From Surf Wiki (app.surf) — the open knowledge base
Alterations in osteoclast morphology following long-term 17beta-estradiol administration in the mouse
Authors: Helen E Gruber, Igor J Puzanov, Michael Bennett, Vinay Kumar, Brian Gordon, SL Teitelbaum, C-C Liu, GA Howard, L Pederson, M Kremer, NT Foged, B Winding, C Ritchie, LA Fitzpatrick, MJ Oursler, E Eriksen, D Colvard, N Berg, M Graham, K Mann, TC Spelsberg, BL Riggs, BS Komm, C Terpening, D Benz, K Graeme, A Gallegos, M Kore, MJ Oursler, P Osdoby, J Pyfferoen, BL Riggs, IJ Puzanov, M Bennett, V Kumar, SC Miller, WSS Jee, CMT Plasmans, PHK Jap, W Kuijpers, TJHH Slooff, SC Miller, WSS Jee, U Lucht, DM Kallio, PR Garant, C Minkin, G Accardo, A Aleotti, D Ricci, A Pazzi, C Minkin, HE Gruber, HJ Norton, FR Singer, GD Roodman, HK Väänäen, M Horton, A Teti, PC Marchisio, AZ Zallone, N Udagawa, N Takahashi, T Akatsu, T Sasaki, A Yamaguchi, H Kodama, TJ Martin, T Suda, N Takahashi, T Akatsu, N Udagawa, T Sasaki, A Yamaguchi, JM Moseley, TJ Martin, T Suda, DJ Baylink, J Farley, L Donahue, CJ Rosen, B Barr, J Lee, W Beamer, TA Linkhart, SG Linkhart, Y Kodama, JR Farley, HP Dimai, KR Wright, JE Wergedal, M Sheng, WG Beamer, LR Donahue, CJ Rosen, DJ Baylink, N Udagawa, N Takashashi, T Akatsu, H Tanaka, T Sasaki, T Nishihara, T Koga, TJ Martin, T Suda, L.C. Hofbauer, F Gori, BL Riggs, DL Lacey, CR Dunstan, TC Spelsberg, S Khosla, L.C. Hofbauer, S. Khosla, D.R. Dunstan, D.L. Lacey, T.C. Spelsbert, B.L Riggs, T Sunyer, J Lewis, P Collin-Osdoby, P Osdoby, KD Brubaker, CV Gay, CV Gay, NL Kief, PJ Bekker, G Fiorelli, F Gori, U Frediani, FTA Franceschelli, C Tosti-Guerra, S Benvenuti, L Gennari, L Becherini, ML Brandi, RL Jilka, G Hangoc, G Firasole, G Passeri, DC Williams, JS Abrams, B Boyce, H Broxmeyer, SC Manolagas, G Girasole, RL Jilka, G Passeri, S Boswell, G Boder, DC Williams, SC Manolagas, T Hackett, M Tutt, M Lipscomb, M Bennett, G Koo, V Kumar, M Bennett, EE Baker, JW Eastcott, V Kumar, D Yonkosky, WE Seaman, TD Gindhart, JS Greenspan, MA Blackman, N Talal, V. Kumar, J Ben-Ezra, M Bennett, G Sonnenfeld, JR Roubinian, N Talal, JS Greenspan, JR Goodman, PK Siiteri, WE Seaman, TD Gindhart, JS Greenspan, MA Blackman, N Talal, WE Seaman, TD Gindhart
Journal: BMC Cell Biology (2001)
Abstract
Although the role of the osteoclast in bone resorption is becoming better understood, much remains to be learned about osteoclastogenesis and the exact mechanism of action of anti-resorbing agents such as 17β-estradiol. This study investigated bone and morphologic osteoclast alterations following long-term estrogen administration to the B6D2F1 mouse. B6D2F1 mice aged 4-5 weeks were exposed to high levels of estrogen via implanted silastic tubing for at least 12 weeks; controls received empty tubing. Femurs of control and treated mice were assessed with radiology, quantitative histomorphometry and transmission electron microscopy. After 8 weeks of treatment, there was radiologic evidence of severe osteosclerosis and 86% of femoral marrow space was replaced with bone. After 12 weeks histologic studies of treated animals revealed that osteoclasts were positive for tartrate-resistant acid phosphatase but showed markedly abnormal ultrastructure which prevented successful bone resorption. Findings extend our understanding of osteoclast structure and function in the mouse exposed in vivo to high doses of estrogen. Ultrastructural examination showed that osteoclasts from estrogen-treated mice were unable to seal against the bone surface and were unable to form ruffled borders.
