Cai L, Wang P
Institute of Radiation Medicine, Norman Bethune University of Medical Sciences, Changchun, People's Republic of China.
Mutagenesis. 1995 Mar;10(2):95-100. doi: 10.1093/mutage/10.2.95.
In earlier studies we have shown that either a single exposure or multiple exposures to a low dose of X-rays (0.05 Gy) induced a significant cytogenetic adaptive response in mouse germ cells. In this paper, a very low-dose rate (20 microGy/min) of chronic 60Co gamma-irradiation was used to pre-irradiate mice for 40 days. Then, another 40 days later, these mice were treated with a subsequent large dose of X-irradiation, followed 24 h later by cytogenetic analysis of their spermatocytes. Analysis for radiation-induced DNA and chromosomal damage was also carried out in splenocytes, bone marrow cells and spermatocytes of the offspring of mice adapted by the low-dose rate of chronic gamma-irradiation. Results demonstrated that (i) cumulative gamma-irradiation (1.10 Gy) at the dose rate 20 microGy/min induced a marked cytogenetic adaptive response in the mouse germ cells (stem spermatogonia); (ii) the sensitivity of offspring's bone marrow cells and spermatocytes to 1.5 Gy X-ray-induced chromosome aberrations was not influenced by the low-dose radiation delivered to paternal germ cells; (iii) either constitutive or post-irradiation DNA repair capacity (UV-induced unscheduled DNA synthesis, UDS) was not modified in the offspring's splenocytes; (iv) the sensitivity of the offspring's splenocytes to radiation-induced cell killing was also not altered. These results suggest that low-dose radiation delivered to the male parents with a significant induction of cytogenetic adaptive response in their germ cell does not likely cause any risk of damaging effects to the offspring of those irradiated male mice.
在早期研究中我们已经表明，单次或多次暴露于低剂量X射线（0.05 Gy）会在小鼠生殖细胞中诱导显著的细胞遗传学适应性反应。在本文中，使用非常低剂量率（20微戈瑞/分钟）的慢性60Coγ射线照射对小鼠进行40天的预照射。然后，40天后，对这些小鼠进行后续大剂量X射线照射，24小时后对其精母细胞进行细胞遗传学分析。还对经慢性γ射线低剂量率适应的小鼠后代的脾细胞、骨髓细胞和精母细胞进行了辐射诱导的DNA和染色体损伤分析。结果表明：（i）以20微戈瑞/分钟的剂量率进行的累积γ射线照射（1.10 Gy）在小鼠生殖细胞（精原干细胞）中诱导了显著的细胞遗传学适应性反应；（ii）后代骨髓细胞和精母细胞对1.5 Gy X射线诱导的染色体畸变的敏感性不受传递给父本生殖细胞的低剂量辐射的影响；（iii）后代脾细胞中的组成型或照射后DNA修复能力（紫外线诱导的非计划DNA合成，UDS）未发生改变；（iv）后代脾细胞对辐射诱导的细胞杀伤的敏感性也未改变。这些结果表明，传递给雄性亲本并在其生殖细胞中显著诱导细胞遗传学适应性反应的低剂量辐射不太可能对那些受照射雄性小鼠的后代造成任何损害风险。
