MICROPLASTICS AND ASSOCIATED CONTAMINANTS: POTENTIAL IMPACT ON CELLS AND DEVELOPING ORGANISMS

Differently from macroplastics, the effects of microplastics (MPs) on living organisms are still largely uncharacterized. It has been proposed that MPs can interact with multiple chemicals in the environment, many of which may act as Endocrine Disrupting Chemicals (EDCs), with deleterious consequences especially on developing organisms. Previous studies in our laboratory investigated the biological impact of MPs collected from seawater.1 However, experimental studies with environmental MPs pose technical challenges mainly due to plastics heterogeneity. To overcome this issue, in the present work we employed polystyrene MPs of specific sizes (5-0.5 μm), surface chemistry (virgin and –COOH functionalized, the latter to mimic environmentally aged MPs) and toxicant absorption (pristine and Bisphenol A-sorbed). We tested the impact of MPs exposure on early stages of developing zebrafish (zf) larvae and on several mammalian cell models, including liver, pre-adipocyte, and endothelial cell lines. MPs were internalized by cultured cells and ingested by zf larvae, accumulating in the intestine. In vitro cytotoxic effects were observed only in cells exposed to very high concentrations of functionalized MPs. In zf larvae, survival, hatching, and heartbeat were monitored until 6 dpf; MPs alone did not lead to macroscopic deleterious effects on developing zf. The adsorption of Bisphenol A (BPA) on MPs was tested using a UHPLC-tandem MS method. Following 24 h incubation, the adsorption yield of BPA (25 μM) on MPs was about 50%. The exposure to MPs preadsorbed with non-toxic concentrations of BPA had no toxic effects. We are currently testing further biological effects, including the induction of oxidative stress, lipid accumulation, and alterations in gene expression. Collectively, our results suggest that polystyrene MPs can be ingested by zf larvae and are internalized by cultured cells, carrying adsorbed contaminants such as BPA, with potential developmental and metabolic effects on cells and organisms. Reference 1. Capriotti M et al. Chemospere 2021;263:128090