毒死蜱暴露对蚯蚓的亚慢性神经毒性研究
Study of subchronic neurotoxicity of chlorpyrifos exposure to
earthworms
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摘要:蚯蚓作为土壤生态系统中重要的生物类群,在维持土壤生态系统的功能中起着重要作用。毒死蜱是我国使用量较大的有机磷农药品种之一,对以蚯蚓为代表的土壤生物具有潜在威胁。本课题选择云南林地常见的蚯蚓优势种-皮质远盲蚓(Amynthas corticis)为实验生物,从毒死蜱暴露引发的蚯蚓脑部神经递质(乙酰胆碱、多巴胺、5-羟色胺、谷氨酸)、离子通道特征酶(Ca2+-Mg2+-ATP、Ca2+-ATP酶)变化入手,对毒死蜱亚慢性神经毒性导致的蚯蚓运动、学习记忆等神经行为变化进行研究,运用综合毒性指数 IBR 评价蚯蚓生物标志物变化,开展毒死蜱暴露对蚯蚓的亚慢性神经毒性研究。结果表明,毒死蜱暴露引发了蚯蚓神经递质乙酰胆碱、多巴胺、5-羟色胺、谷氨酸的异常变化,毒死蜱对蚯蚓的神经损伤导致了蚯蚓的运动迟缓和学习记忆障碍。暴露 28d 时,8、12 mg·kg-1 毒死蜱对蚯蚓的IBR 值分别为 3.2275,4.5246;暴露 56d 时的 IBR 值分别为 3.8848,5.8995,毒死蜱对蚯蚓的亚慢性神经毒性随着毒死蜱暴露浓度、暴露时间增加而增强。研究发现毒死蜱慢性神经毒性虽然不会导致蚯蚓死亡,但其产生的蚯蚓运动迟缓、记忆障碍等神经行为变化,会严重影响蚯蚓的生存质量,不利于蚯蚓的生存和发展,将导致蚯蚓种群质量下降。由于蚯蚓在土壤生态系统中的重要作用,蚯蚓种群质量的下降将加剧土壤生态系统风险。Abstract:As a important biological species in soil ecosystems, earthworms play a significant role in maintaining the function of soil ecosystems. Chlorpyrifos is one of the most widely used organophosphorus pesticides in China, which is a potential threat to soil organisms represented by earthworms. This study used Amynthas corticis, a dominant species of earthworms commonly found in Yunnan woodlands, as the experimental organism to investigate the changes of neurotransmitters (acetylcholine, dopamine, 5-hydroxytryptamine, glutamic acid) and ion channel characteristic enzymes (Ca2+-Mg2+-ATPase, Ca2+-ATPase) in earthworm brain caused by chlorpyrifos exposure, the changes of earthworm neural behavior such as exercise, learning and memory caused by chlorpyrifos subchronic toxicity, evaluated the changes in earthworm biomarkers using the integrated biomarker response (IBR), and conducted a study of subchronic neurotoxicity of chlorpyrifos exposure in earthworms. The results showed that chlorpyrifos exposure caused abnormal changes in the earthworm neurotransmitters acetylcholine, dopamine, 5-hydroxytryptamine, and glutamate, and that neurological damage by chlorpyrifos led to motor retardation and learning and memory impairment in earthworms. The subchronic neurotoxicity IBR values of 8 and 12 mg·kg-1 chlorpyrifos for earthworms at 28 d exposure were 3.2275 and 4.5246, respectively. The IBR values at 56 d exposure were 3.8848 and 5.8995, respectively, and the subchronic neurotoxicity of chlorpyrifos to earthworms increased with increasing exposure concentration and time of exposure to chlorpyrifos. In summary, our study indicated that although chlorpyrifos subchronic neurotoxicity did not lead to earthworm mortality, it produced neurobehavioral changes in earthworms such as Bradykinesia and memory impairment, which could seriously affect the quality of earthworm survival and was detrimental to earthworm survival and development, leading to a decline in the quality of earthworm populations. Therefore, due to the important role of earthworms in soil ecosystems, a decline in the quality of earthworm populations will exacerbate soil ecosystem risks.
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Key words:
- Earthworms /
- Chlorpyrifos /
- Subchronic neurotoxicity /
- Neurobehavioral /
- Soil pollution
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