title: BMP-2 induced early bone formation in spine fusion using rat ovariectomy osteoporosis model.
abstract: BACKGROUND
  Bone morphogenetic proteins (BMPs) enhance bone formation. Numerous animal studies have established that BMPs can augment spinal fusion. However, there is a lack of data on the effect of BMP-2 on spinal fusion in the osteoporotic spine.
  
  
  OBJECTIVE
  To investigate whether recombinant human BMP-2 (rhBMP-2) enhances spine fusion in an ovariectomized rat model.
  
  
  METHODS
  In vivo animal study.
  
  
  METHODS
  Female Sprague-Dawley rats (n=60) were ovariectomized or sham operated and randomized into three groups: Sham (sham operated+fusion), ovariectomy (OVX) (OVX+fusion), and BMP (OVX+fusion+BMP-2). Six weeks after ovariectomy, unilateral lumbar spine fusion was performed using autologous iliac bone with/without rhBMP-2 delivered on a collagen matrix. For each group, gene expression and histology were evaluated at 3 and 6 weeks after fusion, and bone parameters were measured by microcomputed tomography at 3, 6, 9, and 12 weeks.
  
  
  RESULTS
  Real-time reverse-transcription polymerase chain reaction at 3 weeks showed markedly increased expression of osteoblast-related markers (namely alkaline phosphatase, osteocalcin, Runx2, Smad1, and Smad5) in the BMP group compared with the other groups (p=.0005, .0005, .003, .009 and .012, respectively). Although the Sham and OVX groups showed both sparse and compacted bones between transverse processes at 6 weeks, the BMP group had a significantly larger bone mass within the fusion bed at 3 weeks and later. All rats in the BMP group had bridging bone at 3 weeks; at 12 weeks, bridging bones in the Sham and OVX groups were about 50% and 25%, respectively, of that in the BMP group.
  
  
  CONCLUSIONS
  Recombinant human BMP-2 enhances spinal fusion in OVX rats and acts during early bone formation. Therapeutic BMP-2 may therefore improve the outcome of spinal fusion in the osteoporotic patient.
authors: Department of Neurosurgery, Seoul National University Boramae Medical Center, 5 Gil 20, Boramae-Road, Dongjak-Gu, Seoul 110-744, Korea.
authors: Sung Bae
authors: SB
authors: Park
authors: Seong Hoon
authors: SH
authors: Park
authors: Na-Hyung
authors: NH
authors: Kim
authors: Chun Kee
authors: CK
authors: Chung
mesh_terms: D000818:Animals; D055396:Bone Morphogenetic Protein 2 / Q000627:therapeutic use*; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D010012:Osteogenesis / Q000187:drug effects*; D015663:Osteoporosis, Postmenopausal / Q000601:surgery*; D010052:Ovariectomy; D051381:Rats; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000627:therapeutic use; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013123:Spinal Fusion / Q000379:methods*; D016212:Transforming Growth Factor beta / Q000627:therapeutic use*
chemical_list: D055396:Bone Morphogenetic Protein 2; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; C499469:recombinant human bone morphogenetic protein-2
keywords: Bone morphogenetic protein; Osteoporosis; Rat; Spine