Polysaccharides from Lachnum sp. Inhibited colitis-associated colon tumorigenesis in mice by modulating fecal microbiota and metabolites.

It is still uncertain whether the consumption of Lachnum sp. polysaccharides (LEP) alleviates colorectal cancer (CRC) through the gut microbiota. In this study, our efforts are focused on the influence of LEP on CRC, intestinal barrier and inflammation, and fecal microbiota and the metabolites, in azoxymethane (AOM)/dextran sodium sulfate (DSS)-induced CRC mice. Results showed that LEP inhibited CRC mouse colon shortening and weight loss, decreased tumor incidence, restored intestinal barrier integrity, and reduced excessive inflammation. LEP consumption significantly altered microbiota overall structure and community, with reduced pernicious bacteria (such as Parabacteroides, Escherichia_Shigella, Desulfovibrio and Helicobacter), and increased beneficial bacterium (such as Alistipes, Alloprevotella and Ruminiclostridium). Fecal-metabolome profile indicated that a total of 43 metabolites were clearly changed, with 10 down-regulated and 33 up-regulated metabolites. In addition, short-chain fatty acids (SCFAs), including acetic acid, propionic acid and n-butyric acid, were significantly increased after LEP administration. Moreover, a strong correlation between the fluctuant gut microbiota and metabolites was found. These findings provided not only deeper insights into the responsibility of LEP for CRC alleviation, and but also the potential of LEP as a promising candidate for CRC prevention and treatment.