Periodic acid

To visualize mucus, colonic tissue samples were fixed overnight in Methacarn at RT [90 (link)], prior to dehydration with ethanol and Histo-Clear (Diamed Lab Supplies, Mississauga, ON). Sections (5 µm) were deparaffinized on a 60 °C heating bed, cleared with xylene, and rehydrated in a decreasing ethanol gradient (100, 90, 70, 50%) according to a standard protocol (Abcam, Toronto, ON). For mucus visualization, sections were stained with Alcian Blue (pH 2.5; American MasterTech, Lodi, CA), followed by 0.5% Periodic Acid (American MasterTech, Lodi, CA) at RT for 5 min, and Schiff’s solution (American MasterTech, Lodi, CA) at 4 °C for 15 min. Slides were examined with a Zeiss Axioskop Epifluorescent microscope (Zeiss Canada Ltd., Toronto ON).

Colonic tissue samples were collected from the same region of the distal colon from each sampled mouse and were fixed overnight in methacarn (60% methanol, 30% chloroform, 10% glacial acetic acid) (87 (link)) prior to dehydration with ethanol and Histo-Clear (Diamed Lab Supplies). Sections (5 µm) were deparaffinized for 5 min on a 60°C heating bed, cleared with xylene, and rehydrated in a decreasing ethanol gradient (100%, 90%, 70%, and 50%) according to a standard protocol (Abcam, Inc., Toronto, Ontario, Canada). To visualize mucus, sections were stained with alcian blue (American MasterTech, Lodi, CA) (pH 2.5) for 30 min, 0.5% periodic acid (American MasterTech, Lodi, CA) for 5 min, and Schiff’s solution (American MasterTech, Lodi, CA) and were stored at 4°C for 15 min (AB-PAS).