Optimization And Evaluation Of Preparation Protocol In Small-diameter Decellularized Scaffolds For Vascular Tissue Engineering And The Study On Xenotransplantation In Situ

The core of vascular tissue engineering(VTE)is the seeding cells,the scaffolds which could support the cells live in and the interactions between cells and scaffolds.Finding a suitable scaffold is the most crucial step.Vascular scaffold is the 3-D falsework for seeded cell growth in vitro,provides the mechanical strength and characteristics for vessel rebuilding.In the scaffold,there was the biological information which could promote cell attachment,growth and proliferation.During the regeneration process of vessel,it supports the cell growth,migration,differentiation,and the extracellular matrix secretion,meanwhile,it decided the new vessel structure.Therefore,vascular scaffolds in tissue engineering of blood vessels play a very important role.Currently,the large diameter vessels(0>6 mm)have a lot of clinical applications,while there were still many problems needed to be solved in small diameter's((?):? 6 mm).The use of decellularized natural matrices takes advantage of the structure and mechanical performance of natural tissue extracellular matrix(ECM)while avoiding any adverse immunological reactions due to its origin.The decellularization process refers to the removal of antigenic cellular material from the vessel.Each step in detail of the decellularization process will have effect for the microstructure and composition of ECM,furthermore,effect the biocompatibility and graft-versus-host reaction.Therefore,in this thesis,the rabbit carotid artery((?)= 2 mm)was chose as the source of small diameter vascular scaffold.Compared with the decellularization process of ovine artery,the whole process for rabbit arteria carotis was optimized in conditions and agents in chemistry,physics and biology.There were five groups set in total.The results were evaluated using various microscopy and immunostaining techniques,such as scanning electron microscopy(SEM),H&E staining,Masson's trichrome staining,picrosirius red staining,mechanical testing in vitro,and subcutaneously implanted in rats for biocompatibility in vivo.Our findings showed that a 2 h digestion time with lx EDTA,replacing non-ionic detergent with double-distilled water for rinsing and the application of UV crosslinking gave rise to an ECM scaffold with the highest biocompatibility,lowest cytotoxicity and best mechanical properties for use in vivo or in situ pre-clinical research in VTE in comparison.Furthermore,we did the pre-operation with this acellular TEVG replacing the abdominal cavity in rat in situ.In six samples,the longest survival time is 10 days and it certified the acellular tissue engineering vessel graft(TEVG)could works in this xenotransplantation model in laboratory.In theory and practice,it was validated the feasibility of acellular vessel scaffold xenotransplantation in situ;the diameters of rabbit carotid artery and rat abdominal aortic could matched well,which could be stablished as a small natural ECM TEVG model in laboratory research.The last hypothesis was the surgical transplant success rates may be relevant with the body weight of rats and the food-intake way.As we still have blockage in the surgery such as intestinal obstruction.It needs further researches to confirm in detail.