Nitric oxide synthase induction and cytotoxic nitrogen-related oxidant formation in conjunctival epithelium of dry eye (Sjögren's syndrome)
Language English Country United States Media print-electronic
Document type Journal Article, Research Support, Non-U.S. Gov't
PubMed
17600738
DOI
10.1016/j.niox.2007.04.006
PII: S1089-8603(07)00041-9
Knihovny.cz E-resources
- MeSH
- Models, Biological MeSH
- Adult MeSH
- Nitrogen metabolism MeSH
- Epithelium metabolism MeSH
- Immunohistochemistry MeSH
- Conjunctiva metabolism pathology MeSH
- Middle Aged MeSH
- Humans MeSH
- Nitric Oxide metabolism MeSH
- Oxidants metabolism MeSH
- Sjogren's Syndrome metabolism MeSH
- Nitric Oxide Synthase metabolism MeSH
- Tumor Necrosis Factor-alpha metabolism MeSH
- Check Tag
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Male MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- Nitrogen MeSH
- Nitric Oxide MeSH
- Oxidants MeSH
- Nitric Oxide Synthase MeSH
- Tumor Necrosis Factor-alpha MeSH
Until now, the expression and possible role of nitric oxide and nitrogen related oxidants in the human dry eye have not been investigated. Therefore, we examined immunohistochemically nitric oxide synthase isomers (NOS), enzymes generated nitric oxide, nitrotyrosine, a cytotoxic byproduct of nitric oxide and malondialdehyde, a byproduct of lipid peroxidation, in conjunctival epithelium of patients with dry eye, Sjögren's syndrome (SS). Moreover, in conjunctival epithelium of patients with dry eye (SS) the immunohistochemical staining of some pro-inflammatory cytokines was demonstrated: mature interleukin-1 beta (IL-1beta), interleukin 6 (IL-6), interleukin 8 (IL-8) and tumor necrosis factor alpha (TNF-alpha). Conjunctival epithelial cells were obtained by the method of impression cytology. Normal eyes served as controls. In contrast to the normal eyes where endothelial nitric oxide synthase (NOS3) as well as inducible nitric oxide synthase (NOS2) were only slightly expressed in conjunctival epithelium, in dry eye both NOS (mainly NOS2) were gradually expressed along the severity of dry eye symptoms which was in accord with pro-inflammatory cytokine immunodetection (IL-1beta, IL-6, IL-8, TNF-alpha) in dry eye conjunctival cytology samples. This was in contrast to normal eyes where the staining of pro-inflammatory cytokines was weak or completely absent. Peroxynitrite formation (demonstrated by nitrotyrosine residues) and lipid peroxidation (evaluated by increased malondialdehyde staining) were also found in conjunctival epithelium of dry eye with highly pronounced symptoms of dryness. In conclusion, results point to the suggestion that reactive nitrogen species are involved in the pathogenesis or self-propagation of autoimmune dry eye (SS).
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