Effect of recombinant human bone morphogenetic protein 7 on bone density during distraction osteogenesis of the rabbit mandible.
OBJECTIVE
To examine whether the quality of bone generation in distraction osteogenesis of the rabbit mandible is enhanced by administering recombinant human bone morphogenetic protein 7 (rhBMP-7) to the lengthened site at the end of the distraction phase.


METHODS
Prospective randomized study of 24 rabbits undergoing distraction osteogenesis of the mandible, followed by injection of rhBMP-7 or a lactate buffer.


METHODS
McGill University animal care facility.


METHODS
Twenty-four white New Zealand rabbits underwent unilateral mandibular osteotomy and application of an Orthofix uniplanar M-100 fixator (Orthofix Inc., Verona, Italy) to the mandible. Mandibular distraction was carried out for 3 weeks. The animals were divided into three groups: group 1 (eight rabbits), control group: distraction, no injection; group 2 (eight rabbits), study group: distaction + injection of 200 microg of rhBMP7-lactate buffer; group 2 (eight rabbits), comparison group: distraction + injection of lactate buffer. All rabbits were sacrificed 7 weeks after surgery. The mandibles underwent radiology and bone densitometry analysis.


METHODS
Radiology assessment of bone generation within distracted segments and objective analysis of bone mineral density.


RESULTS
Radiology confirmed the presence of bone generate within distraction sites. Densitometry showed a difference in bone mineral density among the three groups (p < .05).


CONCLUSIONS
Local injection of a single dose of 200 microg of rhBMP-7 did enhance bone density when compared with the control group, although not in a statistically significant way when analyzed by an x-ray bone densitometer. This study serves as a starting point for future studies in bone tissue engineering by guiding the strategic administration of rhBMPs and the use of new state-of-the-art technologies, such as micro CT scanning, to analyze in a more detailed way, the effects of rhBMP administration.
Zakhary
Kristina
K
Department of Otolaryngology-Head and Neck Surgery, McGill University, Montreal, QC.
Motakis
Dimitri
D
Hamdy
Reggie H
RH
Campisi
Paul
P
Amar
Yannick
Y
Lessard
Marie-Lucie
ML
D015502:Absorptiometry, Photon; D000818:Animals; D015519:Bone Density / Q000187:drug effects*; D055419:Bone Morphogenetic Protein 7; D019485:Bone Morphogenetic Proteins / Q000008:administration & dosage / Q000494:pharmacology*; D001861:Bone Regeneration / Q000187:drug effects; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging / Q000187:drug effects / Q000502:physiology*; D010012:Osteogenesis / Q000187:drug effects; D019857:Osteogenesis, Distraction; D011446:Prospective Studies; D011817:Rabbits; D011897:Random Allocation; D016212:Transforming Growth Factor beta / Q000008:administration & dosage / Q000494:pharmacology*; D016896:Treatment Outcome
C525819:BMP7 protein, human; D055419:Bone Morphogenetic Protein 7; D019485:Bone Morphogenetic Proteins; D016212:Transforming Growth Factor beta