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Effect of Single Versus Multiple Fractures on Systemic Bone Loss in Mice
Author(s) -
Zhang Chenggui,
Zhu Junxiong,
Jia Jialin,
Guan Zhiyuan,
Sun Tiantong,
Zhang Wang,
Yuan Wanqiong,
Wang Hong,
Leng Huijie,
Song Chunli
Publication year - 2021
Publication title -
journal of bone and mineral research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.882
H-Index - 241
eISSN - 1523-4681
pISSN - 0884-0431
DOI - 10.1002/jbmr.4211
Subject(s) - medicine , tibia , femur , osteoclast , bone mineral , x ray microtomography , osteoporosis , cortical bone , anatomy , surgery , radiology , receptor
Systemic bone loss after initial fracture contributes to an increased risk of secondary fracture. Clinical research has revealed an association between the risk of future fracture and the number or magnitude of prior fractures. However, the change in systemic bone mass after single versus multiple fractures is unknown. We used ipsilateral femur and tibia fractures as multiple fractures and a femur or tibia fracture as a single fracture to investigate the influence of single versus multiple fractures on systemic bone mass. Seventy‐two adult male C57BL/6J mice underwent transverse osteotomies of the ipsilateral femur and/or tibia with subsequent internal fixation. The dynamic change of in vivo whole‐body BMD was assessed at 4 days, 2 weeks, and 4 weeks after fracture. The microstructure of the L 5 vertebral body and contralateral femur was assessed using micro‐CT (μCT) and biomechanical tests (vertebral compression test and three‐point bending test) at 2 and 4 weeks. Tartrate‐resistant acid phosphatase (TRAP) staining, sequential fluorescence labeling, and systemic inflammatory cytokines were also quantified. A greater decrease in whole‐body BMD was observed after multiple than single fractures. The trabecular bone volume fraction, trabecular number, and trabecular thickness of the L 5 vertebral body were significantly reduced. There were no significant differences in cortical thickness, trabecular bone microstructure, or bone strength in the contralateral femur. At 4 days and 2 weeks, we observed significant increases in the serum levels of IL‐6 and TNF‐α. We also observed an increase in the osteoclast number of the L 5 vertebral body at 4 days. These data indicate that systemic bone loss might increase with the number or severity of prior fractures, and the mechanism may be partly associated with an increased osteoclast number and a more severe inflammatory response. © 2020 American Society for Bone and Mineral Research (ASBMR).