Environmental and Occupational Hazards Control Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Department of Environmental Health Engineering, School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Department of Clinical Sciences, Faculty of Veterinary Sciences, Bu-Ali Sina University Hamedan, Iran.
Environ Pollut. 2020 Jun;261:114158. doi: 10.1016/j.envpol.2020.114158. Epub 2020 Feb 10.
Humans are potentially exposed to nano(micro)plastics, however their interaction with tissues and cells in humans remains largely unknown. This premise is particularly notable with nano-sized plastic particulates, a potentially most pernicious form of plastic pollution. In this study, even in a hypothetical scenario in terms of dose (1, 3, 6 and 10 mg/kg-day) and exposure time (five weeks), the potential endocrine disturbances with particular reference to reproductive toxicity of polystyrene nanoplastics (PS NPs, average size = 38.92 nm) was studied in male rats considering biomarkers of semen quality, changes in hormonal milieu and molecular signatures of endocrine disruption. Sperm DNA integrity and its chromatin structure were also analyzed. There observed significant inverse associations between exposure to PS NPs and serum concentrations of testosterone, luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Tissue and cell impairments were also noticed even at the lowest tested dosage, though the severity of lesions followed a clear dose-response pattern. DNA damage as well as alterations in sperm morphology and viability were evident, again proportionally with the amount of exposure dosage. RT-qPCR data were in accordance with the results of physio-histological alterations and fluorescence imaging, as significant down-regulation of PLZF, DAZL, FSH and LH gene expressions were noticed in the testis of exposed animals, suggesting that exposure interferes with spermatogenesis and also with HPT-axis. However, among those with highest exposure dosage, expressions of FSH and LH were significantly increased. ABP modulation further revealed evidence of a nonlinear dose response. The association between PS NPs exposure and GnRH was indeed in an unexpected positive direction, though these end-points were less sensitive at higher doses. Although additional evidence is warranted, the present work provides new insights into the possible risks of plastic nanoparticles exposure in humans, especially since the problem is growing and will persist for a long time.
人类可能会接触到纳米（微）塑料，但它们与人体组织和细胞的相互作用在很大程度上尚不清楚。这一前提在纳米级塑料颗粒中尤为明显，这是一种潜在的最有害的塑料污染形式。在这项研究中，即使在剂量（1、3、6 和 10 mg/kg-天）和暴露时间（五周）的假设情况下，也研究了聚苯乙烯纳米塑料（PS NPs，平均粒径=38.92nm）对雄性大鼠的潜在内分泌干扰，特别是生殖毒性，考虑了精液质量生物标志物、激素环境变化和内分泌干扰的分子特征。还分析了精子 DNA 完整性及其染色质结构。观察到暴露于 PS NPs 与血清中睾丸激素、促黄体生成素（LH）和促卵泡激素（FSH）浓度呈显著负相关。即使在最低测试剂量下也观察到组织和细胞损伤，但损伤的严重程度遵循明显的剂量反应模式。还观察到 DNA 损伤以及精子形态和活力的改变，再次与暴露剂量成正比。RT-qPCR 数据与生理-组织学改变和荧光成像的结果一致，暴露动物睾丸中 PLZF、DAZL、FSH 和 LH 基因的表达显著下调，表明暴露会干扰精子发生，也会干扰 HPT 轴。然而，在暴露剂量最高的动物中，FSH 和 LH 的表达显著增加。ABP 调节进一步揭示了非线性剂量反应的证据。PS NPs 暴露与 GnRH 之间的关联实际上呈出乎意料的正相关，尽管在较高剂量下这些终点不太敏感。尽管需要更多的证据，但目前的工作为塑料纳米颗粒暴露对人类可能带来的风险提供了新的见解，尤其是因为这个问题正在加剧，并将持续很长时间。
