title: Dual effect of melatonin as proinflammatory and antioxidant in collagen-induced arthritis in rats.
abstract: The aim of this study was to determine the effects of melatonin on proinflammatory status of rats with collagen-induced arthritis (CIA). CIA was induced in male Wistar rats with an emulsion of type II collagen in Freund's Incomplete Adjuvant (C-II/FIA). For 14 days, control and pinealectomized rats received a subcutaneous injection of 100 microL melatonin (30 microg) or vehicle (saline on 1% ethanol). Levels of cytokines interleukin (IL)-1beta and IL-6 were determined in the serum, peripheral blood mononuclear cells, and joints. Levels of anti-type II collagen antibody, nitrite/nitrate, and lipid peroxidation (LPO) were determined in the serum, joints, and brain. Treatment with melatonin significantly increased the levels of IL-1beta, IL-6, nitrite/nitrate and LPO in joints. However, melatonin significantly reduced the levels of nitrite/nitrate and LPO in serum and brain. Moreover, CIA in pinealectomized rats presented significantly reduced levels of IL-1beta and IL-6, titers of anti-type II collagen antibodies, levels of nitrite/nitrate, and LPO in joints but elevated levels in serum and brain. Melatonin has been described as a proinflammatory and antioxidant agent. In a process of inflammation as CIA, melatonin acts with a markedly proinflammatory effect at local and peripheral levels maintaining its antioxidant effect only at peripheral level.
authors.affiliation: Department of Medical Biochemistry, The University of Seville School of Medicine and Virgen Macarena Hospital, Seville, Spain.
authors.forename: Antonio J
authors.initials: AJ
authors.lastname: Jiménez-Caliani
authors.forename: Silvia
authors.initials: S
authors.lastname: Jiménez-Jorge
authors.forename: Patrocinio
authors.initials: P
authors.lastname: Molinero
authors.forename: Juan M
authors.initials: JM
authors.lastname: Guerrero
authors.forename: Jose M
authors.initials: JM
authors.lastname: Fernández-Santos
authors.forename: Inés
authors.initials: I
authors.lastname: Martín-Lacave
authors.forename: Carmen
authors.initials: C
authors.lastname: Osuna
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology*; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D001169:Arthritis, Experimental / Q000188:drug therapy / Q000378:metabolism*; D024043:Collagen Type II / Q000276:immunology; D005121:Extremities / Q000473:pathology; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology; D007596:Joints / Q000473:pathology; D008297:Male; D008550:Melatonin / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D000276:Adjuvants, Immunologic; D000975:Antioxidants; D024043:Collagen Type II; D007074:Immunoglobulin G; D008550:Melatonin