title: Ovariectomy-Induced Osteopenia Influences the Middle and Late Periods of Bone Healing in a Mouse Femoral Osteotomy Model.
abstract: OBJECTIVE
  It is known that bone healing is delayed in the presence of osteoporosis in humans. However, due to the complexities of the healing of osteoporotic fractures, animal models may be more appropriate for studying the effects of osteoporosis in more detail and for testing drugs on the fracture repair process. The purpose of this study was to investigate the influence of ovariectomy-induced osteopenia in bone healing in an open femoral osteotomy model, and to test the feasibility of this model for evaluating the healing process under osteopenic conditions.
  
  
  METHODS
  Ovariectomized (OVX) mouse models were employed to assess the effects of osteopenia on fracture healing, A mid-shaft femur osteotomy model was also established 3 weeks after ovariectomy as an osteopenic fracture group (OVX group). Femurs were then harvested at 2 weeks and 6 weeks after fracture for X-ray radiography, micro-computed tomography (micro-CT), histology, and biomechanical analysis. A sham-operated group (sham group) was used for comparison.
  
  
  RESULTS
  The OVX mice had significantly lower bone volume density (BVF), volumetric bone mineral density (vBMD), and tissue mineral density (TMD) in the fracture calluses at 6 weeks (p<0.05), and similar trend was observed in 2 weeks. Additionally, larger calluses in OVX animals were observed via micro-CT and X-ray, but these did not result in better healing outcomes, as determined by biomechanical test at 6 weeks. Histological images of the healing fractures in the OVX mice found hastening of broken end resorption and delay of hard callus remodeling. The impaired biomechanical measurements in the OVX group (p<0.05) were consistent with micro-CT measurements and radiographic scoring, which also indicated delay in fracture healing of the OVX group.
  
  
  CONCLUSIONS
  This study provided evidence that ovariectomy-induced osteopenia impair the middle and late bone healing process. These data also supported the validity of the mouse femoral osteotomy model in evaluating the process of bone healing under osteopenic conditions.
authors.affiliation: 1 Research Institute of Orthopaedics, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine , Shanghai, China .|3 Institute of Traumatology and Orthopaedics , Shanghai Academy of Traditional Chinese Medicine, Shanghai, China .
authors.forename: Jian
authors.initials: J
authors.lastname: Pang
authors.affiliation: 2 Department of Breast Surgery, Longhua Hospital Affiliated to Shanghai University of Traditional Chinese Medicine , Shanghai, China .
authors.forename: Meina
authors.initials: M
authors.lastname: Ye
authors.affiliation: 3 Institute of Traumatology and Orthopaedics , Shanghai Academy of Traditional Chinese Medicine, Shanghai, China .
authors.forename: Xinfeng
authors.initials: X
authors.lastname: Gu
authors.affiliation: 1 Research Institute of Orthopaedics, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine , Shanghai, China .
authors.forename: Yuelong
authors.initials: Y
authors.lastname: Cao
authors.affiliation: 1 Research Institute of Orthopaedics, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine , Shanghai, China .
authors.forename: Yuxin
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: 1 Research Institute of Orthopaedics, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine , Shanghai, China .
authors.forename: Hailing
authors.initials: H
authors.lastname: Guo
authors.affiliation: 1 Research Institute of Orthopaedics, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine , Shanghai, China .
authors.forename: Yongfang
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: 1 Research Institute of Orthopaedics, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine , Shanghai, China .
authors.forename: Hongsheng
authors.initials: H
authors.lastname: Zhan
authors.affiliation: 1 Research Institute of Orthopaedics, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine , Shanghai, China .
authors.forename: Yinyu
authors.initials: Y
authors.lastname: Shi
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D001851:Bone Diseases, Metabolic / Q000000981:diagnostic imaging / Q000209:etiology* / Q000473:pathology* / Q000503:physiopathology; D004195:Disease Models, Animal; D005260:Female; D005264:Femoral Fractures / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D005269:Femur / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology; D017102:Fracture Healing; D008810:Mice, Inbred C57BL; D010027:Osteotomy; D010052:Ovariectomy; D055114:X-Ray Microtomography