Potential nervous threat of nanoplastics to Monopterus albus: Implications from a metabolomics study

Nanoplastics, as a new class of environmental pollutants, have been frequently detected in environmental media and organisms. Monopterus albus (M. albus) is an important economic aquatic product with a high dietary consumption. However, the potential biological effects of nanoplastics on M. albus remain unknown. In this study, the effects of polystyrene nanoplastics (PS-NPs) at different concentrations (0, 0.5, 1, 5 and 10 mg/L) on M. albus were investigated using an untargeted metabolomics approach. The results showed that 59, 44, 24, and 31 individual differential metabolites and 16, 9, 6, and 2 significant differential metabolic pathways were significantly changed in 0.5, 1, 5, and 10 mg/L respectively, indicating the greater effect of PS-NPs at the relatively low concentrations. After further analysis, there are four same significant differential metabolic pathways for the 0.5 and 1 mg/L groups, i.e., ABC transporters, cAMP signaling pathway, Neuroactive ligand-receptor interaction, and Synaptic vesicle cycle. In addition, there was one mutual differential metabolic pathway (Neuroactive ligand-receptor interaction) among the four groups, indicative of the probably universal nervous influence of nanoplastics on M. albus. In a word, the current work suggests that PS-NPs might affect the nervous systems of M. albus through disturbing their liver metabolism, and nanoplastics at relatively low concentrations may possess a greater effect, which provides significant information for assessing the toxic effect and exposure risk of nanoplastics to organisms in aquatic environment.