National Institute of Nutrition and Seafood Research, N-5817 Bergen, Norway.
J Environ Radioact. 2010 Mar;101(3):230-6. doi: 10.1016/j.jenvrad.2009.11.004. Epub 2009 Dec 6.
These experiments were designed to investigate transcriptional effects in Atlantic salmon (Salmo salar) after exposure in vivo to ionizing gamma radiation combined with subtoxic levels of aluminum (Al) and cadmium (Cd). Juvenile fish (35 g) in freshwater with or without Al and Cd (255 microg Al/L + 6 microg Cd/L) were exposed to a 75 mGy dose of gamma-irradiation, and induced responses were compared to those of controls. The transcriptional levels of eight genes encoding proteins known to respond to stress in fish were quantified in liver of fish exposed for 5 h to gamma radiation, to Al and Cd or to the combination of Al, Cd and gamma radiation. The studied genes were caspase 3B, caspase 6A, caspase 7, p53 (apoptosis), glutathione reductase (GR), phospholipid hydroperoxide glutathione peroxidase (GSH-Px), (oxidative stress), metallothionein (MT-A) (metal stress) and ubiquitin (Ubi) (protein degradation). The results showed that gamma-irradiation alone induced significant upregulation of caspase 6A, GR, GSH-Px, MT-A and Ubi compared to the control group, while 5 h exposure to Al+Cd alone did not induce any of the studied genes compared to the control. No significant upregulation of the series of investigated genes could be observed in fish exposed to gamma-irradiation in combination with Al+Cl. In conclusion, the results suggest that the presence of Al+Cd in the water counteracted the gamma-irradiation effect by modifying the transcription of genes encoding proteins involved in the defense mechanisms against free radicals in the cells.
这些实验旨在研究大西洋鲑（Salmo salar）在体内暴露于电离伽马辐射与亚毒性水平的铝（Al）和镉（Cd）联合作用后的转录效应。淡水环境中的幼鱼（35 克），无论是否含有 Al 和 Cd（255 微克 Al/L + 6 微克 Cd/L），均接受 75 mGy 剂量的伽马辐射暴露，将诱导的反应与对照组进行比较。在暴露于伽马辐射、Al 和 Cd 或 Al、Cd 和伽马辐射组合 5 小时后，对鱼类肝脏中已知对鱼类应激反应有响应的 8 种编码蛋白的基因的转录水平进行了定量。研究的基因包括 caspase 3B、caspase 6A、caspase 7、p53（凋亡）、谷胱甘肽还原酶（GR）、磷脂氢过氧化物谷胱甘肽过氧化物酶（GSH-Px）（氧化应激）、金属硫蛋白（MT-A）（金属应激）和泛素（Ubi）（蛋白降解）。结果表明，与对照组相比，单独的伽马辐射单独诱导 caspase 6A、GR、GSH-Px、MT-A 和 Ubi 的显著上调，而单独暴露于 Al+Cd 5 小时与对照组相比，没有诱导任何研究基因的表达。在暴露于伽马辐射与 Al+Cl 联合作用的鱼类中，未观察到所研究基因系列的显著上调。总之，结果表明，水中 Al+Cd 的存在通过改变细胞内自由基防御机制相关蛋白编码基因的转录，抵消了伽马辐射的作用。
