Age-related differential expression of stress-activated pathways following repetitive mechanical loading in rats.
Ensey-J; Li-S; Kashon-ML; Hollander-MS; Cutlip-RG; Baker-BA
FASEB J 2011 Apr; 25(Meeting Abstracts):699.5
It is not known if maladaptation observed in aged populations following mechanical loading is influenced by a disparate molecular signaling profile compared with young populations. The purpose of this project was to identify if systemic and local gene candidates were associated with maladaptation following repetitive stretch-shortening contraction (SSC) loading in young and old rats. The left dorsiflexor muscles of young (3 mo) and old (30 mo) male Fischer 344 x BN rats were exposed for 4.5 weeks to 80 maximum SSCs per exposure in vivo. RNA was isolated from blood leukocytes and tibialis anterior muscle from the left hindlimb was harvested 24h after last exposure. cRNA samples were prepared and loaded onto Sentrix Rat-Ref12 Beadchips. Genes involved in signaling and regulation of the p38 MAPK stress pathway were clearly evident. Regulators of the p38 MAPK pathway were down-regulated in the blood from old rats (RPL7, RPL29), while other transcripts (ANXA2) influenced by the expression of these ribosomal protein transcripts were up-regulated in blood from old rats. The transcripts for MAP2K6 and EEF2K of the p38 MAPK stress pathway were simultaneously increased in skeletal muscle from aged rats after repetitive SSC loading. These data suggest that cross-talk between the systemic vasculature and local tissue may be involved in regulating the stress signaling response and subsequent maladaptation to SSC loading with aging.
Age-groups; Age-factors; Laboratory-animals; Animals; Animal-studies; Cell-function; Cellular-function; Physical-stress
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