Objective    To investigate the therapeutic effect of endothelial progenitor cells (EPCs) in ameliorating rat progressive focal segmental glomerular sclerosis (FSGS) model induced by adriamycin.    Methods    Bone marrow mononuclear cells from male SD rats

after cultured by adherence method

were identified as EPCs. Female SD rats were

divided into normal control group

adriamycin induced renal disease (ADR) group

EPCs transplantation group. ADR group and EPCs group underwent unilateral nephrectomy and received 5

3 mg/kg of adriamycin via tail vein 1 week and 2 weeks after operation

while the control group underwent sham operation and received 0.9% sodium chloride solution of equal volume. The whole body irradiation by 5 Gy X ray was done 1 week after the 2

nd

injection of adriamycin

then immediately 1×10

6

EPCs were transplanted via tail vein. The rats in control group and ADR group were only injected with 0.9% sodium chloride solution after whole body irradiation. The body weight and urine protein were measured before operation (0 week) and 4 (1 week after EPCs transplantation)

8

12 and 16 weeks after nephrectomy. Y chromatosome incorporation was detected with in situ hybridization at the 4

th

and 16

th

week. The histological and ultrastructural changes of kidney were evaluated at the 16

th

week.    Results    At the 4

th

and 16

th

weeks

Y chromatosome positive cells could be found incorporation in the area of glomerular and tubular epithelial cells. Since the 4

th

week

the weight of rats in both ADR group and EPC group became significantly less than that in control group and  since the 8th week that in ADR group became less than that in EPC group (P0.05). The proteinuria and Scr were more severe in ADR group than that in EPC group and control group. In ADR group

mesangial proliferation and the tubulointerstitial fibrosis were more remarkable than that in EPC group and control group. The results of electron microscope showed that the lesions in podocytes and mesangial cells in ADR group were more severe than that of in EPC group at the 16

th

week. The image analysis showed that the index of glomerular sclerosis in ADR group and EPC group was significantly higher than that in control group

but was much better in EPC group than that in ADR group;

The opening degree of glomerular capillary cavity in EPC group was significantly higher than that of in ADR group

and so did the capillary sectional area.    Conclusion    EPCs transplantation can ameliorate renal damages and may delay the progression of glomerular sclerosis and tubulointerstial fibrosis induced by adriamycin.