Effets délétères des dérivés stables du monoxyde d’azote, marqueur inflammatoire des uvéites, sur les différentes tuniques de l’œil de bœuf en culture

Abstract

Uveitis is an intraocular inflammation affecting various eye segments. This disease is characterized by a high level of nitric oxide production. It is estimated via the quantification of its end products: nitrites and nitrates. In a previous study, we showed the cytotoxic effect of these molecules on bovine retina in vitro. In this study, we investigated the effect of these two molecules on cultured ocular explants in vitro. After clinical examination, healthy bovine eyes were obtained immediately after enucleation and were transported to the laboratory at +4 degrees C. After dissection, ocular explants from anterior and posterior segments were cultured in DMEM supplemented with 10% of FBS, 2mM glutamine, 100UI penicillin, and 100UI/ml streptomycin. Cultures were treated with either nitrites or nitrates at different concentrations (300-500 microM). After culture incubation (24-48h), ocular explants were fixed in buffered formalin and the histological study was performed. All structures showed structural alterations in relation with culture duration and molecule concentrations. The different structures showed different degrees of sensitivity depending on the type and concentration of the metabolite used. Sclerotic analysis showed very little response to the two molecules, whereas the cornea and ciliary process epithelia showed the highest sensitivity. Our results showed a cytotoxic effect of nitrites and nitrates on ocular structures in vitro. This effect was correlated with molecule concentration and duration of exposure. The structural alterations observed suggest that nitric oxide, via its products, is implicated in the ocular lesions observed during uveitis.