Study of galectin-9 in experimental atopical dermatitis treated or not with dexamethasone

Abstract

Galectin-9 (Gal-9) belongs to a protein family characterized by a conserved carbohydrate recognition domain (CRD) of approximately 135 amino acids responsible for its binding to ²-galactoside sugars. In experimental models of inflammation, Gal-9 has been pointed as an anti-inflammatory mediator. However, in relation to its mechanisms of action in allergy, Gal-9 can play a dual role, either regulating or activating the cellular response. Thus, we will evaluate the expression pattern of Gal-9 and its relationship with inflammatory cells in ovalbumin (OVA)-induced experimental atopic dermatitis in mice. The experimental procedures were approved by the Ethics Committee in Animal Experimentation of the Federal University of São Paulo - UNIFESP (CEUA nº 1906060115/2015). Four experimental groups (n = 6 animals/group) will be evaluated: NAÏVE, SHAM, DA (atopic dermatitis), and DA+DEX (atopic dermatitis treated with dexamethasone). Male Balb/c mice were immunized with a subcutaneous injection of ovalbumin (OVA; 5 µg) in the days 0 and 7. After immunization, mice was challenged with 250 µg OVA diluted in 50 µl of Johnson's Baby ® oil, in the days 11, 14 to 18 and 21 to 24. Part of the sensitized mice was treated with rGal-1 by intraperitoneal injection (0,3 or 3 µg/mice) or dexamethasone (1 mg/kg) diluted in 0.1 mL of sterile saline, in the last week of the protocol, days 21 to 24 (once a day). After 24 hours of the last OVA challenge, or just oil (Sham), mice were euthanized to skin collection. Studies will be conducted through: I) histological analysis and quantification of inflammatory cells; II) localization and possible modulation of Gal-9 expression in the skin through immunohistochemistry, immunofluorescence and western blotting. The results will contribute to a better understanding of the cellular and molecular mechanisms that involve the biological actions of Gal-9 in the allergy, as well as possible therapeutic targets for the skin inflammatory processes. (AU)