Fig. 4. Collagenase treatment altered goblet cell morphology and mucus layer thickness as indicated by UEA-1 mucopolysaccharide labeling and decreased mucin 2 immunoreactivity (MUC2-IR). A) Tissue exposed to media containing no collagenase exhibited healthy goblet cell morphology with “goblet” shaped goblet cells indicated by white arrows. The mucus layer remained intact. B) Goblet cell shape became more circular when exposed to low levels of collagenase and the mucus layer remained intact. C) Goblet cells lost their distinct shape when exposed to high levels of collagenase and the mucus layer decreased in thickness. D) Apical MUC2-IR in tissue not exposed to collagenase. E) Apical MUC2-IR decreased in a dose dependent manner when exposed to low collagenase and F) high collagenase. Arrows indicate alterations in goblet cells morphology, M = mucus layer, L = lumen, scale bars are 25 μm.