Intraluminal neutrophils limit epithelium damage by reducing pathogen assault on intestinal epithelial cells during Salmonella gut infection
Fig 5
Investigation of the role of intraluminal neutrophils in a mouse model with reduced systemic disease.
A) Experimental scheme for Panels B-F. Ampicillin pretreated C57BL/6 mice were infected orally with 5x107 CFU of S.TmssaV for 3 days. Mice were divided into four groups: 1) Control (I.P. PBS; black filled symbols) without gentamicin, 2) Neutrophil depletion (I.P. α-Ly6G; orange filled symbols) without gentamicin, 3) Control (I.P. PBS; black empty symbols) with gentamicin in drinking water starting from day 1 p.i., and 4) Neutrophil depletion (I.P. α-Ly6G; orange empty symbols) with gentamicin in drinking water starting from day 1 p.i. Total S.TmssaV pathogen loads B) in cecal content, C) in the cecal tissue at day 3 p.i. in each group. D) Quantification of gut inflammation by Lipocalin-2 levels in cecal content. E) Representative micrographs of cecal tissue sections, stained for epithelial marker EpCam and Salmonella LPS. Lu. = Lumen. Ep. = Epithelium. White arrows point at expelled epithelial cells. Scale bar = 50 μm. F) Microscopy-based quantification of luminal IECs per 63x field of view (i.e., cells/high power field; hpf). Each data point is the average of 5 fields of view (FOV) per section. Upper ends of the bars indicate the median. Panels B-F) Pooled from total 4 independent experiments; at least 2 for each group: Group-1 (n = 12 mice), group-2 (n = 9 mice), group-3 (n = 6 mice), group-4 (n = 6 mice). Two-tailed Mann Whitney-U tests were used to compare two indicated groups in each panel. p≥0.05 not significant (ns), p<0.05 (*), p<0.001 (***).