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Objective. In the pathogenesis of pterygium, the protective role of glutathione and nitric oxide production is unclear. These are important factors for homeostasis in the redox state of cells. The aim of this study was to determine the levels of these and related parameters in pterygium tissue.Patients and Methods. The study sample consisted of 120 patients diagnosed with primary or recurrent pterygium. Five groups of tissue samples were examined: control, primary pterygium, recurrent pterygium, and two groups of primary pterygium given a one-month NAC presurgery treatment (topical or systemic). The levels of endothelial nitric oxide synthase (eNOS), nitric oxide (NO), 3-nitrotyrosine (3NT), reduced and oxidized glutathione (GSH and GSSG), and catalase (CAT) were evaluated in tissue homogenates.Results. Compared with the control, decreased levels of eNOS, NO, and 3-nitrotyrosine as well as the degree of oxidation of GSH (GSSG%) were observed in primary and recurrent pterygium. 3-Nitrotyrosine and GSSG% were reduced in the other pterygium groups. GSH and CAT were enhanced in recurrent pterygium and systemic-treated primary pterygium but were unchanged for topical-treated primary pterygium. There was a strong positive correlation of eNOS with NO and 3NT, GSSG% with NO and 3NT, and GSH with GSSG and CAT. Women showed a higher level of GSH and catalase in primary pterygium, whereas a lower level of GSH and a higher level of NO in recurrent pterygium.Conclusion. The results are congruent with the following proposed sequence of events leading to a protective response of the organism during the pathogenesis of primary pterygium: a decreased level of eNOS provokes a decline in the level of NO in pterygium tissue, which then leads to reduced S-nitrosylation of GSH or other thiols and possibly to the modulation of the intracellular level of GSH through synthesis and/or mobilization from other tissues.

Background There was not investigated the participation of glutathione (GSH), endothelial nitric oxide synthase (eNOS) and nitric oxide (NO) in pterygium pathogenesis and the effects of the precursor of GSH synthesis N-acetylcysteine in treatment prior to surgery.Methods The levels of eNOS, NO, 3-nitrotyrosine, reduced and oxidized GSH (GSSG) and catalase were measured in tissue homogenates of 120 patients with primary or recurrent pterygium, and systemic or topical pretreatment with N-acetylcysteine, compared to control group.Results A decrease in eNOS, NO, 3-nitrotyrosine, and GSH oxidation degree (GSSG%) was observed in primary pterygium, which remained decreased in other pathological groups in case of GSSG% and 3-nitrotyrosine. The levels of GSH and catalase increased in recurrent pterygium, even more, they increased in the group with systemic treatment, while topical treatment did not affect them, compared with control or primary pterygium groups. High positive correlation in groups of the study was observed between behavior of eNOS with NO or GSSG%, while GSH showed it with GSSG or catalase. Women showed a higher level of GSH and catalase in primary pterygium group, lower its level and a higher level of NO in recurrent pterygium. It was observed in women positive correlation in groups of study of GSSG% with 3-nitrotyrosine alone, while in men with NO.Conclusions Study data do not contradict the assumption about the following possible sequence of events in pathogenesis of the primary pterygium: decrease in the activity of eNOS and consequently of NO, decrease in S-nitrosation of GSH, possible modulation of the intracellular level of GSH through synthesis and/or mobilization from other tissues.

Stress seems to affect the onset and evolution of diverse illnesses with an inflammatory substrate. Whether physiological or psychological, stress increases epithelial permeability. In the mucosa of the nasal cavity and upper respiratory tract, the epithelial barrier is regulated in large part by bicellular and tricellular tight junctions (bTJs and tTJs, respectively). The junctional complexes are composed of multiple membrane proteins: claudins, tight-junction-associated MARVEL proteins (TAMs: occludin, tricellulin and marvelD3), and scaffolding proteins such as ZO-1, -2 and -3. The aim of the present study was to examine the possible modification of nasal permeability and TJ protein expression in a mouse model of acute psychological stress (a 4-h immobility session). Serum corticosterone was quantified from plasma samples to verify the onset of stress. Evaluation was made of the relative concentration of key proteins in nasal mucosa by using Western blot, and of changes in permeability by analyzing FITC-Dextran leakage from the nose to the blood. Compared to the control, the stressed group showed a greater epithelial permeability to FITC-Dextran, a reduced expression of occludin and tricellulin, and an elevated expression of ZO-2 and claudin-4. This evidence points to increased paracellular flow of large molecules through an altered structure of tTJs. Apparently, the structure of bTJs remained unchanged. The current findings could provide insights into the relation of stress to the onset/exacerbation of respiratory infections and/or allergies.