Abstract: Objective To investigate the protective effect of 3,3′-diindolylmethane (DIM) on radiation-induced injury in mouse hematopoietic system. Methods Thirty C57BL/6 mice were randomly divided into control group, 2 Gy irradiation group and 2 Gy irradiation + DIM group (n=10 for each group). Mice of control group received sham irradiation, and the other two groups accepted 2 Gy 137Cs γ-ray total body irradiation. Mice in 2 Gy irradiation +DIM group were intraperitoneally injected 75 mg/kg DIM 30 min before irradiation. Mice of other two groups were treated with reference solution. After 7 d and 15 d of 2 Gy irradiation, the peripheral blood samples were collected to count the number of bone marrow nuclear cells (BMNCs). The level of reactive oxygen species(ROS) was measured by DCFH- DA. The levels of colony forming unitsgranulocyte-macrophage (CFU-GM) were also detected. Results The numbers of white blood cell (WBC), platelet count (PLT), BMNCs and CFU-GM were significantly decreased and the ROS level of bone marrow cells increased significantly in the irradiated group than those of control group (P＜0.05). Compared to 2 Gy irradiation group, the numbers of WBC, PLT, BMNCs and CFU-GM were significantly increased in 2 Gy irradiation +DIM group, and the level of ROS was decreased significantly (P＜0.05). Conclusion DIM has a protective effect on hematopoietic cells following radiation-induced injury, which may be related with the decreased ROS level.

Key words: radiation injuries, hematopoietic system, reactive oxygen species, bone marrow cells, mice, inbred C57BL, 3,3′-diindolylmethane