Figure 3

Induction of chemically-induced colitis. 8-week-old male WT and ERAP1^−/− mice (n = 11) were treated with a 3% DSS solution in drinking water for 7 days, followed by regular drinking water for 11 days. The DSS solutions were made fresh at day 0 and 3 and left until day 7. Mice were monitored until day 18 after the start of DSS. (a) Survival plot of WT and ERAP1^−/− DSS-treated mice. Differences in group survival were analyzed with the Kaplan-Meier test. Disease Activity Index of WT and ERAP1^−/− mice was determined as described in materials and methods and graphed in (b). Two-way ANOVA with Bonferroni test were used to determine significant differences. (c) Representative images of H&E staining for histopathological changes in colon tissue of naïve and DSS-treated WT and ERAP1^−/− mice (n = 4). Semiquantitative scoring of histopathology of colons was performed, as described in Materials and Methods section and plotted as bar graph in (d). Data are expressed as the mean ± SEM. p values calculated by student’s t-test, where *p < 0.05, **p < 0.01 and ****p < 0.0001. Data are representative of three independent experiments, with similar results.