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Treatment with melatonin after onset of experimental uveitis attenuates ocular inflammation
Author(s) -
Sande P H,
Dorfman D,
Fernandez D C,
Chianelli M,
Domínguez Rubio A P,
Franchi A M,
Silberman D M,
Rosenstein R E,
Sáenz D A
Publication year - 2014
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/bph.12873
Subject(s) - melatonin , electroretinography , uveitis , medicine , retinal , inflammation , endocrinology , hamster , pharmacology , ophthalmology
Background and Purpose 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 S yrian hamster. Here, we have assessed the anti‐inflammatory effects of melatonin administered after the onset of ocular inflammation. Experimental Approach 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 PGE 2 and PGF 2α 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. Key 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 and Implications These results indicate that treatment with melatonin, starting after the onset of uveitis, attenuated ocular inflammation induced by LPS in the S yrian hamster and support the use of melatonin as a therapeutic resource for uveitis treatment.