title: Immune stimulation by exogenous melatonin during experimental endotoxemia.
abstract: Melatonin has been shown to enhance the immune response under immune-compromised conditions. However, its immune-modulatory effects under inflammatory conditions are unclear at present. Both pro- and anti-inflammation has been reported. To study time-dependent effects of melatonin on the general immune response during endotoxemia in more detail, we used two models in male rats: per-acute endotoxemia was induced by lipopolysaccharide (LPS) bolus injection (2.5 mg/kg), sub-acute endotoxemia by LPS infusion (2.5 mg/kg × h). Melatonin was applied directly before and 2 h after LPS administration (3 mg/kg, each). The LPS-induced formation of the pro-inflammatory cytokines tumor necrosis factor alpha, interferon-gamma, interleukin (IL)-1α/β, IL-5, and IL-6 and of the anti-inflammatory cytokine IL-10 was further amplified by melatonin, although it was only significant during per-acute endotoxemia. In both models, melatonin had no effect on the LPS-induced nitric oxide release. These findings show that exogenous melatonin is capable of enhancing the general immune response under inflammatory conditions.
authors.affiliation: Institute of Physiological Chemistry, University Hospital Essen, Essen, Germany, katharina.effenberger-neidnicht@uni-duisburg-essen.de.
authors.forename: Katharina
authors.initials: K
authors.lastname: Effenberger-Neidnicht
authors.forename: Lisa
authors.initials: L
authors.lastname: Brencher
authors.forename: Martina
authors.initials: M
authors.lastname: Broecker-Preuss
authors.forename: Tim
authors.initials: T
authors.lastname: Hamburger
authors.forename: Frank
authors.initials: F
authors.lastname: Petrat
authors.forename: Herbert
authors.initials: H
authors.lastname: de Groot
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D016207:Cytokines / Q000096:biosynthesis / Q000097:blood; D019446:Endotoxemia / Q000188:drug therapy* / Q000276:immunology*; D007249:Inflammation / Q000188:drug therapy / Q000276:immunology; D008070:Lipopolysaccharides / Q000008:administration & dosage; D008297:Male; D008550:Melatonin / Q000097:blood / Q000276:immunology / Q000494:pharmacology*; D009569:Nitric Oxide / Q000097:blood* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
chemical_list: D000893:Anti-Inflammatory Agents; D016207:Cytokines; D008070:Lipopolysaccharides; D009569:Nitric Oxide; D008550:Melatonin