Background
Although the role of the osteoclast in bone resorption is becoming better understood, much remains to be learned about osteoclastogenesis and the exact mechanism of action of anti-resorbing agents such as 17β-estradiol. This study investigated bone and morphologic osteoclast alterations following long-term estrogen administration to the B6D2F1 mouse. B6D2F1 mice aged 4-5 weeks were exposed to high levels of estrogen via implanted silastic tubing for at least 12 weeks; controls received empty tubing. Femurs of control and treated mice were assessed with radiology, quantitative histomorphometry and transmission electron microscopy.
Results
After 8 weeks of treatment, there was radiologic evidence of severe osteosclerosis and 86% of femoral marrow space was replaced with bone. After 12 weeks histologic studies of treated animals revealed that osteoclasts were positive for tartrate-resistant acid phosphatase but showed markedly abnormal ultrastructure which prevented successful bone resorption.
Conclusions
Findings extend our understanding of osteoclast structure and function in the mouse exposed in vivo to high doses of estrogen. Ultrastructural examination showed that osteoclasts from estrogen-treated mice were unable to seal against the bone surface and were unable to form ruffled borders.
Background
].
]; since marrow space is lessened due to the osteosclerosis, the spleen provides the source for T and B cells and macrophages.
The objective of the present study was to assess the functional state of osteoclasts in estrogen-treated mice by determining if osteoclasts retained tartrate-resistant acid phosphatase activity (TRAP) and normal ultrastructural features.
Results
were exposed side-by-side on the same film.
Radiographs of femurs from control (A and C) and estradiol-treated (B, D and E) mice. In control femurs (A and C), note that the marrow space and cortical margins are apparent but cannot be seen in specimens from estradiol-treated mice (B, D and E). Femurs marked A and B, and those marked C, D and E were radiographed as a group on the same X-ray film using one exposure to eliminate variability in exposure and development of the films.
). Since the normal, pre-estradiol treatment endosteal margin could still be histologically identified on these specimens, specimens were evaluated with quantitative histomorphometry by first measuring the old, normal marrow area and then measuring the small marrow cavity areas present at time of harvest. On average 86% of mid-shaft marrow space was replaced by bone in estradiol-treated mice at 8 weeks (p < 0.0001 control vs estradiol-treated).
, TRAP, X 640).
). In order to further investigate this observation, transmission electron microscopy was performed to examine the fine structure of the Ocl in estradiol-treated and control specimens.
).
, X 4,230)
Discussion
].
].
], the quantity of bone resorbed depends on the balance between expression of RANKL and of its inhibitor, osteoprotegerin (OPG). Hofbauer et al suggest that the stimulation of the pool of M-CSF precursors to committed osteoclastogenesis by RANKL may be one of the central pathophysiologic pathways involved in increasing the number of osteoclasts in osteoporosis.
].
].
]. Future in vivo studies combining estradiol and selected interleukins may further elucidate how the network of signals from the marrow microenvironment influences both Ocl development and Ocl function.
Conclusions
Findings extend our understanding of osteoclast structure and function in the mouse exposed in vivo to high doses of estrogen. Ultrastructural examination showed that osteoclasts from estrogen-treated mice were unable to seal against the bone surface and were unable to form ruffled borders.
Materials and Methods
].
inhalation) and femurs were harvested from 13 control and 33 estradiol-treated mice. Cross-sections of the femur and sections of femoral metaphyses and epiphyses were studied. For light microscopy, specimens were either fixed in 10% neutral buffered formalin, decalcified and embedded in paraffin or processed non-decalcified and embedded in methyl methacrylate. For ultrastructural studies, specimens were fixed in Karnovsky's fixative, post-fixed in osmium tetroxide, decalcified, and embedded in Spurr resin. Thin sections were prepared and grids were stained with uranyl acetate and lead citrate. Sections were viewed on a Phillips CM10 transmission electron microscope. Light microscopic sections were evaluated with quantitative histomorphometry using OsteoMeasure software (OsteoMetrics, Inc., Decatur, GA). Tartrate-resistant acid phosphatase (TRAP) localization was performed to identify osteoclasts with light microscopy. Protocols were approved by the appropriate Institutional Animal Care and Use Committee.
Statistical analysis of quantitative histomorphometric data used standard statistical methods; means and standard deviations were calculated. Unpaired t-tests were used to test for differences between means; a p-value of <0.05 was considered statistically significant.
Acknowledgements
The authors thank Audrey Stasky, Jane Ingram and Tracie McClain for assistance with light microscopy, and Winston Wiggins, Pat Hill and Daisy Ridings for assistance with electron microscopy.
Ask Mako anything about Alterations in osteoclast morphology following long-term 17beta-estradiol administration in the mouse — get instant answers, deeper analysis, and related topics.
Research with MakoFree with your Surf account
Create a free account to save articles, ask Mako questions, and organize your research.
Sign up freeThis content may have been generated or modified by AI. CloudSurf Software LLC is not responsible for the accuracy, completeness, or reliability of AI-generated content. Always verify important information from primary sources.
Report