Joint toxicity of permethrin and cypermethrin at sublethal concentrations to the embryo-larval zebrafish

• Published in: Chemosphere (Oxford) 2014-02, Vol.96, p.146-154
• Main Authors: Yang, Ye, Ma, Huihui, Zhou, Jinghua, Liu, Jing, Liu, Weiping
• Format: Article
• Language: English
• Subjects: Agnatha. Pisces; Animal, plant and microbial ecology; Animals; Applied ecology; Biological and medical sciences; Cypermethrin; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on vertebrates; Embryo, Nonmammalian - drug effects; Embryology: invertebrates and vertebrates. Teratology; Fundamental and applied biological sciences. Psychology; Insecticides - toxicity; Joint toxicity; Larva - drug effects; Oxidative Stress; Permethrin; Permethrin - toxicity; Pyrethrins - toxicity; Pyrethroids; Teratology. Teratogens; Water Pollutants, Chemical - toxicity; Zebrafish; Zebrafish - embryology
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2013.10.014

[Display omitted] •The mixture of PM and CP produced greater sublethal toxicity to zebrafish.•The developmental toxicity of PM and CP was related to disruption of ion channels.•The mixture of PM and CP caused greater inhibition in proneural gene expression.•The mixture of PM and CP increased SOD and CAT activities in embryos. Pyrethroids, the widely used pesticides, are highly toxic to aquatic organisms. However, little information is so far available regarding the joint toxicity of type I and type II pyrethroids to fish. Zebrafish is a well-accepted aquatic vertebrate model for toxicity assessment due to small size, easy husbandry, high fecundity and transparent embryos. In this study, we utilized embryo-larval zebrafish to elucidate the combined effects of sublethal concentrations of permethrin (PM) and cypermethrin (CP), which are the most frequently used type I and type II pyrethroids, respectively. Fish were exposed from 3h postfertilization (hpf) to 144 hpf to binary mixtures of nominal concentrations of 100, 200, 300μgL−1 PM (PM100, PM200, PM300) and 10, 20, 30μgL−1 CP (CP10, CP20, CP30). Analytical data of the real concentrations of the chemicals showed a significant degradation of the pyrethroids but an obvious recovery after the renewal of the exposure solution. Defect rates of embryos exposed to these low concentrations of single PM or CP exhibited no statistically significant difference from the control,while the application of combination of PM and CP resulted in deleterious effects on zebrafish embryonic development. In all PM200 and PM300 exposure groups, increasing CP concentrations acted additively to the action of PM in terms of all sublethal endpoints. Co-treatment of embryos with the specific sodium channel blocker MS-222 and pyrethroids (individuals or the mixture) caused a decline in the incidences of body axis curvature and spasms compared to treatment of animals with pyrethroids alone, suggesting that the developmental toxicity of PM and CP to zebrafish was related to disruption of ion channels. We further revealed that mixture of the two pyrethroids caused greater down-regulation in the mRNA levels of proneural genes. The individual pesticides had no effect on the activity of superoxide dismutase (SOD), while the mixture exposure caused significant induction. Treatment with CP or the mixture increased the activity of catalase (CAT). Taken together, our data indicated that the mixture of PM and CP caused higher incidence of morpholo