title: Therapeutic effect of melatonin in experimental uveitis.
abstract: Uveitis is a common ophthalmic disorder that can be induced in hamsters by a single intravitreal injection of bacterial lipopolysaccharide (LPS). To examine the therapeutic effects of melatonin on uveitis, a pellet of melatonin was implanted subcutaneously 2 hours before the intravitreal injection of either vehicle or LPS. Both 24 hours and 8 days after the injection, inflammatory responses were evaluated in terms of i) the integrity of the blood-ocular barrier, ii) clinical signs, iii) histopathological studies, and iv) retinal function. Melatonin reduced the leakage of proteins and cells in the anterior segment of LPS-injected eyes, decreased clinical signs such as dilation of the iris and conjunctival vessels, and flare in the anterior chamber, and protected the ultrastructure of the blood-ocular barrier. A remarkable disorganization of rod outer segment membranous disks was observed in animals injected with LPS, whereas no morphological changes in photoreceptor outer segments were observed in animals treated with melatonin. Furthermore, melatonin prevented a decrease in LPS-induced electroretinographic activity. In addition, melatonin significantly abrogated the LPS-induced increase in retinal nitric-oxide synthase activity, tumor necrosis factor-alpha, and nuclear factor kappaB p50 and p65 subunit levels. These results indicate that melatonin prevents the clinical, biochemical, histological, ultrastructural, and functional consequences of experimental uveitis, likely through a nuclear factor kappaB-dependent mechanism, and support the use of melatonin as a new therapeutic strategy for the treatment of uveitis.
authors.affiliation: Laboratorio de Neuroquímica Retiniana y Oftalmología Experimental, Universidad de Buenos Aires, Centro de Estudios Farmacológicos y Botánicos Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina.
authors.forename: Pablo Horacio
authors.initials: PH
authors.lastname: Sande
authors.forename: Diego Carlos
authors.initials: DC
authors.lastname: Fernandez
authors.forename: Hernán Javier
authors.initials: HJ
authors.lastname: Aldana Marcos
authors.forename: Mónica Silvia
authors.initials: MS
authors.lastname: Chianelli
authors.forename: Julieta
authors.initials: J
authors.lastname: Aisemberg
authors.forename: Dafne Magalí
authors.initials: DM
authors.lastname: Silberman
authors.forename: Daniel Alberto
authors.initials: DA
authors.lastname: Sáenz
authors.forename: Ruth Estela
authors.initials: RE
authors.lastname: Rosenstein
mesh_terms: D000818:Animals; D001813:Blood-Retinal Barrier / Q000033:anatomy & histology / Q000378:metabolism; D006224:Cricetinae; D003412:Cricetulus; D004195:Disease Models, Animal; D004596:Electroretinography; D005123:Eye / Q000033:anatomy & histology / Q000276:immunology / Q000473:pathology; D006801:Humans; D020007:Implants, Experimental; D008070:Lipopolysaccharides / Q000276:immunology; D008297:Male; D008550:Melatonin / Q000627:therapeutic use*; D008647:Mesocricetus; D014605:Uveitis / Q000139:chemically induced / Q000188:drug therapy* / Q000276:immunology / Q000473:pathology
chemical_list: D008070:Lipopolysaccharides; D008550:Melatonin