Panel A includes fluorescent images and a bar graph. The fluorescent images show the small intestine from sham and Bb-infected mice at 14 and 28 days post-infection (dpi), stained for CD45 (green) and DAPI (blue). The bar graph summarizes the number of CD45 cells per unit area, with the y-axis labeled CD45 cells per unit area and the x-axis labeled Days post-infection. Panel B shows fluorescence staining images of E-cadherin (red) and DAPI (blue) in the small intestine of sham- and Bb-infected mice at 14 and 28 dpi. Panel C consists of three bar graphs showing the relative mRNA expression of tight junction markers cadherin-1, occludin, and tight junction protein 1 (tjp1) in the small intestine of sham and Bb-infected mice at various dpi. The y-axis is labeled Relative expression, and the x-axis is labeled Days post-infection. Panel D includes a bar graph and a line graph. The bar graph shows serum FITC-dextran concentrations in the serum of Bb- and sham-infected mice 4 hours after intragastric administration of FITC-dextran at indicated dpi, with the y-axis labeled FITC Dextran (micrograms per milliliter) and the x-axis labeled Days post-infection. The line graph shows the fold-change in Bb-infected mice compared to the mean of the sham group at each time point, with the y-axis labeled Fold change and the x-axis labeled Days post-infection. The graphs and images collectively depict the effects of Bb infection on gastrointestinal tract permeability and structural integrity in mice.
Bb induces GI tract permeability without obvious alterations to its structural integrity. All images were acquired at 20× magnification. The scale bar indicates 50 μm. (A) Left, fluorescent images of the small intestine from sham and Bb-infected mice at 14 and 28 dpi stained for CD45 (green) and DAPI (blue); right, summary of results. (B) Fluorescence staining of E-cadherin (red) and DAPI (blue) in the small intestine of sham- and Bb-infected mice at 14 and 28 dpi. (C) Relative mRNA expression of tight junction markers cadherin-1 and occludin, and tjp1 in the small intestine of sham and Bb-infected mice at the indicated dpi. (D) Left, serum FITC-dextran concentrations in serum of Bb- and sham-infected mice 4 h after intragastric administration of FITC-dextran at indicated dpi; right, data are shown as fold change in Bb-infected mice compared with the mean of the sham group at each time point. Statistical analyses were conducted using the Mann–Whitney U test. Bars indicate the mean ± SEM; each symbol represents data from one mouse (n = 4–8 per group). Each time point represents one independent experiment (A–C) except for days 28 in A and 14 in C, which was done twice. (D) Longitudinal data represent the same group followed over time with results on day 28 conducted in at least two additional independent studies that showed statistical significant differences between sham- and Bb-infected mice. *P < 0.05, **P ≤ 0.01, and ns, not significant (P > 0.05). tpj1, tight junction protein 1.