Document Detail


Analysis of ovariectomy and estrogen effects on body composition in rats by X-ray and magnetic resonance imaging techniques.
MedLine Citation:
PMID:  10646123     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Resistance of bone to fracture--bone strength--has been shown to depend on both the amount of bone and its architectural spatial organization. In vivo magnetic resonance (MR) techniques have the capability of imaging bone tissue, including the trabecular microarchitecture and the marrow composition. We have applied in vivo and ex vivo MR methods to the tibia in an ovariectomized rat model of osteoporosis. Specifically, in vivo high-resolution three-dimensional MR imaging and localized MRS were facilitated by specialized coils and high field magnets, resulting in enhanced sensitivity of detection. As a result, in vivo and ex vivo differences in marrow composition were found between sham-ovariectomized, ovariectomized, and ovariectomized animals treated with 17-beta-estradiol. Estrogen effects were detected in vivo 7 days after surgery (3 days into treatment) as a decrease in the tibial fat signal level. The in vivo effects of ovariectomy were observed 56 days after surgery as an increase in MR image fat signal level and spectral fat/water ratio in the proximal tibia. Ex vivo measurements of tibial marrow water signal discriminated clearly between the sham and ovariectomized groups and showed increased individual variations in the treatment group. Imaging further showed that the highest fat content is observed in the epiphysis. Computed tomography confirmed ovariectomy-induced loss of bone in the proximal tibial metaphysis compared with the sham group. This loss of cancellous bone with ovariectomy is consistent with the MR observations of increases in both fat and water in the metaphysis. These data showed that MR techniques complement X-ray techniques in the bone, water, and fat compositional analysis of the appendicular skeleton in response to ovariectomy and pharmacological treatment.
Authors:
J C Sharp; J C Copps; Q Liu; L N Ryner; R A Sebastian; G Q Zeng; S Smith; J O Niere; B Tomanek; M Sato
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research     Volume:  15     ISSN:  0884-0431     ISO Abbreviation:  J. Bone Miner. Res.     Publication Date:  2000 Jan 
Date Detail:
Created Date:  2000-02-11     Completed Date:  2000-02-11     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8610640     Medline TA:  J Bone Miner Res     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  138-46     Citation Subset:  IM    
Affiliation:
Institute for Biodiagnostics, National Research Council of Canada, Winnipeg, Manitoba, Canada.
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MeSH Terms
Descriptor/Qualifier:
Adipose Tissue
Animals
Body Composition*
Body Water
Bone Density / drug effects*
Bone and Bones / anatomy & histology*,  drug effects
Estrogens / pharmacology*
Female
Magnetic Resonance Imaging
Ovariectomy
Rats
Rats, Sprague-Dawley
Chemical
Reg. No./Substance:
0/Estrogens

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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