title: Impact of endurance training on murine spontaneous activity, muscle mitochondrial DNA abundance, gene transcripts, and function.
abstract: We hypothesized that enhanced skeletal muscle mitochondrial function following aerobic exercise training is related to an increase in mitochondrial transcription factors, DNA abundance [mitochondrial DNA (mtDNA)], and mitochondria-related gene transcript levels, as well as spontaneous physical activity (SPA) levels. We report the effects of daily treadmill training on 12-wk-old FVB mice for 5 days/wk over 8 wk at 80% peak O(2) consumption and studied the training effect on changes in body composition, glucose tolerance, muscle mtDNA muscle, mitochondria-related gene transcripts, in vitro muscle mitochondrial ATP production capacity (MATPC), and SPA levels. Compared with the untrained mice, the trained mice had higher peak O(2) consumption (+18%; P < 0.001), lower percentage of abdominal (-25.4%; P < 0.02) and body fat (-19.5%; P < 0.01), improved glucose tolerance (P < 0.04), and higher muscle mitochondrial enzyme activity (+19.5-43.8%; P < 0.04) and MATPC (+28.9 to +32.4%; P < 0.01). Gene array analysis showed significant differences in mRNAs of mitochondria-related ontology groups between the trained and untrained mice. Training also increased muscle mtDNA (+88.4 to +110%; P < 0.05), peroxisome proliferative-activated receptor-gamma coactivator-1alpha protein (+99.5%; P < 0.04), and mitochondrial transcription factor A mRNA levels (+21.7%; P < 0.004) levels. SPA levels were higher in trained mice (P = 0.056, two-sided t-test) and significantly correlated with two separate substrate-based measurements of MATPC (P < 0.02). In conclusion, aerobic exercise training enhances muscle mitochondrial transcription factors, mtDNA abundance, mitochondria-related gene transcript levels, and mitochondrial function, and this enhancement in mitochondrial function occurs in association with increased SPA.
authors.affiliation: Division of Endocrinology, Nutrition and Metabolism, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
authors.forename: Lisa S
authors.initials: LS
authors.lastname: Chow
authors.forename: Laura J
authors.initials: LJ
authors.lastname: Greenlund
authors.forename: Yan W
authors.initials: YW
authors.lastname: Asmann
authors.forename: Kevin R
authors.initials: KR
authors.lastname: Short
authors.forename: Shelly K
authors.initials: SK
authors.lastname: McCrady
authors.forename: James A
authors.initials: JA
authors.lastname: Levine
authors.forename: K Sreekumaran
authors.initials: KS
authors.lastname: Nair
mesh_terms: D000818:Animals; D015153:Blotting, Western; D004272:DNA, Mitochondrial / Q000378:metabolism*; D004734:Energy Metabolism / Q000502:physiology; D020869:Gene Expression Profiling; D005951:Glucose Tolerance Test; D008297:Male; D051379:Mice; D008931:Mitochondria, Muscle / Q000378:metabolism*; D009043:Motor Activity / Q000502:physiology*; D018482:Muscle, Skeletal / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D010805:Physical Conditioning, Animal / Q000502:physiology*; D010807:Physical Endurance / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D004272:DNA, Mitochondrial; D012333:RNA, Messenger; D014157:Transcription Factors