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A low protein diet alters bone material level properties and the response to in vitro repeated mechanical loading.

Dubois-Ferrière V, Rizzoli R, Ammann P - Biomed Res Int (2014)

Bottom Line: However, it remains unknown whether these alterations of bone tissue could influence the response to repeated mechanical loading.Humeri were then monotonically loaded to failure.Material level properties were also evaluated through a nanoindentation test.

View Article: PubMed Central - PubMed

Affiliation: Division of Bone Diseases, Department of Internal Medicine Specialties, University of Geneva Hospitals and Faculty of Medicine, 4 Rue Gabrielle Perret-Gentil, 1211 Geneva 14, Switzerland.

ABSTRACT
Low protein intake is associated with an alteration of bone microstructure and material level properties. However, it remains unknown whether these alterations of bone tissue could influence the response to repeated mechanical loading. The authors investigated the in vitro effect of repeated loading on bone strength in humeri collected from 20 6-month-old female rats pair-fed with a control (15% casein) or an isocaloric low protein (2.5% casein) diet for 10 weeks. Bone specimens were cyclically loaded in three-point bending under load control for 2000 cycles. Humeri were then monotonically loaded to failure. The load-displacement curve of the in vitro cyclically loaded humerus was compared to the contralateral noncyclically loaded humerus and the influence of both protein diets. Material level properties were also evaluated through a nanoindentation test. Cyclic loading decreased postyield load and plastic deflection in rats fed a low protein diet, but not in those on a regular diet. Bone material level properties were altered in rats fed a low protein diet. This suggests that bone biomechanical alterations consequent to cyclic loading are more likely to occur in rats fed a low protein diet than in control animals subjected to the same in vitro cyclic loading regimen.

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Related in: MedlinePlus

Preliminary determination of cyclic loading. Number of cycles to failure according to different loading parameters based on the maximal load (LMAX) to failure of the contralateral bone. *Test stopped at 18000 cycles.
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fig2: Preliminary determination of cyclic loading. Number of cycles to failure according to different loading parameters based on the maximal load (LMAX) to failure of the contralateral bone. *Test stopped at 18000 cycles.

Mentions: Depending on loading forces, bone samples tolerate a different number of cycles before fracture (Figure 2). A loading force corresponding to 60% of maximal force of the contralateral noncyclically loaded humerus allowed a fatigue loading without failure after at least 2000 cycles. However, when increasing the force to higher values, bone rapidly failed. By contrast, a decrease in loading force did not result in failure after more than 18000 cycles. Under the latter condition, only minimal changes would be observed between loaded and nonloaded humeri. Therefore, a loading force of 60% of the maximal load was applied.


A low protein diet alters bone material level properties and the response to in vitro repeated mechanical loading.

Dubois-Ferrière V, Rizzoli R, Ammann P - Biomed Res Int (2014)

Preliminary determination of cyclic loading. Number of cycles to failure according to different loading parameters based on the maximal load (LMAX) to failure of the contralateral bone. *Test stopped at 18000 cycles.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4150450&req=5

fig2: Preliminary determination of cyclic loading. Number of cycles to failure according to different loading parameters based on the maximal load (LMAX) to failure of the contralateral bone. *Test stopped at 18000 cycles.
Mentions: Depending on loading forces, bone samples tolerate a different number of cycles before fracture (Figure 2). A loading force corresponding to 60% of maximal force of the contralateral noncyclically loaded humerus allowed a fatigue loading without failure after at least 2000 cycles. However, when increasing the force to higher values, bone rapidly failed. By contrast, a decrease in loading force did not result in failure after more than 18000 cycles. Under the latter condition, only minimal changes would be observed between loaded and nonloaded humeri. Therefore, a loading force of 60% of the maximal load was applied.

Bottom Line: However, it remains unknown whether these alterations of bone tissue could influence the response to repeated mechanical loading.Humeri were then monotonically loaded to failure.Material level properties were also evaluated through a nanoindentation test.

View Article: PubMed Central - PubMed

Affiliation: Division of Bone Diseases, Department of Internal Medicine Specialties, University of Geneva Hospitals and Faculty of Medicine, 4 Rue Gabrielle Perret-Gentil, 1211 Geneva 14, Switzerland.

ABSTRACT
Low protein intake is associated with an alteration of bone microstructure and material level properties. However, it remains unknown whether these alterations of bone tissue could influence the response to repeated mechanical loading. The authors investigated the in vitro effect of repeated loading on bone strength in humeri collected from 20 6-month-old female rats pair-fed with a control (15% casein) or an isocaloric low protein (2.5% casein) diet for 10 weeks. Bone specimens were cyclically loaded in three-point bending under load control for 2000 cycles. Humeri were then monotonically loaded to failure. The load-displacement curve of the in vitro cyclically loaded humerus was compared to the contralateral noncyclically loaded humerus and the influence of both protein diets. Material level properties were also evaluated through a nanoindentation test. Cyclic loading decreased postyield load and plastic deflection in rats fed a low protein diet, but not in those on a regular diet. Bone material level properties were altered in rats fed a low protein diet. This suggests that bone biomechanical alterations consequent to cyclic loading are more likely to occur in rats fed a low protein diet than in control animals subjected to the same in vitro cyclic loading regimen.

Show MeSH
Related in: MedlinePlus