Ugt1ΔIEC and Ugt1F/F mice were treated with 3% DSS in drinking water for 5 days to induce acute colitis and IEC apoptosis. After another 5 days recovery with regular water, colon tissues were collected. (A) Expression of UGT1A, p53, p21, Bax, caspase-9, and caspase-3 detected by Western blot anaylsis. GAPDH was used as a loading control. Quantitation of each Western blot is presented in Supplemental Figure 2. (B) TUNEL staining of colons from untreated mice or DSS-treated mice (100× Magnification). At least four mice were analyzed in each group and the experiment was repeated twice. (C) Quantitation of the number of TUNEL positive cells in DSS-treated mice.