title: The effects of chronic exercise on the inflammatory cytokines interleukin-6 and tumor necrosis factor-α are different with age.
abstract: Aging is associated with chronic low-grade inflammation, and interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) are key mediators of the inflammatory process. IL-6, especially muscle-derived IL-6, is expected to mediate the beneficial metabolic effects of exercise. There was no report that directly compares the effects of chronic endurance exercise on cytokine responses between old and young subjects in the same situation. Therefore, we compared the effects of endurance exercise on the expression of IL-6 and TNF-α in old and young rats. Young (3-month-old) and old (20-month-old) male Fisher rats were trained for 12 weeks on the treadmill. We measured serum TNF-α and IL-6 concentrations by enzyme-linked immunosorbent assay and examined mRNA expression of TNF-α and IL-6 in muscle, liver, and white adipose tissue using reverse transcription - polymerase chain reaction. We found that old rats had higher basal IL-6 levels in the liver, as well as in the serum and the muscle. After chronic endurance exercise, young rats exhibited significant decreases in serum TNF-α levels and hepatic IL-6 expression. However, old rats exhibited no significant changes in either serum or tissue cytokine levels after endurance exercise. These findings suggest that chronic endurance exercise could influence the inflammatory response of hepatic tissues, as well as muscle, and that the effects of chronic endurance exercise on inflammatory cytokine levels are different between old and young rats and an exercise program tailored for old subjects will be needed to obtain beneficial anti-inflammatory effects from exercise.
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Min Kyong
authors.initials: MK
authors.lastname: Moon
authors.forename: Bong Jun
authors.initials: BJ
authors.lastname: Cho
authors.forename: You Jin
authors.initials: YJ
authors.lastname: Lee
authors.forename: Sung Hee
authors.initials: SH
authors.lastname: Choi
authors.forename: Soo
authors.initials: S
authors.lastname: Lim
authors.forename: Kyong Soo
authors.initials: KS
authors.lastname: Park
authors.forename: Young Joo
authors.initials: YJ
authors.lastname: Park
authors.forename: Hak Chul
authors.initials: HC
authors.lastname: Jang
mesh_terms: D052436:Adipose Tissue, White / Q000276:immunology; D000375:Aging / Q000276:immunology* / Q000502:physiology*; D000818:Animals; D015870:Gene Expression / Q000276:immunology; D007249:Inflammation / Q000097:blood / Q000503:physiopathology*; D015850:Interleukin-6 / Q000097:blood / Q000235:genetics* / Q000276:immunology; D008099:Liver / Q000276:immunology / Q000378:metabolism; D008297:Male; D018482:Muscle, Skeletal / Q000276:immunology; D010805:Physical Conditioning, Animal; D010807:Physical Endurance / Q000276:immunology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011916:Rats, Inbred F344; D014409:Tumor Necrosis Factor-alpha / Q000097:blood / Q000235:genetics* / Q000276:immunology
chemical_list: D015850:Interleukin-6; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha