FIGURE 1.

Ccr9^−/− mice show signs of exacerbated DSS-mediated chronic colitis. A, WT and Ccr9^−/− mice were subjected to 4 DSS cycles (consisting of 2% DSS administration for 7 d in drinking water followed by water for 7 d). Weight was monitored daily and weight loss was calculated as percent of initial body weight. Data represent the mean of 4 independent experiments. Arrowhead highlights differences between WT and Ccr9^−/− mice after first DSS cycle. B, IBD scores of chronic DSS-treated WT and Ccr9^−/− mice were determined blindly by a pathologist after H&E staining of distal colonic tissue sections. C, Representative H&E staining of colonic tissue sections harvested in WT (left) and Ccr9^−/− mice (right) >100 days after initiation of DSS exposure (10× magnification). D, mRNA profiling of proinflammatory and anti-inflammatory cytokines in colonic tissues from DSS-treated WT and Ccr9^−/− mice. The mRNA transcripts were quantified by qPCR and normalized to the housekeeping gene HPRT. Data represent 1 out of 4 experiments. E, CCL25 transcript qPCR analysis in colons harvested from WT and Ccr9^−/− mice treated with DSS. Data represent an individual experiment out of 4. *P < 0.05; **P < 0.005; ***P < 0.0005.