The Experimental Study Of Bone Morphogenetic Protein-nano-HAP-collagen Repairing Periodontal Bone Defects

Objective:To establish the animal model of periodontal bone defects,to observe and evaluate the effects of growth factors(GFs)-scaffolds tissue engineering on the periodontal regeneration,and to estimate the feasibility of recombinant human bone morphogenetic protein-2(rhBMP-2)and nano-HAP-Collagen(nHAC)applied for periodontal tissue engineering.Methods:The rhBMP-2 combined with nHAC were transplanted into man-made periodontal bone defects,and the groups covered only with nHAC or with noting were the controls.The animals were sacrificed after 8 weeks and the periodontal bone regeneration was observed histologically.Bone mineral density and bone histomorphometry were measured.Results:1.8 weeks after surgery,bone mineral density was measured.The difference was not statistically significant between group of rhBMP-2-nHAC and normal group (P＞0.05).2.8 weeks after surgery,the rhBMP-2-nHAC group exhibited a lot of new periodontal tissue.The periodontal bone defects were filled with new alveolar bone in the group of rhBMP-2-nHAC.The structure of new alveolar bone is compact and similar to the normal.The material was absorbed fully.New periodontal ligament fibers were dense and rich in blood vessels.3.8 weeks after surgery,nHAC group exhibited fewer new bone regeneration than rhBMP-2-nHAC group.There was incomplete absorbing material under the microscope,nHAC was partly degradation,new bone surrounded the material.New periodontal ligament fibers were lesser dense.4.8 weeks after surgery,in the bone histomorphometry study,the difference of the value of STS,DTS,MAR,TBV,TOS and TBOS were statistically significant among the three groups(P＜0.05).The value of rhBMP-2-nHAC and nHAC groups were significantly higher than that of the control group(P＜0.05).The difference of those value were statistically significant between group of rhBMP-2-nHAC and nHAC,too(P＜0.05).Conclusion:1.New bone density inducing by 1.0mg/ml rhBMP-2 is not different from normal bone density. 2.The rhBMP-2-nHAC compound materials is of better osteoconductive and osteoinductive activity,which can be used to promote periodontal regeneration.3.NHAC is a kind of ideal scaffold material for tissue engineering,which has better osteoconductive activity.Degradation and absorbing of material match with new bone growing.4.The rhBMP-2-nHAC group exhibited more new bone than that of nHAC and control groups,rhBMP-2-nHAC compound material can induce more new alveolar bone.5.The GFs-scaffolds style of tissue engineering could contribute to enhance the periodontal bone regeneration,the rhBMP-2 and nHAC could be used as the GF and the scaffold material for periodontal tissue engineering.