title: Interleukin-10 limits intense acute swimming-induced muscle mechanical hyperalgesia in mice.
abstract: What is the central question of this study? This study investigated the role of the endogenous anti-inflammatory cytokine interleukin-10 in intense acute swimming-induced muscle mechanical hyperalgesia in mice. What is the main finding and its importance? Endogenous interleukin-10 has a key role in limiting exercise-induced muscle pain in a model presenting similarities to delayed-onset muscle soreness in mice. Interleukin-10 reduced muscle pain by diminishing leucocyte recruitment, hyperalgesic cytokine production, oxidative stress and myocyte damage. Interleukin-10 (IL-10) is an antihyperalgesic cytokine. In this study, IL-10-deficient (IL-10(-/-) ) mice were used to investigate the role of endogenous IL-10 in intense acute swimming-induced muscle mechanical hyperalgesia, which presents similarities with delayed-onset muscle soreness. An intense acute swimming session of 1 or 2 h induced significant muscle mechanical hyperalgesia in a time-dependent manner in wild-type mice compared with the sham group 24 h after the session, which was further increased in IL-10(-/-) mice (P ˂ 0.05). Intraperitoneal treatment of wild-type mice with IL-10 (1-10 ng) reduced muscle mechanical hyperalgesia in a dose-dependent manner and reversed the enhanced muscle hyperalgesia in IL-10(-/-) mice (P ˂ 0.05). The 2 h swimming session induced increases in tumour necrosis factor-α, interleukin-1β and IL-10 production in the soleus muscle. However, tumour necrosis factor-α and interleukin-1β production in the soleus muscle were even higher in IL-10(-/-) mice between 2 and 6 h after the stimulus (P ˂ 0.05). There was no statistical difference in the levels of the antihyperalgesic cytokines interleukin-4, interleukin-5, interleukin-13 and transforming growth factor-β between wild-type and IL-10(-/-) mice (P ˃ 0.05). Interleukin-10 deficiency also resulted in increased myeloperoxidase activity, greater depletion of reduced glutathione levels, increased superoxide anion production and the maintenance of high plasma concentrations of creatine kinase (until 24 h after the swimming session) in soleus muscle (P ˂ 0.05). These results demonstrate that endogenous IL-10 controls intense acute swimming-induced muscle mechanical hyperalgesia by limiting oxidative stress and cytokine production.
authors.affiliation: Departamento de Ciências Patológicas, Centro de Ciências Biológicas, Universidade Estadual de Londrina, Londrina, Paraná, Brazil.
authors.forename: Sergio M
authors.initials: SM
authors.lastname: Borghi
authors.forename: Felipe A
authors.initials: FA
authors.lastname: Pinho-Ribeiro
authors.forename: Ana C
authors.initials: AC
authors.lastname: Zarpelon
authors.forename: Thiago M
authors.initials: TM
authors.lastname: Cunha
authors.forename: Jose C
authors.initials: JC
authors.lastname: Alves-Filho
authors.forename: Sergio H
authors.initials: SH
authors.lastname: Ferreira
authors.forename: Fernando Q
authors.initials: FQ
authors.lastname: Cunha
authors.forename: Rubia
authors.initials: R
authors.lastname: Casagrande
authors.forename: Waldiceu A
authors.initials: WA
authors.lastname: Verri
mesh_terms: D000818:Animals; D006930:Hyperalgesia / Q000139:chemically induced* / Q000378:metabolism*; D007249:Inflammation / Q000378:metabolism; D016753:Interleukin-10 / Q000235:genetics / Q000378:metabolism*; D008297:Male; D008810:Mice, Inbred C57BL; D032342:Muscle Cells / Q000166:cytology; D018482:Muscle, Skeletal / Q000503:physiopathology*; D063806:Myalgia / Q000139:chemically induced*; D018384:Oxidative Stress / Q000502:physiology; D013550:Swimming
chemical_list: C556062:IL10 protein, mouse; D016753:Interleukin-10