Medical Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada.
Dose Response. 2007 Nov 23;5(4):323-32. doi: 10.2203/dose-response.07-026.Cassidy.
Chinook salmon cells were exposed to gamma radiation and chromosome damage was assessed using the micronucleus assay. The salmon cells were resistant to radiation at all doses compared to human and mammalian cells. We used an indirect approach to determine if prior low dose exposures at environmental dose levels might alter the consequences of radiation exposures to high doses of radiation (adaptive response). The cells adapted but only at doses which were above levels that might be expected environmentally. The "adaptive response" endpoint was useful to show biological responses to exposure, however, under these conditions it might not help in risk assessment of aquatic organisms since the cells seem to be very resistant and environmental radiation levels are typically extremely low. Preliminary experiments were conducted on two other fish cell model systems (Rainbow Trout and Medaka) to optimize conditions for the micronucleus assay for future environmental radiation studies. Since fish cells appear to be more radiation resistant than mammalian cells, we postulate that radiation risk in the whole organism may also be lower. Therefore whole body studies designed to test effects with the specific aim of assessing relative risk between species are in process.
奇努克三文鱼细胞暴露在伽马射线下，使用微核试验评估染色体损伤。与人类和哺乳动物细胞相比，三文鱼细胞在所有剂量下都对辐射有抗性。我们使用间接方法来确定环境剂量水平下的先前低剂量暴露是否可能改变高剂量辐射暴露的后果（适应性反应）。细胞适应了，但仅在环境中可能预期的剂量以上。“适应性反应”终点对于显示暴露的生物学反应很有用，但是在这些条件下，它可能无助于水生生物的风险评估，因为细胞似乎非常耐受，而且环境辐射水平通常极低。在两种其他鱼类细胞模型系统（虹鳟鱼和青鳉鱼）上进行了初步实验，以优化未来环境辐射研究中微核试验的条件。由于鱼类细胞对辐射的抗性似乎比哺乳动物细胞更强，我们推测整个生物体的辐射风险也可能更低。因此，正在进行旨在测试特定物种之间相对风险的全身研究。
