Mouchet F, Gauthier L, Mailhes C, Jourdain M J, Ferrier V, Devaux A
Laboratoire d'Ecologie des Hydrosystèmes, Centre Universitaire de formation et de Recherche Jean-François Champollion, Campus d'Albi, Albi cedex, France.
J Toxicol Environ Health A. 2005 May 28;68(10):811-32. doi: 10.1080/15287390590930234.
Management of contaminated dredged sediments is a matter of great human concern. The present investigation evaluates the genotoxic potential of aqueous extracts of five sediments from French channels (draining water from dredged sediments), using larvae of the frog Xenopus laevis. Two genotoxic endpoints were analyzed in larvae: clastogenic and/or aneugenic effects (micronucleus induction after 12 d of exposure) and DNA-strand breaking potency (comet assay after 1 and 12 d of exposure) in the circulating blood. Additionally, in vitro bacterial assays (Microtox and Ames tests) were carried out and the results were compared with those obtained with larvae. Physicochemical analyses were also taken into account. Analytical analyses highlighted in the five draining waters a heavy load of contaminants such as metals and hydrocarbons. The results obtained with the micronucleus test established the genotoxicity of three draining waters. The comet assay showed that all 5 draining waters were genotoxic after 1 d of exposure. Although 3 of them were still genotoxic after 12 d of exposure, DNA damage globally decreased between d 1 and 12. The comet assay can be considered as a genotoxicity-screening tool. Data indicate that both tests should be used in conjunction in Xenopus. Bacterial tests (Ames) revealed genotoxicity for only one draining water. The results confirm the relevance of the amphibian model and the need to resort to bioassays in vivo such as the Xenopus micronucleus and comet assays for evaluation of the ecotoxicological impact, an essential complement to the physicochemical data.
受污染疏浚沉积物的管理是备受人类关注的问题。本研究使用非洲爪蟾的幼体，评估了来自法国海峡的五种沉积物（疏浚沉积物排水）水提取物的遗传毒性潜力。对幼体分析了两个遗传毒性终点：致断裂和/或非整倍体效应（暴露12天后的微核诱导）以及循环血液中的DNA链断裂能力（暴露1天和12天后的彗星试验）。此外，还进行了体外细菌试验（Microtox和Ames试验），并将结果与幼体试验结果进行比较。同时也考虑了物理化学分析。分析表明，这五种排水中含有大量金属和碳氢化合物等污染物。微核试验结果证实了三种排水具有遗传毒性。彗星试验表明，所有5种排水在暴露1天后均具有遗传毒性。虽然其中3种在暴露12天后仍具有遗传毒性，但DNA损伤在第1天至第12天总体上有所下降。彗星试验可被视为一种遗传毒性筛选工具。数据表明，在非洲爪蟾试验中应同时使用这两种试验。细菌试验（Ames试验）仅显示一种排水具有遗传毒性。结果证实了两栖动物模型的相关性，以及需要采用体内生物测定法，如非洲爪蟾微核试验和彗星试验，来评估生态毒理学影响，这是对物理化学数据的重要补充。
