Behavioral, molecular and physiological responses of embryo-larval zebrafish exposed to types I and II pyrethroids. (March 2019)

• Record Type: Journal Article
• Authors: Awoyemi, Olushola M.; Kumar, Naveen; Schmitt, Cassandra; Subbiah, Seenivasan; Crago, Jordan
• Is Part Of: Chemosphere. Volume 219(2019)
• Page Start: 526
• Page End: 537
• Publication Date: 2019-03
• Subjects: Pyrethroids -- Exposure assessment -- Developmental toxicity -- Gene expression -- Oxidative stress -- Apoptosis; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2018.12.026
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Pyrethroids are potent neurotoxicants that may elicit multiple pathways of toxicity in non-target organisms. Comparative studies on the mechanistic and developmental effects of types I and II pyrethroids against non-target aquatic species are limited. This study assessed the effects of the two pyrethroid types against embryo-larval zebrafish ( Danio rerio ) at environmentally relevant and laboratory concentrations. Zebrafish embryos were exposed to type-I (permethrin, bifenthrin) and type-II (deltamethrin, λ-cyhalothrin, fenvalerate, esfenvalerate) pyrethroids at 1000, 10, 0.1, 0.01, 0.0 μg/L, starting at 5-h post-fertilization (hpf) through 5-d post-fertilization (dpf) under static exposure conditions. Swimming behavior (distance traveled and velocity) was assessed at 5-dpf. The relative expression of Nrf2a, GST, Casp-9 and p53 mRNA transcripts, carboxyl esterase (CES) activity and total reactive oxygen species (ROS) were measured. The stability of the pyrethroids across 5 days was analyzed. Bifenthrin-(10 μg/L) and esfenvalerate-(1000 μg/L) significantly (p < 0.05) reduced total distance traveled by larvae while 1000 μg/L deltamethrin and λ-cyhalothrin were lethal causing body axis curvature and pericardial edema. At environmentally relevant concentrations-(μg/L) compared to control, permethrin-(0.122) upregulated Nrf2a and Casp-9 expressions while λ-cyhalothrin-(0.053) downregulated Nrf2a and fenvalerate-0.037 downregulated GST. At laboratory concentrations-(μg/L), permethrin-(1000) upregulated Nrf2a, Casp-9 and p53 expressions, bifenthrin-(10) upregulated Casp-9 while fenvalerate-(0.1) and esfenvalerate-(1000) downregulated GST. There was concentration dependent increase in CES activity which correlated positively with total ROS. Pyrethroid concentrations decreased significantly by day 5. This study showed disparity in the mechanistic effects across the pyrethroids types and their instability in aqueous media may underestimate toxicity against non-target aquatic species when exposed in their natural environment. Graphical abstract: Image 1 Highlights: All six pyrethroids were significantly unstable in the aqueous exposure media. DEL and λ-CYH at 1000 μg/L were lethal and impaired larval morphology. BIF and ESF had significant impact on larval behavior. No alteration in pyrethroid metabolism but there was still toxicity. PER and BIF upregulated Nrf2a, Casp-9 and/or p53, λ-CYH downregulated Nrf2a, FEN and ESF downregulated GST.