The Study Of Vascularization And Osteogenesis In Transplantation Of BFGF-PLGA/CPC Composites With Bone Mesenchymal Stem Cells

Objective To create a new type of artificial bone with the polylactic acid- polyglycolic acid copolymer (PLGA) / fibroblast growth factor (bFGF) microspheres and calcium phosphate cement (CPC) mixed to promote bone growth material with the in vitro proliferation of bone marrow-derived mesenchymal stem cells (bMSCs) after co-culture to repair the large animal bone defect. And observe that whether or not this tissue-engineered bone can promote the vascularization and the role of osteoplastic situation, in order to further study of vascularization in bone tissue engineering to provide a basis of experiment.Methods Healthy New Zealand rabbits (n=30) were used in the study. Right radius of the animals was made a 15mm-long defect. The animals then were ramdonly devided into two groups. Group A (n=15) served as the experimental group which was transplanted with the new-type engineering bone. Group B (n=15), the control group, was transplanted with the engineering bone without bFGF added in. X-ray photography, HE staining, Scan electron microscopy (SEM) and Emission Computed Tomography(ECT) were employed to observe the vascularization and osteogenesis of the engineering bone at 4 (n=5), 8 (n=5) and 12 (n=5) weeks after transplantation.Results1.It was showed that osteogenesis in group A was faster than that in Group B. 12 weeks after transplantation, continuous callus of the engineered bone was formed, the bone shape was remodeled and majority of the composites was degraded in group A. While in group B, although continuous callus was also formed and with partly bone remodeling, there still remained a large amount of undegraded composites.2.Lane-Sandhu score showed that there was significant difference between group A and B (P<0.05) on the X-ray photos 8 weeks after transplantation. While there was no difference 12 weeks after transplantation.3. Lane-Sandhu score also showed significant difference between group A and B (P<0.05) on histological morphology under light microscope 8 weeks after transplantation. While there was no difference 12 weeks after transplantation.4. ECT showed that the first 8 weeks after transplantation was the rapid stage of osteogenesis, while the 8^th to the 12^th week after transplantation was the slow and mature stage of osteogenesis. Osteogenesis and vascularization in groupA was superior to that in group B.5.SEM showed that the speed of osteogenesis in group A was faster than that in group A. Twelve weeks after transplantation, a large number of bone tissue and matured trabecula were formed within the implant, even near the central part. While in group B, the new formed bone tissue and trabecula was shapeless and disorganized with small quantity.Conclusion The bFGF-PLGA/CPC composites is good for osteogenesis and vascularization in-vivo. It is expected to become an ideal scaffold for bone tissue engineering.