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

摘要：目的 探讨不同剂量137Csγ-射线照射后不同时间点C57 BL/6小鼠造血细胞放射敏感性的差异。方法 选取6~8周龄雄性C57BL/6小鼠72只，完全随机法分为对照组和照射组。照射组小鼠分别接受2、4、6 Gy137Csγ射线一次性全身照射，对照组小鼠接受假照射。小鼠分别于受照后14 d、35d和56d断颈处死，取外周血进行血象测定，取骨髓细胞测定有核细胞数目和造血干/祖细胞数目。结果 不同剂量照射后小鼠的外周血常规指标有明显变化，白细胞数目明显下降，其次是血小板数目，且具有剂量效应关系；在照射后14d，2Gy、4Gy和6Gy照射组小鼠骨髓有核细胞数目与对照组比较分别下降21.9%、39.9%和54.4%（t=4.311、6.401、8.007，P<0.05）；照射后35d和56d，6Gy照射组小鼠骨髓有核细胞和造血祖细胞数目显著低于对照组（t=4.185、3.596，P<0.05）。照射后14d、35d和56d，2Gy、4Gy和6Gy照射组小鼠骨髓造血干细胞数目持续低于对照组（t=9.706、3.427~7.465，P<0.05）。结论 不同剂量137Csγ-射线照射对小鼠造血系统造成不同程度的损伤，造血祖细胞较造血干细胞辐射敏感，且辐射对造血干细胞造成的损伤是持久性的。

The difference of radiosensitivity between hematopoietic stem and progenitor cells toward difference dose of radiation

Abstract: Objective To observe the difference of radiosensitivity between hematopoietic stem and progenitor cells toward difference dose of 137Csγ--ray irradiation. Methods Seventy-two C57BL/6 mice were randomly divided into control group and irradiated groups (n=18 for each). Mice of control group received sham irradiation, and the rest accepted 2、4 and 6Gy total body irradiation respectively, dose rate 1.01Gy/min. After irradiation 14 day、35day and 56day, the peripheral bloods were collected by balls enucleation. The number of bone marrow mononuclear cells、hematopoietic stem and progenitor cells were counted. Results Peripheral blood of irradiated mice had significant changes in the number of white blood cells and platelets in a dose-response relationship; at 14d post-radiation compared with the control group, the number of bone marrow mononuclear cells (BMMNCs) was decreased 21.9%、39.9% and 54.4%（t=4.311、6.401、8.007，P<0.05）；the number of BMMNCs and hematopoietic progenitor cells (HPCs) were significantly lower at 35d and 56d after 2Gy、4Gy and 6Gy irradiation（t=4.185、3.596，P<0.05）； the number of bone marrow hematopoietic stem cells in the irradiated group were lower than that in the control group at 14d、35d and 56d （t=9.706、3.427~7.465，P<0.05）. Conclusions 137Cs γ-ray irradiation on mouse hematopoietic system has some damage, the radiosensitivity of HPC is markedly higher than that of the HSC, where the difference ; the damage caused by radiation to hematopoietic stem cells is persistent.