Background: Plastic pollution has emerged as a significant environmental hazard, with microplastics (MPs) posing potential risks to both human and animal health.
Objectives: This study aimed to evaluate the effects of polystyrene MPs on the immune system, inflammation, autoantibody production, and autoimmune diseases, as well as changes in hematological and biochemical parameters in laboratory mice
Methods: Twenty-four male NMRI mice (25-35 g) aged 16 weeks were randomly divided into four groups and exposed to 0.1 mL of polystyrene MPs (2 µm diameter, 1 mg/kg) via gavage for 40 and 60 consecutive days. Blood samples were collected for complete blood count (CBC), sedimentation rate, biochemical (aspartate transaminase [AST], alanine transaminase [ALT], blood urea nitrogen [BUN], creatinine, uric acid), and immunological (indirect immunofluorescence for autoantibodies) analyses.
Results: Polystyrene MPs induced autoantibodies in serum at a dilution of 1:40 after 60 days. Mice developed microcytic hypochromic anemia after 40 and 60 days of exposure to polystyrene MPs. White blood cell (WBC) counts increased after 40 days but decreased after 60 days compared to the control group. Platelet counts increased significantly after 40 and 60 days. Sedimentation rates increased in exposed mice after 40 and 60 days.
Conclusion: The findings suggest that exposure to polystyrene MPs for 60 days may induce autoimmune-like disease in mice. Changes in hematological parameters, as well as increased sedimentation in mice and positive autoantibody titers in mice exposed to MPs for 60 days, could be the result of inflammation or the development of an autoimmune-like disease.