Vávrová J, Petýrek P
Purkynĕ Medical Research Institute, Hradec Králové.
Folia Biol (Praha). 1988;34(6):399-408.
Split-dose irradiation of mice with two doses of 0.5 Gy given at 2 to 5 h interval damages haemopoietic stem cells (CFU-S) less than single exposure to 1 Gy. Also in comparison with whole-body single exposure of mice to a high sublethal dose of 7 Gy, splitting this dose into two doses of 3.5 Gy given at 4-h interval brought about more rapid recovery of CFU-S in femoral bone marrow and of bone marrow cellularity. At 360 days after irradiation with 7 Gy gamma-rays, a secondary decrease in CFU-S was apparent in bone marrow, which was more profound in the single-exposure group than in the group given split doses amounting to 7 Gy. The protective effect of short-term dose splitting was also evident in an investigation of mortality of irradiated mice. The LD50/30 value in mice exposed to a single dose of gamma-rays (8.3 Gy) increased to 10.5 Gy, when the dose was split (two doses, 4-h interval).
对小鼠进行分次照射，间隔2至5小时给予两剂0.5 Gy，对造血干细胞（CFU-S）的损伤小于单次照射1 Gy。与小鼠全身单次暴露于7 Gy的高亚致死剂量相比，将该剂量分为两剂3.5 Gy，间隔4小时给予，可使股骨骨髓中的CFU-S和骨髓细胞数量更快恢复。在用7 Gy γ射线照射360天后，骨髓中CFU-S出现二次下降，单剂量照射组比给予相当于7 Gy的分次剂量组更明显。短期分次剂量的保护作用在对照射小鼠死亡率的研究中也很明显。当剂量分次（两剂，间隔4小时）时，暴露于单剂量γ射线（8.3 Gy）的小鼠的LD50/30值增加到10.5 Gy。
