Premium
Stereological analysis of Akt in muscles of young and old rats following a single bout of stretch‐shortening contractions
Author(s) -
Rader Erik P,
Ensey James,
Baker Brent A
Publication year - 2013
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.27.1_supplement.1150.4
Subject(s) - protein kinase b , sarcopenia , medicine , anabolism , endocrinology , contraction (grammar) , anatomy , biology , signal transduction , microbiology and biotechnology
Careful design of resistance training programs is critical for offsetting age‐related sarcopenia. To address this, we implemented a non‐injurious stretch‐shortening contraction (SSC) protocol to muscles of rats. Following 4.5 weeks of resistance‐type training, muscles of young rats increased force by ~30% and mass by ~16%, while old rats sustained force deficits of ~30% with no change in muscle mass; no overt signs of histopathology were noted. Age‐related maladaptation to training may be due to aberrant Akt signaling – signaling influential in cellular survival/growth. Purpose To characterize volume density of Akt positive muscle fibers following an acute bout of non‐injurious SSCs with aging. Methods Dorsiflexor muscles of 12wk. and 30mo. old Fischer 344xBN Hybrid rats were exposed to SSCs in vivo . At 6h, 3d, and 5d, tibialis anterior muscles were removed for stereological analysis of transverse sections labeled for pan‐Akt (N =3 per group). Results For control muscles and muscles at 6h, pan‐Akt volume density represented ~40% of total tissue volume and was independent of age. At 3d and 5d post SSC, pan‐Akt levels were unaltered for old rats while values for young rats were decreased relative to values for old (p<0.05). Conclusion While the training‐induced decrease in Akt at young age needs further study, the lack of change in Akt levels at old age is consistent with an overall blunted response to training.