Abstract: Objective　To observe the effects of thymoquinone on the hematopoietic radiation injury in mice. Methods　Fifteen ICR mice were randomly divided into control group, irradiated group, and thymoquinone group according to body weight. The control group received sham irradiation, and the rest received 2.0 Gy total body irradiation. Thymoquinone was intragastrically administrated with 10 mg/kg 1 d before irradiation and continued for 3 days after irradiation, the other two groups were intragastrically administered with normal saline. After 2.0 Gy irradiation for 7 day, the peripheral blood samples were collected and bone marrow nucleated cells were counted. The reactive oxygen species (ROS) and colony forming unit granulocyte- macrophage (CFU-GM) were detected. Results　Compared to the control group, white blood cells (WBC), red blood cells (RBC), hemoglobin (HGB), hematocrit (HCT) and platelet (PLT), bone marrow mononuclear cells (BMMNC) and CFU-GM of mice decreased significantly in irradiated group, the ROS level increased (P＜0.05). The WBC, RBC, HGB and PLT of the peripheral blood cells significantly decreased in the thymoquinone group (P＜0.05). The WBC, BMMNC and CFU-GM were enhanced significantly in the thymoquinone group compared with those of irradiation group (P＜0.05). Conclusion　The thymoquinone shows protective effects on the radiation-induced hematopoietic damage by inhibiting ROS levels to improve the proliferation of bone marrow cells.

Key words: whole-body irradiation, radiation injuries, blood cells, reactive oxygen species, hematopoietic system, bone marrow cells, thymoquinone