Mizoribine Inhibits the Proliferation of Renal Stem/Progenitor Cells by G1/S Arrest during Renal Regeneration

Immunosuppressive agents are generally administered to treat kidney diseases. However, it is unclear whether renal stem/progenitor cells are directly affected by the immunosuppressive agents. We used normal rat kidney cells, ureteric bud cells and rat kidney stem/progenitor cells in this study. Mizoribine (MZR), cyclophosphamide (CPA) and cyclosporine (CyA) were added to the culture media of these cells. We evaluated the effects of these immunosuppressive agents on cell proliferation using an electrical cell-substrate impedance sensing system (ECIS) and their effects on the process of renal regeneration using the ischemia-reperfusion (I/R) injury rat model. The ECIS data showed that proliferation of each of the 3 types of cells was significantly suppressed by MZR. MZR treatment enhanced renal tubular injury in ischemia-reperfusion (I/R) injured rats, and significantly decreased levels of M-phase cells and Nestin-positive cells. These results suggested that MZR inhibits the cell cycle of renal stem/progenitor cells;thus, physicians should take note that MZR might affect not only inflammation but also renal regeneration.