RADA16-I/TRSAW水凝胶修饰的支架即刻构建组织工程骨及其成骨效果和机制的研究

骨髓富集物因含有促成骨的细胞而具有较好的骨修复效果。课题组通过RADA16-I肽来缩小支架材料的孔径提高骨髓中细胞的富集，取得了较好的成骨效果；但手段单一、成骨诱导能力不强是其瓶颈。甲状旁腺素相关蛋白功能肽-TRSAW，带净正电荷兼具成骨诱导能力，而骨髓中细胞表面带负电荷，二者可通过正负电荷相互吸附。构建一种新型的自组装肽RADA16-I/TRSAW，验证是否可通过电荷吸附作用提高细胞的富集效率。锚定支架上的TRSAW更利于局部稳定发挥成骨作用，虽已证实VEGFR2信号通路参与其中，但是二者如何作用并不清楚。本研究通过富集效率检测和信号通路研究验证假说：TRSAW对成骨相关细胞的作用是以Src激酶介导的VEGFR2信号通路实现的。本研究创新性在于首次提出电荷吸附提高骨髓富集的理论及阐明修饰支架的成骨诱导机制，为进一步提高骨髓的富集效率提供新的策略，为骨移植提供了一种新的可供选择的材料。

The resource of a great deal of and highly osteoinductive bone graft is a huge problem during bone tansplantation. Tissue-engineered bone fabricated by autogeneic cells and scaffold has a known and better effectiveness than scaffold alone. However, some issues inhibit its wide application in clinic just like long proliferative time in seeding cells, high technologies in fabrication process, and high requirements on storage and transport. The enriching construct from bone marrow and scaffold by quich fabricated technology shows a good osteoinduction and a promising outlook. At present, low enriching rate and single enriching strategy limit the development of .enriching construct from bone marrow. For raising enriching rate and promoting osteogenesis, a new self-assembling peptide (SAP), RADA 16-I linked with TRSAW, is developed and is used to modify scaffold to improve enrichment of cells from bone marrow and to promote osteogenesis. The potential mechanism incldes that the pore diameter of scaffold will be shrinked by nanoscale fiber of SAP and raise retension of cells and factors from bone marrow; the charges derived from new SAP will increase adhension of cells in bone marrow; the biocompatibility of scaffold will receive benefit from SAP’s similar sructure to extracellular matrix; the osteogenic differentiation triggered by TRSAW will accelerate the osteogenesis of the construct formed by bone marrow and composite scaffold. During osteogenesis of enriching construct trigger by TRSAW, Src kinase plays an important role and interacted with VEGFR2 to induce a series reactions on the osteogenic related cells. The interface modification of new SAP shall renovate the current enriching strategy which depends on the only retension with shrinking pore size. Furthermore, the charges from SAP will increase more enrichment of cells from bone marrow, that has been not focused on before. The study will supply a new stratrgy for bone marrow construct and explore the potential mechanism.