Study on the intervention mechanism of Ganodermalucidum polysaccharides in mice with atopic dermatitis

Taishan Red Reishi Mushroom, also known as Taishan Ganoderma lucidum, is a medicinal and edible mushroom. Polysaccharides from Taishan Ganodermalucidum (GLP) represent its most significant bioactive component. This study aims to examine the structural characteristics of the GLP polysaccharide fraction and the intervention mechanism of the GLP in mice with atopic dermatitis. After purification by a DEAE-52 cellulose gel column, GLP-2, which has a molecular weight of 8495 Da, is composed of galactose (Gal), fucose (Fuc), mannose (Man), and glucose (Glc). NMR characterization and bond structure analysis have verified that the primary structure of the main chain of GLP-2 consists of →6) α-D-Galp-(1→ and →4) α-D-Galp-(1→sequences. Further analysis through 16S rRNA gene sequencing and metabolomic analysis of fecal microbiota showed that GLP-2 increased the relative abundance of Prevotella and Ruminococcus, and elevated the levels of beneficial short-chain fatty acids, including acetic acid and butyric acid. GLP-2 inhibited the increase of reactive oxygen species through HO-1 and NRF2 pathways, thereby alleviating oxidative stress on cells. Additionally, GLP-2 promoted the differentiation of immune cells from Th0 towards Th1, decreased mast cell infiltration, regulated serum IgE and inflammatory factor IL-4 levels, and reduced inflammation through MAPK/NF-κB pathways. Furthermore, GLP-2 promoted the restoration of damaged skin barrier function. In conclusion, it can be stated that GLP-2 has the potential to alleviate the symptoms of atopic dermatitis in mice.