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The role of skeletal muscle characteristics in the decline of VO 2peak in rats
Author(s) -
Toedebusch Ryan,
Ruegsegger Gregory,
Booth Frank
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.1055.9
Subject(s) - skeletal muscle , citrate synthase , medicine , turnover , sarcopenia , age groups , cardiology , endocrinology , biology , demography , biochemistry , management , sociology , economics , enzyme
Maximal aerobic capacity is a strong predictor or mortality in humans and rodents. It has been established that VO 2peak declines with age beginning in the 3 rd decade of life in humans. There is a paucity of data examining the underlying mechanisms that may be responsible for this VO 2peak decline. Organ systems that likely play significant roles include the heart, brain and skeletal muscle. The purpose of this study was to assess skeletal muscles role during the initial decline from lifetime apex‐VO 2peak in rats, and to assess the ability of physical activity to modify the decline. Two groups of rats, one with access to a voluntary running wheel (WG) and one with no wheel access (NWG) underwent VO 2peak testing weekly beginning at 10 weeks of age until the end of the study. Voluntary wheel running began at 5‐weeks of age and peaked at 10‐weeks of age. Lifetime apex‐VO 2peak occurred at 19 weeks of age, and decreased until reaching a steady at 27 weeks of age. There was no difference in mass between 19‐weeks and 27‐weeks in tricep, gastrocnemius, and soleus muscles, discounting the previous associations between declining muscle mass and VO 2peak . Currently, we are deciding which of these muscles to use for subsequent analysis. To this end, PGC1α mRNA was compared in all three muscles between 19 and 27‐weeks to aid in selecting a muscle for RNA‐sequencing and protein analysis. PGC1α mRNA was not different in any muscle between 19 and 27‐weeks of age. PGC1α in the tricep showed the WG had 150% higher expression at both 19 and 27 weeks of age compared to the NWG. Also, mitochondrial quantity is being assessed through protein analysis of COX‐IV and cytochrome c. This will aid in our decision for selection of one skeletal muscle to perform RNA‐sequencing on.