Effect Of Bone Regeneration Materials Combining With RhBMP-2 On Healing Of Bone Defect

ObjectiveTo evaluate the property of CPC combining with rhBMP-2 in bone regeneration processes in bone defect by fabricating and investigating the CPC/rhBMP-2 complex material in animal trial in vitro.Methods(1) Paraffin particle in various diameters were chosen as the pore creating materials to fabricate the porous CPC materials. RhBMP-2 was added by means of absorption-freeze-dry methods to prepare CPC/rhBMP-2 complex materials which was airtight-sealed preserved in -4℃.(2) ectopic osteogenesis inducing trial in rats:the CPC/rhBMP-2 complex materials (in contradistinction to gelatin sponge/rhBMP-2) were implanted into the muscle of the rats, by which the properties of CPC/rhBMP-2 in bone regeneration was researched.(3) trials on segmental bone defect in radius of canines:the CPC/ rhBMP-2 complex materials (in contradistinction to gelatin sponge/rhBMP-2) were implanted into the segmental bone defect site in radius of canines created previously. The properties of CPC/ rhBMP-2 in bone regeneration within segmental bone defect were evaluated after harvest.Results(1) ectopic osteogenesis inducing trial in rats:The tissue mineral density and the trabecular thickness of the specimens with rhBMP-2 were increased in all the three time point of 2,4 and 8 weeks after implantation. The differences were statistically significant. Histological analysis:inflammatory infiltration and cartilage cells can be observed around the graft in experimental group after 4 weeks and the graft were degraded after 8 weeks while some cartilage cells and osteoblast can be observed. In contrast, few regenerated bone can be found in the control group.(2) trials on segmental bone defect in radius of canines:X-ray shows large quantity of new bone were regenerated after 8 weeks in the experimental group and the bridge has already formed between the two ends. After 16 weeks, the formerly defective radius healed perfectly. In contrast, only few regenerated bone tissue was observed in the ends in blank control group.The bone mineral density of the specimens in experimental group was significantly higher than that in the control group.Histological analysis:A large quantity of regenerated bone and mature bone cells can be observed in the previous defective site in specimens of the experimental group. The ends have reconnected with each other perfectly while the cortical bone has combined.Conclusions:Porous Calcium Phosphate Cement has favorable osteogenesis capability as the carrier of rhBMP-2 to promote the bone regeneration process...