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Markers of Muscle Protein Synthesis and Breakdown in Slow‐twitch Skeletal Muscle of Rodents Aged 3 to 24 months
Author(s) -
Haun Cody T.,
Mumford Petey W.,
Mobley Brooks C.,
Kephart Wesley C.,
Holland Maleah,
Osburn Shelby C.,
Martin Jeffrey S.,
Young Kaelin C.,
Kavasis Andreas N.,
Lowery Ryan P.,
Wilson Jacob M.,
Roberts Michael D.
Publication year - 2016
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.30.1_supplement.lb174
Subject(s) - skeletal muscle , soleus muscle , sarcopenia , medicine , endocrinology , muscle atrophy , muscle mass , atrophy , protein degradation , chemistry , biology , biochemistry
PURPOSE Muscle protein synthesis (MPS) and muscle protein degradation (MPD) are well known modulators for muscle mass maintenance. Given that slow‐twitch skeletal muscle atrophies with aging, we sought to examine the effects of aging on MPS and MPD markers in the soleus muscle of rodents ranging from 3 to 24 months. MEHTODS Male Fischer 344 rats (300–600g) were successfully aged to 3, 6, 12, 18 and 24 months, were injected with puromycin (0.02 mg/g body mass), euthanized, soleus muscle was extracted and wet skeletal muscle weights were obtained. Muscle tissue was then processed for biochemical processing. MPS was assessed via the SUNsET method, and MPD was assessed using whole lane densitometry via ubiquitin immunoblotting. RESULTS Relative soleus masses revealed significant between‐group differences throughout the lifespan (p=0.004); specifically, masses were 20% greater in 3 versus 18 month old rats (p=0.010) and 20% greater in 3 versus 24 month old rats (p=0.013). Interestingly, MPS levels were not different between any of the age groups. Poly‐ubiquinated protein levels were trending (p=0.051), but not different between any of the age groups. CONCLUSION It appears that soleus muscle atrophy occurs with aging. However, this does not appear to be reflected via decrements in MPS and increases in protein poly‐ubiquination. Mechanisms related to slow‐twitch skeletal muscle atrophy remain to be determined and should be further investigated. Support or Funding Information ACKNOWLEDGEMENTS: This study was supported in part by a contract from The University of Tampa (to M.D.R. from J.M.W.) as well as laboratory start‐up funds from M.D.R.