The chorion is the first protective barrier set to prevent numerous pollutants from damaging the developing embryo. However, depending on their size, some nanoplastics (NPs) can pass through this barrier and reach the embryo, while all microplastics (MPs) remain on the outside. This study brings a straight approach to compare MPs and NPs, and assess their direct and indirect effects on zebrafish embryos and larvae. Zebrafish eggs were exposed before 2 h post fertilization (hpf) to polystyrene MPs (5 μm) and NPs (250 nm) at a concentration of 1000 μg/L until 96 hpf. Physiotoxicity and neurotoxicity were assessed prior and post-hatching through several biomarkers. Response to hypoxia (upregulation of and ) were found in embryos exposed to MPs, and partly found in those exposed to NPs. Embryos exposed to NPs showed significant tachycardia, reduced O consumption and increased apoptosis in the eyes, whereas MPs affected the expressions of all genes related to the neurodevelopment of embryos (). Post-hatching, physiological responses were muted. MPs and NPs exposures ended by evaluating larval behaviours during dark-and-light cycles. Both sizes of plastic particles negatively affected the visual motor response (VMR) and vibrational startle response (VSR). Thigmotaxis levels were significantly increased by NPs whereas MPs showed anxiolytic properties. This study shows that both MPs and NPs affect the physiology and neurodevelopment of zebrafish at different levels, before and after hatching.

中文翻译：

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缩小尺寸：探索塑料颗粒尺寸对早期斑马鱼生理和神经反应的影响


绒毛膜是第一道保护屏障，旨在防止多种污染物损害发育中的胚胎。然而，根据其大小，一些纳米塑料 (NP) 可以穿过此屏障并到达胚胎，而所有微塑料 (MP) 仍留在外部。这项研究采用直接方法来比较 MP 和 NP，并评估它们对斑马鱼胚胎和幼虫的直接和间接影响。斑马鱼卵在受精后 2 小时 (hpf) 前暴露于浓度为 1000 μg/L 的聚苯乙烯 MP (5 μm) 和 NP (250 nm)，直至 96 hpf。通过几种生物标志物在孵化前和孵化后评估生理毒性和神经毒性。暴露于 MP 的胚胎中发现了对缺氧的反应（ 和 的上调），部分发现于暴露于 NP 的胚胎中。暴露于 NP 的胚胎表现出明显的心动过速、眼部 O 消耗减少和细胞凋亡增加，而 MP 则影响与胚胎神经发育相关的所有基因的表达。孵化后，生理反应减弱。通过评估幼虫在明暗循环期间的行为来结束 MP 和 NP 的暴露。两种尺寸的塑料颗粒都会对视觉运动反应（VMR）和振动惊吓反应（VSR）产生负面影响。 NP 显着增加趋触性水平，而 MP 则表现出抗焦虑特性。这项研究表明，MP 和 NP 都会在孵化前后不同程度地影响斑马鱼的生理和神经发育。