Induction of Oxidative Stress After Oral Exposure to Polystyrene Microplastics in Mice

Microplastic pollution has attracted significant attention in recent years due to evidence that these particles can accumulate in organisms’ tissues and organs and induce adverse health effects, with oxidative stress being a key underlying mechanism of toxicity. The present study investigated the effects of polystyrene microplastics (0.1 μm in diameter) administered at a dose of 0.1 mg/day/animal for 4 weeks, followed by a 2-week recovery period without exposure, on oxidative stress markers in the liver, kidney, and spleen and on hematological and blood biochemical parameters in mice. The results showed a statistically significant increase in white blood cell counts, including lymphocytes, granulocytes, and monocytes, at week 5, indicating the development of an inflammatory response. During the last week of the recovery period (week 6), values returned to levels that approached baseline. Changes in lipid peroxidation demonstrated an induction of oxidative stress, accompanied by alterations in glutathione levels and antioxidant enzyme activities, with a tendency toward recovery after cessation of polystyrene microplastic exposure. In conclusion, these findings demonstrated that even short-term exposure to low doses of polystyrene microplastics could trigger oxidative stress and inflammatory responses, highlighting their potential health risks and the need for further investigation into their long-term biological effects.