The current hypothesis of how colitis-inducing injury occurs is that DSS can damage the mucosal membrane of the colon allowing the dissemination of pro-inflammatory intestinal contents (e.g. bacteria and their products) into the crypt. The DSS model is widely used in IBD research due to its rapidity, simplicity, reproducibility, and controllability. https://www.creative-biolabs.com/drug-discovery/therapeutics/dextran-sulfate-sodium-dss-induced-rodent-colitis-model.htm