Daphnetin Mitigates Ovalbumin-Induced Allergic Rhinitis in Mice by Regulating Nrf2/HO-1 and TLR4/NF-kB Signaling

BACKGROUND: Allergic rhinitis (AR) is an inflammatory disorder of nasal mucosa resulting from allergen exposure. Daphnetin (DAP) is a coumarin derivative that has various bioactivities. Nevertheless, its specific function in AR is unclear. OBJECTIVES: This study is aimed to explore the specific function of DAP in AR. METHODS: An AR murine model was established by ovalbumin (OVA) induction. Murine sneezing and rubbing behaviors were observed. Hematoxylin-eosin was used for histopathological observation of nasal mucosa. ELISA was utilized for detection of cytokine production in murine serum. Oxidative stress-associated markers were assessed by commercial assay kits. Western blotting was utilized for evaluating protein levels of Toll-like receptor 4 (TLR4) and nuclear factor kappa B (NF-κB) in nasal mucosa. RESULTS: DAP alleviated OVA-induced nasal symptoms, inflammatory response and oxidative stress in the AR murine model. DAP activated nuclear factor erythroid 2-related factor 2/heme oxygenase-1 (Nrf2/HO-1) signaling and inactivated TLR4/NF-κB signaling in murine nasal mucosa. CONCLUSION: DAP mitigates OVA-induced AR in mice by activating Nrf2/HO-1 signaling and inactivating TLR4/NF-κB signaling.