title: Changes of mesenchymal stromal cells mobilization and bone turnover in an experimental bone fracture model in ovariectomized mice.
abstract: OBJECTIVE
  The aim of this study was to characterize the mesenchymal stromal cells (MSCs) and endothelial progenitor cells (EPCs) mobilization, and bone turnover in osteoporotic fracture healing in ovariectomized mice.
  
  
  METHODS
  In total, 112 female C57/BL mice were divided into two groups. The first group was sham-operated (SO), and the other group was ovariectomized (OVX). After three weeks, the right femora of the mice were fractured under anesthesia and internally fixed with steel pin. Peripheral blood and bone marrow were was collected for flow cytometry analysis, at 0 hours (h), 12 h, 24 h, 72 h and 168 h after fracture. MSCs and EPCs levels were assessed using cell surface antigens in different combinations (CD44+ CD34-CD45-, and CD34+ KDR+CD45-) by flow cytometry. At 0, 14, 28 and 42 days after fracture, sera were assayed for circulating levels of procollagen type I-N-terminal propeptide (P1NP) and C-terminal telopeptide of type I-collagen (CTX) by ELISA. Femurs were harvested at 2 weeks and 6 weeks after fracture for X-ray radiography, micro-computed tomography (micro-CT) and histology.
  
  
  RESULTS
  Our results showed that bone marrow and peripheral blood MSCs numbers of the OVX mice were significantly lower than the SO mice, at 12 h, 24 h and 72 h after fracture. In addition, circulating P1NP and CTX levels of the OVX mice were significantly higher than the SO mice, at 2 and 4 weeks.
  
  
  CONCLUSIONS
  Results of the present study revealed disorders of bone marrow MSCs mobilization and bone turnover may partially account for the delay of osteoporotic fracture healing.
authors.affiliation: Research Institute of Orthopedics, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine Shanghai 201203, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Pang
authors.affiliation: Research Institute of Orthopedics, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine Shanghai 201203, China.
authors.forename: Hai-Ling
authors.initials: HL
authors.lastname: Guo
authors.affiliation: Research Institute of Orthopedics, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine Shanghai 201203, China.
authors.forename: Dao-Fang
authors.initials: DF
authors.lastname: Ding
authors.affiliation: Research Institute of Orthopedics, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine Shanghai 201203, China.
authors.forename: Yu-Yun
authors.initials: YY
authors.lastname: Wu
authors.affiliation: Research Institute of Orthopedics, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine Shanghai 201203, China.
authors.forename: Yong-Fang
authors.initials: YF
authors.lastname: Zhao
authors.affiliation: Department of Orthopedics, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine Shanghai 201203, China.
authors.forename: Xin-Feng
authors.initials: XF
authors.lastname: Gu
authors.affiliation: Department of Orthopedics, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine Shanghai 201203, China.
authors.forename: Yu-Xin
authors.initials: YX
authors.lastname: Zheng
mesh_terms: D000818:Animals; D015519:Bone Density / Q000502:physiology; D016723:Bone Remodeling / Q000502:physiology*; D004195:Disease Models, Animal; D005260:Female; D005264:Femoral Fractures / Q000378:metabolism / Q000473:pathology*; D059630:Mesenchymal Stem Cells / Q000473:pathology*; D051379:Mice; D008810:Mice, Inbred C57BL; D058866:Osteoporotic Fractures / Q000378:metabolism / Q000473:pathology*; D010052:Ovariectomy
keywords: MSCs; Osteoporosis; bone healing; mobilization; mouse