Abstract: Objective To observe the effects of p38 inhibitor SB203580 (SB) on the immune cells in the radiated mice. Methods C57BL / 6 mice were divided into control group, irradiated group, SB group. The control group received sham irradiation, and the rest accepted 6 Gy total body irradiation. Mice in SB group were intraperitoneally injected 15mg/kg at 1,3,5,7,9 day after irradiation. After mice exposed to 6Gy irradiation 10 day, the peripheral bloods and bone marrow cells were collected. The immune cells phenotypes in peripheral bloods were analyzed by flow cytometry, ROS (reactive oxygen species) level of bone marrow cells were detected by kits. Results Compared to control group，the proportion of CD8, B220 and WBC in the irradiated mice significantly decreased, ROS level of bone marrow cells increased (p <0.01). Compared to irradiation group, the CD8 and WBC in SB treated group increased, ROS level in bone marrow cells of SB treated group decreased (p <0.05). Conclusion The results indicate that p38 inhibitor can protect the immune cells from radiation injury by lowing the ROS level and it might used as a therapeutic method for the radiation injury .

Key words: p38 inhibitor, total body irradiation, peripheral blood, immune cells phenotypes, mice