A novel underuse model shows that inactivity but not ovariectomy determines the deteriorated material properties and geometry of cortical bone in the tibia of adult rats

Autor: Takami Furuhama, Kouji Naruse, Hideyuki Yamato, Yuko Mikuni-Takagaki, Keiichi Ohya, Isamu Kashima, Kazuhiro Aoki, Yumi Ito, Yusuke Kozai, Kazuaki Miyagawa, Kiichi Nonaka, Yumiko Nagai
Rok vydání: 2010
Předmět:
Aging
Bone density
Endocrinology
Diabetes and Metabolism
Osteoporosis
Bone Matrix
Walking
Spectrum Analysis
Raman
Bone remodeling
Endocrinology
Bone Density
Orthopedics and Sports Medicine
Quantitative computed tomography
Lumbar Vertebrae
medicine.diagnostic_test
Osteocyte
General Medicine
Anatomy
musculoskeletal system
Immunohistochemistry
Biomechanical Phenomena
Raman spectroscopy and quality of bone
medicine.anatomical_structure
Bone Morphogenetic Proteins
Female
Original Article
Bone Remodeling
Epiphyses
Cancellous bone
Genetic Markers
musculoskeletal diseases
Ovariectomy
Models
Biological
Osteocytes
Underuse
medicine
Animals
Femur
Tibia
Rats
Wistar
SOST/sclerostin
business.industry
Body Weight
X-Ray Microtomography
medicine.disease
Rats
Cortical bone
business
human activities
Biomarkers
Zdroj: Journal of Bone and Mineral Metabolism
ISSN: 1435-5604
0914-8779
DOI: 10.1007/s00774-010-0241-9
Popis: Our goal in this study was to determine to what extent the physiologic consequences of ovariectomy (OVX) in bones are exacerbated by a lack of daily activity such as walking. We forced 14-week-old female rats to be inactive for 15 weeks with a unique experimental system that prevents standing and walking while allowing other movements. Tibiae, femora, and 4th lumbar vertebrae were analyzed by peripheral quantitative computed tomography (pQCT), microfocused X-ray computed tomography (micro-CT), histology, histomorphometry, Raman spectroscopy, and the three-point bending test. Contrary to our expectation, the exacerbation was very much limited to the cancellous bone parameters. Parameters of femur and tibia cortical bone were affected by the forced inactivity but not by OVX: (1) cross-sectional moment of inertia was significantly smaller in Sham-Inactive rat bones than that of their walking counterparts; (2) the number of sclerostin-positive osteocytes per unit cross-sectional area was larger in Sham-Inactive rat bones than in Sham-Walking rat bones; and (3) material properties such as ultimate stress of inactive rat tibia was lower than that of their walking counterparts. Of note, the additive effect of inactivity and OVX was seen only in a few parameters, such as the cancellous bone mineral density of the lumbar vertebrae and the structural parameters of cancellous bone in the lumbar vertebrae/tibiae. It is concluded that the lack of daily activity is detrimental to the strength and quality of cortical bone in the femur and tibia of rats, while lack of estrogen is not. Our inactive rat model, with the older rats, will aid the study of postmenopausal osteoporosis, the etiology of which may be both hormonal and mechanical. Electronic supplementary material The online version of this article (doi:10.1007/s00774-010-0241-9) contains supplementary material, which is available to authorized users.
Databáze: OpenAIRE
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