| How to eliminate the antigenicity of bone xenograft while retaining its osteoinductive activities is an unsolved problem in the orthopaedic field worldwide. This paper presents an encouraging apprpach to the difficult question by designing following procedures: extracting the bone morphogenetic protein (BMP) from cortical bone; eliminating the antigenicity of can cell ous bone by chemical extraction; and reconstituting the graft with the treated cancellus serving as a framework for BMP. Bioassay in mouse thigh pouch showed that the reconstituted graft, with only 0.5mg BMP in it, demonstrated a difinitive osteoinductive activity, while both the cancellous framework and BMP alone in same dose failed to form any osseous tissue in the same experimental system. Bone defect model of rabbit also confirmed a good repair ability of the graft, which was much superier than that of the cancellous bone or bioactive glass ceramic (BGC), and even comparable with that of bone autograft Immunologically, the reconstituted graft was also accepted by host, immune rejection was few in all the implantation.The recombination of bovine BMP and treated calf cancellous bone provides a hopeful method to study xenogeneic bone, which should not only avoid the intense immune reaction aroused in the host but also endow the graft with highly osteoinductive ability. This may be best way to solve the problem of xenogeneic bone grafting. As a clinical bone bank material, xenogeneic bone has a great potential owing to its aboundant sources and simple, economical characters. Genetic engineering have been carried out for large-scale production of synthetic human BMP, which will make the reconstituted bone xenograft a highly osteoinductive biomaterial in orthopaedic surgery and relative fields.
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