Jia Zhong-Qiang, Liu Di, Sheng Cheng-Wang, Casida John E, Wang Chen, Song Ping-Ping, Chen Yu-Ming, Han Zhao-Jun, Zhao Chun-Qing
Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China.
Environmental Chemistry and Toxicology Laboratory, Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, 94720-3112, United States.
Environ Pollut. 2018 Jan;232:183-190. doi: 10.1016/j.envpol.2017.09.032. Epub 2017 Sep 15.
Fluralaner is a novel isoxazoline insecticide which shows high insecticidal activity against parasitic, sanitary and agricultural pests, but there is little information about the effect of fluralaner on non-target organisms. This study reports the acute toxicity, bioconcentration, elimination and antioxidant response of fluralaner in zebrafish. All LC values of fluralaner to zebrafish were higher than 10 mg L at 24, 48, 72 and 96 h. To study the bioconcentration and elimination, the zebrafish were exposed to sub-lethal concentrations of fluralaner (2.00 and 0.20 mg L) for 15 d and then held 6 d in clean water. The results showed medium BCF of fluralaner with values of 12.06 (48 h) and 21.34 (144 h) after exposure to 2.00 and 0.20 mg L fluralaner, respectively. In the elimination process, a concentration of only 0.113 mg kg was found in zebrafish on the 6th day after removal to clean water. After exposure in 2.00 mg L fluralaner, the enzyme activities of SOD, CAT, and GST, GSH-PX, CarE and content of MDA were measured. Only CAT and CarE activities were significantly regulated and the others stayed at a stable level compared to the control group. Meanwhile, transcriptional expression of CYP1C2, CYP1D1, CYP11A were significantly down-regulated at 12 h exposed to 2.00 mg L of fluralaner. Except CYP1D1, others CYPs were up-regulated at different time during exposure periods. Fluralaner and its formulated product (BRAVECTO) are of low toxicity to zebrafish and are rapidly concentrated in zebrafish and eliminated after exposure in clean water. Antioxidant defense and metabolic systems were involved in the fluralaner-induced toxicity. Among them, the activities of CAT and CarE, and most mRNA expression level of CYPs showed fast response to the sub-lethal concentration of fluralaner, which could be used as a biomarker relevant to the toxicity.
氟虫腈是一种新型异恶唑啉类杀虫剂，对寄生性、卫生性和农业害虫均表现出高杀虫活性，但关于氟虫腈对非靶标生物影响的信息较少。本研究报道了氟虫腈在斑马鱼体内的急性毒性、生物富集、消除及抗氧化反应。氟虫腈在24、48、72和96小时对斑马鱼的所有LC值均高于10mg/L。为研究生物富集和消除情况，将斑马鱼暴露于亚致死浓度的氟虫腈（2.00和0.20mg/L）中15天，然后在清水中饲养6天。结果显示，暴露于2.00和0.20mg/L氟虫腈后，氟虫腈的生物富集系数（BCF）中等，分别在48小时时为12.06，144小时时为21.34。在消除过程中，转移至清水6天后，斑马鱼体内仅检测到浓度为0.113mg/kg。暴露于2.00mg/L氟虫腈后，测定了超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、谷胱甘肽S-转移酶（GST）、谷胱甘肽过氧化物酶（GSH-PX）、羧酸酯酶（CarE）的酶活性及丙二醛（MDA）含量。与对照组相比，仅CAT和CarE活性受到显著调节，其他指标保持稳定水平。同时，暴露于2.00mg/L氟虫腈12小时后，细胞色素P450 1C2（CYP1C2）、细胞色素P450 1D1（CYP1D1）、细胞色素P450侧链裂解酶（CYP11A）的转录表达显著下调。除CYP1D1外，其他细胞色素P450在暴露期间的不同时间上调。氟虫腈及其制剂（倍宠清）对斑马鱼毒性较低，在斑马鱼体内迅速富集，暴露于清水后可被消除。抗氧化防御和代谢系统参与了氟虫腈诱导的毒性作用。其中，CAT和CarE的活性以及大多数细胞色素P450的mRNA表达水平对氟虫腈亚致死浓度表现出快速响应，可作为与毒性相关的生物标志物。
