A Technique to Generate a Murine Model of Dextran Sulfate Sodium-Induced Colitis

To induce dextran sulfate sodium, or DSS colitis, replace the regular drinking water with 3% DSS solution ad libitum for seven days, measuring each mouse's body weight, DSS solution consumption, and stool production daily. At the end of the seven-day treatment, place the mouse in the supine position, and use small scissors to make a three-centimeter-long midline incision in the abdomen.

Then, use forceps to lift the colon to allow it to be separated from the surrounding mesentery, and extract the whole colon until the cecum and rectum are visible. Transect the tissue at the colonocecal margin and deep within the pelvis, to free the proximal and distal colon respectively.

Measure and record the length of the isolated colon, and use a 10-milliliter syringe equipped with a gavage needle to flush the colon with 10 milliliters of ice-cold PBS to remove the feces and blood until the eluate runs clear. For histological identification, divide the tissue samples into equally-sized proximal, middle, and distal sections, and fix the tissues in 4% paraformaldehyde overnight at four degrees Celsius.