Development of fast-dissolving sublingual nanofibers containing allergen and curcumin for immune response modulation in a mouse model of allergic rhinitis

Curcumin (CUR) has been considered a potential therapeutic agent for allergic reactions due to its antioxidant and anti-inflammatory activities. Nanofibers have attracted increasing attention in drug delivery. The aim of this study was to investigate the combined therapeutic effects of curcumin and allergen in nanofiber-based treatments in order to increase the effectiveness of sublingual immunotherapy (SLIT) efficacy in a mouse model of allergic rhinitis. Nanofibers containing CUR (1.25% and 2.5%) and ovalbumin 2% (OVA) as an allergen were prepared via electrospinning and characterized. BALB/c mice were sensitized with OVA to the induced allergic rhinitis model. SLIT with free and/or nanofibers was carried out. IL-4, INF-γ, and IgE serum levels were measured using ELISA. Splenocyte proliferation was evaluated by the MTT assay. Lung and nasal histological examinations and nasal lavage fluid (NALF) cell counting were carried out. Nanofibers containing 1.25% CUR and 2% OVA were chosen as the optimal formulations. SLIT treatment with the CUR and OVA nanofiber co-administration led to a significantly decreased serum IgE. Nanofiber containing 2.5 µg of CUR/mouse combined with OVA nanofiber showed a significant decrease in IL-4 and an increase in IFN-γ compared to other groups. NALF assessment showed a significant decrease in specific cell and eosinophil counts in the treated nanofiber groups. The histopathological results of NAL in the optimal formulations were near normal, with diminished cellular infiltration and inflammation. Our findings suggest that co-sublingual administration of allergen and CUR nanofibers can be considered as potential immunomodulatory agents.