Cellular distribution of Hsp70 expression in rat skeletal muscles. Effects of moderate exercise training and chronic hypoxia.

Details

Serval ID
serval:BIB_B821E775F839
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Cellular distribution of Hsp70 expression in rat skeletal muscles. Effects of moderate exercise training and chronic hypoxia.
Journal
Cell Stress and Chaperones
Author(s)
Tarricone E., Scapin C., Vitadello M., Esposito F., Margonato V., Milano G., Samaja M., Gorza L.
ISSN
1355-8145
Publication state
Published
Issued date
2008
Peer-reviewed
Oui
Volume
13
Number
4
Pages
483-495
Language
english
Abstract
Rat hindlimb muscles constitutively express the inducible heat shock protein 72 (Hsp70), apparently in proportion to the slow myosin content. Since it remains controversial whether chronic Hsp70 expression reflects the overimposed stress, we investigated Hsp70 cellular distribution in fast muscles of the posterior rat hindlimb after (1) mild exercise training (up to 30 m/min treadmill run for 1 h/day), which induces a remodeling in fast fiber composition, or (2) prolonged exposure to normobaric hypoxia (10%O(2)), which does not affect fiber-type composition. Both conditions increased significantly protein Hsp70 levels in the skeletal muscle. Immunohistochemistry showed the labeling for Hsp70 in subsets of both slow/type 1 and fast/type 2A myofibers of control, sedentary, and normoxic rats. Endurance training increased about threefold the percentage of Hsp70-positive myofibers (P < 0.001), and changed the distribution of Hsp70 immunoreactivity, which involved a larger subset of both type 2A and intermediate type 2A/2X myofibers (P < 0.001) and vascular smooth muscle cells. Hypoxia induced Hsp70 immunoreactivity in smooth muscle cells of veins and did not increase the percentage of Hsp70-positive myofibers; however, sustained exposure to hypoxia affected the distribution of Hsp70 immunoreactivity, which appeared detectable in a very small subset of type 2A fibers, whereas it concentrated in type 1 myofibers (P < 0.05) together with the labeling for heme-oxygenase isoform 1, a marker of oxidative stress. Therefore, the chronic induction of Hsp70 expression in rat skeletal muscles is not obligatory related to the slow fiber phenotype but reveals the occurrence of a stress response.
Keywords
Animals, Biological Markers/metabolism, Cell Hypoxia, HSP70 Heat-Shock Proteins/metabolism, Heme Oxygenase-1/metabolism, Hindlimb/metabolism, Male, Malondialdehyde/blood, Muscle Fibers, Slow-Twitch/cytology, Muscle Fibers, Slow-Twitch/enzymology, Muscle, Skeletal/anatomy & histology, Muscle, Skeletal/cytology, Organ Size, Oxidative Stress, Physical Conditioning, Animal, Protein Transport, Rats, Rats, Sprague-Dawley
Pubmed
Web of science
Create date
15/10/2009 8:29
Last modification date
20/08/2019 15:26
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