Administration of mesenchymal stem cells, not conditioned medium, improves renal function and reduces mortality. (A) Creatinine and (B) blood urea nitrogen (BUN) levels at each time point for bilateral ischemia–reperfusion (I/R) model mice treated with phosphate-buffered saline, mesenchymal stem cells (MSCs), conditioned medium (CM) or Dulbecco’s modified Eagle’s medium (DMEM) (n = 26/each group). Data presented as mean ± standard deviation. (C) Survival curves at each time point for mice subjected to bilateral I/R injury followed by intravenous injection with MSCs, vehicle, DMEM or CM (n = 20/each group, P = 0.02 MSC group vs. vehicle group). (D) Body weight curves during the study period for the MSC group, DMEM group, CM group and vehicle group. *P < 0.05 versus vehicle group.