Document Detail


Exercise alters mineral and matrix composition in the absence of adding new bone.
MedLine Citation:
PMID:  18703871     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The mechanical properties of bone are dictated by its amount, distribution and 'quality'. The composition of the mineral and matrix phases is integral to defining 'bone quality'. Exercise can potentially increase resistance to fracture, yet the effects of exercise on skeletal fragility, and how alterations in fragility are modulated by the amount, distribution and composition of bone, are unknown. In this investigation, the effects of exercise on the size, composition, mechanical properties and damage resistance of bones from mice of various ages, background strains and genetic makeup were assessed, as a means of testing the hypothesis that mechanical loading can improve skeletal fragility via compositional alterations. C57BL/6 mice (4-month-old males) ran on a treadmill for 21 days. Tibiae from exercised and control mice were analyzed for cross-sectional geometry, mechanical properties, microdamage and composition. Exercise significantly increased strength without increasing cross-sectional properties, suggesting that mechanical stimulation led to changes in the bone matrix, and these changes led to the improvements in mechanical properties. Consistent with this interpretation, the mineral/matrix ratio was significantly increased in exercised bones. The number of fatigue-induced microcracks was significantly lower in exercised bones, providing evidence that exercise modulates fatigue resistance. The ratio of nonreducible/reducible cross-links mirrored the damage data. Similar trends (exercise induced increases in mechanical properties without increases in cross-sectional properties, but with compositional changes) were also observed in 2-month-old biglycan-deficient and wild-type mice bred on a C57BL/6x129 genetic background.
Authors:
David H Kohn; Nadder D Sahar; Joseph M Wallace; Kurtulus Golcuk; Michael D Morris
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2008-08-15
Journal Detail:
Title:  Cells, tissues, organs     Volume:  189     ISSN:  1422-6421     ISO Abbreviation:  Cells Tissues Organs (Print)     Publication Date:  2009  
Date Detail:
Created Date:  2008-12-09     Completed Date:  2009-02-10     Revised Date:  2014-09-11    
Medline Journal Info:
Nlm Unique ID:  100883360     Medline TA:  Cells Tissues Organs     Country:  Switzerland    
Other Details:
Languages:  eng     Pagination:  33-7     Citation Subset:  IM    
Copyright Information:
Copyright 2008 S. Karger AG, Basel.
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MeSH Terms
Descriptor/Qualifier:
Animals
Bone Density / physiology*
Bone Matrix / metabolism*
Bone and Bones / physiology*
Fractures, Bone / physiopathology
Male
Mice
Mice, Inbred C57BL
Physical Conditioning, Animal*
Tensile Strength
Tibia / physiology
Time Factors
Grant Support
ID/Acronym/Agency:
R01 AR 052010/AR/NIAMS NIH HHS; R01 AR052010/AR/NIAMS NIH HHS; R01 AR052010-04/AR/NIAMS NIH HHS; R90-DK071506/DK/NIDDK NIH HHS
Comments/Corrections

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