Enhanced effects of BMP‐binding peptide combined with recombinant human BMP‐2 on the healing of a rodent segmental femoral defect

BMP‐binding peptide (BBP) enhances the osteogenic activity of recombinant human bone morphogenetic protein‐2 (rhBMP‐2), but the mechanism underlying the enhancement remains unclear. We aimed to elucidate the potential enhanced efficacy of BBP using critical‐sized segmental femoral bone defects in rats. Seventy defects in seven groups of rats were filled with various amounts (0, 2, 5, and 10 µg) of rhBMP‐2 with or without 1000 µg BBP. Radiographs were obtained after 4 and 8 weeks. The animals were euthanized at 8 weeks, and femoral specimens were assessed manually, evaluated for bone volume using microcomputed tomography, and subjected to histological or biomechanical analysis. Although 10 µg rhBMP‐2 yielded consistent results in terms of bone healing and quality of bone repair across the segmental defect, lower doses of rhBMP‐2 failed to induce satisfactory bone healing. However, the combined administration of lower doses of rhBMP‐2 and BBP induced the formation of significantly large amounts of bone. Our results suggest that the combined administration of rhBMP‐2 and BBP facilitates bone healing and has potential clinical applications. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:258–264, 2010