Amereh Fatemeh, Eslami Akbar, Fazelipour Simin, Rafiee Mohammad, Zibaii Mohammad Ismail, Babaei Mohammad
Environmental and Occupational Hazards Control Research Center , Shahid Beheshti University of Medical Sciences , Tehran , Iran . Email:
Department of Environmental Health Engineering , School of Public Health and Safety , Shahid Beheshti University of Medical Sciences , Tehran , Iran.
Toxicol Res (Camb). 2019 Oct 2;8(6):953-963. doi: 10.1039/c9tx00147f. eCollection 2019 Nov 1.
Toxicity evaluations of micro- or nano-sized plastics in rodent species commonly employed for toxicity analyses based on which risk assessment for humans could be performed are still largely lacking. Given this knowledge gap, the present work was aimed at determining the potential impact of chronic exposure to polystyrene nanoplastics (PS NPs) on the thyroid endocrine status and biochemical stress in a rat model. Young adult male rats were orally administered with PS NPs (1, 3, 6 and 10 mg kg day) for five weeks. Thyroid hormones (THs) l-thyroxine (T4), l-triiodothyronine (T3), l-free triiodothyronine (FT3), and l-free thyroxine (FT4) as well as thyroid stimulating hormone (TSH) serum levels of normal rats and those exposed to PS NPs were compared. Serum levels of high-density lipoprotein (HDL), low-density lipoprotein (LDL), cholesterol, and creatinine, as well as glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) enzymes were also measured. Exposure to PS NPs suppressed the serum levels of T3 and circulating levels of THs, whereas TSH increased significantly. Though exposure to PS NPs did not affect the molar ratios of T3/T4, it induced a slight, but significant, increase in FT3/FT4. In addition, exposure to plastic nanoparticles showed signs of nephrotoxicity induction and kidney injury in exposed organisms as can be inferred from the significantly higher serum levels of creatinine in exposed groups. Our results provide clear evidence of an association between exposure to plastic NPs and thyroid endocrine disruption as well as metabolic deficit, and generate new leads for future research efforts.
基于可对人类进行风险评估的目的，在常用于毒性分析的啮齿动物物种中对微米或纳米级塑料进行毒性评估的研究仍非常缺乏。鉴于这一知识空白，本研究旨在确定大鼠模型中长期暴露于聚苯乙烯纳米塑料（PS NPs）对甲状腺内分泌状态和生化应激的潜在影响。将年轻成年雄性大鼠口服给予PS NPs（1、3、6和10 mg/kg/天），持续五周。比较正常大鼠和暴露于PS NPs的大鼠的甲状腺激素（THs）——左旋甲状腺素（T4）、左旋三碘甲状腺原氨酸（T3）、游离三碘甲状腺原氨酸（FT3）和游离甲状腺素（FT4）以及促甲状腺激素（TSH）的血清水平。还测量了高密度脂蛋白（HDL）、低密度脂蛋白（LDL）、胆固醇和肌酐的血清水平，以及谷氨酸草酰乙酸转氨酶（GOT）和谷氨酸丙酮酸转氨酶（GPT）的酶水平。暴露于PS NPs会抑制T3的血清水平和THs的循环水平，而TSH显著升高。虽然暴露于PS NPs不影响T3/T4的摩尔比，但它会导致FT3/FT4略有但显著增加。此外，从暴露组中肌酐血清水平显著升高可以推断，暴露于塑料纳米颗粒会在暴露的生物体中显示出肾毒性诱导和肾损伤的迹象。我们的结果提供了明确的证据，证明暴露于塑料纳米颗粒与甲状腺内分泌紊乱以及代谢缺陷之间存在关联，并为未来的研究工作提供了新的线索。
