Inotodiol suppresses allergic inflammation in allergic rhinitis mice

Inotodiol has been proven to have antitumor, antiviral, anti-inflammatory, and antiallergic properties. This study investigated the immunomodulatory capability of inotodiol in allergic rhinitis (AR) mice.Forty BALB/c mice were divided into four groups, 10 mice each: control (CON), AR with phosphate-buffered saline (PBS) treatment (AR), inotodiol treatment (AR+Ino), and dexamethasone treatment (AR+Dex). Episodes of sneezing and nose rubbing were counted. Cytokines in nasal lavage fluid (NLF) and immunoglobulin in blood serum were measured. Nasal mucosae from each group were used for protein, reverse transcriptase-polymerase chain reaction (RT-PCR), and histological analyses. Splenocytes were cultured for evaluation of cytokine production in each group.Symptoms of rubbing and sneezing improved in the group of AR+Ino and AR+Dex than in the AR. NLF in the AR+Ino and AR+Dex also showed a significant decrease in interleukin (IL)-5, IL-10, and IL-13 compared to the AR. In addition, the number of eosinophils, goblet cells, and mast cells were notably lower in the nasal mucosae of the AR+Ino and AR+Dex. IL-4 and IL-17A in the AR+Ino and AR+Dex groups were decreased compared to the AR. Chemokines related to mast cell degradation were also decreased in the AR+Ino and AR+Dex groups. Total immunoglobulin (Ig)E, specific IgE and ovalbumin (OVA)-specific IgG1, and histamine levels were also significantly lower in the AR+Ino and AR+Dex groups. IL-10 and IL-13 were notably increased in the splenocytes of the AR after OVA stimulation, whereas the other groups showed no change.These results indicate inotodiol can help suppress allergic responses by immunomodulation activities.