Laboratoire de Radioécologie de Cherbourg-Octeville, Institut de Radioprotection et de Sûreté Nucléaire/DEI/SECRE, Cherbourg-Octeville, France.
Radiat Res. 2011 Jul;176(1):38-48. doi: 10.1667/rr2525.1. Epub 2011 May 16.
In the North-Cotentin (Normandy, France), the marine environment is chronically exposed to liquid releases from the La Hague nuclear fuel recycling plant (Areva NC), resulting in a small increase in radioactivity compared to natural background. The transcriptional expression levels of stress genes were investigated in oysters exposed to ionizing radiation. Adult oysters were kept for 6 weeks in (60)Co-labeled seawater (400 Bq liter(-1)), resulting in a total dose of 6.2 mGy. Transcriptional expression of target genes was monitored by reverse-transcription quantitative polymerase chain reaction. Nine genes were selected for their sensitivity to ionizing radiation based on the literature and available DNA sequences. They included genes encoding chaperone proteins and genes involved in oxidative stress regulation, cell detoxification and cell cycle regulation. Of the nine genes of interest, metallothionein (MT) and multi-drug resistance (MDR) displayed significant overexpression in response to chronic exposure to an internal low dose. For comparison, oysters were acutely exposed to an external high dose for 100 min, resulting in 20 Gy, and the same target gene expression analysis was carried out. As in the case of chronic exposure to the low dose, MT and MDR displayed significant increases. The results suggest that the transcriptional expression levels of cell stress genes may be used as a biosensor of exposure of oysters to ionizing radiation, with a particular focus on the MT and MDR genes. However, the upregulation of these potential players in the cellular response to radiation-induced stress was not correlated with mortality or apparent morbidity. The possible role of these stress genes in the resistance of oysters to ionizing radiation is discussed.
在北科唐（诺曼底，法国），海洋环境长期受到拉阿格核燃料再处理厂（阿海珐集团）的液体排放物的放射性污染，与自然背景相比，放射性略有增加。本研究调查了受电离辐射影响的牡蛎中应激基因的转录表达水平。成年牡蛎在（60）Co 标记的海水中（400 Bq 升(-1)) 暴露 6 周，总剂量为 6.2 mGy。通过反转录定量聚合酶链反应监测靶基因的转录表达。根据文献和现有 DNA 序列，选择 9 个对电离辐射敏感的基因。这些基因包括伴侣蛋白基因和参与氧化应激调节、细胞解毒和细胞周期调节的基因。在所关注的 9 个基因中，金属硫蛋白（MT）和多药耐药（MDR）基因在慢性低剂量内暴露时表现出明显的过度表达。相比之下，牡蛎急性暴露于外部高剂量 100 分钟，剂量为 20 Gy，并进行了相同的靶基因表达分析。与慢性低剂量暴露的情况一样，MT 和 MDR 基因表达显著增加。结果表明，细胞应激基因的转录表达水平可用作牡蛎暴露于电离辐射的生物传感器，特别是 MT 和 MDR 基因。然而，这些细胞对辐射应激反应的潜在参与者的上调与死亡率或明显发病率无关。讨论了这些应激基因在牡蛎对电离辐射抗性中的可能作用。
