title: Trained men display increased basal heat shock protein content of skeletal muscle.
abstract: OBJECTIVE
  1) To compare the baseline levels of heat shock and antioxidant protein content in the skeletal muscle of trained and untrained humans and 2) to characterize the exercise-induced stress response of aerobically trained human skeletal muscle to an acute exercise challenge.
  
  
  METHODS
  Resting muscle biopsies were obtained from the vastus lateralis muscle of six untrained and six aerobically trained young males. To characterize the stress response of a trained population, the trained subjects also performed a 45-min nondamaging running exercise protocol at an intensity corresponding to 75% of V O2max. Muscle biopsies were obtained from the vastus lateralis muscle at 48 h and 7 d after exercise.
  
  
  RESULTS
  Trained subjects displayed significantly higher (P<0.05) resting levels of heat shock protein 60 (HSP60, 25%), alphaB-crystallin (43%), and manganese superoxide (MnSOD, 45%) protein content compared with untrained subjects. Trained subjects also exhibited no significant change (P > 0.05) in resting levels of HSP70 (16%), HSC70 (13%), and total superoxide dismutase (SOD) activity (46%) compared with untrained subjects. Resting HSP27 levels were unaffected by exercise training (P > 0.05). In the trained subjects, exercise failed to induce significant increases (P>0.05)in muscle content of HSP70, HSC70, HSP60, HSP27, alphaB-crystallin, and MnSOD protein content or in the activity of SOD at any time point after exercise.
  
  
  CONCLUSIONS
  This study demonstrates for the first time that trained men display a selective up-regulation of basal heat shock and antioxidant protein content and do not exhibit a stress response to customary running exercise. It is suggested that an increase in these protective systems functions to maintain homeostasis during the stress of exercise by protecting against disruptions to the cytoskeleton/contractile machinery, by maintaining redox balance, and by facilitating mitochondrial biogenesis.
authors.affiliation: Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UNITED KINGDOM. J.P.Morton@ljmu.ac.uk
authors.forename: James P
authors.initials: JP
authors.lastname: Morton
authors.forename: Don P M
authors.initials: DP
authors.lastname: Maclaren
authors.forename: Nigel T
authors.initials: NT
authors.lastname: Cable
authors.forename: Iain T
authors.initials: IT
authors.lastname: Campbell
authors.forename: Louise
authors.initials: L
authors.lastname: Evans
authors.forename: Anna C
authors.initials: AC
authors.lastname: Kayani
authors.forename: Anne
authors.initials: A
authors.lastname: McArdle
authors.forename: Barry
authors.initials: B
authors.lastname: Drust
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D000328:Adult; D000975:Antioxidants / Q000032:analysis / Q000378:metabolism*; D001706:Biopsy; D001833:Body Temperature Regulation; D006360:Heat-Shock Proteins / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology; D012420:Running / Q000502:physiology*; D013312:Stress, Physiological / Q000502:physiology
chemical_list: D000975:Antioxidants; D006360:Heat-Shock Proteins