A quantitative analysis of the effect of insulin-like growth factor-1 infusion during mandibular distraction osteogenesis in rabbits.
OBJECTIVE
To quantify, by histomorphometry, the effects of local insulin-like growth factor-1 (IGF-1) during mandibular distraction at various rates.


METHODS
Mature rabbits underwent bilateral mandibular corticotomy and distraction lengthening. Recombinant IGF-1 was administered to two groups of rabbits via osmotic infusion pumps. Distraction regimes were as follows: Group A, 1 mm/day for 15 days; Group B, as for A plus IGF-1; Group C, 3 mm/day for 5 days; Group D, as for C plus IGF-1; and Group E, sham-operated controls. After a 28-day consolidation period, rabbits were sacrificed and bone deposition quantified using DEXA scanning, three-point bending, histological examination and sampled for histomorphometric analysis.


RESULTS
DEXA scanning and three-point bending failed to detect any effect of distraction rate or of IGF-1 infusion. Histological and histomorphometric analysis suggested 1 mm/day to be the ideal distraction rate, as this was associated with greater osteoblastic activity and consistent bony union. However, IGF-1 infusion significantly enhanced osteoblastic activity at both distraction rates and resulted in bony union when distraction was performed at 3 mm/day.


CONCLUSIONS
Distraction osteogenesis at a rate of 1 mm/day provides greater osteogenic stimulus than 3 mm/day. Exogenous IGF-1 has a positive influence on osteoblastic activity during distraction. Its effect is probably minimised by high levels of endogenous IGF-1.
Stewart
K J
KJ
Department of Plastic and Reconstructive Surgery, St George Hospital, Kogarah, Australia.
Weyand
B
B
van't Hof
R J
RJ
White
S A
SA
Lvoff
G O
GO
Maffulli
N
N
Poole
M D
MD
D000818:Animals; D001696:Biomechanical Phenomena; D015519:Bone Density; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D008297:Male; D008334:Mandible / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D010006:Osteoblasts / Q000502:physiology; D019857:Osteogenesis, Distraction / Q000379:methods*; D011817:Rabbits; D011994:Recombinant Proteins / Q000494:pharmacology; D013314:Stress, Mechanical
D011994:Recombinant Proteins; D007334:Insulin-Like Growth Factor I