Nano-polystyrene has gained considerable attention because of its growing accumulation in the environment. Although several studies have attempted to elucidate its action on physiological functions, studies investigating human metabolic disturbance were scarce. This study developed two investigative designs using exposure to human epithelial colorectal cells (Caco-2); the first exposed cells to a high concentration of 50 nm nano-polystyrene for 24 h (acute), whilst the second exposed cells to a relatively lower concentration for over 1.5 months (chronic). Exposure concentrations were determined based on bioassays: 10 and 80 μg mL⁻¹ for the acute model and 0.1 μg mL⁻¹ for the chronic exposure model. Following acute exposure, untargeted metabolic profiling revealed the alteration in lipid metabolic pathways, including steroid and arachidonic acid metabolism. On the other hand, chronic exposure induced relatively minor disturbances. However, there was still a potential effect on fatty acid biosynthesis, indicating that acute and chronic exposure to nano-polystyrene may disturb lipid homeostasis. We also confirmed changes in the expression levels of lipid transcriptional regulatory factor coding genes, namely sterol regulatory element-binding transcription factors 1 and 2. The total fatty acid composition was further investigated to verify metabolic disturbance by chronic exposure. Our findings indicated that both exposure conditions of high concentration with a short period and low concentration with an extended period to nano-polystyrene were associated with the cellular disturbance of the lipid metabolism.

中文翻译：

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暴露于纳米聚苯乙烯可诱导Caco-2中脂质稳态的代谢改变

纳米聚苯乙烯由于其在环境中的积累不断增长而备受关注。尽管有几项研究试图阐明其对生理功能的作用，但有关人类代谢紊乱的研究却很少。这项研究利用暴露于人上皮结直肠细胞（Caco-2）开发了两种研究设计。第一个暴露的细胞暴露于高浓度的50 nm纳米聚苯乙烯24小时（急性），而第二个暴露的细胞暴露于相对较低的浓度达1.5个月以上（长期）。基于生物测定确定暴露浓度：10和80微克毫升^-1为急性模型和0.1微克毫升^-1对于慢性暴露模型。急性暴露后，未靶向的代谢谱分析揭示了脂质代谢途径的改变，包括类固醇和花生四烯酸代谢。另一方面，慢性暴露引起的干扰相对较小。但是，仍然对脂肪酸的生物合成有潜在的影响，表明急性和慢性暴露于纳米聚苯乙烯可能会干扰脂质体内平衡。我们还证实了脂质转录调节因子编码基因，即固醇调节因子结合转录因子1和2的表达水平发生了变化。进一步研究了总脂肪酸组成，以验证慢性暴露引起的代谢紊乱。