MO015ANALYZING THE EFFECT OF MICROPLASTIC PARTICLES ON HUMAN PODOCYTES

Abstract Background and Aims Despite increasing use of plastic based products and their potential health risks on the humans, very little is known about their possible accumulation in the food chain and their further long-term effect on the human health. Recently, there are increasing reports related to the potential risk of polystyrene microplastics to the human respiratory system and human intestinal epithelia cell line. In this study, we assayed the primary effect of microplastic particles on the human kidney cells. To that aim, we used human podocytes cells and four different types of plastic particles including; polyvinyl chloride (PVC), polypropylene (PP), polyamide (PA) and tyre wear particles to evaluate the effects of microplastics on the viability and morphology of human podocytes in vitro. Method In this study, we applied different biological methods such as, cell viability test and phalloidin staining, to assay the toxicity of particles and their further effects on the actin cytoskeleton organization in human podocytes, respectively. Furthermore, Raman imaging is used to track particle attachment on the cells and to evaluate the possible changes in the cell compartment following the particle treatment. The particle uptake by the cells and changes in cellular biological features were visualized with the use of scanning electron microscopy (SEM). Results As a primary result, the cytotoxicity response of particle treatment was found to be dependent on the polymer type. As an example higher concentration of PP particle as compared to PVC, PA, and tyre wear caused a similar rate of cell mortality. Furthermore, the degree of particle attachment on the cells depended on their adhesion properties, which was higher in PA, PVC and tyre wear in comparison to PP particles. These particles remained attached to the cell surface even after two-three times of washing with PBS. Based on the phalloidin staining results, particle treatment induced cytoskeleton reorganization in podocytes in vitro. With the use of Raman imaging particle attachment was confirmed based on the fingerprint spectra related to each particle. Conclusion This study suggests that exposure duration and particle concentrations are two of the key factors to evaluate the toxicological effect of particles on podocytes as a highly-specialized epithelial cells in the kidney. It is supposed that two mechanisms can be related to the harmful effects of plastic particles on podocytes. First, particle attachment on the cell surface leading to limitation of nutrient uptake by the cells. Second, uptake of smaller size particles into the cells through phagocytosis. More studies are necessary to determine the direct effect of microplastics on human kidney cells.