To validate whether FGF23 and SDF-1 could affect the therapeutic ability of EPCs in vivo, control, SDF-1-treated, FGF23-treated, and FGF23 plus SDF-1 co-incubated EPCs were injected into the tail vein of the IR-AKI SCID mice. The gene discussed is CXCL12; the disease is acute kidney injury.