2,2',3,5',6-Pentachlorobiphenyl (PCB-95) is an environmentally relevant, chiral PCB congener that has been shown to act as a developmental neurotoxicant (DNT), targeting the developing brain. However, understanding enantioselective toxic effects for PCB-95 is in its infancy. To investigate these toxic effects, zebrafish embryos were exposed to racemates and enantiomers of PCB-95. Brain areas and pathology were studied. Results indicated dose dependent reduction of brain sizes with increased brain cell death in racemic and R_a (-)-PCB-95 treated groups. To provide a mechanistic basis for the observed neurotoxicity, gene expressions of antioxidant proteins such as Cu/Zn-SOD, Mn-SOD, and GPx were analysed. Antioxidant genes were up regulated with the PCB-95 exposure and racemic PCB-95 showed higher toxicity. These results suggest that the exposure to PCB-95 contributed to developmental neurotoxicity in early developing zebrafish larvae and may confer risks associated with enantioselective enrichment of PCB-95 in the environment.

Graphical Abstract

中文翻译：

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2,2',3,5',6-五氯联苯 (PCB-95) 对斑马鱼幼虫大脑发育的对映选择性毒性作用

2,2',3,5',6-五氯联苯 (PCB-95) 是一种与环境相关的手性 PCB 同源物，已被证明可作为发育神经毒物 (DNT)，靶向发育中的大脑。然而，了解 PCB-95 的对映选择性毒性作用还处于起步阶段。为了研究这些毒性作用，将斑马鱼胚胎暴露于 PCB-95 的外消旋体和对映体。研究了大脑区域和病理学。结果表明，外消旋组和R _a (-)-PCB-95 治疗组中脑大小的剂量依赖性减小，脑细胞死亡增加。为观察到的神经毒性、抗氧化蛋白（如Cu/Zn-SOD、Mn-SOD和GPx）的基因表达提供机制基础进行了分析。抗氧化基因随着 PCB-95 暴露而上调，外消旋 PCB-95 表现出更高的毒性。这些结果表明，暴露于 PCB-95 会导致早期发育的斑马鱼幼虫的发育神经毒性，并可能带来与环境中 PCB-95 的对映选择性富集相关的风险。

图形概要