Finally, an infectious model with Citrobacter rodentium (C. rodentium) was used to induce colitis in MMP-9 knockout mice.19 Consistent with our recent data on MMP-9 knockout mice in DSS-induced and TNBS-induced models of inflammatory colitis,9 similar development of inflammatory parameters was observed in MMP-9 knockout and WT mice. Here, MMP9 is linked to colitis.