Department of Biomedical Sciences, Atlantic Veterinary College, University of Prince Edward Island, 550 University Avenue, Charlottetown, PE, Canada C1A 4P3.
Ecotoxicol Environ Saf. 2011 May;74(4):658-67. doi: 10.1016/j.ecoenv.2010.10.016. Epub 2010 Oct 28.
The influence of metal-metal interactions on uptake, accumulation, plasma transport and chronic toxicity of dietary Cu, Cd and Zn in rainbow trout (Oncorhynchus mykiss) was explored. Juvenile rainbow trout were fed diets supplemented with (μg/g) 500 Cu, 1000 Zn and 500 Cd singly and as a ternary mixture at 2.5% body weight daily ration for 28 days. Complex interactions among the metals dependent on the tissue/organ, metals ratios and duration of exposure were observed. While Zn did not accumulate, whole-body Cd and Cu concentrations increased following linear and saturation patterns, respectively. Early enhanced whole-body Cu accumulation in fish exposed to the metals mixture was correlated with reduced Cd concentration whereas late enhancement of Cd accumulation corresponded with elevated Cd concentration. This suggests early mutual antagonism and late cooperation between Cd and Cu probably due to interactions at temporally variable metal accumulation sites. At the level of uptake, Cd and Cu were either antagonistic or mutually increased the concentrations of each other depending on the duration of exposure and section of the gut. At the level of transport, enhanced Cd accumulation in plasma was closely correlated with reduced concentrations of both Zn and Cu indicating competitive binding to plasma proteins and/or antagonism at uptake sites. Compared to the Cu alone exposure, Cu concentrations were either lower (gills and carcasses) or higher (liver and kidney) in fish exposed to the metals mixture. On the other hand, Cd accumulation was enhanced in livers and carcasses of fish exposed to the mixture compared to those exposed to Cd alone, while Zn stimulated Cu accumulation in gills. Chronic toxicity was demonstrated by elevated malondialdehyde levels in livers and reduced concentrations of Zn and Cu in plasma. Overall, interactions of Cd, Cu and Zn are not always consistent with the isomorphous competitive binding theory.
研究了金属-金属相互作用对虹鳟（Oncorhynchus mykiss）摄入、积累、血浆转运和慢性毒性的影响。用（μg/g）500Cu、1000Zn 和 500Cd 单独和作为三元混合物以 2.5%体重日摄食量喂养 28 天的幼虹鳟。观察到金属之间的复杂相互作用取决于组织/器官、金属比例和暴露时间。虽然 Zn 没有积累，但全身 Cd 和 Cu 浓度分别按照线性和饱和模式增加。暴露于金属混合物的鱼中早期增强的全身 Cu 积累与降低的 Cd 浓度相关，而晚期增强的 Cd 积累与升高的 Cd 浓度相对应。这表明 Cd 和 Cu 之间早期存在相互拮抗作用，晚期存在合作作用，可能是由于在时间变化的金属积累部位发生相互作用。在吸收水平上，Cd 和 Cu 之间要么相互拮抗，要么相互增加对方的浓度，具体取决于暴露时间和肠道的不同部位。在转运水平上，血浆中 Cd 积累增强与 Zn 和 Cu 浓度降低密切相关，表明与血浆蛋白竞争结合和/或在吸收部位拮抗。与单独暴露 Cu 相比，暴露于金属混合物的鱼中的 Cu 浓度要么更低（鳃和尸体），要么更高（肝脏和肾脏）。另一方面，与单独暴露 Cd 相比，暴露于混合物的鱼的肝脏和尸体中的 Cd 积累增加，而 Zn 刺激了鳃中的 Cu 积累。肝脏中丙二醛水平升高和血浆中 Zn 和 Cu 浓度降低表明存在慢性毒性。总的来说，Cd、Cu 和 Zn 的相互作用并不总是与同晶竞争结合理论一致。
