Key Laboratory of Pesticide Toxicology & Application Technique, Shandong Agricultural University, Tai'an, Shandong 271018, PR China; College of Plant Protection, Shandong Agricultural University, Tai'an, Shandong 271018, PR China.
Research Center of Pesticide Environmental Toxicology, Shandong Agricultural University, Tai'an, Shandong 271018, PR China.
Sci Total Environ. 2021 Jul 10;777:145957. doi: 10.1016/j.scitotenv.2021.145957. Epub 2021 Feb 27.
Pyraclostrobin, one of the most widely used fungicides globally, is highly toxic to aquatic organisms, which restricts its application in paddy fields. Most studies have focused on the molecular mechanism of pyraclostrobin toxicity; however, the exposure routes and target organs of pyraclostrobin in fish are poorly known. Here, we found that the lethal effects of aquatic exposure, head immersion, trunk immersion and oral exposure on the toxicity and accumulation of pyraclostrobin in adult zebrafish were different. The major pathway leading to pyraclostrobin accumulation, followed by high hazard to fish, was crossing over the gill rather than the intestine or skin. Additionally, serious histological abnormalities, mitochondrial dysfunction, energy deficiency and respiratory impairment occurred in the gills, while no overt change was observed in the heart and brain at the organic and cellular levels. This result suggested that the gill is the dominant portal and target organ of pyraclostrobin in fish, a fact that has been further verified by intravenous injection. The differences in the toxicity and translocation factor of crystalline and dissolved pyraclostrobin in fish demonstrated that reducing the concentration in the branchial environment is a vital direction for the future design of an effective toxicity regulation strategy to protect key sites from pyraclostrobin attack.
吡唑醚菌酯是全球应用最广泛的杀菌剂之一，对水生生物具有高毒性，这限制了其在稻田中的应用。大多数研究都集中在吡唑醚菌酯毒性的分子机制上；然而，吡唑醚菌酯在鱼类中的暴露途径和靶器官知之甚少。在这里，我们发现水生暴露、头部浸泡、躯干浸泡和口服暴露对成年斑马鱼毒性和吡唑醚菌酯积累的致死效应不同。导致吡唑醚菌酯积累的主要途径是通过鳃，而不是肠道或皮肤，随后对鱼类造成高危害。此外，在鳃中还发生了严重的组织学异常、线粒体功能障碍、能量缺乏和呼吸损伤，而在心脏和大脑中则没有观察到明显的有机和细胞水平的变化。这一结果表明，鳃是鱼类中吡唑醚菌酯的主要门户和靶器官，这一事实通过静脉注射得到了进一步验证。晶体和溶解态吡唑醚菌酯在鱼类中的毒性和转运因子的差异表明，降低鳃环境中的浓度是未来设计有效毒性调控策略以保护关键部位免受吡唑醚菌酯攻击的重要方向。
