title: Bone consolidation is enhanced by rhBMP-2 in a rabbit model of distraction osteogenesis.
abstract: Recombinant human bone morphogenetic protein-2 (rhBMP-2) is a differentiation factor which has been shown to induce bone formation and heal bony defects in a variety of animal models. A possible application of rhBMP-2 is to accelerate bone regeneration during distraction osteogenesis. which clinically is a long procedure, often involving significant complications. In this study we tested the ability of rhBMP-2 to accelerate the consolidation phase of distraction osteogenesis in a rabbit model of leg lengthening. Tibiae were lengthened 2 cm over a period of ten days. rhBMP-2 was administered at the end of the lengthening phase. Two modes of rhBMP-2 application were tested: surgical implantation of rhBMP-2/ACS (absorbable collagen sponge) into the regenerate (50 microl of 1.5 mg/ml rhBMP-2, total dose = 75 microg rhBMP-2), and percutaneous injection of rhBMP-2/buffer (0.1 ml of 0.75 mg/ml rhBMP-2. total dose = 75 microg rhBMP-2) into three sites within the regenerate. Also, there were three groups of control animals: (1) no surgical intervention, (2) surgical implantation of buffer/ACS and (3) percutaneous injection of buffer. Rabbits were sacrificed at 5, 14 and 28 days after the interventions. Radiographic evaluation indicated a significant increase in bony union of the distraction regenerate in the rhBMP-2 treated groups compared with the untreated groups at 5 and 14 days. At 28 days, formation of a cortex and reestablishment of the medullary canal was evident only in the rhBMP-2 treated groups. The bone mineral content (BMC) of the regenerate was significantly higher in the rhBMP-2 treated groups at 5 and 14 days. However, at 28 days, BMC of the regenerate was similar in all groups. The average volumetric density of the regenerate was significantly higher in the rhBMP-2 injection group at day 14. In Summary, both injection of rhBMP-2/buffer and implantation of rhBMP-2/ACS enhanced the consolidation stage of distraction osteogenesis in this rabbit model.
authors.affiliation: The Department of Trauma and Orthopaedic Surgery, Queen's University of Belfast, Musgrave Park Hospital, UK. g.li@qub.ac.uk
authors.forename: Gang
authors.initials: G
authors.lastname: Li
authors.forename: Mary L
authors.initials: ML
authors.lastname: Bouxsein
authors.forename: Cynthia
authors.initials: C
authors.lastname: Luppen
authors.forename: X Jian
authors.initials: XJ
authors.lastname: Li
authors.forename: Martin
authors.initials: M
authors.lastname: Wood
authors.forename: Howard J
authors.initials: HJ
authors.lastname: Seeherman
authors.forename: John M
authors.initials: JM
authors.lastname: Wozney
authors.forename: Hamish
authors.initials: H
authors.lastname: Simpson
mesh_terms: D000818:Animals; D015519:Bone Density; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000494:pharmacology*; D001861:Bone Regeneration / Q000187:drug effects*; D008297:Male; D010012:Osteogenesis; D019857:Osteogenesis, Distraction; D011817:Rabbits; D011994:Recombinant Proteins / Q000494:pharmacology; D016212:Transforming Growth Factor beta
chemical_list: C525718:BMP2 protein, human; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta