Figure 1: Experimental set-up and body weight analysis after induction of acute and chronic colitis with DSS.

(a) Acute colitis was induced in male and female WT and MMP-9^−/− mice by oral administration of 3% DSS for 7 days in drinking water followed by 2 days of normal drinking water before killing at day 9 (*). Pooled data from three replicated acute DSS experiments are shown. The pooled group of acute DSS exposed mice comprised of WT mice (n=20) and MMP-9^−/− mice (n=20). Control mice received normal drinking water throughout the experiments (WT mice (n=18) and MMP-9^−/− mice (n=21)). To induce chronic colitis, three cycles of 1.75–2.00% DSS were administered, whereby one cycle of DSS comprised 1 week of DSS followed by a recovery period of 2 weeks with normal drinking water. All mice were killed at day 63 (*). Pooled data from three separate chronic DSS experiments are shown. The pooled group of chronic DSS exposed mice comprised WT mice (n=9) and MMP-9^−/− mice (n=9). Control mice received normal drinking water throughout the experiments (WT mice (n=10), MMP-9^−/− mice (n=5)). (b) Relative body weight curves of WT and MMP-9^−/− mice in acute (left panel) and chronic (right panel) DSS colitis. (c) Left panel: absolute body weight loss of mice included in the acute model at day 9. Middle panel: absolute body weight loss of mice included in the chronic model at day 52. Right panel: absolute body weight loss of mice included in the chronic model at day 63. Median values with interquartile range are represented when applicable. Statistical analyses were performed with Mann–Whitney U tests (***P≤0.001).