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 language | English |
---|---|
Pages (from-to) | 37-45 |
Number of pages | 9 |
Journal | Mechanisms of Ageing and Development |
Volume | 133 |
Issue number | 1 |
Early online date | 28 Dec 2011 |
DOIs | |
Publication status | Published - Jan 2012 |
Keywords
- dietary restriction
- ageing
- high resolution respirometry
- PGC-1a
- mitochondrial biogenesis