The Application And Research Of PRP In Endothelialization Of Tissue-engineered Blood Vessels

Background and objectiveVascular transplantation has become an ideal substitute for the treatment of heart and peripheral vascular diseases.However,there is no ideal product for smalldiameter blood vessels for clinical application.The rapid-endothelialization and complete physiological functions are a major challenge for small-diameter vascular grafts.PRP is a plasma extract,a large amount of growth factors(GFs)can be released through a granules when it activated.PRP can promote angiogenesis,tissue regeneration and repair.However,the application of PRP in Tissue-engineered blood vessels(TEBVs)has not been reported in the literature.TEBVs loaded with PRP were prepared by electrospinning process,The role of PRP in endothelialization and angiogenesis in TEBVs was discussed,and expect to provide reference and theoretical basis for the application of PRP in TEBVs.Methods1.Taking New Zealand rabbits as the research object,PRP was obtained by the two-step centrifugation.Collecting PRP supernatant when it activated by calcium chloride as material for TEBVs.vascular endothelial cells(VECs)and vascular smooth muscle cells(VSMCs)were obtained respectively by enzyme digestion and tissue adherence method from the common carotid artery of Rabbit.The primary cells were cultured to be used for experiment when cultured to the 3rd to 6th generation.2.VECs and VSMCs were co-cultured in different concentrations of PRP to definite the optimal concentration,which can improve the competitive growth advantage of VECs relative to VSMCs.TEBVs and mats loaded with PRP were fabricated based on PLLA and Gelatin,and then characterized in terms of biological properties.3.TEBVs loaded with 5%PRP were transplanted applying rabbit carotid artery replacement model.The endothelialization of TEBVs were evaluated by variety of ways.Results1.The purity of the primary cells was above 95%,which met the experimental requirements.The results of the co-culture model showed that 5%PRP could improve the competitive growth ability of VECs relative to VSMCs.2.The TEBVs loaded with 5%PRP were successfully fabricated.It has good histocompatibility,hydrophilicity,mechanical properties and degradability.The results of ELISA showed concentrated growth factors(VEGF,PDGF,TGF-β1)can released stably for 25days.3.Cell experiments confirmed that the mats loaded with 5%PRP can effectively promote the proliferation,migration,and S phase ratio of VECs and VSMCs.It also promoted the density of VECs layer and completed the function of VECs.4.In vivo experiments,we confirmed that 5%PRP is helpful for the reconstruction and optimization of vascular intimal tissue,up-regulates the expression of eNOS in functional VECs,maintains the contractile phenotype of VSMCs,and is beneficial to the regeneration of the outer wall of TEBVs.ConclusionPRP can effectively promote the endothelialization of small diameter TEBVs.