Encyclopedia of Experiments: Immunology
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Transcript
To induce colitis — an inflammatory bowel disease — in a murine model, take a mouse housed in a cage.
Replace the drinking water with a solution of dextran sulfate sodium, DSS, a colitis-inducing polysaccharide. Allow the mouse to consume the solution to develop colitis.
Upon consumption, DSS enters the lumen of the mouse's colon. The colon contains a thick mucus layer, providing a physical barrier between the commensal microbes and the underlying epithelial cell monolayer.
DSS penetrates the mucus layer, entering the epithelial cells. Inside the cells, DSS alters the expression of tight-junction proteins and induces apoptosis, resulting in the disruption of the epithelial layer and mucosal barrier. This allows the entry of luminal microbes into the lamina propria — the underlying tissue with resident dendritic cells and macrophages.
The immune cells recognize the microbes, activating downstream signaling to secrete pro-inflammatory cytokines. Cytokines cause the infiltration of a large number of T cells which mount an exaggerated immune response, resulting in inflammation.
Monitor the treated mouse for gastrointestinal disorders and weight loss, indicating the onset of colitis.
Euthanize the mouse; surgically isolate the entire colon. Divide the colon into proximal, middle, and distal sections and add a fixative for tissue preservation.
The tissue is ready for downstream assays to evaluate colitis.
