MMP9 and ulcer disease: Anatomic and microscopic alterations were also produced by DSS, including colon shortening, MMP-9 increase, ulcers, altered crypt, crypt abscesses, vacuolar hydropic degeneration, submucosal edema, and mucosal/submucosal massive inflammatory infiltrates (Figures 2D–H and Supplementary Figures 4E–I).