An Experiment Study On The Osteogenic Efficiency Of Antigen-extracted Xenogeneic Cancellous Bone

Objective:In the present study, we investigate the effects and mechanisms of the allogeneic bone, as a scaffold, in repairing mandibular defect. We try to find out the applicability of the allogeneic bone in repairing bone defect instead of autogenous bone. We determine the repairment effects and degradability of allogeneic bone in vivo.Materials and methods:Twenty-four New Zealand Rabbits with Twenty-four defects are divided into 2 groups in random:antigen-extracted xenogeneic cancellous bone group, antigen-extracted xenogeneic cancellous bone/rhBMP-2 group. Twelve bone defects of each group are classified into 3 time points(4,8,12weeks). Eight rabbits are chosen from each time point. Observations, X-ray test, hematoxylin and eosin stain and bone density measurement are conducted on each rabbit.Results:(1) From observation, the implanted materials were stable and solid. In antigen-extracted xenogeneic cancellous bone group, the material augmented as time went by after implanting on the bone defect, while the bone defect were completely repaired after 4 weeks of implantation in antigen-extracted xenogeneic cancellous bone/rhBMP-2 group.(2) The X-ray showed the implanted materials were degraded after a period of time, and were replaced by autogenous bone. In the 12th week, the implanted materials were replaced by autogenous bone in antigen-extracted xenogeneic cancellous bone/rhBMP-2 group, while implanted materials were entirely degraded.(3) The bone density measurement showed after implantation, bone density was enhanced. In the 12th week, there was obvious difference between two groups.(4) The hematoxylin and eosin stain showed there were more neovascularization,new fibrosis and new bone formation in antigen-extracted xenogeneic cancellous bone/rhBMP-2 group than in antigen-extracted xenogeneic cancellous bone group. The implanted material of antigen-extracted xenogeneic cancellous bone/rhBMP-2 group degraded much faster than that of antigen-extracted xenogeneic cancellous bone group. (5) There was significant difference in new bone area ratio between two groups among all weeks.Conclusion:An antigen-extracted xenogeneic cancellous bone has good biocompability, which can act as scaffold in bone repairment. It can be the carrier of rhBMP-2, which continues bone formation. Therefore, antigen-extracted xenogeneic cancellous bone is a kind of good material for bone repairment.