低剂量三唑类杀菌剂对水生生物长期暴露的毒性效应及其机理研究

Triazole fungicides, which are of high efficiency, broad¬-spectrum, low toxicity and long-lasting, are widely used in agricultural industry. But the increasing application of triazole fungicides can result in the pollution of environment and pose environmental risks to human health. The current research mainly focus on the short-term toxic effects of triazole fungicides, our previous studies showed that the aquatic organisms at different life stages exhibited different levels of toxicity to triazole fungicides, but the literature regarding the toxicity effects and its mechanism of long-term exposure to low doses of triazole fungicides in aquatic organisms is relatively scarce. In this proposal, we will investigate the effects of triazole fungicides (triadimefon, propiconazole, difenoconazole and tebuconazole) on the acute and chronic toxicity, physiological biochemical index, ultrastructure and different signaling pathways in zebrafish and rare minnow at different life stages, then elucidate the potential toxicity and its mechanism of triazole fungicides on zebrafish and rare minnow. The differences and similarities between the parental and offspring of zebrafish and rare minnow were also investigated, and further help us to screen sensitive biomarkers for early diagnosis of low-dose of triazole fungicides in the environment. The results of this project can provide diagnostic methods for long-term exposure to low doses of pesticide on environmental organisms, also provide the scientific basis for rational pesticide use and estimated ecological risk.

三唑类杀菌剂因其高效、广谱、低毒以及长效性而广泛应用于农业生产中，因而不可避免地对生态环境和人类健康产生一定的危害。项目组前期研究发现，三唑类杀菌剂对水生生物不同生长阶段的毒性效应差异较大，但现有的研究主要关注其对生物体某个生长阶段的短期影响，有关低剂量三唑类杀菌剂长期暴露对水生生物不同生长阶段的毒性效应及其机理研究还十分薄弱。本项目拟以斑马鱼和我国特有种稀有鮈鲫为模式生物，通过研究三唑类杀菌剂（三唑酮、丙环唑、苯醚甲环唑和戊唑醇）对斑马鱼和稀有鮈鲫不同生命阶段的急性和慢性毒性、生理生化指标、超微结构以及不同信号通路的影响，阐明三唑类杀菌剂的毒性规律和致毒机理，并通过与染毒斑马鱼和稀有鮈鲫子代毒性效应的比较，筛选出用于早期诊断环境中低剂量三唑类杀菌剂污染的敏感生物标志物。本项目研究结果可为低剂量农药长期暴露对环境生物的毒理诊断提供方法论，同时也为农药合理使用和生态风险评价提供基础科学依据。

三唑类杀菌剂因其高效、广谱、低毒以及长效性广泛应用于农业生产中，因而其在环境中的残留对水生生物的影响也日益得到关注。本项目拟通过对三唑类杀菌剂（三唑酮、丙环唑、苯醚甲环唑和戊唑醇）对斑马鱼和稀有鮈鲫不同生命阶段的毒性效应研究，阐明三唑类杀菌剂的毒性规律和致毒机理。研究发现，三唑类杀菌剂对斑马鱼和稀有鮈鲫的生长发育具有一定的致畸性，对胚胎、仔鱼、幼鱼和成鱼不同生命阶段具有一定的毒性差异。研究表明，三唑酮对斑马鱼和稀有鮈鲫具有内分泌干扰效应，对胚胎和仔鱼发育过程中内分泌系统以及氧化胁迫相关元件的表达、活性和合成都有一定的调控作用。戊唑醇、丙环唑、苯醚甲环唑能够引起胚胎-仔鱼阶段的肝脏萎缩、卵黄囊吸收延迟、卵黄囊水肿，并且诱导成鱼肝脏变性或损伤，干扰其脂质代谢，抑制性细胞的成熟进而干扰其性腺发育，引起肠道菌群的紊乱等。同时利用转录组和代谢组学分析发现，三唑类杀菌剂能够同时调控多个信号通路，在基因和代谢物水平共同调控类固醇激素生物合成、脂肪酸代谢、氨基酸和核苷酸糖合成等多个代谢途径，并且能够同时调控CYP450酶系CYP3c3，CYP2k18, CYP2k22和CYP27b1基因的表达。相关研究结果进一步明确了三唑类杀菌剂对水生生物的毒性效应和环境风险，为环境中三唑类杀菌剂的污染诊断提供有效的生物标志物。