| Objective:Bone defects due to trauma, tumor, infection, deformity and the other causes are very common in clinical, and the method of treatment mostly is bone transplantation. There are some literature reports, what showed the probability of bone transplantation for various reasons is just lower than that of blood transfusion in U.S.A. At present, the major method of bone defects is repaired with autogenous bone, allograft bone and xenograft bone transplantation. Autogenous bone sources are very limited, inevitably increase the new trauma. The allogeneic bone transplantation dealed with deep-frozen and preserved are used in many countries, which has many difficultities such as sources of tension, immune rejection, infection or disease transmission. How to fasten the growth after implantation in vivo is the other important topic of the world.Studies have shown that, vascular endothelial growth factor(VEGF), basic fibroblast growth factor(bFGF), bone morphogenetic protein(BMP), transforming growth factor-β1(TGF-β1) are the important moderating roles in the process of angiogenesis, in which VEGF have been proved as the strongest cytokines induced angiogenesis. The ability of BMP has been also confirmed. Along with the rapid development of multidisciplinary such as molecular biology, materials science and genetic engineering techniques, a bright future has come on in the promotion of local angiogenesis and to accelerate bone growth used cytokine.Recently, many researches of the revascularization in local tissue used VEGF and the promotion of bone growth used BMP are more and more studied. And the approach are mostly used the following methods, such as a local injection ,in vivo gene transfer , or the composite of implantation. Because of the existence of hemodilution in vivo and the poor directional transfection efficiency, there are some shortcomings if the above methods are adopted, for example ,the in low gene expression and the expression of short period of time.We certified that the protein and lipid composition of deproteinised bone(DPB) made by the means of hydrogen peroxide ether had been basi-removed,which lowered or eliminated the immunogenicity. So rejection after implantation could be avoided too. Because of the Materials made from the cancellous bone, DPB has high porosity and aperture in the 100-300μm or so.It is better to retain the original three-dimensional porous bone - grid structure system. The material not only has the valid space frame and the good bone conduction,but also can provide a ideal place for cells to attach,growth, proliferation and osteogenic. In the light of the above,we tried to compound DPB, the VEGF-165 and BMP-2 in vitro. The composite of rhBMP-2/rhVEGF-165/DPB was implanted in the models of the segmental bone defects in rabbits. Deep frozen bones(Shanxi OsteoRad Biomaterial Co.Ltd ) were be done as the same method in vivo.At last,we compared the results of the revascularization and osteogenesis in 2 groups , which of them promote the repair of bone defect better can provide experimental basis for clinical use.Etio-experiment undertakes research from 3 aspects, and the main means,results and conclusions as follow:1. The manufacture of bio-derived bone(DPB): the spongy bone taken from the cows's distal femur by hydrogen peroxide - ether means.2. The experiment on DPB combined with rhVEGF-165+rhBMP-2, Controlled dry, weighed, sterilized and reserved.3. The experiment study on the models of the segmental bone defects in rabbits implanted respectively with rhVEGF-165/rhBMP-2/DPB or deep frozen bones(Shanxi OsteoRad Biomaterial Co.Ltd ).Methods:68 adult New Zealand rabbits were randomly divided into 2 groups:group A and group B. All of the left forearm radial bones were manufactured into the models of bone defect about 15mm. The rhVEGF-165/rhBMP-2/DPB(group A) or deep frozen bones(Shanxi OsteoRad Biomaterial Co.Ltd ,group B) were randomly implanted into the defects. After the 1, 2, 4, 8, 12, 16 weeks, 2 rabbits were randomly drawed out from two groups. X-ray observation and HE staining were performed; After the 3 days and the 1, 2, 4, 8 weeks, 2 rabbits were randomly drawed out from two groupsd and vas capillare analysis by ink perfusion was performed; After the 4, 8, 12, 16 weeks, 3 rabbits were randomly drawed out from two groups and vitodynamics test was performed.Results: In each time period, these tests displayed that the vascularization in group A were obviously more than those in group B;the callus formation and union between the material and host bone in group A were both better than those in group B;but there was no significant difference in later immunological rejection in 2 groups. Summing up, rhVEGF-165/rhBMP-2/DPB transplantation release rhVEGF-165 and rhBMP-2 slowly, persistently, effectively, and locally. It also induced the formation of bone, promoted the early re-vascularization of grafts, spelled affluent target cells and growth factor for bone union, made transplant s gradually"activate", created best microenvironment for bone formation, achieved early bone union between transplant and host bone, made transplant s become autologous tissue of accepters. It offered an effective therapeutic tool for repairation of bone defect.
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