Objective To explore the underlying possible mechanism of Dahuang Zhechong Wan（ DZW 大黄虫丸 DZW） in treating chronic myeloid leukemia（ CML）. Methods The CXCR4 gene was directional cloned to eukaryotic expression vector p Bud CE4. 1 carrying with double promoters

and transfected into K562 cell. Screen the steady K562 / CXCR4 cells with high expression of human CXCR4 protein. 16 nude mice were randomly divided to a control group and three DZW groups respectively with a large

medium and small dose

4 mice in each group. The three DZW groups with a large

medium and small dose were respectively received DZW gavage in 270 mg / ml

135 mg / ml and 70 mg / ml

3ml one time

once daily for 3 days. The control group was given normal saline gavage in3 ml

once daily for 3days. On the third day

give gavage once every 3hours for three times. The blood was collected from the heart one hour after the last administration

and the serum was separated for DZW serum preparation. Effects of DZW serum in different concentrations on K562 / CXCR4 cells proliferation and apoptosis were respectively determined by MTT and TUNEL methods. Changes in the expression of different group CXCR4 cells were tested by Western blotting method. Results Compared with the control group

the A490 absorbance of three DZW group cells at large

medium and small doses were significantly lower at 24 h

48h

72 h and 96 h. The longer the DZW action time with large

medium and small doses

the higher the drug concentration

and the higher was the cell inhibition rate.The cell apoptosis rate was 0. 28% in the control group

and in the large

medium and small doses DZW groups were60. 79%

28. 91% and 10. 14%. CXCR4 expressions significantly decreased in the large

medium and small doses DZW groups than that in the control group. The increasing the dose

the lower was the CXCR4 expression. Conclusion DZW could intervene in the CML developing process by restraining K562 / CXCR4 cells proliferation

inducing their apoptosis and decreasing CXCR4 expression.