Objective        To investigate the possible underlying mechanism of apoptosis in MUTZ-8 cells induced by cytarabine.       Methods       The cells were divided into 5 groups

negative control group

0.1 μmol/L Ara-c group

1 μmol/L Ara-c group

10 μmol/L Ara-c group

and 10 μmol/L Ara-c+62.5 μmol/L ALA group. The proliferation of MUTZ-8 cells in above groups was measured by MTT assay. Apoptotic rate was assessed by Annexin V/PI double staining and luminescent dyes-Hoechst33258. Mitochondrial membrane potential of the cells was determined by flow cytometry. Using a ROS probe (2′

7′-dichlo-rofluorescein diacetate

DCFH-DA)

the level of reactive oxygen species (ROS) was detected by flow cytometry and fluorescence microscopy.       Results        MTT assay indicated cytarabine resulted in a stronger inhibition in cell viability when compared with the cells of negative control group (P0.05). Apoptotic rates of the cells in cytarabine groups were significantly increased as compared with negative control group (P0.05). Mitochondrial membrane potential levels of the cells were decreased in cytarabine groups  as compared with negative control group (P0.05). ROS levels in all cytarabine groups were up-regulated as compared with negative control group (P0.05).       Conclusion       Cytarabine effectively inhibits the growth and induces the apoptosis in MUTZ-8 cells

which might be related to the elevation of ROS level.