FIG. 3.

C. rodentium infection results in reduction of Muc2 and Tff3 gene expression. (A) Representative RT-PCR analysis of Muc2 and Tff3 gene expression in distal colonic tissues of naïve C57BL/6 mice or mice at days 6 and 10 p.i. β-Actin was used as a loading control. Differences in levels of expression relative to the levels in naïve (uninfected) mice after normalization to β-actin were determined by densitometric analysis, as shown in the graph on the right. The bars indicate the means for three independently infected mice per time point. The error bars indicate the standard errors of the means. Asterisk, P < 0.05; ns, not significant (P > 0.05), as determined by Student's t test. (B) Immunoperoxidase staining for Muc2 (upper panels) and Tff3 (lower panels) protein (brown) in serial sections of distal colons from either naïve mice (left panels) or mice at day 10 p.i. (right panels). In control mice, Muc2-positive cells are present from the crypt base to the luminal surface, whereas Tff3 expression is restricted to the top half of the crypts (arrows). The arrowheads indicate cells that are coexpressing the Muc2 and Tff3 proteins. Note the lack of staining in intact crypts at day 10 p.i. (arrows in left panels). Bar = 50 μm.