Repair of rat cranial bone defects with nHAC/PLLA and BMP-2-related peptide or rhBMP-2.

An ideal artificial substitute has good biocompatibility properties and is able to provide for rapid bone formation. Bone morphogenetic protein-2 (BMP-2) is considered as one of the most important growth factors for bone regeneration. In this study, a synthetic BMP-2-related peptide (designated P24) corresponding to residues of the knuckle epitope of BMP-2 was introduced into a bioactive scaffold based on nano-hydroxyapatite/collagen/poly(L-lactic acid) (nHAC/PLLA); its in vitro release kinetics was then measured. A 5 mm diameter cranial bone defect was created in the calvariae of 30 rats and randomly implanted with three groups of biomaterials: Group A (nHAC/PLLA alone); Group B (P24/nHAC/PLLA composite); and Group C (recombinant human BMP-2 (rhBMP-2)/nHAC/PLLA composite). The P24/nHAC/PLLA implants significantly stimulated bone growth similarly to the rhBMP-2/nHAC/PLLA implants based on the radiographic and three-dimensional CT evaluation and histological examination, thereby confirming the enhanced bone healing rate of these compounds compared with the stand-alone nHAC/PLLA scaffold material. The osteoinductive ability of 3 mg P24 was similar to that of 1 µg rhBMP-2. P24/nHAC/PLLA is a promising scaffold biomaterial for bone tissue regeneration.