title: Effectiveness of daily eccentric contractions induced via kilohertz frequency transcutaneous electrical stimulation on muscle atrophy.
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.
authors.affiliation: Department of Rehabilitation Science, Kobe University Graduate School of Health Sciences, 7-10-2 Tomogaoka, Kobe 654-0142, Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Tanaka
authors.affiliation: Department of Rehabilitation Science, Kobe University Graduate School of Health Sciences, 7-10-2 Tomogaoka, Kobe 654-0142, Japan.
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Nakanishi
authors.affiliation: Department of Physical Therapy, Himeji Dokkyo University, 7-2-1 Kamiono, Himeji 670-8524, Japan.
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Murakami
authors.affiliation: Laboratory of Musculoskeletal Functional Research and Regeneration, Institute of Biomedical & Health Sciences, Integrated Health Sciences, Hiroshima University, 1-2-3 Kasumi, Hiroshima 734-8553, Japan.
authors.forename: Naoto
authors.initials: N
authors.lastname: Fujita
authors.affiliation: Department of Food Science and Nutrition, Nagoya Women's University, Nagoya 467-8610, Japan.
authors.forename: Hiroyo
authors.initials: H
authors.lastname: Kondo
authors.affiliation: Laboratory of Cell Biology and Life Science, Graduate School of Human and Environmental Studies, Kyoto University, Kyoto 606-8501, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Ishihara
authors.affiliation: Brain Research Institute and Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095-7239, USA.
authors.forename: Roland R
authors.initials: RR
authors.lastname: Roy
authors.affiliation: Department of Rehabilitation Science, Kobe University Graduate School of Health Sciences, 7-10-2 Tomogaoka, Kobe 654-0142, Japan. Electronic address: fujino@phoenix.kobe-u.ac.jp.
authors.forename: Hidemi
authors.initials: H
authors.lastname: Fujino
mesh_terms: D000818:Animals; D000071316:Forkhead Box Protein O3; D051858:Forkhead Transcription Factors / Q000378:metabolism; D006614:Hindlimb / Q000473:pathology; D008297:Male; D009119:Muscle Contraction; D009124:Muscle Proteins / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D009133:Muscular Atrophy / Q000517:prevention & control*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D017207:Rats, Sprague-Dawley; D038601:Ribosomal Protein S6 / Q000378:metabolism; D044843:SKP Cullin F-Box Protein Ligases / Q000378:metabolism; D004561:Transcutaneous Electric Nerve Stimulation; D057149:Ubiquitinated Proteins / Q000378:metabolism
chemical_list: C499515:FOXO3 protein, rat; D000071316:Forkhead Box Protein O3; D051858:Forkhead Transcription Factors; D009124:Muscle Proteins; D038601:Ribosomal Protein S6; D057149:Ubiquitinated Proteins; C486692:Fbxo32 protein, rat; D044843:SKP Cullin F-Box Protein Ligases; C494920:Akt1 protein, rat; D051057:Proto-Oncogene Proteins c-akt
keywords: Concentric contractions; Eccentric contractions; Isometric contractions; Muscle atrophy; Transcutaneous electrical stimulation; Ubiquitin–proteasome pathway