DSS-Induced Colitis Model in Mice

Mice were administered DSS (MP Biomedicals, Solon, OH) at 0.25, 0.5, 1.0 and 4.0% in drinking water ad libitum for 7 days (5 mice per group). Control mice were given water only. During this period, mice were weighed and feces were collected every day and frozen at −20°C. After 7 days, mice were bled via retroorbital plexus and hemolysis-free serum was collected by centrifugation using serum separator tubes (BD Biosciences, Franklin Lakes, NJ). Mice were sacrificed by CO₂ euthanasia. Spleen and colon weights and lengths were measured. A small piece (50 mg) of proximal colon was taken for MPO analysis and RNA extraction, and the rest of the colon fixed in 10% buffered formalin for histological studies. For fecal Lcn-2 expression during mucosa healing, mice were given 1.5% DSS in drinking water for 7 days followed by 29 days of water without DSS prior to analysis of fecal Lcn-2.