title: Intermittent bout exercise training down-regulates age-associated inflammation in skeletal muscles.
abstract: Aging is characterized by the progressive decline in mass and function of the skeletal muscle along with increased susceptibility to inflammation, oxidative stress, and atrophy. In this study, we investigate the effect of intermittent bout and single bout exercise training on inflammatory molecules in young (3 months) and old (22 months) male Sprague-Dawley rats. The rats were divided into 6 groups. Young and old rats were randomly assigned for control and two exercise training groups, single bout (S type): 30 min/day, 5 days/week for 6 weeks and intermittent bout (I type): three times for 10 min/day, 5 days/week for 6 weeks respectively. The exercise training was carried out by a treadmill at a speed of 15m/min (young) or 10 m/min (old) with a slope of 5°. After 48 h of the final exercise bout, muscle samples were collected for biochemical assay. I type exercise training reduced the serum levels of inflammatory molecules such as interleukin-1β (IL-1β), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and malondialdehyde (MDA) in old rats. By contrast, interleukin-4 (IL-4) and superoxide dismutase (SOD) were elevated. Consequently in skeletal muscles, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) were decreased significantly in the old group of I type. However, the matrix metalloproteinase-2 (MMP-2) level had no positive effects. Also, phosphorylation of mammalian target of rapamycin (p-mTOR) and myogenic differentiation (MyoD) were increased markedly in S and I types of old rats. These results suggest that I type exercise training appears more effective to reduce age-associated inflammatory molecules, and may recommend in regulating against chronic complicated disease induced by aging.
authors.affiliation: Department of Oral Biochemistry, Institute of Oral Bioscience, School of Dentistry, Republic of Korea; Department of Sports Science, College of Natural Science, Chonbuk National University, Jeonju, Republic of Korea.
authors.forename: Jeong-Seok
authors.initials: JS
authors.lastname: Kim
authors.affiliation: Department of Oral Biochemistry, Institute of Oral Bioscience, School of Dentistry, Republic of Korea. Electronic address: yihokn@chonbuk.ac.kr.
authors.forename: Ho-Keun
authors.initials: HK
authors.lastname: Yi
mesh_terms: D000375:Aging / Q000235:genetics*; D000818:Animals; D051546:Cyclooxygenase 2 / Q000378:metabolism; D016207:Cytokines / Q000097:blood*; D015536:Down-Regulation; D007249:Inflammation / Q000378:metabolism*; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism / Q000473:pathology*; D017570:MyoD Protein / Q000097:blood; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D018384:Oxidative Stress / Q000502:physiology*; D010805:Physical Conditioning, Animal / Q000379:methods*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013482:Superoxide Dismutase / Q000097:blood; D058570:TOR Serine-Threonine Kinases / Q000097:blood
chemical_list: D016207:Cytokines; D017570:MyoD Protein; C057363:MyoD1 myogenic differentiation protein; D008315:Malondialdehyde; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; D051546:Cyclooxygenase 2; C489691:Ptgs2 protein, rat; D013482:Superoxide Dismutase; C546845:mTOR protein, rat; D058570:TOR Serine-Threonine Kinases; D020778:Matrix Metalloproteinase 2; C522363:Mmp2 protein, rat
keywords: Inflammatory molecules; MyoD; SOD; Single bout exercise training; p-mTOR