D-Pinitol Attenuated Ovalbumin-induced Allergic Rhinitis in Experimental Mice via Balancing Th1/Th2 Response.

Allergic rhinitis (AR) is a complex, chronic immunoinflammatory disorder of the membrane lining of the nasal mucosa. D-Pinitol is considered a cyclic polyol with a potential effect against various allergies. In the present study, we evaluated the anti-allergic effect of pinitol on ovalbumin (OVA)-induced AR model in mice. BALB/c mice were initially sensitized with an intraperitoneal injection of OVA and divided into 5 groups (n=18, in each group) for a treating schedule of distilled water (DW), montelukast (10 mg/kg), and pinitol (5, 10, and 20 mg/kg) through the mouth. Two saline-injected groups were considered as controls by orally administrating DW and pinitol 20. Thereafter, test and control groups were intranasally challenged by OVA and saline, respectively. Our results showed that the OVA challenge caused a marked elevation in AR symptoms like nasal rubbing, sneezing, and discharge which were remarkably diminished using pinitol (10 and 20 mg/kg) and the results were comparable with montelukast. Additionally, increased levels of total and OVA-specific serum Immunoglobulin (Ig) E and IgG1 were significantly attenuated by pinitol as compared to the control group but not the montelukast group. In AR-induced mice, pinitol had significant modulatory effects on representative markers of Th2 (GATA binding protein 3), signal transducer and activator of transcription-6, Interleukins (IL)-4, IL-5, IL-13, suppressors of cytokine signaling 1, Toll-like receptor 4, and myeloid differentiation factor 88), and Type 1 T helper (Th1) immune responses (T-box protein expressed in T cells and Interferon-gamma) as well as the histopathological aberrations induced in the nasal mucosa. In conclusion, Pinitol had potential effects on OVA-induced AR mice through amelioration of nasal symptoms and balancing the Th1/Th2 immune responses during the allergic rhinitis condition.