title: Random mtDNA deletions and functional consequence in aged human skeletal muscle.
abstract: Mitochondrial respiratory chain deteriorates with age, mostly in tissues with high energy requirements. Damage to mitochondrial DNA (mtDNA) by reactive oxygen species is thought to contribute primarily to this impairment. However, the overall extent of random mtDNA mutations has still not been evaluated. We carried out molecular and biochemical analyses in muscle biopsies from healthy young and aged subjects. Deleted mtDNA accumulation was followed by both quantitative PCR analysis to quantify total mtDNA, and Southern-blotting, to determine deleted to full length mtDNA ratio. Enzymatic activities of the mitochondrial respiratory chain were measured in all subjects. Randomly deleted mtDNA appeared mainly in the oldest subjects (beyond 80 years old), affecting up to 70% of mtDNA molecules. The activities of complexes III and IV of the respiratory chain, complexes with mtDNA encoded subunits, are lower in the aged subjects. Physical activity could be one major parameter modulating the mitochondrial respiratory chain activity in aged muscle.
authors.affiliation: INRA U1019,Université d'Auvergne, Clermont-Ferrand, France.
authors.forename: Béatrice
authors.initials: B
authors.lastname: Chabi
authors.forename: Bénédicte
authors.initials: B
authors.lastname: Mousson de Camaret
authors.forename: Arnaud
authors.initials: A
authors.lastname: Chevrollier
authors.forename: Stéphane
authors.initials: S
authors.lastname: Boisgard
authors.forename: Georges
authors.initials: G
authors.lastname: Stepien
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000375:Aging / Q000235:genetics* / Q000378:metabolism*; D004252:DNA Mutational Analysis / Q000379:methods*; D004272:DNA, Mitochondrial / Q000235:genetics*; D004579:Electron Transport / Q000502:physiology*; D005260:Female; D017353:Gene Deletion; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D013223:Statistics as Topic
chemical_list: D004272:DNA, Mitochondrial