Abstract
In previous studies, we have reported that the BMP‐2‐derived peptide KIPKASSVPTELSAISTLYL, corresponding to BMP‐2 residues 73–92, binds to a BMP‐2‐specific receptor, and elevates both alkaline phosphatase activity and osteocalcin mRNA in the murine mesenchymal cell line, C3H10T1/2. This 73–92 peptide conjugated to a covalently crosslinked alginate gel induced ectopic bone formation in rat calf muscle, and activated osteoblasts to promote the repair of rat tibial bone defects. Here, we report repair of 20‐mm long rabbit radial bone defects using the 73–92 peptide combined with a porous α‐tricalcium phosphate (TCP) scaffold. In vitro, the 73–92 peptide was released from the porous α‐TCP scaffold over more than one week. In vivo, radiomorphometric analysis showed that the 73–92 peptide combined with the porous α‐TCP scaffold promoted calcification in the implanted area in a dose‐dependent manner, and that 5 mg of the 73–92 peptide induced connection of 20‐mm long defects, defects of critical size, 12 weeks after implantation. Histological examination revealed newly formed bone and a marrow cavity in the implanted area. The area of bone denser than 690 mg/cm^3^ induced by the 73–92 peptide was nearly equal to that of the contralateral radius. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006