A single oral exposure to polyethylene terephthalate microplastics causes mild metabolic and gastrointestinal disruption: dose and sex determinants

Polyethylene terephthalate (PET) microplastics, derived from consumer products such as plastic bottles and clothing, are pervasive in the environment with documented detection in human arteries and brains among other tissues, although their health impacts remain unclear. This study evaluated the biological effects of a single oral exposure to PET microplastics in female and male rats. Three-month-old Sprague-Dawley rats were exposed once via oral gavage to sterile water vehicle, or 5 mg/kg (low PET), or 50 mg/kg (high PET) of PET microplastics derived from cryomilling of plastic nurdles. Immediately after exposure, animals were monitored for ∼18 hours in an indirect calorimetry apparatus for changes in metabolic rate, respiratory exchange ratio, and differences between light and dark periods. At the end of the monitoring period, tissue samples were collected to measure systemic indicators of inflammation and injury, metabolic function, and changes in gene expression in the liver and gastrointestinal tissue. The findings indicate that males exposed to low PET, but not high PET, had significant decreases in metabolic rate, respiratory exchange ratio, and blood insulin. Low PET also caused significant changes in gene expression in the duodenum in males. However, males had dose-dependent increases in serum platelets. Females exposed to PET were limited to decreased metabolic rate with high PET, and dose-dependent increases in serum LDL. In summary, although there was variability across dose and sex, these findings suggest that exposure to PET has the potential to cause mild metabolic dysfunction and systemic and organ toxicity.

聚对苯二甲酸乙二醇酯（PET）微塑料源自塑料瓶、衣物等消费品，广泛分布于环境中，且已有文献报道在人体动脉、大脑及其他组织中检出这类微塑料，但其对健康的影响仍不明确。本研究针对雌雄大鼠开展单次经口暴露PET微塑料的实验，评估其生物学效应。实验选用3月龄的斯普拉格-道利（Sprague-Dawley）大鼠，通过灌胃法单次给予无菌水溶剂（对照组）、5mg/kg（低剂量PET组）或50mg/kg（高剂量PET组）的、由塑料原料粒经低温研磨制备的PET微塑料。暴露结束后，立即使用间接测热仪对大鼠进行约18小时的监测，记录其代谢率、呼吸交换比的变化，以及明暗周期下的指标差异。监测周期结束后，采集组织样本以检测全身炎症与损伤指标、代谢功能指标，以及肝脏和胃肠道组织的基因表达变化。结果显示，低剂量PET暴露的雄性大鼠代谢率、呼吸交换比及血液胰岛素水平均显著降低，而高剂量PET暴露的雄性大鼠未出现此类变化；低剂量PET暴露还会导致雄性大鼠十二指肠的基因表达发生显著改变，但雄性大鼠的血清血小板计数呈现剂量依赖性升高。雌性大鼠仅在高剂量PET暴露时出现代谢率降低，且血清低密度脂蛋白（LDL）水平呈剂量依赖性升高。综上，尽管不同剂量与性别间存在差异，但本研究结果表明，PET微塑料暴露可能引发轻度代谢功能障碍，以及全身性与器官毒性。