title: Does orchiectomy enhance the immune-stimulatory effects of melatonin during experimental Chagas' disease?
abstract: Melatonin has been reported to play a fundamental role in T-cell immunoregulation. Control of Trypanosoma cruzi parasitism during the acute phase of infection is considered to be critically dependent on direct macrophage activation by cytokines. The aim of this work was to evaluate the influence of exogenous melatonin treatment and the influences exerted by sexual hormones during the acute phase of the experimental Chagas' disease in rats. With melatonin treatment, orchiectomized animals (CMOR and IMOR) displayed the highest concentrations of IFN-γ and TNF-α. On the 7th day post-infection, untreated and treated orchiectomized animals (IOR and IMOR) showed an enhanced number of peritoneal macrophages. Nitric oxide levels were also increased in untreated and treated orchiectomized (IOR and IMOR) when compared to the other groups, with or without LPS. Our data suggest that melatonin therapy associated with orchiectomy induced a stimulating effect on the immune response to the parasite.
authors.affiliation: Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo (FCFRP-USP), Brazil. fasantello@yahoo.com.br
authors.forename: Fabricia Helena
authors.initials: FH
authors.lastname: Santello
authors.forename: Leony Cristina
authors.initials: LC
authors.lastname: Caetano
authors.forename: Marina Del Vecchio
authors.initials: Mdel V
authors.lastname: Filipin
authors.forename: Vânia
authors.initials: V
authors.lastname: Brazão
authors.forename: Luana Naiara
authors.initials: LN
authors.lastname: Caetano
authors.forename: Míriam Paula Alonso
authors.initials: MP
authors.lastname: Toldo
authors.forename: José Clóvis
authors.initials: JC
authors.lastname: do Prado
mesh_terms: D000818:Animals; D014355:Chagas Disease / Q000188:drug therapy* / Q000276:immunology; D005786:Gene Expression Regulation / Q000502:physiology; D007371:Interferon-gamma / Q000235:genetics / Q000378:metabolism; D008070:Lipopolysaccharides; D017737:Macrophages, Peritoneal / Q000502:physiology; D008297:Male; D008550:Melatonin / Q000494:pharmacology*; D009569:Nitric Oxide / Q000097:blood; D009919:Orchiectomy; D018512:Parasitemia; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism
chemical_list: D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; D007371:Interferon-gamma; D008550:Melatonin