Open AccessSarcopenia Accelerates at Advanced Ages in Fisher 344xBrown Norway Rats
Author(s) -
Entela B. Lushaj,
Jody K. Johnson,
Debbie McKenzie,
Judd M. Aiken
Publication year - 2008
Publication title -
the journals of gerontology. series a, biological sciences and medical sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.134
H-Index - 189
eISSN - 1758-535X
pISSN - 1079-5006
DOI - 10.1093/gerona/63.9.921
Subject(s) - sarcopenia , atrophy , muscle mass , medicine , muscle atrophy , muscle fibre , fiber type , vastus medialis , vastus lateralis muscle , physiology , anatomy , skeletal muscle , physical medicine and rehabilitation , electromyography
Although the age-dependent loss of muscle mass and strength, sarcopenia, is an inevitable process, its onset and progression are not well established. Here we defined the onset and the progression of sarcopenia in a healthy aging animal model, Fisher 344xBrown Norway rats. Vastus lateralis, rectus femoris, and vastus medialis muscles (three of the quadriceps muscles) were analyzed at 5 months of age and at 3-month intervals between 12 and 39 months of age. We found an age-dependent decline in muscle mass and fiber number and an increase in fiber atrophy and nonmuscle tissue. Significant changes of fiber number and muscle mass were not observed until very late in life (30-33 months) and were concurrent, whereas fiber cross-sectional area (CSA) gradually declined from maximum CSA (24 months). Sarcopenic declines identified between 30 and 36 months did not continue to 39 months, possibly due to the increased proportion of type I fibers.