Hossain M, Uma Devi P
Department of Radiobiology, Kasturba Medical College, India.
Int J Radiat Biol. 2000 Oct;76(10):1397-402. doi: 10.1080/09553000050151673.
To study long-term changes in the adult locomotor activity of mice after exposure to gamma radiation at the early fetal stage of development.
Pregnant Swiss albino mice were exposed locally on the abdominal area to a single dose of 0.25-1.5 Gy of 60Co gamma radiation at the dose rate of 1 Gy/min. When the F1 offspring were 6 months old, their locomotor and exploratory behaviour was assessed by the open-field and dark/bright arena tests. Animals were again subjected to the dark/bright arena test at 12 and 18 months of age in order to study the persistence of the effects.
Irradiation produced a noticeable disturbance in the normal behaviour pattern of the mice. There was a significant dose-dependent decrease in the open-field activity of 6-month-old mice. In the dark/bright arena test, the time spent and lines crossed in the dark area showed a significant decrease, while their activities in the brightly lit area increased significantly, indicating a reduced aversion to bright light. These effects were evident even at a dose of 0.3 Gy and increased linearly with dose. The significant behavioural changes persisted at 12 months, but at 18 months the difference in the time spent and lines crossed in the dark and bright areas were not significantly different from sham-irradiated control values below 0.5 Gy.
These results show that day 14 of gestation in Swiss albino mice is a time of high risk for inducing long-term changes in the adult locomotor function by gamma-radiation doses below 1 Gy. Using a range of radiation doses and different observation times we have demonstrated that the effect increases linearly with dose, but there appears to be a threshold of 0.3-0.5 Gy for producing significant persistent changes in the adult ambulatory activity.
研究小鼠在发育早期胎儿阶段暴露于γ辐射后成年期运动活动的长期变化。
怀孕的瑞士白化小鼠腹部局部接受单次剂量为0.25 - 1.5 Gy的60Coγ辐射，剂量率为1 Gy/分钟。当F1代后代6个月大时，通过旷场试验和明暗箱试验评估其运动和探索行为。为研究效应的持续性，在动物12个月和18个月大时再次进行明暗箱试验。
辐射对小鼠的正常行为模式产生了明显干扰。6个月大小鼠的旷场活动存在显著的剂量依赖性降低。在明暗箱试验中，小鼠在暗区停留的时间和穿越的线条数显著减少，而在明亮区域的活动显著增加，表明对强光的厌恶减少。即使在0.3 Gy的剂量下这些效应也很明显，并随剂量呈线性增加。显著的行为变化在12个月时仍然存在，但在18个月时，低于0.5 Gy剂量组在暗区和亮区停留时间及穿越线条数的差异与假照射对照组相比无显著差异。
这些结果表明，瑞士白化小鼠妊娠第14天是一个高风险时期，低于1 Gy的γ辐射剂量可诱导成年期运动功能的长期变化。通过使用一系列辐射剂量和不同观察时间，我们证明了效应随剂量呈线性增加，但在成年期行走活动中产生显著持续变化似乎存在0.3 - 0.5 Gy的阈值。
