Investigating the Epigenetic Effects of Polystyrene Nanoplastic Exposure in Bluegill (Lepomis macrochirus) Epithelial Cells Using Methylation-Sensitive AFLPs

Microplastics, remnants of macroplastics that have broken down to fragments smaller than 5 mm, and nanoplastics, broken down even further to sizes < 1 μm, are pervasive in aquatic ecosystems. These plastic particles are consumed by microscopic organisms, leading to bioaccumulation up trophic levels. The accumulation of plastic in the organismal gut can result in various repercussions, including cellular contamination and genomic modifications such as DNA methylation. While methylation has been studied in teleost fishes, the impact of nanoplastic exposure on this process in any species remains largely unexplored. This study delves into this largely uncharted territory, investigating the accumulation of methylation due to nanoplastic exposure within the genome of cultured bluegill BF-2 cells (Lepomis macrochirus) using methylation-sensitive AFLPs. The methylation state was analyzed through capillary gel analysis and electropherograms. Differential methylation occurred between several control and experimental groups due to nanoplastic exposure; however, these differences were not dose- or time-dependent. These results could suggest that higher dosages and exposure times to nanoplastics do not result in increased methylation levels in congruence with the dosage and exposure time; rather, only the presence of nanoplastics is enough to cause DNA methylation changes.