Figure 4.

IAA supplementation enhanced the mucosal barrier function by promoting mucin sulfation.

(a) Representative micrographs of MUC2 immunohistochemistry (left panel) and quantification of MUC2 positive cells/crypt (right panel) in colon sections from different groups of mice. Scale bars: 30 µm. (b) Representative micrographs (left panel) and quantification (right panel) of AB-PAS staining (mucus layer was stained blue or purple) in distal colon sections from different groups of mice. Scale bars: 300 µm. (c) Representative micrographs (left panel) and quantification (right panel) of HID-AB staining (sulfomucin was stained brown) in distal colon sections from different groups of mice. Scale bars: 300 µm. (d) Immunofluorescence staining of DAPI (blue) and MALII lectin (green) in the distal colons (left panel) and quantification of the mean fluorescent intensity (MFI) (right panel). Scale bars: 50 µm. (e) The relative mRNA expression levels of Papss2, Slc35b3, and GlcNAc6st2 in the colon of mice by quantitative RT-PCR. (f) The protein expression of Papss2 in the colon of different groups of mice by western blot and quantification of the value of Papss2/β-actin. (g) Representative micrographs of immunohistochemical detection of Papss2 in mice colonic tissues (left panel) and quantification of the abundance of Papss2 (right panel). Scale bars: 30 µm. ns, not significant, *p < .05, **p < .01, ***p < .001.