Institute for Radiological Protection and Nuclear Safety, Radiological Protection and Human Health Division, Radiobiology and Epidemiology Department, Laboratory of Experimental Toxicology, Fontenay-aux-Roses Cedex, France.
J Radiat Res. 2010;51(1):37-45. doi: 10.1269/jrr.09064.
The Chernobyl accident released many radionuclides in the environment. Some are still contaminating the ground and thus the people through dietary intake. The long-term sanitary consequences of this disaster are still unclear and several biological systems remain to be investigated. Cholesterol metabolism is of particular interest, with regard to the link established between atherosclerosis and exposure to high-dose ionizing radiations. This study assesses the effect of cesium-137 on cholesterol metabolism in rats, after a chronic exposure since fetal life. To achieve this, rat dams were contaminated with cesium-137-supplemented water from two weeks before mating until the weaning of the pups. Thereafter, the weaned rats were given direct access to the contaminated drinking water until the age of 9 months. After the sacrifice, cholesterol metabolism was investigated in the liver at gene expression and protein level. The cholesterolemia was preserved, as well as the cholesterol concentration in the liver. At molecular level, the gene expressions of ACAT 2 (a cholesterol storage enzyme), of Apolipoprotein A-I and of RXR (a nuclear receptor involved in cholesterol metabolism) were significantly decreased. In addition, the enzymatic activity of CYP27A1, which catabolizes cholesterol, was increased. The results indicate that the rats seem to adapt to the cesium-137 contamination and display modifications of hepatic cholesterol metabolism only at molecular level and within physiological range.
切尔诺贝利事故向环境中释放了许多放射性核素。一些放射性核素仍在通过饮食摄入污染土壤和人们。这场灾难的长期卫生后果仍不清楚，仍有几个生物系统需要研究。胆固醇代谢是特别值得关注的，因为已经证实动脉粥样硬化与暴露于高剂量电离辐射之间存在联系。本研究评估了慢性暴露于放射性核素铯-137对大鼠胆固醇代谢的影响，这种慢性暴露始于胚胎生命前两周的母体接触，一直持续到幼崽断奶。此后，断奶大鼠可以直接接触受污染的饮用水，直到 9 个月大。牺牲后，在基因表达和蛋白质水平上研究了肝脏中的胆固醇代谢。结果显示，胆固醇血症和肝脏中的胆固醇浓度保持不变。在分子水平上，胆固醇储存酶 ACAT2、载脂蛋白 A-I 和参与胆固醇代谢的核受体 RXR 的基因表达显著降低。此外，分解胆固醇的 CYP27A1 的酶活性增加。这些结果表明，大鼠似乎适应了铯-137 的污染，仅在分子水平和生理范围内显示出肝脏胆固醇代谢的变化。
