Center for Environment and Water Resources, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, PR China.
School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, UK.
J Hazard Mater. 2020 Jun 5;391:122153. doi: 10.1016/j.jhazmat.2020.122153. Epub 2020 Jan 21.
The metabolic process and toxicity mechanism of dietary inorganic arsenic (iAs) in freshwater fish remain unclear to date. The present study conducted two iAs [arsenate (As(V)) and arsenite (As(III))] dietary exposures in freshwater fish crucian carp (Carassius auratus). The fish were fed on As supplemented artificial diets at nominal concentrations of 50 and 100 μg As(III) or As(V) g (dry weight) for 10 d and 20 d. We found that the liver, kidney, spleen, and intestine of fish accumulated more As in As(V) feeding group than that in As(III), while the total As levels in muscle were similar between As(V) and As(III) group at the end of exposure. Reduction of As(V) to As(III) and oxidation of As(III) to As(V) occurred in fish fed with As(V) and As(III), respectively, indicating that toxicity of iAs was likely elevated or reduced when iAs was absorbed by fish before entering into human body through diet. Biomethylation to monomethylarsonic acid and dimethylarsinic acid and transformation to arsenocholine and arsenobetaine were also found in the fish. The linear regression analysis showed a positive correlation between secondary methylation index and the malondialdehyde content in tissues, highlighting the vital role of arsenic dimethylation in the oxidative damages in fish.
目前，淡水鱼中膳食无机砷（iAs）的代谢过程和毒性机制仍不清楚。本研究在淡水鱼鲫鱼（Carassius auratus）中进行了两种 iAs（砷酸盐（As(V)）和亚砷酸盐（As(III)））的膳食暴露实验。将鲫鱼喂食含砷的人工饲料，名义浓度分别为 50 和 100μg As(III)或 As(V)g（干重），暴露时间分别为 10 天和 20 天。我们发现，与喂食 As(III)相比，喂食 As(V)的鱼的肝脏、肾脏、脾脏和肠道中积累了更多的砷，而在暴露结束时，肌肉中的总砷水平在 As(V)和 As(III)组之间相似。在喂食 As(V)和 As(III)的鱼中，分别发生了 As(V)向 As(III)的还原和 As(III)向 As(V)的氧化，这表明当 iAs 通过饮食进入人体之前被鱼吸收时，iAs 的毒性可能会升高或降低。在鱼体内还发现了砷的一甲基化生成一甲基胂酸和二甲基砷酸，以及三甲基砷化氧和三甲基胂甜菜碱的转化。线性回归分析显示，次级甲基化指数与组织中丙二醛含量呈正相关，这突出了砷的二甲基化在鱼的氧化损伤中的重要作用。
