在麦穗鱼中硒（IV）和硒（VI）的生物积累和影响的差异。
The differences in bioaccumulation and effects between Se(IV) and Se(VI) in the topmouth gudgeon Pseudorasbora parva.
机构信息
Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China.
The Key Laboratory of Clean Combustion for Electricity Generation and Heat-Supply Technology, College of Energy and Power, Shenyang Institute of Engineering, Shenyang, 110136, China.
出版信息
Sci Rep. 2018 Sep 14;8(1):13860. doi: 10.1038/s41598-018-32270-z.
Selenium (Se) might be protective against oxidative stress at nutritional levels, but elevated Se concentrations in the diet has been revealed as the main culprit for the extinction of natural fish populations in Se-contaminated lakes. Though Se predominate as waterborne selenite (IV) and selenate (VI) in the water, the differences in bioaccumulation, effects (e.g., oxidative stress, antioxidants etc.) and molecular mechanisms between Se(IV) and Se(VI) have been relatively understudied in wild fish. In this study, the P. parva were exposed to waterborne Se (10, 200 and 1000 μg/L of Se(IV) or Se(VI)) and sampled at 4, 14 and 28 days. Bioaccumulation, tissue distributions of Se and following effects in different tissues were evaluated. The results showed that the levels of Se in the gills and intestine were significantly elevated with a seemingly concentration-dependent pattern in the Se(IV) treatment, with respectively 173.3% and 57.2% increase after 28 days of exposure, relative to that of Se(VI) treatment. Additionally, significant accumulation of Se was also observed in the muscle of Se(IV) treated fish. Se exposure increased the MDA levels in the brain and gills in the Se(IV) treatment, but less apparent in the Se(VI) treatment. Meanwhile, Se exposure lowered (at least 56%) the activity of GST in the gills, but increased the activity of AChE in the muscle (69%) and brain (50%) after 28 d. Most importantly, after 28 d of exposure, Se exposure caused significant decrease in GSH levels in the gills (at least 35%) and in all tissues examined at the highest test concentration. In general, the results showed that Se(IV) led to faster accumulation of Se than Se(VI) in P. parva, and the resulted lipid peroxidation was closely related to the levels of antioxidants, especially GSH. Our results suggest that the ecotoxicological effects of waterborne selenite and selenate differ in this freshwater species in the field.
硒（Se）在营养水平上可能对氧化应激具有保护作用，但饮食中高浓度的硒已被发现是受污染湖泊中天然鱼类灭绝的主要罪魁祸首。尽管硒在水中主要以水溶态亚硒酸盐（IV）和硒酸盐（VI）形式存在，但在野生鱼类中，硒（IV）和硒（VI）之间的生物累积、效应（如氧化应激、抗氧化剂等）和分子机制的差异相对研究较少。在这项研究中，斑马鱼幼鱼暴露于水溶态硒（10、200 和 1000μg/L 的硒（IV）或硒（VI））中，并在第 4、14 和 28 天取样。评估了生物累积、硒在组织中的分布以及不同组织中的后续效应。结果表明，在硒（IV）处理组中，鳃和肠道中的硒水平显著升高，呈浓度依赖性，与硒（VI）处理组相比，28 天后分别增加了 173.3%和 57.2%。此外，在硒（IV）处理组的肌肉中也观察到显著的硒积累。硒暴露在硒（IV）处理组中增加了大脑和鳃中的 MDA 水平，但在硒（VI）处理组中则不太明显。同时，硒暴露在 28d 后降低了鳃中 GST 的活性（至少 56%），但增加了肌肉（约 69%）和大脑（约 50%）中的 AChE 活性。最重要的是，暴露 28d 后，硒暴露导致鳃中 GSH 水平显著下降（至少 35%），在所有检测组织中，在最高测试浓度下也出现了这种情况。总的来说，结果表明，硒（IV）在斑马鱼幼鱼中的累积速度快于硒（VI），且由此产生的脂质过氧化与抗氧化剂水平密切相关，尤其是 GSH。我们的结果表明，在这种淡水物种中，水溶态亚硒酸盐和硒酸盐的生态毒理学效应不同。
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