Fig. 3

Probiotics alleviated gut barrier permeability and bacterial translocation. a Representative images of claudin-1, occludin, and ZO-1 expression in small intestinal epithelial cells from three independent experiments. b Quantification of claudin-1, occludin, and ZO-1 expression (n = 5 ~ 6 per group). c Representative immunofluorescence images of claudin-1, occludin, and ZO-1 staining in the terminal ileum. d Representative TEM images of ileum enterocytes revealing cell–cell junctional complexes. The inset shows magnified views of the tight junction. e Serum concentrations of FD4 in NEC mice treated with PBS or probiotics (n = 5 ~ 6 per group, representative data from three independent experiments). f Representative agar plates from NEC + PBS and NEC + probiotic splenic lysates, plated and incubated for 24 h. Data are expressed as mean values ± SD. Statistical analyses were performed with Student’s two-tailed unpaired t-test in (b, e), *p < 0.05; **p < 0.01; n.s., not significant; FD4, FITC-dextran 4 kDa. Scale bars represent 2 μm in (d)