ABSTRACT
Pterygium is a common ocular surface disease observed in humans. Chronic ultraviolet (UV) exposure is extensively recognized as an aetiological factor in the pathogenesis of this disease. This hypothesis is sustained by epidemiological and histopathological data in relation to UV injured skin. Although some findings have indicated that genetic factors, anti-apoptotic and immunological mechanisms are involved in the pathogenesis of pterygium, the mechanism by which it develops remains poorly understood. In this study, we analysed the in vivo production of IL-17A, IL-6, IL-10 and nitric oxide (NO) in the tears and sera from Algerian patients. Interestingly, we observed that IL-6, IL-17A and NO production in the tears and sera of all patients was strongly associated with inflammatory infiltration, NOS2, NF-κB and Bcl2 expression in pterygia biopsies. Collectively, our results indicate a relationship between local inflammation and anti-apoptotic processes in pterygium disease, leading to both tissue damage and enhanced cellular proliferation.
Subject(s)
Interleukin-17/metabolism , Interleukin-6/metabolism , Nitric Oxide/metabolism , Pterygium/metabolism , Adult , Conjunctiva/pathology , Female , Humans , Interleukin-10/blood , Interleukin-10/metabolism , Interleukin-17/blood , Interleukin-6/blood , Male , Middle Aged , NF-kappa B/blood , NF-kappa B/metabolism , Nitric Oxide/blood , Nitric Oxide Synthase Type II/blood , Nitric Oxide Synthase Type II/metabolism , Proto-Oncogene Proteins c-bcl-2/blood , Proto-Oncogene Proteins c-bcl-2/metabolism , Pterygium/blood , Pterygium/pathology , Tears/metabolismABSTRACT
INTRODUCTION: Several studies have reported a significant production of nitric oxide (NO) with peroxynitrite formation in the setting of intraocular inflammation. In a previous study, we showed the cytotoxic effect of nitrites and nitrates, stable metabolites of NO, on the various tissues forming the layers of the eye, with variable degrees of tissue sensitivity. This study aims to investigate the effect of peroxynitrite on whole ocular bovine explants in culture. METHODS: Healthy ocular bovine eyes, obtained immediately upon enucleation, were dissected and samples were taken from the anterior and posterior segments, and then cultured in DMEM supplemented with 10% fetal bovine serum, 2mM L-glutamine and antibiotics. Cultures were treated with 3-morpholino-sydonimin N-ethyl-carbamide (SIN-1) (molecule which produces NO and superoxide anion O(2)(.-)) at varying concentrations (100 to 500 µM) over 24 hours. After incubation, the explants were fixed in 10% buffered formalin, and histological study was performed. RESULTS: Most of the structures showed changes on tissue and cellular levels after incubation with the peroxynitrite donor and various responses depending on the concentration used. These observations reflect variable concentration-dependent tissue sensitivity. The epithelia (cornea, iris and ciliary process) showed high sensitivity in comparison with sclera, which developed greater resistance. CONCLUSION: In all, our results indicate a deleterious effect of peroxynitrite on bovine ocular structures in vitro. This effect is proportional to the concentration used. These results corroborate those reported by other teams and suggest the role of peroxynitrite derived from NO in the ocular lesions observed in the setting of uveitis.
