title: A quantitative analysis of the effect of insulin-like growth factor-1 infusion during mandibular distraction osteogenesis in rabbits.
abstract: 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.
authors.affiliation: Department of Plastic and Reconstructive Surgery, St George Hospital, Kogarah, Australia.
authors.forename: K J
authors.initials: KJ
authors.lastname: Stewart
authors.forename: B
authors.initials: B
authors.lastname: Weyand
authors.forename: R J
authors.initials: RJ
authors.lastname: van't Hof
authors.forename: S A
authors.initials: SA
authors.lastname: White
authors.forename: G O
authors.initials: GO
authors.lastname: Lvoff
authors.forename: N
authors.initials: N
authors.lastname: Maffulli
authors.forename: M D
authors.initials: MD
authors.lastname: Poole
mesh_terms: 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
chemical_list: D011994:Recombinant Proteins; D007334:Insulin-Like Growth Factor I