The Effect of Subacute Exposure to Low-Density Polyethylene (LDPE) Microplastics on Oxidative Stress and Membrane Damage in Alveolar Macrophage Cells of Rattus Norvegicus Wistar Strain

Introduction: Inhalation of microplastics (MPs) can damage lung tissue. Alveolar macrophages express superoxide dismutase (SOD) as a defensive response to foreign substances. Additionally, F2-isoprostane (IsoP) is a specific biomarker of oxidative stress induced by reactive oxygen species (ROS). This study aimed to analyze the effects of Mps inhalation on alveolar macrophages. Materials and Methods: This true experimental study employed a post-test-only control group design using 21 Wistar rats. MPs aerosols at concentrations of 1 mg/L/day and 2 mg/L/day were inhaled for 28 days. Airborne MPs were measured using passive sampling methods. SOD and IsoP expression levels were evaluated using immunohistochemistry, and their correlations with MPs levels were analyzed using Spearman’s rank correlation test. Results: The average level of MPs in the air chamber of treatment group 1 was 17.59 particles/unit chamber, and that of treatment group 2 was 35.95 particles/unit chamber. The average expression of SOD and IsoP in the 1 mg/L exposure samples was 15.16 cells/field of view and 17.54 cells/field of view, while in the 2 mg/L exposure samples, there were 10.63 cells/field of view and 23.28 cells/field of view. The effect of MPs levels in chamber air on the expression of SOD and IsoP in alveolar macrophages in lung tissue was significant (p < 0.05). Conclusions: Subacute exposure to MPs causes oxidative stress and damage to the membrane of macrophage cells. The dose of exposure to MPs in the study may be higher than the presence of MPs in the air in reality.