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本验实采用剂量率分别为7.8、15.1、31.0和61.0×10~(-3)mGy/min的~(60)Coγ线预先照射小鼠,持续20h,使累积剂量分别达到9.3、18.2、37.2和72.9mGy。从而诱发了小鼠骨髓细胞对再次大剂量(1.5Gy)急性照射的适应性反应。染色体分析表明,除最低剂量组外,各不同剂量的预先照射都使大剂量诱发的染色单体裂隙、断裂和无着丝点断片率明显降低于预期值(p<0.01);而双着丝点加环型畸变率的降低无显著意义,在各不同剂量的预先照射组均可见到由随后大剂量诱发的畸变细胞率明显低于预期值(P<0.01)。染色体总畸变率和畸变细胞率与预期值的相对降低率有随预照射剂量的增加而降低的趋势。
In this experiment, mice were pre-irradiated with ~ (60) Coγ line with dose rates of 7.8, 15.1, 31.0 and 61.0 × 10 ~ (-3) mGy / min respectively for 20h, with the cumulative doses of 9.3, 18.2 and 37.2 And 72.9 mGy. Thereby inducing the adaptive response of mouse bone marrow cells to a second dose of acute exposure (1.5 Gy). Chromosomal analysis showed that, except for the lowest dose group, pre-irradiation with different dosages significantly reduced the number of chromatid fissures, ruptures and no-filament fragments (p <0.01) induced by large doses; however, There was no significant difference between the two groups in the reduction of ring distortion. The rate of aberrant cells induced by the subsequent large dose of radiation was significantly lower than the expected value (P <0.01) at each dose of pre-irradiation group. The relative reduction rate of total chromosome aberration rate and aberrant cell ratio from the expected value tended to decrease as the pre-irradiation dose increased.