Abstract：
Dimethoate (DMT) is one of the most harmful and commonly used organophosphate pesticides in agricultural lands to control different groups of parasitic insects. However, this pesticide is considered a dangerous pollutant for aquatic organisms following its infiltration in coastal ecosystems through leaching. Yet, our investigation aimed to gain new insights into the toxicity mechanism of DMT in the muscles of the green crab Carcinus aestuarii, regarding oxidative stress, neurotransmission impairment, histological aspects, and changes in lipid composition, assessed for the first time on the green crab\'s muscle. Specimens of C. aestuarii were exposed to 50, 100, and 200 µg DMT L-1 for 24 h. Compared to the negative control group, the higher the DMT concentration, the lower the saturated fatty acids (SFA), and the higher the monounsaturated fatty acids (MUFA). The significant increase in polyunsaturated fatty acid n-6 (PUFA n-6) was related to the high release, mainly, of linoleic acid (LA, C18: 2n6) and arachidonic acid (ARA, C20: 4n6) levels. Biochemical biomarkers showed that DMT exposure promoted oxidative stress, highlighted by increased levels of hydrogen peroxide (H2O2), malondialdehyde (MDA), advanced oxidation protein product levels (AOPP), and protein carbonyl (PCO). Furthermore, the antioxidant defense system was activated, as demonstrated by the significant changes in the enzymatic activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and reduced glutathione (GSH) levels associated with an adaptation process of C. aestuarii to cope with the DMT exposure. This pesticide significantly impairs the neurotransmission process, as evidenced by the inhibition of acetylcholinesterase (AChE) activity. Finally, several histopathological changes were revealed in DMT-treated crabs, including vacuolation, and muscle bundle loss.This research offered new insights into the toxic mechanism of DMT, pointing to the usefulness of fatty acid (FA) composition as a sensitive biomarker in littoral crabs.
摘要：
乐果酸盐（DMT）是农田中最有害且最常用的有机磷农药之一，用于控制不同种类的寄生虫。然而,这种农药通过浸出渗入沿海生态系统后，被认为是水生生物的危险污染物。然而，我们的研究旨在获得对DMT在绿蟹Carcinusaestuarii肌肉中的毒性机制的新见解，关于氧化应激，神经传递障碍，组织学方面，和脂质成分的变化，第一次评估了青蟹的肌肉。将C.aestuarii的标本暴露于50、100和200µgDMTL-1中24小时。与阴性对照组相比，DMT浓度越高,饱和脂肪酸(SFA)越低，单不饱和脂肪酸（MUFA）越高。多不饱和脂肪酸n-6(PUFAn-6)的显著增加与高释放有关,主要是,亚油酸(LA，C18：2n6）和花生四烯酸（ARA，C20:4n6)水平。生化生物标志物显示DMT暴露促进氧化应激,过氧化氢(H2O2)含量增加，丙二醛（MDA），高级氧化蛋白产物水平（AOPP），和蛋白质羰基（PCO）。此外，抗氧化防御系统被激活,如超氧化物歧化酶（SOD）的酶活性的显着变化所证明的，过氧化氢酶(CAT),谷胱甘肽过氧化物酶（GPx），和减少与C.aestuarii适应过程相关的谷胱甘肽（GSH）水平以应对DMT暴露。这种杀虫剂会显著损害神经传递过程，如乙酰胆碱酯酶（AChE）活性的抑制所证明。最后,在DMT处理的螃蟹中发现了几种组织病理学变化，包括空泡,和肌肉束损失。这项研究为DMT的毒性机制提供了新的见解，指出脂肪酸（FA）成分作为一种敏感的生物标志物的有用性。
