The post-treatment with melatonin attenuates experimental ocular inflammation.

SANDE PABLO; DORFMAN DAMIAN; FERNANDEZ DIEGO; CHIANELLI MONICA; DOMINGUEZ RUBIO ANA PAULA; FRANCHI, ANA MARIA; SILBERMAN DAFNE; ROSENSTEIN RUTH ESTELA; SANZ DANIEL

BRITISH JOURNAL OF PHARMACOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2014

0007-1188

BACKGROUND AND PURPOSE: Uveitis is a prevalent intraocular inflammatory disease and one of the most damaging ocular conditions. Previously, we showed that melatonin prevents ocular inflammation induced by an intravitreal injection of bacterial lipopolysaccharide (LPS) in the Syrian hamster. With this background, the aim of this work was to assess the anti-inflammatory effect of melatonin administered after the onset of ocular inflammation. EXPERIMENTAL APPROACH: Eyes were intravitreally injected with vehicle or LPS. Melatonin was intraperitoneally supplied every 24 h, starting 12 h or 24 h post-LPS injection. A clinical evaluation (with a score index based on clinical symptoms), the number of infiltrating cells, protein concentration, and prostaglandin (PG) E2 and PGF2α levels in the aqueous humor, as well as retinal nitric oxide synthase (NOS) activity, lipid peroxidation and TNFα levels were assessed. Retinal function was assessed by scotopic electroretinography, and light microscopy and immunohistochemistry were used to evaluate the retinal structure. KEY RESULTS: Both post-treatments with melatonin significantly decreased clinical symptoms, reduced the leakage of cells and proteins, and decreased PG levels in aqueous humor from eyes injected with LPS. In addition, melatonin avoided the decrease in scotopic electroretinogram a- and b-wave amplitude, protected the retinal structure, and reduced the increase in NOS activity lipid peroxidation, and TNFα levels induced by LPS. CONCLUSIONS AND IMPLICATIONS: These results indicate that a post-treatment with melatonin significantly attenuated ocular inflammation induced by LPS in the Syrian hamster, and support the use of melatonin as a therapeutic resource for uveitis treatment.