Altered mechanical environment of bone cells in an animal model of short- and long-term osteoporosis
File(s)Revised Manuscript Verbruggen et al January 2015 B.pdf (1.18 MB)
Accepted version
Author(s)
Verbruggen, SW
Mc Garrigle, MJ
Haugh, MG
Voisin, MC
McNamara, LM
Type
Journal Article
Abstract
Alterations in bone tissue composition during osteoporosis likely disrupt the mechanical environment of bone cells and may thereby initiate a mechanobiological response. It has proved challenging to characterize the mechanical environment of bone cells in vivo, and the mechanical environment of osteoporotic bone cells is not known. The objective of this research is to characterize the local mechanical environment of osteocytes and osteoblasts from healthy and osteoporotic bone in a rat model of osteoporosis. Using a custom-designed micromechanical loading device, we apply strains representative of a range of physical activity (up to 3000 με) to fluorescently stained femur samples from normal and ovariectomized rats. Confocal imaging was simultaneously performed, and digital image correlation techniques were applied to characterize cellular strains. In healthy bone tissue, osteocytes experience higher maximum strains (31,028 ± 4213 με) than osteoblasts (24,921 ± 3,832 με), whereas a larger proportion of the osteoblast experiences strains >10,000 με. Most interestingly, we show that osteoporotic bone cells experience similar or higher maximum strains than healthy bone cells after short durations of estrogen deficiency (5 weeks), and exceeded the osteogenic strain threshold (10,000 με) in a similar or significantly larger proportion of the cell (osteoblast, 12.68% vs. 13.68%; osteocyte, 15.74% vs. 5.37%). However, in long-term estrogen deficiency (34 weeks), there was no significant difference between bone cells in healthy and osteoporotic bone. These results suggest that the mechanical environment of bone cells is altered during early-stage osteoporosis, and that mechanobiological responses act to restore the mechanical environment of the bone tissue after it has been perturbed by ovariectomy.
Date Issued
2015-04-07
Date Acceptance
2015-02-03
Citation
Biophysical Journal, 2015, 108 (7), pp.1587-1598
ISSN
1542-0086
Publisher
Biophysical Society
Start Page
1587
End Page
1598
Journal / Book Title
Biophysical Journal
Volume
108
Issue
7
Copyright Statement
© 2015 by the Biophysical Society
Subjects
Biophysics
02 Physical Sciences
03 Chemical Sciences
06 Biological Sciences
Publication Status
Published