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MR‐determined Sarcopenia and Associated Transcript Factors in Sprague‐Dawley Male Rats
Author(s) -
Lee SangRok,
Wilson Jacob M,
Henning Paul C,
Park YoungMin,
Masad Ihssan,
Grant Samuel C,
Kim JeongSu
Publication year - 2011
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.25.1_supplement.1051.38
Subject(s) - sarcopenia , medicine , endocrinology , biology
Aging mammalian skeletal muscles exhibit sarcopenia. We investigated the effects of aging on myofiber dimensions and mRNA expression associated with sarcopenia in young and old rats. Six 11‐month old and five 25‐month old Sprague‐Dawley male rats were sacrificed for in vitro molecular and magnetic resonance imaging analysis. In the gastrocnemius, diffusion tensor imaging determined water diffusion in myofibers by calculating the fractional anisotropy (FA) and eigenvalues, while mRNA levels of relative biomarkers (mRNA expressions of caspase‐3, TNF‐α, atrogin‐1, myostatin, and activin IIBR) were assessed with PCR. Overall, there were significant decreases in myofiber cross‐sectional area (CSA) and increases in expression of sarcopenia‐related biomarkers in the old group. The λ 2 (−15%) and λ 3 (−21%) values decreased, while FA increased in the old group (+61%, p<0.05), indicating decreased myofiber CSA. Caspase‐3 mRNA expression in the old group was significantly higher than the young group (p<0.05). There was a trend of greater mRNA expressions of TNF‐α (p=0.07) and activin IIBR (p=0.08) in the old compared to the young group while no change in atrogin‐1 was noted (p=0.13). Our findings indicate that the age‐related decline in myofiber CSA appears to be associated with up‐regulation of apoptosis and inflammation signaling in aging muscle.