Imperatorin inhibits allergic airway inflammatory reaction and mucin secretion in ovalbumin-induced asthmatic rats

Purpose: To study the therapeutic effects of imperatorin (IPT) on allergic asthma induced by ovalbumin in rats.
Methods: Asthma was established in rats by injection of ovalbumin (OVA), and IPT (20, 40 and 80 mg/kg) was administered orally for 21 days. Inflammatory cells and cytokines were determined in the bronchoalveolar lavage fluid (BALF); IgE and histamine in the serum were also determined. Furthermore, MUC-5AC expression in the lung tissue was determined by Western blot assay.
Results: Treatment with IPT (20, 40 and 80 mg/kg) decreased inflammatory cells including eosinophils (p < 0.01), neutrophils (p < 0.05), lymphocytes (p < 0.01) and macrophages (p < 0.01). In addition, the four inflammatory cytokines {interleukin (IL) -4, IL-6, IL-13 and tumor necrosis factor (TNF)-α} were significantly decreased by treatment with IPT (20, 40 and 80 mg/kg) dose-dependently (p < 0.01). Furthermore, MUC5AC in lung tissues was significantly down-regulated by treatment with IPT (20, 40 and 80 mg/kg, p < 0.01) in a dose-dependent fashion.
Conclusion: The results show that IPT exerts notable therapeutic effects on allergic asthma in rats via suppression of IgE, histamine, inflammatory cells and cytokines, and also by down-regulating MUC5AC.

Keywords
Imperatorin; Allergic asthma; Inflammatory cytokines; MUC5AC expression; Eosinophils; Neutrophils; Lymphocytes