Polysaccharide of Danggui Buxue Decoction Attenuates Colorectal Cancer via Modulating Intestinal Microflora and Metabolites.

[OBJECTIVE] To explore whether polysaccharide of Danggui Buxue Decoction (formula polysaccharide, FP) could attenuate colorectal cancer (CRC) via modulating intestinal microflora and metabolites.

[METHODS] A total of 30 male C57BL/6 mice were randomly assigned to 3 groups according to body weight, including normal control, CRC model and FP groups (n=10). Dextran sulfate sodium and azoxymethane were used to induce CRC model. The mice in FP group were treated with FP [0.9 g/(kg·d)] for 8 weeks. Then the coloretal length, weight and tumors number of colorectal tissues were observed. Colonic tissues were stained with hematoxylin and eosin to evaluate the histological changes. Tight junction proteins including claudin 1 and zonula occludens-1 (ZO-1) were detected using immunohistochemistry. Serum concentrations of endothelial cell specific molecule-1 and carcino embryonic antigen were determined using enzyme-linked immunosorbent assays. Toll-like receptor 4 (TLR4)/nuclear transcription factor-κB (NF-κB) p65 signal-related mRNA and proteins expressions were detected using real-time polymerase chain reaction and Western blot, respectively. Feces samples were detected with 16S rRNA and liquid chromatography-mass spectrometry and non-targeted metabolomics sequencing was used to analyze the composition of intestinal microbiota and metabolic changes.

[RESULTS] FP significantly inhibited colorectal tumor growth, attenuated body weight loss, repaired colonic structure, improved intestinal barrier dysfunction, reduced colonic inflammatory cytokine levels and inhibited TLR4/NF-κB pathway related mRNA and protein expressions (all P<0.01). Moreover, FP altered the gut microbiota composition of CRC mice dramatically, characterized by a reduction of Firmicutes-Bacteroidetes ratio at the phylum level. FP suppressed Lachnospiraceae_NK4A136_group, Odoribacter and Romboutsia (P<0.05 or P<0.01), and elevated the abundance of Dubosiella, Candidatus_Saccharimonas and Alloprevotella at the genus level (P<0.01). Non-targeted metabolomics sequencing detected significant differences in metabolites, and the functions of differential metabolites were focused on regulating amino acid metabolism, lipid metabolism and metabolism of cofactors and vitamins.

[CONCLUSIONS] FP attenuates colonic injury and intestinal inflammatory response in CRC mice, repairs disrupted-intestinal microbiota, and improves metabolites. This research provides experimental basis for application of FP as a potential therapeutic agent for CRC.