Effect of recombinant human bone morphogenetic protein-2 on bone formation in the acute distraction osteogenesis of rat mandibles.
BACKGROUND
Distraction osteogenesis (DO) is a method of producing new bone directly from the osteotomy site by gradual traction of the divided bone fragments.


OBJECTIVE
The purpose of the present study was to evaluate histomorphometrically whether acute DO would constitute a viable alternative to the conventional continuous distraction treatment and also to verify the capacity of a recombinant human BMP (rhBMP-2) associated with monoolein gel to stimulate bone formation in the acute distraction process.


METHODS
Forty-eight Wistar rats were assigned to three groups: Group 1, treated at a conventional continuous distraction rate (0.5 mm/day), Group 2, treated with acute distraction of 2.5 mm at the time of the surgical procedure, and Group 3, subjected to acute distraction associated with rhBMP-2. The animals from each experimental group were killed at the end of the second or fourth post-operative weeks and the volume fraction of newly formed bone trabeculae was estimated in histological images by a differential point-counting method.


RESULTS
The results showed that after 2 and 4 weeks, bone volumes in the rhBMP-2 group were significantly higher than in the other groups (P<0.05), but no significant difference was observed in the volume fraction of newly formed bone between the continuous and acute DO groups.


CONCLUSIONS
In conclusion, the study indicates that rhBMP-2 can enhance the bone formation at acute DO, which may potentially reduce the treatment period and complications related to the distraction procedure.
Issa
João Paulo Mardegan
JP
Department of Morphology, Physiology and Stomatology, Faculty of Dentistry of Ribeirão Preto, University of São Paulo, São Paulo, Brazil.
do Nascimento
Cássio
C
Lamano
Teresa
T
Iyomasa
Mamie Mizusaki
MM
Sebald
Walter
W
de Albuquerque
Rubens Ferreira
RF
D000818:Animals; D055396:Bone Morphogenetic Protein 2 / Q000008:administration & dosage / Q000502:physiology; D019485:Bone Morphogenetic Proteins / Q000008:administration & dosage / Q000502:physiology*; D004338:Drug Combinations; D016503:Drug Delivery Systems; D005782:Gels; D005989:Glycerides / Q000008:administration & dosage; D006801:Humans; D008297:Male; D008334:Mandible / Q000502:physiology; D019186:Mandibular Advancement / Q000379:methods*; D010012:Osteogenesis / Q000502:physiology*; D019857:Osteogenesis, Distraction / Q000379:methods*; D051381:Rats; D017208:Rats, Wistar; D011994:Recombinant Proteins / Q000008:administration & dosage; D018709:Statistics, Nonparametric; D016212:Transforming Growth Factor beta / Q000008:administration & dosage / Q000502:physiology*
D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D004338:Drug Combinations; D005782:Gels; D005989:Glycerides; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; C499469:recombinant human bone morphogenetic protein-2; C005953:monoolein