RESUMO
BACKGROUND:It has become a hotspot to prepare the bone repair material that exhibits natural bone structure and is used in combination with biological factors. OBJECTIVE:To prepare the recombinant human bone morphogenetic protein-2 (rhBMP-2)/bone repair material, and to evaluate its capacities of release, activity and ectopic osteoinduction. METHODS:A collagen-binding domain was added to the N-terminal of native rhBMP-2 that allowed bind to collagens in the bone repair material. Then, rhBMP-2/bone repair material was obtained through freeze-dried method. The releasing ability of rhBMP-2 in vitro was assayed by ELISA. C2C12 cell lines were loaded to the composite material with 0.25, 0.5 and 1 μg rhBMP-2, respectively. Afterwards, alkaline phosphatase activity was detected at 72 hours. The composite materials with 0, 2, 5 and 10 μg rhBMP-2 were implanted into the quadriceps of Sprague-Dawley rats, respectively. Alkaline phosphatase activity and the newly formed bone were detected at 2 and 4 weeks after implantation. The CY-7-labeled composite material was implanted into the quadriceps of Sprague-Dawley rats to observe its stability. RESULTS AND CONCLUSION:Substantial y no rhBMP-2 from the rhBMP-2/bone repair material was released within 45 days. The alkaline phosphatase activity of C2C12 was in a rise with the increased concentration of rhBMP-2. The stability of the composite material in vivo was better, the alkaline phosphatase activity and ectopic bone formation increased as the concentration of rhBMP-2 rose. To conclude, the rhBMP-2/bone repair material preserves the stability of rhBMP-2, and improves ectopic osteoinduction ability.