Sanghuangporus vaninii polysaccharides attenuate ovalbumin-induced allergic rhinitis in mice by improving the Th1/Th2 lymphocyte balance.

Allergic rhinitis (AR), a highly prevalent chronic disease, causes considerable detriment to the well-being of those affected. Sanghuangporus vaninii, an edible medicinal fungus, has anti-inflammatory, antioxidant, and immunomodulatory properties. In this study, three polysaccharides (SVP1, SVP2, and SVP3) were purified from S. vaninii and administered to an AR mouse model. All SVPs alleviated nasal symptoms and attenuated pathological alterations in AR mice. Notably, SVP2 showed superior efficacy, significantly reducing sneezing by 76.38 % and nose rubbing by 56.92 % relative to the model group control levels. In addition, SVP2 significantly reduced blood IgE (by 31.71 %), eosinophils (by 59.81 %) and the secretion of inflammatory cytokines. Consequently, the underlying mechanism of SVP2 against AR was investigated in greater details. SVP2 modulated immune system parameters in mice, increased the CD4+/CD8+ ratio (by 50.21 % vs. model), and improved the Th1/Th2 balance. Furthermore, analysis of the intestinal microbiota showed that SVP2 affected the microbial composition by increasing the relative abundance of bacteria, including Kineothrix, Lachnospiraceae bacterium UBA3282, Porcincola, Prevotella sp. CAG:873, Dysosmobacter, Roseburia sp. 1XD42-69, and reducing levels of bacteria, such as Limosilactobacillus, Lactobacillus, Eubacterium-F, and Intestinimonas. These findings demonstrate the potential of polysaccharides as AR therapeutics and highlight SVP2 for further development as a treatment.