Diving into old age: muscular senescence in a large-bodied, long-lived mammal, the Weddell seal (Leptonychotes weddellii)
Classic aging theory postulates the absence of pronounced organismal senescence in wild animals since mortality probably occurs first. Large-bodied, long-lived mammals are a recognized exception to this tenet, yet organismal senescence has not been investigated to date in such mammals in the wild. F...
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fthighwire:oai:open-archive.highwire.org:jexbio:212/6/790 2023-05-15T18:43:22+02:00 Diving into old age: muscular senescence in a large-bodied, long-lived mammal, the Weddell seal (Leptonychotes weddellii) Hindle, Allyson G. Horning, Markus Mellish, Jo-Ann E. Lawler, John M. 2009-03-15 00:00:00.0 text/html http://jeb.biologists.org/cgi/content/short/212/6/790 https://doi.org/10.1242/jeb.025387 en eng Company of Biologists http://jeb.biologists.org/cgi/content/short/212/6/790 http://dx.doi.org/10.1242/jeb.025387 Copyright (C) 2009, Company of Biologists Research Article TEXT 2009 fthighwire https://doi.org/10.1242/jeb.025387 2015-03-01T00:40:54Z Classic aging theory postulates the absence of pronounced organismal senescence in wild animals since mortality probably occurs first. Large-bodied, long-lived mammals are a recognized exception to this tenet, yet organismal senescence has not been investigated to date in such mammals in the wild. Furthermore, oxidative stress theory of aging supports the suggestion that exercise hypoxia, as regularly incurred during apneustic foraging in diving mammals might lead to cellular dysfunction and accelerated aging. To determine if an aspect of organismal senescence occurs in wild marine mammals, we examined the pattern of skeletal muscle aging (contractile and connective tissue components of longissimus dorsi and pectoralis muscles) in free-ranging adult Weddell seals (9–26 years). The average myocyte cross-sectional area was 22% greater with age in the longissiums dorsi, but no significant increase occurred in the pectoralis. Cross-sectional area was not related to body mass. Changes in myocyte number per area were consistent with the 35–40% age-increase in extracellular space in both muscle groups. Also consistent with extracellular space remodeling, total and relative collagen contents were significantly elevated in older seals (115% in longissimus dorsi; 65% in pectoralis). The ratio of muscle myocyte to collagen declined with age (50–63%) at both sites. Additionally, a shift towards a higher ratio of type I to type III collagen occurred with advancing age in both muscle groups (79% increase in pectoralis; 49% in longissimus dorsi). We reject the classic tenet and null-hypothesis that Weddell seals do not survive to an age where muscular senescence becomes detectable. Text Weddell Seal Weddell Seals HighWire Press (Stanford University) Weddell Journal of Experimental Biology 212 6 790 796 |
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HighWire Press (Stanford University) |
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English |
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Research Article |
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Research Article Hindle, Allyson G. Horning, Markus Mellish, Jo-Ann E. Lawler, John M. Diving into old age: muscular senescence in a large-bodied, long-lived mammal, the Weddell seal (Leptonychotes weddellii) |
topic_facet |
Research Article |
description |
Classic aging theory postulates the absence of pronounced organismal senescence in wild animals since mortality probably occurs first. Large-bodied, long-lived mammals are a recognized exception to this tenet, yet organismal senescence has not been investigated to date in such mammals in the wild. Furthermore, oxidative stress theory of aging supports the suggestion that exercise hypoxia, as regularly incurred during apneustic foraging in diving mammals might lead to cellular dysfunction and accelerated aging. To determine if an aspect of organismal senescence occurs in wild marine mammals, we examined the pattern of skeletal muscle aging (contractile and connective tissue components of longissimus dorsi and pectoralis muscles) in free-ranging adult Weddell seals (9–26 years). The average myocyte cross-sectional area was 22% greater with age in the longissiums dorsi, but no significant increase occurred in the pectoralis. Cross-sectional area was not related to body mass. Changes in myocyte number per area were consistent with the 35–40% age-increase in extracellular space in both muscle groups. Also consistent with extracellular space remodeling, total and relative collagen contents were significantly elevated in older seals (115% in longissimus dorsi; 65% in pectoralis). The ratio of muscle myocyte to collagen declined with age (50–63%) at both sites. Additionally, a shift towards a higher ratio of type I to type III collagen occurred with advancing age in both muscle groups (79% increase in pectoralis; 49% in longissimus dorsi). We reject the classic tenet and null-hypothesis that Weddell seals do not survive to an age where muscular senescence becomes detectable. |
format |
Text |
author |
Hindle, Allyson G. Horning, Markus Mellish, Jo-Ann E. Lawler, John M. |
author_facet |
Hindle, Allyson G. Horning, Markus Mellish, Jo-Ann E. Lawler, John M. |
author_sort |
Hindle, Allyson G. |
title |
Diving into old age: muscular senescence in a large-bodied, long-lived mammal, the Weddell seal (Leptonychotes weddellii) |
title_short |
Diving into old age: muscular senescence in a large-bodied, long-lived mammal, the Weddell seal (Leptonychotes weddellii) |
title_full |
Diving into old age: muscular senescence in a large-bodied, long-lived mammal, the Weddell seal (Leptonychotes weddellii) |
title_fullStr |
Diving into old age: muscular senescence in a large-bodied, long-lived mammal, the Weddell seal (Leptonychotes weddellii) |
title_full_unstemmed |
Diving into old age: muscular senescence in a large-bodied, long-lived mammal, the Weddell seal (Leptonychotes weddellii) |
title_sort |
diving into old age: muscular senescence in a large-bodied, long-lived mammal, the weddell seal (leptonychotes weddellii) |
publisher |
Company of Biologists |
publishDate |
2009 |
url |
http://jeb.biologists.org/cgi/content/short/212/6/790 https://doi.org/10.1242/jeb.025387 |
geographic |
Weddell |
geographic_facet |
Weddell |
genre |
Weddell Seal Weddell Seals |
genre_facet |
Weddell Seal Weddell Seals |
op_relation |
http://jeb.biologists.org/cgi/content/short/212/6/790 http://dx.doi.org/10.1242/jeb.025387 |
op_rights |
Copyright (C) 2009, Company of Biologists |
op_doi |
https://doi.org/10.1242/jeb.025387 |
container_title |
Journal of Experimental Biology |
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212 |
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6 |
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790 |
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796 |
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1766233751484891136 |