Assessment of the Accumulation and Potential Toxicity of Polystyrene Microplastics in Rats

In recent years, there has been a significant amount of research conducted on microplastics (MPs) as emerging pollutants. These particles, which are < 5 mm in size, are the primary cause of environmental and aquatic contamination. Due to the high exposure to MPs and insufficient information available on their toxicity to humans and animals, it is important to prioritize and assess the risks associated with MPs. This study aimed to investigate the effects of exposure to polystyrene (PS)-MPs on Wistar rats. Following an acclimatization period, 120 rats with an average weight of 190 ± 10 g were randomly allocated into 24 cages a week before the commencement of the experiment. Over varying durations ranging from 1 to 28 days, the rats were exposed to PS-MPs at low (0.5 mg) and high (0.1 mg) doses. Additionally, a control group received corn oil without MPs. The digested tissue samples were observed under a fluorescence microscope, which revealed the presence of small pieces of MPs in the form of fibers, due to environmental pollution. The liver, kidneys, and colon tissues were histopathologically analyzed, and biomarkers of toxicity were measured in the rats' blood. The results of the animal study indicated that PS-MPs were minimally toxic, and there was no tissue damage in the rats. However, some minor signs were found in biochemical biomarkers. Therefore, further research is necessary to fully understand the potential risks associated with exposure to MPs.