Glucosamine has an antiallergic effect in mice with allergic asthma and rhinitis

Background Glucosamine (GlcN) is generally used as a dietary supplement because of its antiinflammatory effects. We evaluated the antiallergic effect of GlcN in mice with allergic asthma and rhinitis. Methods Thirty‐two mice were allocated equally into 4 groups (n = 8). In group A (control), we performed intraperitoneal/intranasal challenge using sterile saline. In group B (asthma/rhinitis), we used ovalbumin for intraperitoneal/intranasal challenge to induce allergic asthma and rhinitis. In groups C and D (GlcN treatment), mice were given 1% and 5% GlcN throughout the period of ovalbumin challenge, respectively. We measured serum total and ovalbumin‐specific immunoglobulin E (IgE), cytokine titers (interleukin‐1, ‐4, ‐5, ‐6, ‐10, and ‐17; tumor necrosis factor‐α; and interferon‐γ), and the number of inflammatory cells (eosinophils, neutrophils, lymphocytes) in bronchoalveolar lavage (BAL) fluid. We also performed histopathologic examination of the lung and nasal cavity. Finally, we performed real‐time polymerase chain reaction for the genes Bcl‐2, EC‐SOD, VEGF, caspase‐3, Bax, COX‐2, Hif‐1α, and heme oxygenase‐1. Results Compared with group B, group D had significant serum total and ovalbumin‐specific IgE decreases after GlcN treatment (p < 0.05). Titers for IL‐4, IL‐5, IL‐6, and IL‐17 in BAL fluid were significantly decreased in group D (p < 0.05). Eosinophils in BAL fluid were significantly decreased in group D compared with group B (p < 0.05). Groups C and D showed significant improvement of inflammation compared with group B. Group D had significant downregulation of EC‐SOD, Bax, Hif‐1α, and heme oxygenase‐1 compared with group B. Conclusion GlcN had a significant antiallergic effect in mice with allergic asthma and rhinitis.