Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1923423 | Acta Histochemica | 2016 | 7 Pages |
Abstract
The effects of daily repeated bouts of concentric, isometric, or eccentric contractions induced by high frequency (kilohertz) transcutaneous electrical stimulation in ameliorating atrophy of the soleus muscle in hindlimb unloaded rats were determined. Five groups of male rats were studied: control, hindlimb unloaded for 2 weeks (HU), or HU plus two daily bouts of concentric, isometric, or eccentric high-frequency electrical stimulation-induced contractions of the calf musculature. Soleus mass and fiber size were smaller, the levels of phosphorylated Akt1 and FoxO3a lower, and atrogin-1 and ubiquitinated proteins higher in the HU, and the HU plus concentric or isometric contraction groups than in the control group. In contrast, daily bouts of eccentric contractions maintained these values at near control levels and all measures were significantly different from all other HU groups. These results indicate that daily bouts of eccentric contractions induced by high-frequency stimulation inhibited the ubiquitin-proteasome catabolic pathway and enhanced the Akt1/FoxO3a anabolic pathway that resulted in a prevention of the atrophic response of the soleus muscle to chronic unloading.
Keywords
PVDFphosphate-buffered saline with Tween 20PBSTTBSTBSATris-buffered saline with Tween 20Muscle atrophyadenosine triphosphatasebovine serum albuminSDS-PAGESDS polyacrylamide gel electrophoresisIsometric contractionsEccentric contractionsCSAATPaseElectrical stimulationTranscutaneous electrical stimulationHindlimb unloadingFoxOUbiquitin–proteasome pathwaycross-sectional areaPolyvinylidene fluoride
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Authors
Minoru Tanaka, Ryosuke Nakanishi, Shinichiro Murakami, Naoto Fujita, Hiroyo Kondo, Akihiko Ishihara, Roland R. Roy, Hidemi Fujino,