Microplastics are ubiquitous environmental pollutants that are a growing concern to many ecosystems, as well as human health. Many of the effects of microplastics on mammalian cells and tissues remain unknown. To address this, we treated L929 murine fibroblasts and Madin–Darby canine kidney (MDCK) epithelial cell lines with 1 μg/mL, 10 μg/mL, or 20 μg/mL of polyethylene (PE) or polystyrene (PS) microspheres in vitro for 6 and 24 h and measured the resulting changes in cell viability, metabolism, and transcriptional expression of inflammatory cytokines and antioxidant enzymes. We observed dose-dependent decreases in cell viability corresponding to increases in doses of both PE and PS. We conducted cell metabolism assays and observed dose-dependent increases in metabolism per cell with increasing doses of both PE and PS. Similarly, we also observed increased expression of the superoxide dismutase-3 gene (SOD3), indicating oxidative stress caused by the microplastics treatments. We also observed increased expression of TNFα, but decreased expression of IFNβ, suggesting different mechanisms by which the microplastics regulate inflammatory responses in mammalian cells. Our results contribute new data to the growing understanding of the effects of microplastics on mammalian cells and indicate complex cellular stress responses to microplastics in the environment.

微塑料是普遍存在的环境污染物，越来越引起许多生态系统以及人类健康的关注。微塑料对哺乳动物细胞和组织的许多影响仍然未知。为了解决这个问题，我们在体外用 1 μg/mL、10 μg/mL 或 20 μg/mL 聚乙烯 (PE) 或聚苯乙烯 (PS) 微球处理 L929 小鼠成纤维细胞和 Madin–Darby 犬肾 (MDCK) 上皮细胞系6 和 24 小时，并测量细胞活力、代谢以及炎症细胞因子和抗氧化酶转录表达的变化。我们观察到，随着 PE 和 PS 剂量的增加，细胞活力呈剂量依赖性下降。我们进行了细胞代谢测定，并观察到随着 PE 和 PS 剂量的增加，每个细胞的代谢呈剂量依赖性增加。同样，我们还观察到超氧化物歧化酶 3 基因 ( SOD3 ) 的表达增加，表明微塑料处理引起了氧化应激。我们还观察到TNFα表达增加，但IFNβ表达减少，表明微塑料调节哺乳动物细胞炎症反应的不同机制。我们的研究结果为人们日益了解微塑料对哺乳动物细胞的影响提供了新数据，并表明细胞对环境中微塑料的复杂应激反应。