title: Lifelong training preserves some redox-regulated adaptive responses after an acute exercise stimulus in aged human skeletal muscle.
abstract: Several redox-regulated responses to an acute exercise bout fail in aged animal skeletal muscle, including the ability to upregulate the expression of antioxidant defense enzymes and heat shock proteins (HSPs). These findings are generally derived from studies on sedentary rodent models and thus may be related to reduced physical activity and/or intraspecies differences as opposed to aging per se. This study, therefore, aimed to determine the influence of age and training status on the expression of HSPs, antioxidant enzymes, and NO synthase isoenzymes in quiescent and exercised human skeletal muscle. Muscle biopsy samples were obtained from the vastus lateralis before and 3 days after an acute high-intensity-interval exercise bout in young trained, young untrained, old trained, and old untrained subjects. Levels of HSP72, PRX5, and eNOS were significantly higher in quiescent muscle of older compared with younger subjects, irrespective of training status. 3-NT levels were elevated in muscles of the old untrained but not the old trained state, suggesting that lifelong training may reduce age-related macromolecule damage. SOD1, CAT, and HSP27 levels were not significantly different between groups. HSP27 content was upregulated in all groups studied postexercise. HSP72 content was upregulated to a greater extent in muscle of trained compared with untrained subjects postexercise, irrespective of age. In contrast to every other group, old untrained subjects failed to upregulate CAT postexercise. Aging was associated with a failure to upregulate SOD2 and a downregulation of PRX5 in muscle postexercise, irrespective of training status. In conclusion, lifelong training is unable to fully prevent the progression toward a more stressed muscular state as evidenced by increased HSP72, PRX5, and eNOS protein levels in quiescent muscle. Moreover, lifelong training preserves some (e.g., CAT) but not all (e.g., SOD2, HSP72, PRX5) of the adaptive redox-regulated responses after an acute exercise bout. Collectively, these data support many but not all of the findings from previous animal studies and suggest parallel aging effects in humans and mice at rest and after exercise that are not modulated by training status in human skeletal muscle.
authors: Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool L3 3AF, UK.
authors: J N
authors: JN
authors: Cobley
authors: MRC-Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing, Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool L69 3GA, UK.
authors: G K
authors: GK
authors: Sakellariou
authors: Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool L3 3AF, UK.
authors: D J
authors: DJ
authors: Owens
authors: Cardiology Department, Liverpool Heart and Chest Hospital, Liverpool L14 3PE, UK.
authors: S
authors: S
authors: Murray
authors: Stepping Hill Hospital, Stockport SK2 7JE, UK.
authors: S
authors: S
authors: Waldron
authors: Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool L3 3AF, UK.
authors: W
authors: W
authors: Gregson
authors: Norwich Medical School, Faculty of Medicine and Health Sciences, University of East Anglia, Norwich, UK.
authors: W D
authors: WD
authors: Fraser
authors: Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool L3 3AF, UK.
authors: J G
authors: JG
authors: Burniston
authors: MRC-Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing, Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool L69 3GA, UK.
authors: L A
authors: LA
authors: Iwanejko
authors: MRC-Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing, Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool L69 3GA, UK.
authors: A
authors: A
authors: McArdle
authors: Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool L3 3AF, UK.
authors: J P
authors: JP
authors: Morton
authors: MRC-Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing, Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool L69 3GA, UK.
authors: M J
authors: MJ
authors: Jackson
authors: Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool L3 3AF, UK. Electronic address: g.l.close@ljmu.ac.uk.
authors: G L
authors: GL
authors: Close
mesh_terms: D000375:Aging; D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D001706:Biopsy; D015444:Exercise / Q000502:physiology*; D055551:HSP27 Heat-Shock Proteins / Q000378:metabolism*; D006801:Humans; D051379:Mice; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000502:physiology; D010084:Oxidation-Reduction; D010805:Physical Conditioning, Animal
chemical_list: D000975:Antioxidants; D055551:HSP27 Heat-Shock Proteins
keywords: Exercise; Free radicals; Reactive oxygen species; Redox; Skeletal muscle