Fig. 5

Sialic acid promotes gut dysbiosis-induced intestinal barrier disruption. The goblet cells of colons from different treated mice are shown by AB-PAS staining (scale bar, 50 μm) (A, C) (n = 7–8). Immunohistochemistry staining was performed to assess the mucin-2 level in the colon using mucin-2 antibody (scale bar, 50 μm). The positive-stained cells are shown in brown (B, D) (n = 7–8). E Relative mRNA levels of colon tight junction proteins, including ZO-1, Occludin, and Claudin-3, from the indicated mice were assessed by qPCR (n = 7–8). Protein levels of colon ZO-1 (F), Occludin (G), and Claudin-3 (H) were measured by western blotting (n = 4). Data are expressed as the mean ± SD (C–H) and one-way ANOVA was performed, followed by Tukey test (C–H). *p < 0.05, **p < 0.01, ***p < 0.001 indicate significance. AB-PAS, Alcian Blue Periodic acid Schiff; MUC2, mucin-2