Mesenchymal stem cells are recruited to the injured kidney. 5-Chloromethylfluorescein diacetate (CMFDA)-labeled mesenchymal stem cells (MSCs) with (A) the individual CMFDA, (B) 4′,6-diamidino-2-phenylindole (DAPI), and (C) merged channels on day 3 after injury. (D) CMFDA-labeled MSCs were present in the injured kidney (arrowheads) on day 3 post ischemia–reperfusion (I/R) injury. (E) Number of MSCs observed in injured and control kidneys over time after I/R injury (n = 6). Data presented as mean ± standard deviation. #P < 0.01 versus the control kidney (bars, 50 μm). LK, left kidney; RK, right kidney.