Fig. 1

Antibiotic (Abx) treatment alters GI structure, delays transit, and increases intestinal permeability in adult mice in a sex-independent manner. a Adult mice of both sexes were treated with a combination of antibiotics for at least 14 days in the drinking water prior to experiments (Abx group). The antibiotic regimen consisted of ampicillin (1 g/L), neomycin (1 g/L), vancomycin (0.5 g/L), and metronidazole (1 g/L), administered as described in “Methods.” The control group received regular water. Experiments were performed between 14 and 28 days. b Body weight variation over the course of the experiment (two-way ANOVA). c–e Intestinal anatomical alterations observed in Abx mice; c cecal wet weight, d small intestinal length, and e colon length. f Fecal pellet wet weight and g wet:dry ratio of feces measured after a 1-h novel environment stress. h Whole gut transit time. i Small intestinal transit distance (as a % of total intestinal length) measured 15 min after gavage with dye. j Distal colonic motility measured by bead expulsion time. k Intestinal permeability assessed by fluorescein-5-6-sulfonic acid (FSA) concentration in the serum 4 h after gavage with FSA. Data are expressed as mean ± SEM. n = 4–5. *p < 0.05, **p < 0.01, ***p < 0.001; Student’s t test