Effect of recombinant human bone morphogenetic protein-2 (rhBMP-2) on bone consolidation on distraction osteogenesis: a preliminary study in rabbit mandibles.
OBJECTIVE
To examine the effectiveness of administering recombinant human bone morphogenetic protein-2 (rhBMP-2) in distraction osteogenesis.


METHODS
Twenty-one mature male Japanese white rabbits underwent unilateral mandibular osteotomy. After 5 days, the osteotomized mandibles were distracted 1mm/day for 10 days. On the first day (groups A-1 [n=4] and A-2 [n=4]) or on the last day (group B [n=5]) of distraction, rhBMP-2 mixed with collagen gel was injected into the distraction zone. In control groups (groups C-1 [n=4] and C-2 [n=4]), the mandibles were distracted without rhBMP-2 injection. At the end of the distraction period (groups A-1 and C-1) and after 2 weeks of consolidation (groups A-2, B, and C-2), the distracted mandibles were harvested and examined with soft radiographs, peripheral quantitative computed tomography (pQCT), and microscopy.


RESULTS
Radioopacity was more marked in the distraction zone of the groups with rhBMP-2 than in control groups. The mineral density of the cortical bone (BMD) was higher in groups B and A-2 than in group C-2. Histologically, bone formation was more advanced in groups A-2 and B than in group C-2. The cortical BMD was higher in group A-1 than in group C-1. Histologically, bone formation was more advanced in groups A-2 and B than in group C-2.


CONCLUSIONS
These results suggest that rhBMP-2 promotes bone formation in distraction osteogenesis.
Yonezawa
Hisanobu
H
Department of Oral and Maxillofacial Surgery, Sensory and Motor Organ Sciences, Graduate School of Medicine and Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan. yoneos@fc.kuh.kumamoto-u.ac.jp
Harada
Kiyoshi
K
Ikebe
Tetsurou
T
Shinohara
Masanori
M
Enomoto
Syoji
S
D015502:Absorptiometry, Photon; D000818:Animals; D015519:Bone Density / Q000187:drug effects*; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000494:pharmacology*; D001861:Bone Regeneration / Q000187:drug effects*; D006801:Humans; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000601:surgery; D023421:Models, Animal; D019857:Osteogenesis, Distraction / Q000379:methods*; D011817:Rabbits; D011994:Recombinant Proteins / Q000494:pharmacology*; D013997:Time Factors; D016212:Transforming Growth Factor beta / Q000494:pharmacology*
D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; C499469:recombinant human bone morphogenetic protein-2