不同剂量137Csγ-射线辐射后造血干/祖细胞辐射敏感性差异研究

The difference in the radiosensitivity between hematopoietic stem and progenitor cells after different doses of ^(137)Csγ-radiation

目的探讨不同剂量^(137)Csγ-射线辐射后不同时间点C57BL/6小鼠造血细胞辐射敏感性的差异。方法采用随机区组法将72只雄性C57BL/6小鼠分为对照组和2、4、6 Gy照射组。照射组给予2、4、6 Gy^(137)Csγ-射线一次性全身照射,对照组给予假照射。分别于受照后14 d、35 d和56 d断颈处死小鼠,取外周血进行血象测定,取骨髓细胞测定有核细胞(BMNCs)、造血干细胞(HSCs)和造血祖细胞(HPCs)数目。结果与对照组相比,照射组小鼠造血系统受到不同程度损伤。外周血白细胞计数(WBC)、红细胞数(RBC)、血小板(PLT)和血红蛋白含量(HGB)均有不同程度的降低,其中HGB对辐射较不敏感,RBC在受照后35 d已基本恢复至正常值,WBC和PLT对辐射较敏感;6Gy照射对WBC和PLT影响较重,恢复缓慢。照射后14 d,照射组BMNCs、HSCs和HPCs数目均低于对照组;照射后35 d和56 d,6 Gy照射组BMNCs和HPCs数目均低于对照组(均P<0.05),2、4 Gy照射组BMNCs和HPCs数目与对照组差异无统计学意义。照射后35 d,照射组HSCs数目均低于对照组;照射后56 d,4、6 Gy照射组HSCs数目均低于对照组(均P<0.05),2 Gy照射组HSCs数目与对照组差异无统计学意义。结论不同剂量^(137)Csγ-射线辐射对小鼠造血系统造成不同程度的损伤,且辐射对HSCs的损伤是持久性的。

Objective To observe the different radiosensitivity induced by different doses of ^（137）Csγ-ray irradiation betweenhematopoietic stem and progenitor cells. Methods Seventy-two C57BL/6 mice were randomly divided into control group andirradiated groups（2, 4 and 6 Csγ-ray irradiation, n=18 for each group）. Mice of control group received sham irradiation, and therest accepted 2, 4 and 6 Gy ^（137）Csγ total body irradiation, respectively. After 14-day, 35-day and 56-day irradiation, the peripheralblood samples were collected by balls enucleation. The number of bone marrow nuclear cells, hematopoietic stem and progenitorcells were counted. Results The peripheral blood of irradiated mice showed significant changes in the number of white bloodcells（WBC）, red blood cells（RBC）, platelets（PLT） and hemoglobin（HGB） in a dose-response relationship. Compared with thecontrol group, the numbers of BMNCs and hematopoietic progenitor cells（HPCs） were significantly lower in irradiated group. At35 d and 56 d after 6 Gy irradiation the numbers of BMNCs and HPCs were significantly lower than those of control group（P 〈0.05）. There were no significant differences in numbers of BMNCs and HPCs between irradiated groups（2 and 4 Gy） and controlgroup. The number of bone marrow hematopoietic stem cells（HSCs） was significantly lower in irradiated group than that in controlgroup after 14-d and 56-d irradiation（P〈 0.05）. Conclusion^（137）Csγ-ray irradiation has some damage in mouse hematopoieticsystem. The damage caused by radiation is persistent to hematopoietic stem cells.