Figure 6.

The protective effect of IFN-λ in DSS-induced colitis is independent of IFNLR1 expression in epithelial cells. (a–d) Colitis progression and severity in WT→WT and WT→IFNLR1-KO chimeras co-housed for 2 weeks and then treated with 2.5% DSS in the drinking water for 7 d (or not (UT), in b), assessed as body weight (a), colon length (b), disease activity index at day 7 (c) and histology (d). (e,f) qPCR analysis of Hmox1 (e) and Sod2 (f) in intestinal epithelial cells at day 7 in mice as in a–d; results presented relative to those of Gapdh. (g) Oxidation of DNA, assessed as 8-oxoguanine (8-oxog) (per ng of DNA) at day 7 in the colon of mice as in a–d. (h–j) Colitis progression and severity in Vil^creIfnlr1^fl/fl and Ifnlr1^fl/fl littermates treated with 2.5% DSS in the drinking water for 7 d (or not (UT), in h), assessed as colon length (h), disease activity index at day 7 (i) and histology (j). (k) qPCR analysis of Hmox1 and Sod2 in intestinal epithelial cells at day 7 in mice as in h–j, presented as in e,f. Original magnification (d,j), ×10. *P < 0.05, **P < 0.01 and ***P < 0.001 (two-way ANOVA (a,b,h) or nonparametric two-tailed t-test (c,e,f,g,I,k)). Data are from one experiment representative of three experiments (a–g; mean + s.e.m. of eight (WT→WT) or four (WT→IFNLR1 KO) mice per group in a–c,e,f) or one experiment representative of three independent experiments (h–k; mean + s.e.m. of five mice per group in h,i,k).