α-Linolenic acid alleviates ovalbumin-induced allergic rhinitis in mice and modulates GPR120-NF-κB signaling

Allergic rhinitis (AR) is a chronic inflammatory disease of the upper respiratory tract mediated by immunoglobulin E (IgE). Alpha-linolenic acid (ALA), an essential dietary omega-3 polyunsaturated fatty acid, has been proposed to possess anti-inflammatory and anti-allergic properties. However, research on the effects of ALA on AR and the underlying mechanisms remains limited. Therefore, we evaluated oral ALA intervention in an ovalbumin (OVA)-sensitized AR mouse model. Nasal symptoms were recorded, and nasal mucosal pathology was evaluated by hematoxylin and eosin staining. Goblet cell hyperplasia and mast cell accumulation were determined by periodic acid-Schiff and toluidine blue staining. Serum OVA-specific IgE and inflammatory cytokines (interferon-gamma [IFN-γ], interleukin-4 [IL-4], IL-6, and IL-1β) were measured by enzyme-linked immunosorbent assay. Additionally, pathway-related molecules in the nasal mucosa were identified by immunohistochemistry, qRT-PCR, and Western blotting. Results indicated that ALA significantly alleviated AR-like symptoms, improved nasal mucosal damage, reduced mast cell aggregation and goblet cell hyperplasia, decreased serum OVA-specific IgE, IL-4, IL-6, and IL-1β levels, and increased IFN-γ levels. Furthermore, ALA inhibited the NF-κB pathway and reduced the phosphorylation levels of IKK and NF-κB p65(Rela). These data indicate that ALA alleviates AR-associated inflammatory responses and may represent a potential therapeutic candidate for AR.