Figure 1. IL-22 deficient mice have normal colonic architecture.

One year old specific-pathogen free IL-22 deficient (Il22−/−) or wild-type (Il22+/+) control mice were euthanized. Colons were excised, fixed, sectioned and stained with H&E. (A) Shown are representative micrographs of five mice per group. (B) Activity (the degree of epithelial injury) and (C) chronicity scores (the degree of chronic inflammation) for the colon sections. Each segment was given a score of 0–4. For chronicity (the degree of chronic inflammation); grade 0, no significant changes; grade 1, mildly increased inflammatory cells in the lamina propia; grade 2, moderately increased inflammation in the lamina propria (multiple foci); grade 3,high level of inflammation with evidence of wall thickening by inflammation; grade 4, maximal severity of inflammation with transmural lymphocytic infiltration and/or architectural distortion. For activity (the degree of epithelial injury); grade 0, no significant changes; grade 1, occasional epithelial injury with focal and superficial or rare cryptitis; grade 2, foci of cryptitis, including rare crypt abscess; grade 4, three plus extensive ulceration. Each dot represent one mouse, line indicates mean.