Intrinsic aerobic capacity correlates with greater inherent mitochondrial oxidative and H2O2emission capacities without major shifts in myosin heavy chain isoform Article (Web of Science)

abstract

  • Exercise capacity and performance strongly associate with metabolic and biophysical characteristics of skeletal muscle, factors that also relate to overall disease risk. Despite its importance, the exact mechanistic features that connect aerobic metabolism with health status are unknown. To explore this, we applied artificial selection of rats for intrinsic (i.e., untrained) aerobic treadmill running to generate strains of low- and high-capacity runners (LCR and HCR, respectively), subsequently shown to diverge for disease risk. Concurrent breeding of LCR and HCR per generation allows the lines to serve as reciprocal controls for unknown environmental changes. Here we provide the first direct evidence in mitochondria isolated from skeletal muscle that intrinsic mitochondrial capacity is higher in HCR rats. Maximal phosphorylating respiration was ∼40% greater in HCR mitochondria, independent of substrate and without altered proton leak or major changes in protein levels or muscle fiber type, consistent with altered control of phosphorylating respiration. Unexpectedly, H2O2emission was ∼20% higher in HCR mitochondria, due to greater reduction of more harmful reactive oxygen species to H2O2; indeed, oxidative modification of mitochondrial proteins was lower. When the higher mitochondrial yield was considered, phosphorylating respiration and H2O2emission were 70–80% greater in HCR muscle. Greater capacity of HCR muscle for work and H2O2signaling may result in enhanced and more immediate cellular repair, possibly explaining lowered disease risks.

authors

  • Seifert, Erin L.
  • Bastianelli, Mark
  • Aguer, Céline
  • Moffat, Cynthia
  • Estey, Carmen
  • Koch, Lauren Gerard
  • Britton, Steven L.
  • Harper, Mary-Ellen

publication date

  • 2012

webpage

published in

number of pages

  • 10

start page

  • 1624

end page

  • 1634

volume

  • 113

issue

  • 10