title: Chronic exercise decreases cytokine production in healthy rat skeletal muscle.
abstract: Skeletal muscle is the source of pro- and anti-inflammatory cytokines, and recently, it has been recognized as an important source of interleukin-6 (IL-6). Acute physical exercise is known to induce a pro-inflammatory cytokine profile in the plasma. However, the effect of chronic physical exercise in the production of pro- and anti-inflammatory cytokines by the skeletal muscle has never been examined. We assessed IL-6, TNF-alpha, IL-1beta and IL-10 levels in the skeletal muscle of rats submitted to endurance training. Animals were randomly assigned to either a sedentary group (S, n = 7) or an endurance exercise trained group (T, n = 8). Trained rats ran on a treadmill for 5 days week(-1) for 8 weeks (60% VO(2max)). Detection of IL-6, TNF-alpha, IL-1beta and IL-10 protein expression was carried out by ELISA. We found decreased expression of IL-1beta, IL-6, TNF-alpha and IL-10 (28%, 27%, 32% and 37%, respectively, p < 0.05) in the extensor digital longus (EDL) from T, when compared with S. In the soleus, IL-1beta, TNF-alpha and IL-10 protein levels were similarly decreased (34%, 42% and 50%, respectively, p < 0.05) in T in relation to S, while IL-6 expression was not affected by the training protocol. In conclusion, exercise training induced decreased cytokine protein expression in the skeletal muscle. These data show that in healthy rats, 8-week moderate-intensity aerobic training down regulates skeletal muscle production of cytokines involved in the onset, maintenance and regulation of inflammation, and that the response is heterogeneous according to fibre composition.
authors.affiliation: Molecular Biology of the Cell Group, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil.
authors.forename: Fábio S
authors.initials: FS
authors.lastname: Lira
authors.forename: Cristiane H
authors.initials: CH
authors.lastname: Koyama
authors.forename: Alex S
authors.initials: AS
authors.lastname: Yamashita
authors.forename: José C
authors.initials: JC
authors.lastname: Rosa
authors.forename: Nelo E
authors.initials: NE
authors.lastname: Zanchi
authors.forename: Miguel L
authors.initials: ML
authors.lastname: Batista
authors.forename: Marília C
authors.initials: MC
authors.lastname: Seelaender
mesh_terms: D000818:Animals; D016207:Cytokines / Q000096:biosynthesis*; D006262:Health; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*; D010805:Physical Conditioning, Animal; D051381:Rats; D017208:Rats, Wistar
chemical_list: D016207:Cytokines