Dietary restriction increases skeletal muscle mitochondrial respiration but not mitochondrial content in C57BL/6 mice

Sarah Hempenstall, Melissa M Page, Katrina R Wallen, Colin Selman

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

Dietary restriction (DR) is suggested to induce mitochondrial biogenesis, although recently this has been challenged. Here we determined the impact of 1, 9 and 18 months of 30% DR in male C57BL/6 mice on key mitochondrial factors and on mitochondrial function in skeletal muscle, relative to age-matched ad libitum (AL) controls. We examined proteins and mRNAs associated with mitochondrial biogenesis and measured mitochondrial respiration in permeabilised myofibres using high resolution respirometry. 30% DR, irrespective of duration, had no effect on citrate synthase activity. In contrast, total and nuclear protein levels of PGC-1a, mRNA levels of several mitochondrial associated proteins (Pgc-1a, Nrf1, Core 1, Cox IV, Atps) and cytochrome c oxidase content were increased in skeletal muscle of DR mice. Furthermore, a range of mitochondrial respiration rates were increased significantly by DR, with DR partially attenuating the age-related decline in respiration observed in AL controls. Therefore, DR did not increase mitochondrial content, as determined by citrate synthase, in mouse skeletal muscle. However, it did induce a PGC-1a adaptive response and increased mitochondrial respiration. Thus, we suggest that a functionally 'efficient' mitochondrial electron transport chain may be a critical mechanism underlying DR, rather than any net increase in mitochondrial content per se.
Original languageEnglish
Pages (from-to)37-45
Number of pages9
JournalMechanisms of Ageing and Development
Volume133
Issue number1
Early online date28 Dec 2011
DOIs
Publication statusPublished - Jan 2012

Keywords

  • dietary restriction
  • ageing
  • high resolution respirometry
  • PGC-1a
  • mitochondrial biogenesis

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