An Experimental Study Of Calcium Phosphate Cement And Allogenic Deproteined Bone/BMP/TNFα Composite As Bone-arthron Graft Material

OBJECTIVE: To evaluate the osteogenesis ,response to immunization and reconstruction of blood vessel of calcium phosphate cement and allogenic deproteined bone-arthron composite graft combined with bone morphogenetic protein(BMP) and tumor necrosis factor α(TNFα),and to discuss the feasibility of this graft in the therapy of bone and arthron defects.This research can theoretically guide us in manufacturing a new bioprosthesis healing and living in host.METHODS: Combine allogenic deproteined bone-arthron and calcium phosphate cement(CPC) with rhBMP and rhTNFαrespectively. A 15mm bone-arthron defect experimental model in the femur of New Zealand rabbits is made,and the animals are divided into three groups at random:①A group: composite allogenic deproteined bone-arthrons are coated with CPC/BMP/TNFα,and also filled in their medullary cavity,which are implanted into the defect of the femur ;②B group: implanted with none-CPC/BMP/TNFαcomposite allogenic deproteined bone-arthrons;③C group: implanted with pure allogenic deproteined bone-arthrons as the control group. In the 4th, 8th, 12th,16th week after transplantation, regular roentgenography, the histological changes and electron microscope observation are studied.We also operate femur artery angiography to observe the reconstruction of blood vessel at the implantation area in the 16th week.RESULTS: In A and B group, a lot of vasoganglion and weave bone are observed in the 4th week. In the 8th week, weave bone and cartilage cell masses increase obviously, and parts of lamellar bone are formed. In the 12th~16th week, composite allogenic deproteined bone-arthron successfully survives, and the fracture is healed. A lot of lamellar bones are formed. There are also many matured cartilage cell masses around the articular facet. New bone formation area in A and B group is much larger than the one in C group in each period from the light microscope observation. Furthermore,from the 12th week,it reveals in A and B group that composite allogenic deproteined bone-arthron begins the "crawling replacement", which is hardly found in the control group. The thickness of fibrous tissue around deproteined bone-arthron in Agroup is less than the one in B or C group(P<0.01),and postoperative infection rate of A group is also less than the one of B or C group.In the 16th week, femur artery angiography shows there are large amount of blood vessels at the implantation area in A and B group,and parts of these vessels grow into DPB.But in C group ,the quantity of blood vessels is little.CONCLUSION: It suggests that DPB/BMP/TNFαcomposite allogenic deproteined bone-arthron has an excellent ability of osteogenesis, stimulating bone formation and angiogenesis and accelerating the heal and replacement of DPB in vivo.When this artificial bone-arthron is coated and filled in its medullary cavity with DPB/BMP/TNFα,the local response to immunization decreases in early time. However, further studies need to be conducted to repair the long-term stability of joint.