Related Experiment Videos
Random mtDNA deletions and functional consequence in aged human skeletal muscle
Béatrice Chabi1, Bénédicte Mousson de Camaret, Arnaud Chevrollier
1INRA U1019,Université d'Auvergne, Clermont-Ferrand, France.
Biochemical and Biophysical Research Communications
|May 18, 2005
Summary
Aging impairs mitochondrial function, particularly in high-energy tissues. This study reveals significant mitochondrial DNA deletions in older adults, impacting respiratory chain complexes and suggesting physical activity may mitigate age-related decline.
Area of Science:
- Gerontology
- Mitochondrial Biology
- Molecular Genetics
Background:
- Mitochondrial respiratory chain function declines with age, especially in high-energy tissues.
- Mitochondrial DNA (mtDNA) damage by reactive oxygen species is a suspected cause, but the extent of random mutations remains unclear.
Purpose of the Study:
- To evaluate the accumulation of deleted mtDNA and its correlation with respiratory chain activity in aging muscle.
- To investigate the impact of age on mtDNA integrity and mitochondrial function.
Main Methods:
- Molecular and biochemical analyses were performed on muscle biopsies from young and aged individuals.
- Quantitative PCR and Southern-blotting were used to assess mtDNA deletion levels.
- Enzymatic activities of mitochondrial respiratory chain complexes were measured.
Main Results:
- Randomly deleted mtDNA was prevalent in subjects over 80 years old, comprising up to 70% of mtDNA molecules.
- Activities of respiratory chain complexes III and IV, which contain mtDNA-encoded subunits, were reduced in aged subjects.
- A correlation between physical activity and preserved mitochondrial respiratory chain activity in aged muscle was suggested.
Conclusions:
- Significant accumulation of deleted mtDNA occurs in very old individuals, contributing to age-related mitochondrial dysfunction.
- Reduced activity of specific respiratory chain complexes is linked to mtDNA deletions in aging muscle.
- Physical activity may play a protective role in maintaining mitochondrial function during aging.