Polysaccharides from Trametes versicolor as a Potential Prebiotic to Improve the Gut Microbiota in High-Fat Diet Mice

Polysaccharides derived from Trametes versicolor have been found to exhibit hypolipidemic activity in hyperlipidemic mice, but the mechanism by which they modulate intestinal flora is still unclear. Currently, this study aimed to investigate the regulatory effects of extracellular (EPTV) and intracellular polysaccharides from T. versicolor (IPTV) on the dysbiosis of intestinal flora in mice fed a high-fat diet (HFD). The results showed that the oral administration of T. versicolor polysaccharides significantly ameliorated lipid accumulation and steatosis in hepatocytes. The gut dysbiosis in the HFD mice was characterized by a decrease in abundance and diversity of bacteria and an increase in the Firmicutes/Bacteroidetes ratio. However, T. versicolor polysaccharides attenuated these changes and reduced the relative abundance of bile-salt-hydrolase (BSH)-producing bacteria, such as Bacillus, Enterococcus, Bifidobacterium, and Lactococcus. It is noteworthy that T. versicolor polysaccharides also restored the disorganization of intestinal fungi in HFD mice, with EPTV treatment leading to a higher relative abundance of Basidiomycota and Ascomycota compared to IPTV. Additionally, T. versicolor polysaccharides enhanced the growth of butyrate-producing bacteria via the buk and but pathways, accompanied by an increase in short-chain fatty acids (SCFAs), especially butyrate. IPTV also increased the expression of G-protein-coupled receptors 41 (GPR41) and 43 (GPR43) by 40.52% and 113.24% each, as compared to 62.42% and 110.28%, respectively, for EPTV. It is suggested that IPTV and EPTV have the potential to counteract hyperlipidemia-associated intestinal flora disorders and improve lipid metabolism.