Polystyrene nanoparticles affect development and induce genotoxicity in Drosophila melanogaster

It is estimated that more than 170 trillion plastic particles float in the World’s oceans, making plastic pollution one of the most important environmental and health emergencies. Micro- and nanofragments accumulate in the fatty tissues of exposed organisms, causing metabolic alterations, genotoxicity and reduced survival. Drosophila melanogaster is an excellent model to examine the genotoxic and tumorigenic potential of nanoplastics (NPs). We examined polystyrene, which is widely utilized in food packaging, is poorly recycled, and constitutes at least 30% of landfills. We reared Oregon[R] wild-type flies on food containing 100 µm polystyrene nanoparticles (PSNPs) to study their biological impact and carcinogenic potential. By SEM analyses, PSNPs didn’t appear susceptible to digestion in the fly. Fluorescent PSNPs accumulated in the intestine and fat bodies of chronically-exposed wild-type flies. Moreover, PSNP-fed flies displayed significant reduction in weight and developmental time, as well as impaired recovery from starvation and heat-shock, but not in larval crawling and climbing assays. We also observed a decline in climbing activity in PSNP-fed DNAlig4 mutants, known to be sensitive to nutritional stresses. Overall, these results suggest that PSNPs impact on fly development and metabolism. Because PSNPs were administered orally, a preliminary molecular analysis on larval guts by qPCR indicated a significantly increased expression of drice and p53 that are genes responding to cell damage. Finally, we evaluated the carcinogenic potential of PSNPs using warts defective mutants, finding increased abnormal masses in exposed flies compared to untreated ones.