Anti mucin 2

The 4% paraformaldehyde fixed ileum tissue samples were embedded in paraffin and sectioned in 5‐μm thickness. The following primary antibodies were incubated overnight at 4°C: anti‐mucin 2 (1:2000; Abcam, Cambridge, UK), anti‐defensin 5 (1:50; Abcam), anti‐defensin 6 (1:5000; Atlas, Bromma, Sweden), anti‐LYZ (1:100; Abcam), anti‐Occludin (1:100; Proteintech, Rosemont, IL, USA), anti‐zonula occludens 1 (anti‐ZO 1) (1:200; Abcam), and anti‐Claudin 1 (1:700; Abcam). The sections were subsequently incubated for 60 min with a biotinylated secondary antibody (1:100; Zhongshan, Beijing, China). All histological images were captured under a light microscope (Leica, Wetzlar, Germany) at 200× magnification. Image‐Pro Plus 6.0 (IPP6.0; Media Cybernetics, Inc., Rockville, MD, USA) was used for morphological analysis.
The inflammation score was determined by a blinded observer and was strictly based on a fully proven method that assigns a histological score of 0–4 to quantify the degree of inflammation. The criteria of this system include inflammatory cells, goblet cell depletion, immune infiltration, and architecture destruction.¹¹