Effect of calcium phosphate cement/bone morphogenetic protein 6/vascular endothelial growth factor in bone defect repair / 中国组织工程研究

ABSTRACT

BACKGROUND:Implantation of bone morphogenetic protein (BMP) or vascular endothelial growth factor (VEGF) alone, without support vectors, is easy to be flushed away by the blood flow, and thus limits the osteogenesis and angiogenesis. OBJECTIVE: To observe the effects of combination of calcium phosphate cement (CPC), BMP-6/VEGF in bone defect repair. METHODS:Defect models of the bilateral medial femoral condyle were prepared in New Zealand white rabbits. Then, the medial femoral condyle was filed with CPC/BMP-6/VEGF, CPC/BMP-6, and CPC, respectively, in the left side, but nothing in the right side as control. After 8 and 16 weeks of implantation, the hard tissue slices were prepared for histological observation and scanning electron microscope observation. RESULTS AND CONCLUSION:Al three kinds of materials showed good biocompatibility, and no obvious inflammation was found. After 8 weeks of implantation, the junction of the CPC/BMP-6/VEGF and bone tissue was almost completely covered by newly formed trabecular bone. With the development of cement degradation, abundant osteoblasts could be found in the surface of newborn trabecular bone. After 16 weeks of implantation, an ongoing cement degradation and bone formation was seen. Moreover, newly formed bone tissue increased and became thicker. The cement in the interface was separated into smal pieces and closely interconnected with the surrounding tissues, and newly formed bone showed a mesh-like ingrowth into the cement. This newly formed bone was mature and could not be distinguished from the original trabecular bone. Both the degradation and osteogenesis of CPC and CPC/BMP-6 were much slower than that of CPC/BMP-6/VEGF (P < 0.05). This study demonstrates angiogenesis and osteogenesis in vivo through the additive effects of VEGF and BMP-6. CPC/BMP-6/VEGF can be an ideal bone substitute in bone repair.