Objective   To study the effect of co-transplantation of human umbilical cord blood-d

erived stromal cells (hUCBDSC) and human umbilical cord bloodmononuclear cells (hUCB-MNC) on hematopoietic reconstruction and engraftment in BALB/c mice with radiation damage.    Methods   One day after irradiation with

60

Coγ at 8.5 Gy

the animals were randomly divided into 4 groups

which were infused with saline

hUCB-MNC（1×10

7

per mouse）

hUCB-MNC（1×10

7

per mouse）and hUCBDSC（1×10

6

per mouse）

and hUCB-MNC (1×10

7

per mouse）and hBMSC （1×10

6

per mouse）respectively

through their tail vein. Survival rate

peripheral hemogram

marrow pathological change

CFU-F

CFU-S

engraftment rate

and homing tracing in each group were detected

respectively.    Results   The survival rate of mice was 75% and 70%，respectively

after cotransplantation of hUCBMNC and hUCBDSC or hBMSC（P0.05）

which was significantly higher than the only hUCB-MNCs group. The number of platelets was increased in the hUCBDSC plus hUCB-MNC group and became normal 21 d after operation. CFU-F

14

（70.40±4.34 /well）

CFU-F

21

（94.20±8.44 /well）

  CFU-S

12

（34.75±4.50 per mouse） and the engraftment rate (34.19±2.60)% were significantly higher in the hUCBDSC co-transplantation group than in other groups (P0.05). hUCB-MNC labeled by CM-DiI were mainly distributed in bone marrow and spleen

especially in hUCBDSC plus hUCB-MNC group（85.20±7.89）(P0.05).    Conclusion   Co-transplantation of hUCBDSC and hUCB-MNCs can significantly promote hematopoietic reconstruction and elevate the engraftment rate.