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Resistance training-induced apoptotic signaling in rat skeletal muscle.
Murlasits-Z; Geronilla-KB; Cutlip-RG; Siu-PM; Alway-SE
FASEB J 2005 Mar; 19(4)(Part1)(Suppl S):A135-A135
The significance of programmed cell death is not well established in post mitotic tissues, such as skeletal muscle. Moreover, it is not clear whether apoptotic signaling contributes to training-induced skeletal muscle hypertrophy. Therefore, this s tudy investigated the effect of resistance training with stretch-shortening contractions on apoptotic markers in young rat skeletal muscle. The left common peroneal nerve was stimulated at 120 Hz to maximally activate the dorsi flexor muscles in young male (3 mo old) Fisher344XBrown rats (n=6), while the right limb served as intra-animal control. Animals were exposed to 14 training sessions of 80 repetitions/session over a four and a half-week exposure period. The animals were sacrificed 24 hours following the last exposure and the tibialis anterior (TA) muscles were removed for protein analysis. Muscle wet weight was 17% (11.9-23.4%) greater in the experimental as compared to the control TA muscle. The anit-apoptotic Bcl2 protein level was significantly (p=0.033) increased by 28.7%, while the proapoptotic Bax protein content remained unchanged in experimental compared to control muslces after the training period. Morever, the Bcl2/Bax ratio, an indicator of apoptotic status, was elevated by 107.4%. Additionally, the level of pro-apoptotic AIF protein, which is thought to play a role in caspase independent signaling, was significantly decreased (p=0.046) by 51.7% in experimental as compared to control muscles. In conclusion, it appears that apoptotic signaling contributes to training-induced hypertrophy in skeletal muscle of young animals, by down regulation of pro- and up regulation of anti-apoptotic proteins.
Laboratory-animals; Animals; Animal-studies; Skeletal-system; Muscles; Musculoskeletal-system; Cell-damage; Skeletal-system-disorders; Exposure-levels; Exposure-assessment
Issue of Publication
Disease and Injury: Musculoskeletal Disorders of the Upper Extremities
The FASEB Journal
Page last reviewed: April 12, 2019
Content source: National Institute for Occupational Safety and Health Education and Information Division