Diethyl phthalate (DEP) has been widely used as a plasticiser in various consumer products, including cosmetics, personal care items, and pharmaceuticals, and recent studies reported a higher abundance of this priority phthalate in the aquatic environment. DEP is a potential endocrine disruptor, affecting immune systems in humans and wildlife even at low-level chronic exposure. As concern over phthalates increases globally, regulatory bodies focus more on their environmental impact. However, limited research is available, particularly using model organisms like planarians. Planarians are ideal for toxicological studies and may provide insightful information on pollutants' neurotoxic, developmental, and ecological effects, especially in freshwater environments where planarians play a vital role in ecosystem balance. Therefore, the objective of the current study was to examine the toxicity of DEP using the freshwater Dugesia sp., as an experimental animal. The LC50 for the test organism was calculated using DEP concentrations of 800, 400, 200, 100, and 50 µM, with an estimated LC50 of 357.24 µM. Furthermore, planarians were exposed to sub-lethal DEP concentration (178.62 µM) for one day as well as eight days to evaluate the impact of DEP on planarian locomotion, feeding behaviour, and regeneration ability. At sub-lethal concentration, locomotion and feeding ability were decreased, and regeneration was delayed. Furthermore, neuro-transmittance in planaria was altered by sub-lethal DEP concentration, as indicated by a reduced acetylcholinesterase (AChE) activity. DEP exposure induced oxidative damage in the tested planarians as shown by a marked increase in stress biomarkers, including lipid peroxidation levels and antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), peroxidase (POX), and glutathione S-transferase (GST). Our study revealed that DEP exposure may prove fatal to freshwater organisms, such as planarians. The observed alterations in behaviour and regeneration ability demonstrate the severity of the effects exerted by DEP as a toxicant in aquatic ecosystems, thereby indicating the need to restrict its usage to protect aquatic environments.

中文翻译：

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邻苯二甲酸二乙酯对淡水涡虫行为、再生和抗氧化防御的影响


邻苯二甲酸二乙酯 （DEP） 已被广泛用作各种消费品中的增塑剂，包括化妆品、个人护理用品和药品，最近的研究报告称，这种优先邻苯二甲酸酯在水生环境中的丰度更高。DEP 是一种潜在的内分泌干扰物，即使在低水平慢性暴露下也会影响人类和野生动物的免疫系统。随着全球对邻苯二甲酸酯的关注度增加，监管机构更加关注其对环境的影响。然而，可用的研究有限，特别是使用涡虫等模式生物。涡虫是毒理学研究的理想选择，可以提供有关污染物的神经毒性、发育和生态影响的有见地的信息，尤其是在涡虫在生态系统平衡中起着至关重要作用的淡水环境中。因此，本研究的目的是使用淡水 Dugesia sp. 作为实验动物来检验 DEP 的毒性。使用 800、400、200、100 和 50 μM 的 DEP 浓度计算测试生物体的 LC50，估计 LC50 为 357.24 μM。此外，涡虫暴露于亚致死性 DEP 浓度 （178.62 μM） 1 天和 8 天，以评估 DEP 对涡虫运动、摄食行为和再生能力的影响。在亚致死浓度时，运动和摄食能力降低，再生延迟。此外，亚致死 DEP 浓度改变了涡虫中的神经传递率，如乙酰胆碱酯酶 （AChE） 活性降低所示。 DEP 暴露在测试的涡虫中诱导氧化损伤，如应激生物标志物的显着增加所示，包括脂质过氧化水平和抗氧化酶，如超氧化物歧化酶 （SOD）、过氧化氢酶 （CAT）、过氧化物酶 （POX） 和谷胱甘肽 S-转移酶 （GST）。我们的研究表明，DEP 暴露可能对淡水生物（例如涡虫）致命。观察到的行为和再生能力的变化表明 DEP 作为水生生态系统中的毒物所施加的影响的严重性，从而表明需要限制其使用以保护水生环境。