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Heat shock protein translocation and expression response is attenuated in response to repeated eccentric exercise
Author(s) -
Vissing K.,
Bayer M. L.,
Overgaard K.,
Schjerling P.,
Raastad T.
Publication year - 2009
Publication title -
acta physiologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.591
H-Index - 116
eISSN - 1748-1716
pISSN - 1748-1708
DOI - 10.1111/j.1748-1716.2008.01940.x
Subject(s) - downregulation and upregulation , eccentric , heat shock protein , hsp27 , medicine , endocrinology , hsp70 , shock (circulatory) , physical exercise , delayed onset muscle soreness , chemistry , muscle damage , biochemistry , physics , quantum mechanics , gene
Aim: This study hypothesized that heat shock protein (HSP) translocation and upregulation is more probable to occur after eccentric exercise than after concentric exercise or repeated eccentric exercise. Methods: Fourteen young, healthy, untrained male subjects completed two bench‐stepping exercise bouts with 8 weeks between bouts, and were compared with a control group ( n = 6). Muscle biopsies collected from m. vastus lateralis of both legs prior to and at 3 h, 24 h and 7 days after exercise were quantified for mRNA levels and/or for HSP27, αβ‐crystallin and inducible HSP70 content in cytosolic and cytoskeletal protein fractions. Results: The first bout of exercise reduced muscle strength and increased muscle soreness predominantly in the eccentric leg ( P < 0.05). These responses were attenuated after the repeated eccentric exercise bout ( P < 0.05), suggesting a repeated bout adaptation. Increases in inducible HSP70 and HSP27 protein content in cytoskeletal fractions were observed exclusively after eccentric exercise ( P < 0.05). For HSP27, an approx. 10‐fold upregulation after first‐bout eccentric exercise was attenuated to a an approximately fourfold upregulation after the repeated eccentric exercise bout. mRNA levels for HSP70, HSP27 and αβ‐crystallin were upregulated within approximately two to fourfold ranges at time points 3 and 24 h post‐exercise ( P < 0.05). This upregulation was induced exclusively by eccentric exercise but with a tendency to attenuated expression 3 h after the repeated eccentric exercise bout. Conclusion: Our results show that HSP translocation and expression responses are induced by muscle damaging exercise, and suggest that such HSP responses are closely related to the extent of muscle damage.