Objective　　　To investigate the radioprotective effect of Angelica polysaccharides (APS) on bone marrow stromal cells (BMSCs) in radiation injured mice.　　　 Methods　　　Two hundred and forty BA

LB/c mice were randomly divided into 10 groups

including a normal group

three NS groups

three 2 mg/kg APS groups and three 8 mg/kg APS groups

and there were 24 mice in each group. All the mice except for those of the normal group underwent X-ray radiation

and the radiated mice were injected with NS

2 mg/kg APS and 8 mg/kg APS for 7

13 and 21 d

respectively. The numbers of white blood cells (WBC)

red blood cells (RBC)

platelets and bone marrow mononuclear cells (BMNCs) in peripheral blood were recorded by cell counting after treatment. The time for BMSC growing to 80% adherence and the number of fibroblast colony-forming unit (CFU-F) were observed. Cell cycle

apoptotic ratio and the expression of CD54 and CD106 on BMSC were detected by flow cytometry.　　　 Results　　　Compared with the normal group

the cell counts of WBC

RBC

platelets and BMNC in peripheral blood of the NS groups decreased significantly (

P

0.05)

the time for BMSCs growing to 80% adherence prolonged significantly (P0.05)

and the number of CFU-F was significantly decreased (

P

0.05). The results of flow cytometry showed that compared with the normal group

the percentage of BMSCs was significantly increased at G

0

/G

1

phase but significantly declined at S phase (

P

0.05)

the apoptotic ratio was significantly increased (

P

0.05)

and the expression of CD54 and CD106 on BMSC was decreased significantly (

P

0.05). Compared with the NS groups

the results of the 2 mg/kg APS groups and 8 mg/kg APS groups showed that the numbers of peripheral blood cells

BMNCs and CFU-F significantly increased (

P

0.05)

the time for BMSC growing to 80% adherence was significantly decreased

the percentage of BMSCs was significantly decreased at G

0

/G

1

phase but significantly increased at S phase (

P

0.05)

the apoptotic ratio was significantly decreased (

P

0.05)

and the expression of CD54

CD106 on BMSC was significantly increased (

P

0.05). The indicators of the 8 mg/k

g APS groups returned to normal levels on the 21st day.　　　 Conclusion　　　For BMSCs

APS can promote adherence and proliferation

accelerate transition from G

0

/G

1

phase to S phase

decline apoptotic ratio

and up-regulate the expression of CD54 and CD106

so as to accelerate the hematopoietic recovery of radiation injured mice.