title: Satellite cell pool expansion is affected by skeletal muscle characteristics.
abstract: BACKGROUND
  We investigated changes in satellite cell (SC) pool size after an acute bout of strenuous exercise and evaluated the influence of baseline SC count and fiber type.
  
  
  METHODS
  Participants completed a downhill running (DHR) intervention (5 × 8 min, 2-min rest; 80% VO2max ; -10% gradient). Muscle biopsies were taken 7 days before VO₂max and 7-9 days after the DHR intervention. Delayed-onset muscle soreness (DOMS) and creatine kinase activity (CK) were measured on days 1, 2, 7, and 9 post-DHR. SCs were identified by Pax7 and laminin staining. Relative distribution of MHC isoforms was determined by electrophoresis.
  
  
  RESULTS
  DOMS and CK peaked on day 1 post-DHR (P < 0.01). The SC pool increased (26%) after DHR (P = 0.005). SCs/total myonuclei after recovery correlated with baseline SCs (r = 0.979, P = 0.003) and VO₂max (r = 0.956, P = 0.011), whereas change in SC pool (Pax7(+) cells/total myonuclei: recovery minus baseline) tended to correlate with percent MHC II (r = 0.848; P = 0.06).
  
  
  CONCLUSIONS
  Interindividual physiological characteristics affect SC pool expansion after a single bout of DHR and are influenced by VO₂max .
authors.affiliation: Department of Physiological Sciences, Stellenbosch University, Private Bag X1, Matieland, 7602 Stellenbosch, South Africa.
authors.forename: Filippo
authors.initials: F
authors.lastname: Macaluso
authors.forename: Naomi E
authors.initials: NE
authors.lastname: Brooks
authors.forename: Carola U
authors.initials: CU
authors.lastname: Niesler
authors.forename: Kathryn H
authors.initials: KH
authors.lastname: Myburgh
mesh_terms: D000328:Adult; D002452:Cell Count / Q000379:methods; D002454:Cell Differentiation / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000166:cytology* / Q000473:pathology / Q000502:physiology; D012420:Running / Q000502:physiology*; D032496:Satellite Cells, Skeletal Muscle / Q000502:physiology*; D055815:Young Adult