Microplastics are emerging environmental contaminants capable of crossing epithelial barriers and circulating systemically, potentially affecting organisms, including humans. This study investigated the hematological and biochemical effects of sub-chronic oral exposure to polystyrene microplastics (PS-MPs) in male Swiss albino mice. Animals received 1 μm PS-MPs in drinking water at 0.01 mg/day for four weeks, followed by a two-week recovery period. Blood samples were collected weekly for hematological and biochemical analysis. PS-MP exposure resulted in an increased number of certain immunocytes after the first week of treatment. The highest values compared with the control group were observed in Week 2, reaching 18.5 ± 4.61 vs. 7.2 ± 1.14; 10.9 ± 2.58 vs. 5.1 ± 1.20; and 5.8 ± 2.35 vs. 2.2 ± 0.69 × 109 cells/L for white blood cells, lymphocytes, and granulocytes, respectively (p < 0.001). A significant increase in platelet count was also observed, becoming evident by Week 6 (725.8 ± 307.96 vs. 470.1 ± 121.87 × 109 cells/L, p < 0.05). The elevated alanine aminotransferase and aspartate aminotransferase activities observed after PS-MP exposure were potentially associated with hepatic pathology, erythrocyte damage, and inflammatory responses. No significant recovery was observed during the period after exposure. These findings demonstrate that sub-chronic oral PS-MP exposure induces inflammatory responses and may disrupt organ function.
Petrov et al. (Tue,) studied this question.