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本文观察了小鼠经γ线100,300,500,700,900,和1100 rad照射后不同时间,股骨CFU-C的辐射效应以及骨髓细胞染色体畸变率。结果表明,在100～700 rad剂量范围内,CFU-C活存率的对数和染色体畸变率与照射剂量之间均有良好的线性关系。照射900～1100 rad后,CFU-C的平均数只有对照的0.5％以下,而染色体畸变率高达90％以上,而且,小鼠受全身照射900 rad以上内源性,脾结节已不出现。可以认为900～1100 rad基本已杀伤小鼠全部造血干细胞,因而是丧失自身造血重建能力的阈剂量。文中还阐述了经300和700 rad γ线照射后的21天中,CFU-C恢复的动态。
In this study, we observed the radiation effect of CFU-C in femurs and the chromosome aberration rate of bone marrow cells irradiated by gamma rays 100, 300, 500, 700, 900, and 1100 rad. The results showed that there was a good linear relationship between the logarithm of CFU-C survival rate and the rate of chromosomal aberrations and irradiation dose in the 100-700 rad dose range. After irradiation of 900 to 1100 rad, the average number of CFU-C was only 0.5% or less of that of the control, and the rate of chromosomal aberrations was as high as 90% or more. Furthermore, the mice were endogenously exposed to more than 900 rad after whole-body irradiation, and no splenic nodules appeared. It can be considered that 900 to 1100 rad has basically killed all hematopoietic stem cells in mice, and thus is a threshold dose for the loss of autologous hematopoietic reconstitution ability. The dynamics of CFU-C recovery in 21 days after irradiation with 300 and 700 rad γ lines are also described.