Figure 2.

Immunohistolocalization of PAR₁ protein expression in the muscularis mucosae of human colon (A–D) and in whole colonic tissues from naive mice (E) and mice with TNBS-induced colitis (F–H). (A) Human biopsy section obtained from a macroscopically normal colon resected from a patient diagnosed with Crohn disease. PAR₁ immunoreactivity was observed in vessels (arrows) and smooth muscle cells (arrowhead) (original magnification, ×100). (B) The same tissue incubated with a blocking peptide for the anti-PAR₁ antibody (original magnification, ×100). PAR₁ staining on the vessel was inhibited (arrow). (C) Tissues of the same patient collected in a macroscopically inflamed area, showing extensive necrosis and inflammatory infiltration of lamina propria by lymphomonocytic cells (inset) and PAR₁-positive vessels (arrow). (D) A higher magnification (×400) of the vessel shown in C (arrows). Infiltrated inflammatory cells were observed in the lumen of the blood vessel. (E) Colonic tissues from naive mice, where PAR₁ was expressed mainly on the epithelium (arrows). (F) Colonic tissues from TNBS-treated mice, with large tissue disruption, mucosal erosions (arrows), and PAR₁ staining in infiltrated cells of the lamina propria (arrowheads) as well as epithelium. (G) The PAR₁ antibody was preincubated with a blocking peptide at 20 μg/ml to show specificity (original magnification, ×40). (H) A higher magnification of infiltrated cells of the lamina propria (arrows and arrowheads) positively stained for PAR₁ (original magnification, ×400).