Salidroside mitigates experimental colitis through cyclic adenosine monophosphate pathway activation and suppression of enteric glial cell responses

Figure 4 Salidroside protected intestinal mucosal barrier and attenuated inflammation in dextran sulfate sodium salt-induced colitis mice. A and B: Immunofluorescent histochemical staining of mouse colonic mucosa with occludin (A) and zonula occludens-1 (ZO-1) (B): Control group (A1-A4 and B1-B4); Dextran sulfate sodium salt (DSS) group (A5-A8 and B5-B8); DSS + salidroside (Sal) group (A9-A12 and B9-B12). The magnified images show the corresponding white square areas in greater detail; C and D: The relative fluorescence intensities of occludin (C) and ZO-1 (D) expression was subjected to quantitative analysis; E: Western blotting analysis was conducted to assess the expression levels of glial fibrillary acidic protein (GFAP), occludin, and ZO-1 in the colon of the mice; F-H: Quantitative analysis was carried out for the expression levels of GFAP (F), occludin (G), and ZO-1 (H) proteins; I: The ultrastructural characteristics of the colonic mucosal epithelium. The black triangle indicates the tight junctions between the epithelial cells of the mucosa: Control group (I1); DSS group (I2); DSS + Sal group (I3); The magnified images show the corresponding black square areas in greater detail (I4-I6); J: Intestinal permeability was detected by measuring serum fluorescein isothiocyanate-dextran levels; K-N: Comparison of interleukin (IL)-1β (K), IL-6 (L), tumor necrosis factor-α (M) and nuclear factor kappa-B (N) expression levels in peripheral blood of the three groups of mice. Data are shown as mean ± SEM (n = 4), P values were calculated using one-way analysis of variance with Tukey’s test for Figure 4C, D, F-H, and J-N. ^aP < 0.05. ^bP < 0.01. DSS: Dextran sulfate sodium salt; Sal: Salidroside; DAPI: 4’,6-diamidino-2-phenylindole; ZO-1: Zonula occludens-1; GFAP: Glial fibrillary acidic protein; GAPDH: Glyceraldehyde-3-phosphate dehydrogenase; FITC: Fluorescein isothiocyanate; IL: Interleukin; TNF: Tumor necrosis factor; NF-κB: Nuclear factor kappa-B.