›› 2011, Vol. 31 ›› Issue (7): 890-.doi: 10.3969/j.issn.1674-8115.2011.07.005

• Original article (Basic research) • Previous Articles     Next Articles

Preliminary study of mechanism of delayed early fracture healing in ovariectomized mice

ZHAO Jian1, ZHAO Qiang1, ZHANG Lian-fang1, DENG Ruo-xian2, QI Jin1, ZHOU Qi1, WANG Jin-shen1, LIN Liu-lan3, DENG Lian-fu1   

  1. 1.Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai Institute of Traumatology and Orthopedics, Shanghai Key Laboratory of Combination of Traditional Chinese and Western Medicine in Prevention and Therapy of Osteo-arthropathy, Shanghai 200025, China；2.School of Medical Devices and Food Sciences, University of Shanghai for Science and Technology, Shanghai 200093, China；3.Rapid Manufacturing Center, Shanghai University, Shanghai 200444, China
  • Online:2011-07-28 Published:2011-07-27
  • Supported by:

    National Natural Science Foundation of China, 30872641；Shanghai Research and Development Base Project, 09dz2200500

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Abstract:

Objective To observe the early fracture healing in ovariectomized mice, and explore the possible mechanism. Methods Forty female C57BL/6 mice aged 6 weeks were randomly divided into ovariectomy group (OVX group) and sham operation group, with 20 rats in each group. Four weeks after ovariectomy in OVX group, right femur fracture mouse models were established in both groups. Two weeks after model establishment, the fracture healing was observed by X-ray examinations, and Micro-CT was used to measure the volumes of callus and mineral density, observe the angiogenesis and determine the vessel volumes and vessel volume fractions in fracture sites after vessel perfusion. Bone tissue samples were prepared 2 weeks after model establishment, the fracture healing was observed by light microscopy with HE staining, and the expression of vascular endothelial growth factor (VEGF) protein in callus tissues was observed with immunohistochemical staining. Results X-ray examinations and histological examinations of fracture samples indicated that the early fracture healing in OVX group was significantly delayed compared with sham operation group. Micro-CT detection revealed that compared with sham operation group, the volume of callus, mineral density, and number of vessels, vessel volume and vessel volume fraction in fracture sites after vessel perfusion were significantly decreased (P<0.05). It was observed by immunohistochemical staining that the expression of VEGF in callus tissues in OVX group was significantly lower than that in sham operation group. Conclusion The early fracture healing is significantly delayed in ovariectomized mice, which may be related to the reduction of angiogenesis in callus tissues.

Key words: osteoporosis, ovariectomy, fracture healing