Figure 4. PAR1 activation increases vessel density in the small intestine.

a, Relative levels of mRNA for PAR1 and PAR2 in segments of small intestine from GF and CONV-R mice (n = 7 or 8 mice per group). b, PECAM-1 staining (red) of sections of small intestine from wild-type (WT), F2r^−/− and F2rl1^−/− mice. Nuclei were stained with Hoechst nuclear dye (blue). c, Quantification of b (n = 6–9 mice per group). d, e, Relative levels of mRNA for PECAM-1 (d) and Ang-1 (e) in segments of small intestine from wild-type, F2r^−/− and F2rl1^−/− mice (n = 6–9 mice per group). f, g, Anti-TF and anti-phospho-TF immunoblots of small-intestinal lysates from (f) WT, F2r^−/− and F2rl1^−/− miceand (g) CONV-D mice treated with PBS (control) or hirudin (1 mg/mouse) immediately before colonization and at 2 h and 4 h after colonization. h, Quantification of the phospho-TF band shown in g (n = 6 or 7 mice per group). i, Anti-TF and anti-phospho-TF immunoblots of primary enterocytes (from CONV-R mice) incubated for 2 h with human thrombin (50 nmol l⁻¹). j, Quantification of the phospho-TF band shown in i (n = 8 mice per group). Female Swiss Webster mice were analysed in a and g–j. Female WT, F2r^−/− and F2rl1^−/− mice on a C57BL6/J genetic background were used in b–f. Scale bars, 20 μm. Results are shown as means ± s.e.m. Asterisk, P < 0.05; three asterisks, P < 0.005; n.s., not significant.