Fig. 6

Fpr2 deficiency increased E. coli population in the colon of mice with colitis. A Increased E. coli counts in the feces of Fpr2^−/− mice after administration of 3% DSS in drinking water for 5 days. Right: Quantitation of E. coli in mouse feces. The results are expressed as E. coli CFU (Log10)/g feces. n = 10–12 mice/group. *P < 0.05. B PCR analysis confirmed that the bacteria isolated from the mouse feces were E. coli. C. Increased numbers of bacteria invaded the colon epithelial cells of Fpr2^−/− mice. Scale bar = 5 μm. Red arrows: Bacteria in colon epithelial cells. Right: Quantitation of bacteria in each epithelial cells. The results were expressed as area occupied by bacteria per cell (µm²). n = 30 cells/group, ****P < 0.0001. D FISH analysis showed that increased number of EUB338 + bacteria attached to the colon mucosa of Fpr2^−/− mice. Red: EUB338 probe⁺ bacteria, Blue: Nuclei. Scale bar = 30 μm. Right: Quantitation of the EUB338 probe⁺ bacteria/field. n = 18–23 fields from 5 mice per group, *P < 0.05. E FISH analysis showed that increased number of number of EC1531 probe⁺ E. coli attached to the colon mucosa of Fpr2^−/− mice. Red: EC1531⁺ E. coli, Blue: Nuclei. Scale bar = 30 μm. Right: Quantitation of the percentage (%) of EC1531⁺ E. coli in EUB338⁺ bacteria, n = 16 fields from 5 mice per group, *P < 0.05. F Increased level of LPS in the feces of Fpr2^−/− mice. The results were expressed as ng/g feces. n = 4 mice/group, **P < 0.01. G Increased level of LPS in the serum of Fpr2^−/− mice. The results were expressed as ng/ml serum. n = 4 mice/group, ****P < 0.0001