Effect of Astragalus membranaceus in Ovalbumin-Induced Allergic Rhinitis Mouse Model

Abstract

Background Astragalus membranaceus (AM), a traditional Chinese medicine, has been used to treat allergic diseases, but the mechanism for treating allergic rhinitis (AR) remains unclear. Objective The purpose of this study was to look at the anti-inflammatory effect of AM on AR and the mechanism of anti-allergy. Methods The mouse model of AR was induced by ovalbumin. Allergic symptoms, number of eosinophils in nasal mucosa, and levels of inflammatory cells in nasal lavage fluid were analyzed. We explored the serum immunoglobulin E (IgE), interleukin-4 (IL-4), IL-5, IL-13, interferon-γ (IFN-γ), and IL-10. Besides, the relative mRNA of IL-4, IL-5, and IL-13 was also detected in nasal mucosa tissue. The proportion of CD4+ CD25+ Foxp3+ T cells in the spleen and nasal lymphoid tissue were analyzed. The mRNA levels of nuclear factor-kappa B p65 (NF-κB p65) and inhibitory kappa B alpha (IκBα), as well as NF-κB p65 DNA binding activity, were tested. We also measured the protein levels of NF-κB p65 and p-NF-κB p65 in nasal mucosa. Results AM could reduce the number of eosinophils in the nasal mucosa and decrease the levels of inflammatory cells in nasal lavage fluid. The serum IgE, IL-4, IL-5, and IL-13 were also decreased, while levels of IFN-γ and IL-10 were increased. The relative mRNA of IL-4, IL-5, and IL-13 was decreased by AM. AM increased the proportion of CD4+ CD25+ Foxp3+ T cells in the spleen and nasal lymphoid tissue. In addition, AM could reduce the activity of NF-kB by inhibiting the mRNA expression and DNA binding activity of NF-κB p65. However, AM had no significant effect on mRNA of IκBα. Above all, AM could reduce the p-NF-κB p65 protein expression of nasal mucosa. Conclusions AM could reduce the secretion of inflammatory cytokines by increasing the level of CD4+ CD25+ Foxp3+ T cells and inhibiting the activation of the NF-κB.