土壤中低剂量有机磷酸酯阻燃剂对蚯蚓的毒性效应及致毒机制研究

Environmental and ecological effects of organophosphorus ester flame retardants (OPEs) which are defined as a “re-emerging” pollutants in the international environmental scicence field, have already become one of the hot research projects in the whole world. This project will use earthworms, a terrestrial invertebrate animal model, to study the biological toxic effects from OPEs exposure. Depending on exposure and toxic effect situation of OPEs, the study will focus on the biological effects of low-dose, long-term exposure to OPEs, based on the acute lethal toxicity and avoidance behavior effects to Eisenia fetida. Combined with the enzyme toxicity,organ and DNA damage of OPEs to earthworms, the biological omics technologies (genomics and metabonomics) will be studied on individual, cellular and molecular levels to elucidate the toxicity mechanism of OPEs. Moreover, the eathworms and soils from OPEs pollution sites were detected with biological omics technologies. The results will be compared to the toxic effects of OPEs exposure of laboratory results. This study will provide scientific knowledge to reveal the potential environmental impact and risk to the ecosystem after the release of OPEs to the pedosphere, and to provide theoretical support for OPEs pollution control and environmental evaluation.

有机磷酸酯（OPEs）阻燃剂是目前国际环境领域又一新兴的污染物，其环境生态效应已成为研究的热门和前沿课题。本项目拟以3-5种典型OPEs为研究对象，以土壤无脊椎动物蚯蚓为模式生物，在考察OPEs对赤子爱胜蚓（Eisenia fetida）急性致死及回避行为影响的基础上，采用生物组学技术（基因组学和代谢组学），分别从个体、细胞和分子水平重点研究低剂量长期暴露下OPEs对蚯蚓的生物毒性效应，结合对酶学、组织和DNA损伤的毒性研究探讨OPEs对蚯蚓的毒性作用机制，并应用实际污染土壤和蚯蚓对实验室OPEs毒性效应结果进行比对验证，明确真实OPEs污染环境中蚯蚓的毒性反应。研究成果将为揭示OPEs进入土壤环境对生态系统的潜在风险提供科学依据，为其污染控制基准和环境评价提供理论支撑。

新型阻燃剂有机磷酸酯（organophosphorus esters，OPEs）因以掺杂混合而非化学键合方式加入到材料中，随着广泛使用，越来越多的OPEs释放到环境中，其环境和健康风险亟待评估。本研究采用赤子爱胜蚓（Eisenia fetida）作为受试生物，通过滤纸接触法和人工土壤法比较不同取代基类型OPEs对蚯蚓的急性毒性效应，显示三种OPEs综合毒性效应大小顺序为TnBP>TCP>TCEP。进一步选取毒性较强的烷基取代类TnBP进行致毒机制研究，结果表明TnBP可在蚯蚓肠道组织中积累，并对其肠道组织结构和消化功能产生影响；结合转录组学和代谢组学等方法，发现TnBP显著破坏蚯蚓肠道上皮细胞膜的稳定性并降低小肠上皮细胞间紧密连接蛋白的表达量，进而影响小肠上皮细胞对糖类、氨基酸等小分子物质的吸收；同时显著降低肠道微生物的多样性，抑制肠道菌群对宿主的糖类物质提供，进一步破坏肠道上皮细胞对糖类物质的消化与吸收。此外，TnBP可在蚯蚓神经组织中积累，扰乱兴奋性神经递质谷氨酸的传递，产生兴奋性神经毒性。TnBP使腹部神经索中谷氨酰胺酶的表达量上升，产生大量谷氨酸，促进突触囊泡对谷氨酸的运输及突触前膜谷氨酸的释放，对谷氨酸受体（GluR）中的离子型受体N-甲基-D-天冬氨酸受体（NMDARs）产生过度刺激，引起神经元兴奋性损伤。OPEs实际污染土壤暴露可抑制蚯蚓生长，产生氧化应激，干扰抗氧化酶系统，显著影响AChE活性。本研究系统地探究了不同取代基类型的OPEs对典型土壤生物蚯蚓的生态毒性效应，揭示OPEs引起蚯蚓致毒的分子机制，为其污染控制和环境评价提供理论支撑。