title: l-Carnitine supplement reduces skeletal muscle atrophy induced by prolonged hindlimb suspension in rats.
abstract: l-Carnitine was recently found to downregulate the ubiquitin proteasome pathway (UPP) and increase insulin-like growth factor 1 concentrations in animal models. However, the effect of l-carnitine administration on disuse muscle atrophy induced by hindlimb suspension has not yet been studied. Thus, we hypothesized that l-carnitine may have a protective effect on muscle atrophy induced by hindlimb suspension via the Akt1/mTOR and/or UPP. Male Wistar rats were assigned to 3 groups: hindlimb suspension group, hindlimb suspension with l-carnitine administration (1250 mg·kg-1·day-1) group, and pair-fed group adjusted hindlimb suspension. l-Carnitine administration for 2 weeks of hindlimb suspension alleviated the decrease in weight and fiber size in the soleus muscle. In addition, l-carnitine suppressed atrogin-1 mRNA expression, which has been reported to play a pivotal role in muscle atrophy. The present study shows that l-carnitine has a protective effect against soleus muscle atrophy caused by hindlimb suspension and decreased E3 ligase messenger RNA expression, suggesting the possibility that l-carnitine protects against muscle atrophy, at least in part, through the inhibition of the UPP. These observations suggest that l-carnitine could serve as an effective supplement in the decrease of muscle atrophy caused by weightlessness in the fields of clinical and rehabilitative research.
authors.affiliation: a Laboratory of Exercise Nutrition, Department of Physical Education, Konkuk University, 120, Neungdong-ro, Gwangjin-gu, Seoul 143-701, Korea.
authors.forename: Jiwoong
authors.initials: J
authors.lastname: Jang
authors.affiliation: b Department of Physical Education, Korea University, Seoul 136-701, Korea.
authors.forename: Jonghoon
authors.initials: J
authors.lastname: Park
authors.affiliation: c Department of Human Movement Science, Seoul Women's University, Seoul 139-774, Korea.
authors.forename: Hyukki
authors.initials: H
authors.lastname: Chang
authors.affiliation: a Laboratory of Exercise Nutrition, Department of Physical Education, Konkuk University, 120, Neungdong-ro, Gwangjin-gu, Seoul 143-701, Korea.
authors.forename: Kiwon
authors.initials: K
authors.lastname: Lim
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002331:Carnitine / Q000627:therapeutic use*; D019587:Dietary Supplements; D004794:Enzyme Repression; D019417:Hindlimb Suspension / Q000009:adverse effects; D007150:Immunohistochemistry; D008297:Male; D009124:Muscle Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D018482:Muscle, Skeletal / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D009133:Muscular Atrophy / Q000209:etiology / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control; D020966:Muscular Disorders, Atrophic / Q000209:etiology / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D046988:Proteasome Endopeptidase Complex; D061988:Proteasome Inhibitors / Q000627:therapeutic use; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D044843:SKP Cullin F-Box Protein Ligases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D000070584:Tripartite Motif Proteins / Q000235:genetics / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D054875:Ubiquitination; D014893:Weightlessness / Q000009:adverse effects
chemical_list: D015415:Biomarkers; D009124:Muscle Proteins; D061988:Proteasome Inhibitors; D000070584:Tripartite Motif Proteins; C486692:Fbxo32 protein, rat; D044843:SKP Cullin F-Box Protein Ligases; C499086:Trim63 protein, rat; D044767:Ubiquitin-Protein Ligases; C111567:parkin protein; D046988:Proteasome Endopeptidase Complex; D002331:Carnitine
keywords: apesanteur; atrophie musculaire; catabolic condition; condition catabolique; hindlimb suspension; l-carnitine; muscle atrophy; muscle-specific ubiquitin E3 ligases; suspension par les membres postérieurs; ubiquitine-ligase E3 spécifique au muscle; weightless