Effect of guided bone regeneration on expression level of bone morphogenetic protein-2 in repair of femoral defects with vascularized engineered-bone in rabbits

Objective To evaluate the effect of guided bone regeneration (GBR) on expression level of bone morphogenetic protein-2 (BMP-2) and bone formation in repair of femoral defects with vascularized engineered-bone in rabbits. Methods Eighteen healthy New Zealand rabbits were randomized into 2 e-qual groups. A segmental bone defect of 150 mm in length was made at the right femur in each rabbit and fixed with a plate. The gaps in the experiment group were plugged with the engineered bones and femoral vascular bundle, which were wrapped by GBR membrane. The vascularized engineered-bone plugged in the gaps in the control group, however, was not wrapped by GBR membrane. The expression levels of BMP-2 of the implants were examined by ELISA kits 4, 8, 12 weeks after implantation. Results The new bone formation was significantly higher in the control group at the end of 4, 8, 12 weeks (P < 0.05). The expression levels of BMP-2 in the control group were also siguificantly higher than in the experimental group at all time points after operation (P<0.05). The expression of BMP-2 peaked at 4 weeks. Conclusion GBR will down-regulate BMP-2 release in models of femoral defect in rabbits. Key words: Tissue engineering;  Neovascularization, physiologic;  Bone morphogenetic proteins; Guided bone regeneration