OBJECTIVE: To study the mobilization effects of stem cell factor (SCF) along with granulocyte colony-stimulating factor（G-CSF）on bone marrow stem cells and endothelial progenitor cells in rats with unilateral ureteral obstruction (UUO). METHODS: Fifty-six healthy male Wistar rats were randomly divided into seven groups: control, SCF, G-CSF, SCF+G-SCF, Sham-operated, UUO and UUO+SCF+G-CSF groups (n=8 each). The rats from the control, SCF, G-CSF and SCF+G-CSF groups were hypodermically injected with normal saline (2 mL/kg), SCF (200 μg/kg), G-CSF (200 μg/kg) and SCF along with G-CSF respectively for 5 days. The rats from the UUO and UUO+SCF+G-CSF groups were subjected to the ligation of right ureter and then were hypodermically injected with normal saline (2 mL/kg) and SCF (200 μg/kg)+G-CSF (200 μg/kg) respectively for 5 days. The sham-operated group had the same operative approach as the UUO and the UUO+SCF+G-CSF groups but the right ureter was not ligated. After operation they received a hypodermical injection of 2 mL/kg normal saline for 5 days. Five days later blood samples were collected. The percentages of CD34+ and CD34+/CD133+ cells in intravenous blood mononuclear cells were detected by flow cytometry. Serum contents of glutamate-pyruvate transaminase (GPT), glutamic oxalacetic transaminase (GOT), urea nitrogen and creatinin were measured. RESULTS: Except for the sham-operated group, the other five groups (SCF, G-CSF, SCF+G-SCF, UUO and UUO+ SCF+G-CSF groups) had significantly higher percentage of CD34+ cells and CD34+/CD133+ cells in intravenous blood mononuclear cells than the control group (P<0.05). There were significant differences in the percentage of CD34+ cells and CD34+/CD133+ cells among the five groups (P<0.05). The UUO+SCF+G-CSF group showed the highest percentage of CD34+ cells and CD34+/CD133+ cells, followed by the SCF+G-CSF group. There were no significant differences in serum contents of GPT, urea nitrogen and creatinin among the seven groups. Except the UUO group showed higher GOT contents, there were no significant differences in the GOT contents among the other six groups.CONCLUSIONS: The mobilization effects of SCF and G-CSF on bone marrow stem cells and endothelial progenitor cells were not always in paraller. A combination of SCF and G-CSF can effectively mobilize stem cells and endothelial progenitor cells, and side effects were not found in the liver and the kidney.［Chin J Contemp Pediatr, 2007, 9 (2):144-148］