The Potential Immunotoxicity Induced by Long‐Term Exposure to Polystyrene Nanoplastics in Rats

ABSTRACT Nanoparticles can be categorized as ‘particulate xenobiotics’ as they are found in living organisms and can interact with the immune system. This study evaluated the potential for immunotoxicity induced by chronic exposure to polystyrene nanoparticles. The work examined specific innate immune cells related to cellular and humoral immunity. Rats were divided into four equal groups: control, rats administered polystyrene nanoparticles at a dose of 10 mg/kg b. wt. The rat group was given a dose of 20 mg/kg b. wt. A group was given a dose of 30 mg/kg b. wt., three times per week, for 3 months. The results of serum IFN‐γ and IL‐2 in exposed groups revealed a significant increase in the release of these proinflammatory substances compared with the control. The data on serum IgG revealed a significant decrease in concentration compared with the control. The immune marker of CD68 showed an increase in the brain, lung and liver. T‐lymphocyte markers CD4 + T and CD8 + T showed a significant decrease in lymphoid tissues after PNP exposure compared with controls. A progressive multi‐organ histopathological alteration across lymphoid organs, including the thymus, spleen, Peyer's patches and bone marrow, was observed. These findings collectively indicate a systemic disruption of immune architecture and function, affecting both central and peripheral immune compartments.