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Age- and gender-related changes in contractile properties of non-atrophied EDL muscle.

Chan S, Head SI - PLoS ONE (2010)

Bottom Line: However, it is not entirely clear whether these changes in contractile properties can occur before there is significant atrophy, and whether males and females are affected differently.In the properties of absolute force and muscle relaxation times, females were affected by ageing to a greater extent than males.Our findings provide further insight into the muscle atrophy, weakness and fatiguability experienced by the elderly.

View Article: PubMed Central - PubMed

Affiliation: School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia.

ABSTRACT

Background: In humans, ageing causes skeletal muscles to become atrophied, weak, and easily fatigued. In rodent studies, ageing has been associated with significant muscle atrophy and changes in the contractile properties of the muscles. However, it is not entirely clear whether these changes in contractile properties can occur before there is significant atrophy, and whether males and females are affected differently.

Methods and results: We investigated various contractile properties of whole isolated fast-twitch EDL muscles from adult (2-6 months-old) and aged (12-22 months-old) male and female mice. Atrophy was not present in the aged mice. Compared with adult mice, EDL muscles of aged mice had significantly lower specific force, longer tetanus relaxation times, and lower fatiguability. In the properties of absolute force and muscle relaxation times, females were affected by ageing to a greater extent than males. Additionally, EDL muscles from a separate group of male mice were subjected to eccentric contractions of 15% strain, and larger force deficits were found in aged than in adult mice.

Conclusion: Our findings provide further insight into the muscle atrophy, weakness and fatiguability experienced by the elderly. We have shown that even in the absence of muscle atrophy, there are definite alterations in the physiological properties of whole fast-twitch muscle from ageing mice, and for some of these properties the alterations are more pronounced in female mice than in male mice.

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Related in: MedlinePlus

Maximum forces.In females, EDL muscles of aged animals had lower absolute force (A) than muscles from adult animals. Specific force (B) was lower in aged compared with adult animals, in both males and females.
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pone-0012345-g002: Maximum forces.In females, EDL muscles of aged animals had lower absolute force (A) than muscles from adult animals. Specific force (B) was lower in aged compared with adult animals, in both males and females.

Mentions: Figure 2 shows the maximum absolute force (A) and the maximum specific force (B) generated by the EDL muscles of adult and aged male and female mice. Absolute forces in males were no different between adult and aged mice. In females, muscles from aged mice showed a 7.2% lower absolute force compared with adult mice (P  =  0.0069). Muscles from aged animals generated significantly lower specific force than muscles from adult animals, in both males and females. The difference was 13% in males (P<0.0001) and 13% in females (P  =  0.0016).


Age- and gender-related changes in contractile properties of non-atrophied EDL muscle.

Chan S, Head SI - PLoS ONE (2010)

Maximum forces.In females, EDL muscles of aged animals had lower absolute force (A) than muscles from adult animals. Specific force (B) was lower in aged compared with adult animals, in both males and females.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2925956&req=5

pone-0012345-g002: Maximum forces.In females, EDL muscles of aged animals had lower absolute force (A) than muscles from adult animals. Specific force (B) was lower in aged compared with adult animals, in both males and females.
Mentions: Figure 2 shows the maximum absolute force (A) and the maximum specific force (B) generated by the EDL muscles of adult and aged male and female mice. Absolute forces in males were no different between adult and aged mice. In females, muscles from aged mice showed a 7.2% lower absolute force compared with adult mice (P  =  0.0069). Muscles from aged animals generated significantly lower specific force than muscles from adult animals, in both males and females. The difference was 13% in males (P<0.0001) and 13% in females (P  =  0.0016).

Bottom Line: However, it is not entirely clear whether these changes in contractile properties can occur before there is significant atrophy, and whether males and females are affected differently.In the properties of absolute force and muscle relaxation times, females were affected by ageing to a greater extent than males.Our findings provide further insight into the muscle atrophy, weakness and fatiguability experienced by the elderly.

View Article: PubMed Central - PubMed

Affiliation: School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia.

ABSTRACT

Background: In humans, ageing causes skeletal muscles to become atrophied, weak, and easily fatigued. In rodent studies, ageing has been associated with significant muscle atrophy and changes in the contractile properties of the muscles. However, it is not entirely clear whether these changes in contractile properties can occur before there is significant atrophy, and whether males and females are affected differently.

Methods and results: We investigated various contractile properties of whole isolated fast-twitch EDL muscles from adult (2-6 months-old) and aged (12-22 months-old) male and female mice. Atrophy was not present in the aged mice. Compared with adult mice, EDL muscles of aged mice had significantly lower specific force, longer tetanus relaxation times, and lower fatiguability. In the properties of absolute force and muscle relaxation times, females were affected by ageing to a greater extent than males. Additionally, EDL muscles from a separate group of male mice were subjected to eccentric contractions of 15% strain, and larger force deficits were found in aged than in adult mice.

Conclusion: Our findings provide further insight into the muscle atrophy, weakness and fatiguability experienced by the elderly. We have shown that even in the absence of muscle atrophy, there are definite alterations in the physiological properties of whole fast-twitch muscle from ageing mice, and for some of these properties the alterations are more pronounced in female mice than in male mice.

Show MeSH
Related in: MedlinePlus