Effect of IR on renal tubular injury. (A-E) Hematoxylin and eosin–stained tissue sections of (A) WT mice undergoing sham surgery followed by 24 hours of reperfusion and of (B) WT, (C) low-TF, (D) C57BL/6 hirudin-treated, and (E) PAR-1^−/− mice undergoing 25 minutes of renal ischemia followed by 24 hours of reperfusion. In panel B, tubular cast formation is indicated by *. (F) Tubular injury scores of WT (n = 16), low-TF (n = 7), and WT (n = 7) mice treated with hirudin and PAR-1^−/− (n = 16) mice undergoing 25 minutes of bilateral ischemia followed by 24 hours of reperfusion or WT mice undergoing sham surgery. IR injury resulted in significant tubular injury in WT mice compared with sham-operated animals (*P < .001). Low-TF, WT mice treated with hirudin and PAR-1^−/− mice had significantly reduced tubular injury compared with WT (**P < .001). Images were captured using an Olympus BX51 microscope equipped with a uPlanFl 40 ×/0.75 numerical aperture (NA) air objective (Olympus, North Ryde, Australia) connected to a Retiga EXi digital camera, and captured with Q capture for Apple Macintosh (QImaging, Burnaby, BC, Canada). Data are expressed as mean ± SEM.