Methomyl (MET) is a carbamate insecticide that has been widely used to protect the crop against insects as an alternative for organophosphorus insecticide. Thus the present study aims to evaluate the potential toxic effects of MET on the developmental stages of Bufo arabicus. Tadpoles were classified into three stages (25, 37, 40). Every stage was divided into two groups, control and MET-treated group (10 ppm for two weeks) after LC50 determination in acute toxicity test for 96 h. Control and MET-treated larvae were examined at the level of morphological, histological, skeleton deformities and immunohistochemical labeling of alpha-synuclein in the spinal cord and dorsal root ganglion. MET-exposed larvae showed hyperactivity, extreme agitation, abnormal swimming and kinking tail as compared to control. Alizarin Red S-Alcian blue staining showed scoliosis in MET-treated tadpoles at 25 and 37 stages; kyphosis, retarded tail regression and reduced ossification of the phalanges of digits for both fore-and hind limbs were noted in MET-exposed tadpoles at 40 stage as compared to control. Histopathological changes in myotomes, notochord and spinal cord were shown in MET-exposed tadpoles as compared to control. Immunohistochemical examination showed an over expression of alpha-synuclein either in the neurons of the spinal cord or in the dorsal root ganglion of MET-exposed tadpoles at stage 40 as compared to control. The present study concluded that MET insecticide induces malformation and teratogenicity effects which were accompanied by neurodegenerative effects for the neurons either in the spinal cord or in the dorsal root ganglion.

中文翻译：

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灭多威杀虫剂对中华大蟾蜍发育阶段的致畸性和神经毒性作用。

甲基苯丙胺（MET）是一种氨基甲酸酯杀虫剂，已被广泛用于保护农作物免受昆虫侵害，作为有机磷杀虫剂的替代品。因此，本研究旨在评估MET对非洲蟾蜍发育阶段的潜在毒性作用。分为三个阶段（25、37、40）。在急性毒性试验中LC50测定96小时后，将每个阶段分为两组，即对照组和MET治疗组（10 ppm，持续两周）。对照和MET处理的幼虫在脊髓和背根神经节中的α-突触核蛋白的形态，组织学，骨骼畸形和免疫组化标记水平上进行了检查。与对照相比，暴露于MET的幼虫表现出活动过度，剧烈躁动，异常游泳和扭结尾巴。茜素红S-Alcian蓝染色在MET处理的t中分别在25和37个阶段出现了脊柱侧凸。与对照组相比，在暴露于MET的t中，在40阶段时，发现后肢的后凸，延迟的尾巴退缩和手指趾骨骨化减少。与对照组相比，在暴露于MET的shown中显示了组织学，脊索和脊髓的组织病理学变化。免疫组织化学检查显示，与对照组相比，第40阶段暴露于MET的t的脊髓神经元或背根神经节中α-突触核蛋白过表达。本研究得出结论，MET杀虫剂会引起畸形和致畸作用，并伴有脊髓或背根神经节中神经元的神经变性作用。