Glyphosate is the active ingredient of some of the most highly produced and used herbicides worldwide. The intensive applications of glyphosate-based herbicides and its half-life in water lead to its presence in many aquatic ecosystems. Whereas recent studies have reported neurotoxic effects of glyphosate including autism-related effects, most of them used extremely high (mg/L to g/L) concentrations, so it is still unclear if chronic, low environmentally relevant concentrations of this compound (ng/L to μg/L) can induce neurotoxicity. In this study we analyzed the neurotoxicity of glyphosate in adult zebrafish after waterborne exposure to environmentally relevant concentrations (0.3 and 3 μg/L) for two weeks. Our data showed that exposed fish presented a significant impairment of exploratory and social behaviors consistent with increased anxiety. The anterior brain of the exposed fish presented a significant increase in dopamine and serotonin levels, as well as in the DOPAC/dopamine and homovanillic acid/dopamine turnover ratios. Moreover, the expression of genes involved in the dopaminergic system, as th1, th2, comtb, and scl6a3 was downregulated. Finally, the brain of exposed fish presented a significant increase in the catalase and superoxide dismutase activities, with a concomitant decrease of glutathione stores. These changes in the antioxidant defense system are consistent with the observed increase in oxidative stress, reflected by the increase in the levels of lipid peroxidation in the brain. The presented results show that current glyphosate concentrations commonly found in many aquatic ecosystems may have detrimental consequences on fish survival by decreasing exploration of the environment or altering social interactions. Furthermore, as zebrafish is also a vertebrate model widely used in human neurobehavioral studies, these results are relevant not only for environmental risk assessment, but also for understanding the risk of chronic low-dose exposures on human health.

草甘膦是世界上某些产量最高和使用最广泛的除草剂的活性成分。草甘膦基除草剂的大量应用及其在水中的半衰期导致其在许多水生生态系统中的存在。尽管最近的研究报道了草甘膦的神经毒性作用，包括与自闭症相关的作用，但大多数都使用了极高的浓度（mg / L至g / L），因此，尚不清楚该化合物是否长期，与环境有关的低浓度（ng / L L至μg/ L）可诱导神经毒性。在这项研究中，我们分析了水暴露于环境相关浓度（0.3和3μg/ L）两周后，成年斑马鱼中草甘膦的神经毒性。我们的数据表明，裸露的鱼对探索和社交行为的严重损害与焦虑加剧相一致。裸露的鱼的前脑呈现出多巴胺和5-羟色胺水平的显着增加，以及DOPAC /多巴胺和高香草酸/多巴胺的周转率显着增加。此外，涉及多巴胺能系统的基因表达th1，th2，comtb和scl6a3被下调了。最后，裸露的鱼类的大脑在过氧化氢酶和超氧化物歧化酶活性方面显着增加，同时谷胱甘肽贮存量也随之减少。抗氧化剂防御系统的这些变化与所观察到的氧化应激增加相一致，反映在大脑中脂质过氧化水平的增加上。提出的结果表明，许多水生生态系统中普遍存在的当前草甘膦浓度可能通过减少对环境的探索或改变社会互动而对鱼类的生存产生不利影响。此外，由于斑马鱼还是人类神经行为研究中广泛使用的脊椎动物模型，因此这些结果不仅与环境风险评估有关，