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The impact of stretch, exercise and drug treatments on structure, function and satellite cell activation in aging muscle

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dc.contributor.supervisor Anderson, Judy (Biological Sciences) en
dc.contributor.author Leiter, Jeffrey Robert Scott
dc.date.accessioned 2009-04-02T15:41:01Z
dc.date.available 2009-04-02T15:41:01Z
dc.date.issued 2009-04-02T15:41:01Z
dc.identifier.uri http://hdl.handle.net/1993/3138
dc.description.abstract Age-related muscle atrophy and the importance of satellite cells in muscle maintenance, growth and repair led us to examine the effects of mechanical stretch, nitric oxide (NO), and age on satellite cell (SC) activation and gene expression in normal young and old mice. Baseline variables (body mass, muscle mass, fiber cross-sectional area (CSA), muscle strength, SC population, stretch activation and gene expression) were obtained from normal C57BL/6 mice at 3-, 8-, 12- and 18-months-of-age. Activation was assayed by 3H-thymidine incorporation into extensor digitorum longus (EDL) muscles isolated for culture. In a second experiment, muscle from 8- and 18-month-old mice was treated with one or more of: stretch; NO-donors (L-Arginine (LA), isosorbide dinitrate (ISDN)) and; Nω-nitro-L-Arginine methyl ester (LN). EDL muscles from 6-month-old mice required a greater stretch stimulus (20% vs. 10% length increase) than EDL from younger mice to increase SC activation. Stretch did not increase SC activation in mice older than 6 months-of-age. NO supplementation from an exogenous source (ISDN) increased SC activation by stretch in 8- but not 18-mo-old EDLs. In a third experiment, 8- and 18-month-old mice were subjected to 3 weeks of voluntary wheel running, or not. The EDL, tibialis anterior (TA), gastrocnemius (GAST) and quadriceps (QUAD) muscles were selected for analysis following sacrifice. The QUAD muscle from 8-month-old mice was the only muscle that demonstrated an exercise-induced increase in SC activation, elevated expression of neuronal nitric oxide synthase (NOS-I) and downregulation of myostatin, a gene that inhibits muscle growth. These results suggest mechanical stimulation of satellite cells and regulation of gene expression that controls muscle growth in voluntary contractile tissue is muscle-specific and age-dependent. en
dc.format.extent 1001775 bytes
dc.format.mimetype application/pdf
dc.language.iso en_US
dc.rights info:eu-repo/semantics/openAccess
dc.subject muscle satellite cells en
dc.subject aging en
dc.subject sarcopenia en
dc.subject exercise en
dc.subject stretch en
dc.subject nitric oxide en
dc.title The impact of stretch, exercise and drug treatments on structure, function and satellite cell activation in aging muscle en
dc.type info:eu-repo/semantics/doctoralThesis
dc.degree.discipline Human Anatomy and Cell Science en
dc.contributor.examiningcommittee Thliveris, James (Human Anatomy and Cell Science) Kong, Jiming (Human Anatomy and Cell Science) Porter, Michelle (Kinesiology and Recreation Management) Allen, Ronald (Department of Animal Science, University of Arizona, USA) en
dc.degree.level Doctor of Philosophy (Ph.D.) en
dc.description.note May 2009 en


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