Abstract: Colorectal cancer is a kind of malignant tumor caused by uncontrolled proliferation of cancer cells. Its development and progression are closely related to the intestinal flora. Chondroitin sulfate is the main polysaccharide in animal tissues, which executes many important physiological functions. More importantly, compared with drugs and surgery, chondroitin sulfate has the characteristics of low toxicity and fewer side effects. In order to investigate the regulatory effect of chondroitin sulfate on the intestinal flora of colorectal cancer-bearing mice, a mouse model of colorectal cancer was established, and after 4 weeks of oral administration with chondroitin sulfate from sturgeon, the intestinal contents of the mice from each group were measured and analyzed. The results showed that chondroitin sulfate could regulate intestinal flora diversity, increase the content of beneficial bacteria such as Saccharibacteria and reduce the content of harmful bacteria to a certain extent in the mouse model of colorectal cancer. The relative abundance of Fusobacteria was 0.008 5% in the model group, and it decreased to 0.001 4% in the high-dose chondroitin sulfate group, which was close to that in the normal group (0.001 3%). The relative abundance of Bacteroidales S24-7 group was 30% in the normal group, and it decreased to 18% in the model group. The relative abundance of Ruminiclostridium 5 was 2.05% in the model group, and it decreased to as low as 0.41% in the high-dose chondroitin sulfate group, which was significantly lower than that in the normal group (0.92%). It is suggested that chondroitin sulfate from sturgeon can reduce the change of intestinal microflora caused by colorectal cancer cell infection, regulate the diversity of intestinal microflora and slow down the development of colorectal cancer and can therefore be considered as a potential prebiotic for intestinal health.

Key words: colorectal cancer, chondroitin sulfate from sturgeon, intestinal flora