title: Treatment with melatonin after onset of experimental uveitis attenuates ocular inflammation.
abstract: OBJECTIVE
  Uveitis is a prevalent intraocular inflammatory disease and one of the most damaging ocular conditions. Pretreatment with melatonin prevented ocular inflammation induced by an intravitreal injection of bacterial LPS in the Syrian hamster. Here, we have assessed the anti-inflammatory effects of melatonin administered after the onset of ocular inflammation.
  
  
  METHODS
  The eyes of male Syrian hamsters were intravitreally injected with vehicle or LPS. Melatonin was injected i.p. every 24 h, starting 12 or 24 h after the LPS injection. A clinical evaluation (with a score index based on clinical symptoms), the number of infiltrating cells, protein concentration and PGE2 and PGF2α levels in the aqueous humour, as well as retinal NOS activity, lipid peroxidation and TNF-α levels were assessed. Retinal function was assessed by scotopic electroretinography, and light microscopy and immunohistochemistry were used to evaluate the state of the retinal structure.
  
  
  RESULTS
  Both treatment regimens with melatonin decreased clinical symptoms, reduced the leakage of cells and proteins, and decreased PG levels in aqueous humour from eyes injected with LPS. In addition, melatonin treatment blocked the decrease in scotopic electroretinogram a- and b-wave amplitude, protected the retinal structure and reduced the increase in NOS activity, lipid peroxidation and TNF-α levels, induced by LPS.
  
  
  CONCLUSIONS
  These results indicate that treatment with melatonin, starting after the onset of uveitis, attenuated ocular inflammation induced by LPS in the Syrian hamster and support the use of melatonin as a therapeutic resource for uveitis treatment.
authors.affiliation: Laboratory of Retinal Neurochemistry and Experimental Ophthalmology, Department of Human Biochemistry, School of Medicine/CEFyBO, University of Buenos Aires/CONICET, Buenos Aires, Argentina.
authors.forename: P H
authors.initials: PH
authors.lastname: Sande
authors.forename: D
authors.initials: D
authors.lastname: Dorfman
authors.forename: D C
authors.initials: DC
authors.lastname: Fernandez
authors.forename: M
authors.initials: M
authors.lastname: Chianelli
authors.forename: A P
authors.initials: AP
authors.lastname: Domínguez Rubio
authors.forename: A M
authors.initials: AM
authors.lastname: Franchi
authors.forename: D M
authors.initials: DM
authors.lastname: Silberman
authors.forename: R E
authors.initials: RE
authors.lastname: Rosenstein
authors.forename: D A
authors.initials: DA
authors.lastname: Sáenz
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D001082:Aqueous Humor / Q000187:drug effects* / Q000378:metabolism; D006224:Cricetinae; D015237:Dinoprost / Q000276:immunology / Q000378:metabolism; D015232:Dinoprostone / Q000276:immunology / Q000378:metabolism; D004195:Disease Models, Animal; D004596:Electroretinography; D007150:Immunohistochemistry; D058449:Intravitreal Injections; D015227:Lipid Peroxidation / Q000187:drug effects; D008070:Lipopolysaccharides / Q000633:toxicity; D008297:Male; D008550:Melatonin / Q000494:pharmacology*; D008647:Mesocricetus; D019001:Nitric Oxide Synthase / Q000187:drug effects / Q000378:metabolism; D012160:Retina / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D014605:Uveitis / Q000139:chemically induced / Q000276:immunology / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha; D015237:Dinoprost; D019001:Nitric Oxide Synthase; D008550:Melatonin; D015232:Dinoprostone