Figure 2. Lesion severity determines gastrointestinal dysfunction. a, Intestinal motility was measured 24 h after fMCAo or sham surgery. Representative fluorescence images of the complete gastrointestinal tract 60 min after gastric instillation of FITC-dextran showing retention of the fluorescent bolus in the upper gastrointestinal tract as a marker of severely impaired motility after fMCAo compared with sham mice. Arrowheads indicate cecum. b, Quantification of fluorescence intensity in intestinal segments. Note the retention of fluorescence signal in the upper gastrointestinal tract after fMCAo (n = 8 per group, 3 individual experiments). c, Number of colony forming units (CFUs) per milligram of murine cecal content cultured under anaerobic conditions after sham or fMCAo surgery (n = 8–9 mice per group, 2 independent experiments). d, No bacterial invasion into lamina propria was found in transverse sections of mouse ileum, which were hybridized using a general bacteria-specific EUB338 probe with Sytox green counterstaining. Left panels: Magnification, 20×; scale bars, 100 μm; right panels: magnification, 63×, scale bars, 10 μm. e, Albumin concentrations were determined by ELISA and are represented as the ratio of the concentrations in feces and plasma from sham- and fMCAo-operated mice (n = 5 mice per group, 2 individual experiments). f, Plasma catecholamine levels, represented as catecholamine metabolite concentrations of metanephrine and normetanephrine, were significantly increased 24 h after fMCAo compared with sham surgery (n = 10 per group, 3 individual experiments). g, Representative cresyl-violet-stained coronal brain sections 3 d after stroke induction in the cMCAo model. The small cortical lesions are outlined in red. h, Principal component (PC) analysis (left) for fecal taxonomic abundance after csham and cMCAo compared with fMCAo, and α diversity for the indicated groups (right) illustrate that small cortical lesions do not affect microbiota compositon. i, Representative fluorescence images (left) and quantitative analysis (right, n = 6) of gastrointestinal motility after csham and cMCAo surgery corresponding to data shown in a and b. Bar graph: *p < 0.05, mean ± SD.