State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China.
Department Evolutionary Ecology and Environmental Toxicology, Institute of Ecology, Evolution and Diversity, Faculty Biological Sciences, Goethe University Frankfurt, Frankfurt 60438, Germany; Department of Ecosystem Analysis, Institute for Environmental Research, ABBt - Aachen Biology and Biotechnology, RWTH Aachen University, Worringerweg 1, Aachen 52074, Germany.
Aquat Toxicol. 2020 Jul;224:105521. doi: 10.1016/j.aquatox.2020.105521. Epub 2020 May 24.
Microplastic pollution has drawn the attention of both scientists and the public regarding their potential ecotoxicological risks. In the present study, we carried out aqueous exposure experiments to adult zebrafish with polystyrene microplastics (5 μm) at a wide range of concentrations (0.001-20 mg/L, equals to 14.5∼2.9 × 10 particles/mL). Our results showed the gastrointestinal tract (GIT) was the dominant microplastic accumulation site in zebrafish, followed by the gill, whereas no microplastics were detected in the brain or muscle. Microplastic accumulation in GIT did not cause obvious damages to intestinal villi in general. However, the thickness of muscularis layer in the foregut reduced by 32% after 1 mg/L (1.45 × 10 particles/mL) microplastic exposure. As there were no signs of oxidative stress or other histological changes found in the fish, we further investigated the energy-supplying influential factors. We found that the zebrafish became hyperactive after microplastic exposure, whose swimming distance had increased to 1.3-2.4 folds than that of control, and also stayed at manic and active states much longer. The fish behavioural alteration is probably attributed to the particulate matter stimulation and the up-regulation of estrogen contents. Results also showed that the excessive movements of zebrafish also led to decreased glucose and acetaldehyde metabolite contents and increased amino acid amounts, which further proved the shortage of energy-supplying substances. Therefore, the present study suggests that micro-sized microplastics can induce obvious behavioural abnormality at concentrations that some other toxicological endpoints may not warn effects.
微塑料污染引起了科学家和公众的关注，因为它们可能具有潜在的生态毒性风险。在本研究中，我们用聚苯乙烯微塑料（5μm）对成年斑马鱼进行了水暴露实验，暴露浓度范围很广（0.001-20mg/L，相当于 14.5∼2.9×10 个颗粒/mL）。结果表明，斑马鱼的胃肠道（GIT）是微塑料的主要蓄积部位，其次是鳃，而大脑和肌肉中未检测到微塑料。一般来说，GIT 中的微塑料积累不会对肠绒毛造成明显损伤。然而，在 1mg/L（1.45×10 个颗粒/mL）微塑料暴露后，前肠的肌层厚度减少了 32%。由于鱼体没有出现氧化应激或其他组织学变化的迹象，我们进一步研究了供能的影响因素。我们发现，微塑料暴露后斑马鱼变得异常活跃，其游动距离增加到对照的 1.3-2.4 倍，并且保持活跃状态的时间更长。鱼的行为改变可能归因于颗粒物质的刺激和雌激素含量的上调。结果还表明，斑马鱼过度运动导致葡萄糖和乙醛代谢物含量降低，氨基酸含量增加，进一步证明了供能物质的短缺。因此，本研究表明，在某些其他毒理学终点可能没有警告作用的浓度下，微尺寸的微塑料可以诱导明显的行为异常。
