Chronic exposure to polystyrene nanoplastics induces intestinal mechanical and immune barrier dysfunction in mice

• Published in: Ecotoxicology and environmental safety Vol. 269; p. 115749
• Main Authors: Li, Lan, Lv, Xin, He, Jing, Zhang, Lianshuang, Li, Boqing, Zhang, Xiaolin, Liu, Sisi, Zhang, Ying
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier 01.01.2024
• Subjects: Caveolins; CD8-Positive T-Lymphocytes; Chronic exposure; Clathrin; Humans; Immune barrier; Interleukin-6; Intestinal mechanical barrier; Lymphocytes T; Mice; Microplastics; Nanoparticles; Occludin; Polystyrene nanoplastics; Polystyrenes - toxicity; Reactive Oxygen Species; Superoxide Dismutase; Tumor Necrosis Factor-alpha; Immune barrier; Intestinal mechanical barrier; Lymphocytes T; Mice; Polystyrene nanoplastics; Chronic exposure
• ISSN: 0147-6513; 1090-2414
• DOI: 10.1016/j.ecoenv.2023.115749

Micro(nano)plastics are prevalent in the environment, and prolonged exposure to them represents a threat to human health. The goal of this study is to assess the health risk of long-term exposure to nanoplastics (NPs) at environmental concentrations on the intestinal mechanical and immune barrier in mice. In this study, mice were provided drinking water containing polystyrene NPs (PS-NPs; 0.1, 1, and 10 mg·L ) for 32 consecutive weeks. The levels of endocytosis proteins caveolin and clathrin and of tight junctional proteins claudin-1, occludin, and ZO-1, and morphological changes, proportion of lymphocytes B in MLNs and lymphocytes T in IELs and LPLs were determined by immunohistochemistry, hematoxylin-eosin, and flow cytometry assays in the intestinal tissues of mice at 28 weeks. The activities or concentrations of ROS, SOD, MDA, and GSH-Px and inflammatory factors (IL-1β, IL-6, and TNF-α) in the intestinal tissues of mice were measured by ELISA at 12, 16, 20, 24, and 32 weeks. Compared with the control group, oral ingested PS-NPs entered the intestinal tissues of mice and upregulated expression levels of the clathrin and caveolin. The intestinal tissue structure of mice in the PS-NPs (1 and 10 mg·L ) exposure groups showed significant abnormalities, such as villus erosion, decreased of crypts numbers and large infiltration of inflammatory cells. Exposure to 0.1 mg·L PS-NPs decreased occludin protein levels, but not claudin-1 and ZO-1 levels. The levels of these three tight junction proteins decreased significantly in the 1 and 10 mg·L PS-NPs exposed groups. Exposure to PS-NPs led to a significant time- and dose-dependent increase in ROS and MDA levels, and concurrently decreased GSH-Px and SOD contents. Exposure to PS-NPs increased the proportion of B cells in MLNs, and decreased the proportion of CD8 T cells in IELs and LPLs. The levels of pro-inflammatory cytokines IL-6, TNF-α and IL-1β were markedly elevated after PS-NPs exposure. Long-term PS-NPs exposure impaired intestinal mechanical and immune barrier, and indicate a potentially significant threat to human health.