Comparative treatment with hyperbaric oxygen therapy in a model of systemic loxoscelism in rats.

Objectives: Spiders of the Loxosceles genus, known as violin spiders, produce venom with dermonecrotic and systemic effects, as it is a species widely distributed in the world, its study represents a high medical relevance. Systemic loxoscelism, which occurs in 1 in 5 cases and is the most frequent in children, can be fatal, so the study of effective therapy is of great relevance. In the present study, we compared different therapeutic options to mitigate the systemic effects of Loxosceles boneti venom in a model in which prepubertal rats were used. Materials and Methods: A model of systemic intoxication by L. boneti venom was provoked in male Wistar rats. Study groups were formed: healthy control, with venom and untreated control, treatment with N-acetylcysteine, and/or hyperbaric oxygenation therapy. Subsequently, pathological analysis of the kidney and lung was performed. The oxidant-antioxidant response was evaluated, and molecular analysis of the COX-1 and COX-2 enzymes was performed. Results: Regenerative changes were observed at the cellular level in both treatments, being more noticeable in the hyperbaric oxygen therapy (HBO) group. The anti-oxidant response was outstanding in the same group. Conclusion: Both treatments offer considerable benefits, however; further studies are needed to provide adequate therapeutics.

Protective Role of Glutathione and Nitric Oxide Production in the Pathogenesis of Pterygium.

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.

Restraint stress increased the permeability of the nasal epithelium in BALB/c mice.

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.