title: Sustained-release rhBMP-2 increased bone mass and bone strength in an ovine model of postmenopausal osteoporosis.
abstract: OBJECTIVE
  The purpose of this study was to analyze the local treatment effects of rhBMP-2 combined with fibrin sealant (FS) on bone mineral density, microarchitectural and mechanical properties in osteoporotic ovine spine.
  
  
  METHODS
  Postmenopausal osteoporosis was induced in eight sheep through ovariectomy (OVX) and a low-calcium diet for a period of 12 months. According to the Latin square design, L3-L6 vertebrae were randomly assigned to four treatment groups: A (rhBMP-2/FS), B (rhBMP-2), C (FS) and D (blank control). All materials were injected into the assigned vertebra transpedicularly. All animals were euthanized 3 months after treatment. Bone mineral density (BMD), microarchitectural and mechanical properties were assessed. ANOVA analysis of variance was used to determine effects of rhBMP-2/FS (α = 0.05).
  
  
  RESULTS
  The BMD in group A (rhBMP-2/FS) was 18.8, 30.4 and 27.9% higher than that in group B, C and D, respectively. Analysis of bone structure by micro-CT revealed higher trabecular bone volume (BV/TV), trabecular thickness (Tb.Th) and trabecular number (Tb.N) in the rhBMP-2/FS group (P < 0.01). In addition, vertebrae treated with rhBMP-2/FS exhibited higher yield stress, ultimate stress, energy absorption and bone modulus compared to the control groups.
  
  
  CONCLUSIONS
  Local administration of rhBMP-2/FS showed a positive trend in improving BMD, microarchitectural parameters and mechanical strength of osteoporotic vertebra. Slow release of rhBMP-2 using FS appeared to be an effective method of protein delivery. The local treatment of osteoporosis in the spine can increase bone strength and reduce fracture risk quickly.
authors.affiliation: Institute of Orthopaedics, Xijing Hospital, The Fourth Military Medical University, No. 17 Changlexi Road, Xi'an, 710032, Shaanxi, People's Republic of China. wuzixiang@fmmu.edu.cn
authors.forename: Zi Xiang
authors.initials: ZX
authors.lastname: Wu
authors.forename: Da
authors.initials: D
authors.lastname: Liu
authors.forename: Shi Yong
authors.initials: SY
authors.lastname: Wan
authors.forename: Geng
authors.initials: G
authors.lastname: Cui
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhang
authors.forename: Wei
authors.initials: W
authors.lastname: Lei
mesh_terms: D015502:Absorptiometry, Photon; D000818:Animals; D001696:Biomechanical Phenomena; D015519:Bone Density; D055396:Bone Morphogenetic Protein 2 / Q000008:administration & dosage*; D003692:Delayed-Action Preparations; D004195:Disease Models, Animal; D005260:Female; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000503:physiopathology*; D010024:Osteoporosis / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology; D017698:Postmenopause; D011994:Recombinant Proteins; D034561:Sheep, Domestic; D016896:Treatment Outcome
chemical_list: D055396:Bone Morphogenetic Protein 2; D003692:Delayed-Action Preparations; D011994:Recombinant Proteins