificial vascular prostheses were10.05%,0.28%and <10μg/ml; wall thickness, water absorbing rate, osmotic pressure,osmotic amount, longitudinal tensile strength, burst pressure and suture retention ofthe artificial vascular prosthesis are0.54±0.022mm,226.02±8.17%,39.25±3.35mmHg,4.90±0.47ml,8.58±1.98N(in dry condition),1986±247mmHg(in wetcondition),3.87±0.43N(in wet condition), respecitively. Theses results apply areference for this kind of biodegradable artificial vascular prothesis.2. The biodegradability, biocompatibility and biological safety of the artificialvascular prosthesis were evaluated. The result showed that, the artificial vascularprosthesis could be degraded stably and heparin in the artificial vascular prosthesiscould degraded continually to keep the anticoagulating ability of the artificialvascular prosthesis in a long time; the vascular endothelial cells grow well on theinner surface of the artificial vascular prosthesis; no inflammation and plateletadhesion occurred, and the cell toxicity, hemolysis, acute systemic toxicity,intracutaneous stimulation were up to clinical demand.3. A preliminary implantation test of the artificial vascular prosthesis wascomplimented. In animal test, the artificial vascular prosthesis was used to replace asection of femoral artery in dogs. In the period of observation, Complete andgradual decomposition of the prosthesis and replacement by a natural blood vesselwere observed, and the patency of the blood could be kept in the whole observingperiod. The results of Hematoxylin and eosin staining, immunohistochemical study,and scanning electron microscope observation showed that the tissual structure of anatural blood vessel has been formed.