Embryonic Exposure to 2,2′,3,5′,6‐pentachlorobiphenyl (PCB‐95) Causes Developmental Malformations in Zebrafish
2020
Ranasinghe, Prabha | Thorn, R. J. (Robert J.) | Seto, Renee | Creton, Robbert | Bridges, William C. | Chapman, Susan C. | Lee, Cindy M.
2,2′,3,5′,6‐Pentachlorobiphenyl (PCB‐95) is an environmental neurotoxicant. There is accumulated evidence that some neurotoxic effects of PCB‐95 are caused by increased spontaneous Ca²⁺ oscillations in neurons resulting from modifying ryanodine receptors (RyR) in calcium‐releasing channels. However, there are large gaps in explaining brain and other developmental malformations on embryonic PCB‐95 exposure. In the present study, we address those deficiencies by studying the toxic effects of PCB‐95 using zebrafish as an ontogenetic model. To characterize these effects, zebrafish embryos with intact chorions were exposed to 4 different concentrations of PCB‐95 (0.25, 0.5, 0.75, and 1 ppm) for 3 consecutive days. The controls were maintained in 0.5 × E2 medium or egg water and in 0.1% (v/v) dimethyl sulfoxide (DMSO)/0.5 × E2 medium or egg water. PCB‐95‐treated groups showed dose‐dependent decreases in survival and hatching rates, with increased rates of developmental malformations when compared to controls. These include morphological malformations, brain cell necrosis, and smaller eye sizes at 5 d post fertilization. These data suggest potential mechanisms underlying the abnormal behavior observed in a visual stimulus assay. The present study provides insight into PCB‐95‐induced developmental toxicity and supports the use of the zebrafish model in understanding the effects of PCB‐95 exposure. Environ Toxicol Chem 2019;39:162–170. © 2019 SETAC
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