Anti-Inflammatory Effect of Melatonin in Experimental Uveítis.

SANDE, PH; FERNANDEZ, DC; CHIANELLI, MS; ROSENSTEIN, RE; SÁENZ, DA

Fort Lauderdale, USA

Congreso; The Association for Research in Vision and Ophthalmology; 2009

Invest Ophthalmol Vis Sci 2009;50: E-Abstract 6020.© 2009 ARVO 6020—D704 Anti-Inflammatory Effect of Melatonin in Experimental Uveitis P. Sande, D. Fernandez, M. Chianelli, R. E. Rosenstein and D. Saenz Human Biochemistry, Sch Med Univ Buenos Aires, Buenos Aires, Argentina Commercial Relationships: P. Sande, None; D. Fernandez, None; M. Chianelli, None; R.E. Rosenstein, None; D. Saenz, None. Support: Ruth Rosenstein, BID 1728 PICT 25364 Abstract Purpose:In a previous report, we showed that melatonin significantly prevents functional and histological consequences of endotoxin-induced uveitis in the golden hamster. The aim of the present work was to analyze whether melatonin can reduce retinal inflammation when administered after bacterial lipopolysaccharide (LPS). Methods:The treatment with melatonin (10 mg/kg, intraperitoneal) started 12 or 24 h after the intravitreal injection of LPS and was repeated every 24 h for 4 days. Clinical observation (conjunctival hyperemia, alterations of episcleral vessels, cornea, iris, crystalline and posterior segment) was analyzed by assigning a score to each of these signs (maximum: 16 points) at different intervals after LPS injection. In order to evaluate the integrity of the hemato-ocular barrier, the number of infiltrating cells and protein content were assessed in the aqueous humor, 36 h after LPS. Retinal function was assessed by electroretinography 8 days after LPS injection, whereas retinal morphology was analyzed by light microscopy of retinal sections, 36 h after LPS. Results:Starting at 12 or 24 h post-LPS, melatonin significantly decreased the clinical score induced by LPS and it significantly reduced the concentration of proteins and the number of infiltrating cells. In addition, melatonin reversed the decrease in ERG a- and b-wave amplitude induced by LPS, and it significantly protected against the histological damage associated to endotoxin-induced uveitis. Melatonin was equally effective in the treatment initiated at 12 h and that initiated at 24 h post- LPS. Conclusions:These results support that melatonin not only prevents but also counteracts LPS-induced uveitis. Therefore, melatonin could be considered a new therapeutic strategy in uveitis treatment. Keywords: melatonin • neuroprotection • uveitis-clinical/animal model © 2009, The Association for Research in Vision and Ophthalmology, Inc., all rights reserved. Permission to republish any abstract or part of an abstract in any form must be obtained in writing from the ARVO Office prior to publication.