Histological score in the chronic DSS model. WT and ICE KO mice were fed with 2% DSS for 5 days followed by 5 days of regular water. This cycle was repeated three times, resulting in a 30-day experimental period. A 1-cm segment of the transverse colon was fixed in 10% buffered formalin. Paraffin sections were stained with hematoxylin/eosin. (Magnifications are 52-, 130-, and 325-fold.) Histologic scoring was performed in a blinded fashion as described in Materials and Methods. (Upper) Histological sections from DSS-fed WT and ICE KO mice with increasing magnifications are shown. As there was no difference between the DSS-exposed ICE KO and non-DSS control mice, control sections are not shown. Bars are mean ± SEM. ***, P < 0.001 vs. DSS WT.