Effects of polymethylmethacrylate nanoplastics on Dicentrarchus labrax

The present study aimed to evaluate the effects of ~45 nm nanoplastics (NPs) on the marine fish Dicentrarchus labrax after a short-term exposure. Animals were exposed to a concentration range of NPs for 96 h and liver, plasma and skin mucus were sampled. Assessed endpoints included biochemical biomarkers and expression of genes related to lipid metabolism, immune system and general cell stress. Abundance of mRNA transcripts related to lipid metabolism, pparα and pparγ, were significantly increased after exposure to NPs. Biochemical endpoints revealed decreased esterase activity levels in plasma, suggesting that the immune system of fish might be compromised by exposure to NPs. Moreover, significantly lower levels of alkaline phosphatase were found in the skin mucus of animals exposed to NPs. The present results suggest that NPs may represent a hazard to this marine fish, potentially interfering with the metabolism of lipids and the correct function of the immune response.