Department of Environment, Faculty of Natural Resources and Environment, Malayer University, Malayer, 95863-65719, Iran.
Department of Environment, Faculty of Natural Resources and Environment, Malayer University, Malayer, 95863-65719, Iran.
Chemosphere. 2020 Jan;238:124595. doi: 10.1016/j.chemosphere.2019.124595. Epub 2019 Aug 14.
Earthworms are often used as test subjects in toxicological studies, due to their ubiquitousness and sensitivity to contaminant exposure. Such testing is typically conducted using Eisenia fetida as the test subject, but continued use of E. fetida (eco) toxicology is questionable. Therefore, in this study three earthworm species, Aporrectodea rosea, Aporrectodea trapezoides and E. fetida, were exposed to lethal and sublethal concentrations of cadmium (Cd) and lead (Pb) nitrate in artificial soil for 7, 14 and 28 days. A biomarker of genotoxicity (TUNEL assay), biochemical markers [malondialdehyde (MDA) and total antioxidant capacity (TAC)], weight loss, lethal toxicity (LC) and subcellular partitioning were assessed. Cadmium and Pb caused significant inhibition in TAC and growth and significant increases in DNA damage and lipid peroxidation in the earthworms. Acute toxicity rank (14 days) for both Cd and Pb were E. fetida > A. trapezoides > A. rosea. Subcellular partitioning of Cd and Pb in the earthworms were cytosol > debris > granules and debris > granules > cytosol, respectively. Comparison of biomarker responses between study species showed that E. fetida proved to be less susceptible to Cd and Pb exposure than A. rosea and A. trapezoides. Therefore, this study confirms that A. rosea and A. trapezoides are more suitable as subjects than E. fetida for the soil toxicity tests, because of both their greater susceptibility to toxicants and in their abundance in the field.
蚯蚓通常被用作毒理学研究的试验对象，因为它们分布广泛，对污染物暴露敏感。这种测试通常使用赤子爱胜蚓作为试验对象，但继续使用赤子爱胜蚓进行（生态）毒理学研究是值得怀疑的。因此，在这项研究中，三种蚯蚓物种，即红色爱胜蚓、威廉环毛蚓和赤子爱胜蚓，在人工土壤中暴露于致死和亚致死浓度的镉（Cd）和铅（Pb）硝酸盐中 7、14 和 28 天。采用 DNA 损伤的生物标志物（TUNEL 测定法）、生化标志物[丙二醛（MDA）和总抗氧化能力（TAC）]、体重减轻、致死毒性（LC）和亚细胞分配来评估。镉和铅导致 TAC 和生长显著抑制，以及蚯蚓体内 DNA 损伤和脂质过氧化显著增加。在急性毒性（14 天）方面，Cd 和 Pb 对赤子爱胜蚓的毒性大于威廉环毛蚓大于红色爱胜蚓。镉和铅在蚯蚓体内的亚细胞分配分别为胞质溶胶＞残渣＞颗粒和残渣＞颗粒＞胞质溶胶。研究物种之间生物标志物反应的比较表明，与红色爱胜蚓和威廉环毛蚓相比，赤子爱胜蚓对 Cd 和 Pb 暴露的敏感性较低。因此，本研究证实，与赤子爱胜蚓相比，红色爱胜蚓和威廉环毛蚓更适合作为土壤毒性测试的试验对象，因为它们对毒物的敏感性更高，并且在野外更为丰富。
