Effects of different 137Cs γ radiation dose on mouse hematopoietic system

Objective To discuss the effects of different dose of radiation on the mouse's hematopoietic system.Methods Mice of 615 strain,ICR strain and IRM-2 strain were given a one-time 4.0 Gy total body irradiation,and then the changes of peripheral white blood cells and bone marrow nuclear cells (BMNC)among those mice were observed at different time points.Mice of IRM-2 and C57BL/6 were given a one-time 6.0 Gy total body irradiation and the changes of peripheral hematological between the two strains were observed forty-five days after irradiation.Results Two days after irradiation,white blood cell and BMNC counts decreased to the lowest level in all the mice of 615 strain,ICR strain and IRM-2 strain.During the following days,white blood cell and BMNC counts raised again.Nine days after irradiation,BMNC count in IRM-2 mice was significantly higher than that in 615 and ICR mice(t=3.725,P＜0.01; t=8.487,P＜0.001).Twelve days after irradiation,white blood cell count in IRM-2 mice was significantly higher than that in the 615 and ICR mice (t=4.811 and 4.302,both P ＜0.001).Twenty-one days after irradiation,compared to the control group,white blood cell count was recovered to 52.0％,60.7％ and 50.8％ of the normal range in IRM-2,ICR and 615 mice separately and BMNC count was recovered to 90.8％,82.1％,75.4％ of the normal range in IRM-2,ICR and 615 mice separately.Forty-five days after 6.0 Gy irradiation,white blood cell,BMNC,hemoglobin and hematocrit counts in IRM-2 mice were significantly higher than those indexes in C57BL/6strain(t=5.629,7.788,4.9289,6.064,all P＜0.001).Compared to the control group,white blood cells,red blood cells,hemoglobin and hematocrit were recovered to 75.0％,98.9％,98.7％,and 97.5％ of the normal range separately in IRM-2 mice.And white blood cells,red blood cells,hemoglobin and hematocrit were recovered to 40.6％,93.8％,93.3％,and 93.8％ of the normal range separately in C57BL/6 mice.Conclusion There are similar recovery trends of hematopoiesis in all strains of mice after irradiation,but IRM-2 mice recovery more quickly than the other strains of mice. Key words: Mice; Radiation injuries, experimental; Hematopoietic system