DEP对蚯蚓抗氧化酶系的影响及DNA损伤

邻苯二甲酸二乙酯(DEP)是一种常见的塑料添加剂,并因塑料制品大量广泛使用而进入土壤环境,但其对土壤动物的毒性及其机制并未完全阐明.本文以赤子爱胜蚓(Eisenia foetida)为研究对象,使其暴露于不同含量DEP的模拟污染土壤,以蚯蚓体内的抗氧化酶活性、ROS含量、GST活性、MDA含量和DNA损伤程度为评估参数,研究含DEP污染土壤对蚯蚓的毒性作用并分析其机制.结果表明,在DEP胁迫作用下,蚯蚓体内的抗氧化酶和谷胱甘肽-S-转移酶(GST)活性、活性氧自由基(ROS)均发生变化并导致基因损伤产生.在28d的实验周期内0.1~50 mg·kg-1DEP的胁迫下,ROS含量水平呈现增加状态,存在"剂量-效应"关系,并且过量的ROS引起脂质过氧化反应造成机体内MDA含量增加.在ROS和MDA共同作用下,蚯蚓体腔内的DNA受到损伤并且损伤程度与DEP含量存在"剂量-效应"关系.从实验结果可以看出,DEP可以对蚯蚓机体和DNA造成一定程度的损伤,表现出较强的生态毒理效应.

Oxidative Stress and DNA Damage Induced by DEP Exposure in Earthworms

Diethyl phthalate (DEP) is a plastic additive that entered the soil environment due to the extensive use of plastic products. However, its toxicity to soil animals and the associated toxicity mechanism were not completely understood. Eisenia foetida was selected as the research object and exposed to simulated contaminated soil with different concentrations of DEP. Antioxidant enzyme activity, reactive oxygen species (ROS) content, Glutathione-S-Transferase (GST) activity, Malondialdehyde (MDA) content and amount of DNA damage in the earthworms were used as evaluation parameters for the study. The results showed that under DEP stress, the activities of antioxidant enzymes, GST and ROS in earthworms changed and resulted in gene damage. Under the stress of 0.1-50 mg·kg^-1 DEP exposure during the 28 d experiment, the level of ROS increased and there was a "dose-effect" relationship. Excessive ROS gave rise to an increase of MDA content in the body from lipid peroxidation. Under the combined action of ROS and MDA, DNA in the body cavity of earthworm was damaged and there was also a "dose-effect" relationship between the degree of damage and the concentration of DEP. In summary, DEP may cause a certain degree of damage to organisms, with damage to the DNA of earthworms representing fairly strong eco-toxicological effects. Therefore, adequate attention should be paid to DEP disposal.