Anti-allergic function of -Tocopherol is mediated by suppression of PI3K-PKB activity in mast cells in mouse model of allergic rhinitis

Background: Alpha-Tocopherol (alpha-TCP), one major form of vitamin E, has been known as a treatment for airway allergic inflammation. However, the role and mechanism of alpha-TCP in treating allergic rhinitis remains unclear. Objective: In this study we examined the inhibitory function of alpha-TCP in a mouse model of allergic rhinitis. Methods: Allergic phenotype was examined by hematoxylin and eosin staining. Total IgE, OVA-specific IgE, OVA-specific IgG1 and OVA-specific IgG2a levels were examined by ELISA. mRNA expression was measured by qPCR, protein levels were examined by Western Blot. Results: Histological analysis of the nasal membranes revealed that there was a significant reduction in inflammatory cells appearance in cross-sections in alpha-TCP treatment of Oval-bumin (OVA)-sensitized mice compared to OVA sensitized animals. In addition, eosinophils were significantly reduced in nasal mucosa of alpha-TCP treatment of OVA-sensitized mice compared to the OVA group. Lower total IgE, OVA-specific IgE, OVA-specific IgG1 and OVA-specific IgG2a levels were found in alpha-TCP treatment of OVA-sensitized mice compared to the OVA group. Furthermore, we found that the subepithelial distribution of tryptase positive mast cells was reduced in the alpha-TCP treatment of OVA-sensitized mice. More importantly, the PI3K-PKB pathway was suppressed by alpha-TCP in mast cells. Conclusions: Our results demonstrated that alpha-TCP-mediated suppression of PI3K-PKB activity in mast cells is a potential mechanism of anti-allergic function of alpha-TCP. (C) 2019 SEICAP. Published by Elsevier Espana, S.L.U. All rights reserved.