EFFECTS OF A DECREASE IN MECHANICAL STRESS ON FEMORAL REGIONAL BONE MINERAL DENSITY AND OSTEOBLAST MICROSTRUCTURE: COMPARISON IN A MODEL OF FREELY MOBILE AND CAST IMMOBILIZED RATS

• KAWAKAMI TOSHIKAZU

  Department of Sport Medicine, Osaka University of Health and Sport Sciences

• TAKISE SADAFUMI

  Department of Sport Medicine, Osaka University of Health and Sport Sciences

• GIMA DAISUKE

  Department of Sport Medicine, Osaka University of Health and Sport Sciences

抄録

Purpose: Decreased mechanical stress causes disuse bone atrophy characterized by reduced bone mass and weakened bone. However, few studies have measured the mechanism behind such changes in different areas of bone. The present morphological study investigated the effects of decreased mechanical stress on bone mineral density in different areas of the femur by measuring bone mineral density and assessing the microstructure of osteoblasts. <br>Methods: Twenty-one 9-week-old male Sprague-Dawley rats were acclimatized for one week, and then were divided into control, exercise, and cast immobilization groups. The study was conducted over an 8-week period, from age 10 weeks to 17 weeks in the rats. Bone mineral density was measured by dual energy X-ray absorption (QDR-2000) in the proximal epiphysis/metaphysis, diaphysis, and distal epiphysis/metaphysis of the femur. The microstructure of osseous cells was examined by Scanning Electron Microscopy (SEM). <br>Results: Bone mineral density of the distal epiphysis/metaphysis was significantly lower in the cast immobilization group than in the exercise or control groups (p<0.001). In the cast immobilization group, scanning electron microscopy of the distal epiphysis/metaphysis revealed no boundary between small osteoblast and smooth neighboring cells; however, in the exercise group, actively osteoblastic osteoblasts covered the bone surface, resembling a stone wall.<br>Conclusion: Decreased mechanical stress caused a decrease in bone mineral density that varied in different areas of the femur. The largest decrease in density occurred in the distal epiphysis/<br>metaphysis. Osteoblast microstructure played an important role.

収録刊行物

• 体力科学

  体力科学 58 (2), 305-316, 2009

  一般社団法人日本体力医学会

キーワード

• bone remodeling
• femoral distal epiphysis/metaphysis
• SEM
• osteoblast

詳細情報

• CRID: 1390001204920468224
• NII論文ID: 10025944273
• NII書誌ID: AN00137986
• DOI: 10.7600/jspfsm.58.305
• ISSN: 18814751
• ISSN: 0039906X
• NDL書誌ID: 10287633
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I10287633
• Web Site: https://www.jstage.jst.go.jp/article/jspfsm/58/2/58_2_305/_pdf
• Web Site: https://search.jamas.or.jp/link/ui/2009289666
• 本文言語コード: ja
• データソース種別:
  • JaLC
  • NDL
  • Crossref
  • CiNii Articles
• 抄録ライセンスフラグ: 使用不可