title: Melatonin reduces the severity of experimental amoebiasis.
abstract: BACKGROUND
  Melatonin has immunomodulatory effects but very little is known about its influence in protozoan infections, such as Entamoeba histolytica, which causes amoebiasis, a disease with significant morbidity and mortality. In this study, we evaluated the effects of exogenous melatonin interference in experimental amoebiasis and on interactions between human blood cells and E. histolytica trophozoites.
  
  
  METHODS
  The effect of melatonin was investigated in models of experimental amoebiasis in hamsters and rats by evaluating the area of necrosis induced by E. histolytica. The activity of melatonin on the interactions between leukocytes and amoebae was determined by examining leukophagocytosis. For in vitro tests, polymorphonuclear and mononuclear human blood leucocytes were incubated with E. histolytica trophozoites.
  
  
  RESULTS
  The areas of amoebic necrosis were significantly reduced in animals treated with melatonin. Melatonin treatment increased leukophagocytosis but was associated with a greater number of dead amoebae.
  
  
  CONCLUSIONS
  These results suggest that melatonin may play a beneficial role in the control of amoebic lesions, raising the possibility that this drug may be used as an adjuvant in anti-amoebic therapy.
authors.affiliation: Department of Parasitology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Aline C
authors.initials: AC
authors.lastname: França-Botelho
authors.forename: Juliana L
authors.initials: JL
authors.lastname: França
authors.forename: Fabrício M S
authors.initials: FM
authors.lastname: Oliveira
authors.forename: Eduardo L
authors.initials: EL
authors.lastname: Franca
authors.forename: Adenilda C
authors.initials: AC
authors.lastname: Honório-França
authors.forename: Marcelo V
authors.initials: MV
authors.lastname: Caliari
authors.forename: Maria A
authors.initials: MA
authors.lastname: Gomes
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D002478:Cells, Cultured; D006224:Cricetinae; D004195:Disease Models, Animal; D004748:Entamoeba histolytica; D004749:Entamoebiasis / Q000469:parasitology* / Q000473:pathology*; D006651:Histocytochemistry; D006801:Humans; D007155:Immunologic Factors / Q000008:administration & dosage*; D007962:Leukocytes / Q000276:immunology / Q000469:parasitology; D008099:Liver / Q000473:pathology; D008297:Male; D008550:Melatonin / Q000008:administration & dosage*; D008853:Microscopy; D010587:Phagocytosis / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D012376:Rodent Diseases / Q000469:parasitology / Q000473:pathology; D055815:Young Adult
chemical_list: D007155:Immunologic Factors; D008550:Melatonin