Experimental Studies On A New Tissue Engineering Bone Lodaded With Bone Morphogenetic Protein And Vascular Endothelial Growth Factor

Objective 1. To search a kind of ideal seeded cell of bone tissue engineering.2. To study the cell biocompatihility of porous PDLLA scaffold in vitro.3. To investigate the efect on bone formation of Poly-DL-Lactide (PDLLA) Calcium BMP and VEGF composites and try to find the mechan isms of optimizing composites so as to develop a new kind of absorbah le osteosynthesis material.Methods 1. Bone malTow tissue was fetched from rabbit, got bone malTow stromal cells by the method of density centrifuge, observed the conformation, growing feature and osteogeneric capability of the cells during culture in vitro by light microscope, transmission electron microscope and measure of osteogeneric capability.2. Bone marrow stromal cells(BMSCs)obtained from rabbits were cultured, induced and proliferated in vitro.The cells were co-cultured with PDLLA (5mg and 100μgVEGF)and BGC and with PDLLA as control group.BMSCs'ability of adhesion and proliferation on these scafolds were examined qualitatively and quanti-cationally.Compared and analyzed the difference between groups.3. High-porosity foams of PDLLA Calcium BMP and VEGF and PDLLA witll the same pore size (in range of 150-300μm) were fabricated into three-dimensional porous material by a solvent-casting particulate-leaching technique with Nacl as the leachable component. One cm radial diaphyseal defected with complete resection of periosteum of 32 rabbits were dividnd into 3 groups in random and repaired respectively with PDLLA Calcium BMP and VEGF and PDLLA and control group. The specimens were harvested in 2,4,8 an d 12 weeks. The amples were examined by X-ray, histology and scanning electronic micro-scope(SEM)to evaluate the efectiveness of defect repair. At 8 and 12 weeks after implantation of grafts, the biomechanical testing (bending strength)was employed to study the quality of bone formation.Results 1. Most of the cultivated bone ma-ow stromal cells were triangle-like or shuttle-like cells. They growed and breeded rapidly, and had osteogeneric capability. They were easy to differentiate to osteoblast.2. BMSCs of rabbits could attach to and extend on the 3 scaffolds.Moreover, experiment group were superior to control group in adhesive and proliferative abilities (P<0.05).3. The bending strongth of porous PDLLA Calcium BMP and VEGF composites group was (52.38±2.56)MPa,and PDLLA group was (29.83±3.14) at 12 weeks after implantation of grafts. There were significant difrences in bending strength between the PDLLA Calcium BMP and VEGF composites group an d the PDLLA group (P<0.01). The former two experiment groups wer signficantly higher in bone formation compared with the control group in every stage of postimplantation(P<0.01).Conclusions 1. The cuhivated bo ne ma-ow stromal cells are matured ones, and could become the more ideal seeded cells for bone tissue engineering.2. Conclusion:The porous PDLLA as bone tissue engineering scaffold has good cell biocompatibility.3. PDLLA Calcium BMP and VEGF composites has good biocompatibility and absorbabi-lity. It has good osteoconductibility when fablicated into porous matedal. The PDLLA Calcium BMP and VEGF composites have better osteoconductibility and improve the quality of novel bone formation. A composite of porous PDLLA Calcium BMP and VEGF is a new valuable bone transplantation material.