ABSTRACT
BACKGROUND: Bone morphogenetic protein 2 is a most widely studied and osteogenic-inducing bone morphogenetic protein. However, simple bone morphogenetic protein can be diluted by tissue fluid and decomposed by protease after implantation, so it is difficult to maintain sustained drug concentration or play an effective role in bone induction. OBJECTIVE: To observe the effect of repairing osteoporotic fracture through calcium phosphate cement/fibrin glue composite as the carrier of bone morphogenetic protein 2. METHODS: Fifty-four female Sprague-Dawley rats were selected to remove bilateral ovaries for making osteoporosis models. Three months later, the middle femoral fracture models were made, and then randomized into three groups, with 18 rats in each group. Kirschner wire fixation group was injected nothing. The fracture end was injected with 0.5 mL calcium phosphate cement/fibrin glue (composite group) or calcium phosphate cement/fibrin glue loaded with recombinant human bone morphogenetic protein 2 (loaded group) . At 4 and 12 weeks after fracture, X-ray examination, micro-CT examination, biomechanical three-point bending test and pathological observation were performed. RESULTS AND CONCLUSION: (1) The fracture healing score in the loaded group was higher than that in the other two groups (P < 0.05) . (2) The bone volume fraction, trabecular thickness and number of trabeculae at 4 and 12 weeks in the loaded group were higher than those in the other two groups (P < 0.05) , and the trabecular segregation was lower than that in the other two groups (P < 0.05) . (3) The maximum load and stiffness at 4 and 12 weeks in the loaded group were higher than those in the other two groups (P < 0.05) , and the elastic modulus at 4 weeks after fracture was higher than that in the other two groups (P < 0.05) . (4) Fibrocartilage callus was mainly seen at 4 weeks after fracture in the Kirschner wire fixation group, and the callus was reconstructed into lamellar bone at 12 weeks after fracture with less callus content. Obvious fibrocartilage callus appeared at 4 weeks after fracture in the composite and loaded groups, and the callus was reconstituted into a plate-like bone at 12 weeks. (5) These results imply that the calcium phosphate cement/fibrin glue composite loaded with recombinant human bone morphogenetic protein 2 can promote the healing of osteoporotic fracture and improve bone strength.