Enhanced Effects of Polystyrene Nanoplastics and Imidacloprid on Organ Damage in Loaches(Misgurnus Anguillicaudatus): Disrupted Gene Expression Leads to Imbalance in Lipid Metabolism

Abstract

The objective of this study was to investigate whether polystyrene nanoplastics (PS-NPs) could potentiate the toxic effects of imidacloprid (IMI) on loach. Loaches were exposed to varying environmental concentrations of PS-NPs in combination with IMI. Subsequently, changes in antioxidant capacity, histopathological features, anti-inflammatory responses, intestinal gene expression, and metabolic profiles were evaluated. The results demonstrated that PS-NPs significantly enhanced the oxidative stress response induced by IMI and promoted the expression of inflammatory factors. Additionally, toxic lesions were observed in the gills, intestines, and liver of the experimental group. PS-NPs exacerbated liver and intestinal toxicity caused by IMI. Intestinal transcriptome sequencing revealed common genes such as HMGCS1, CEL, APOB, CYP8B1, and APOC1. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses indicated significant enrichment in cell cycle regulation and vitamin digestion and absorption pathways across multiple groups. Metabolomics analysis showed a dose-dependent decrease in levels of various metabolites, including hydroxyphenyllactic acid and desamino-tyrosine, particularly affecting lipid metabolism. This study concluded that the accumulation of PS-NPs in aquatic environments can enhance the toxicity of IMI to freshwater loach, potentially disrupting lipid metabolism and digestion and absorption processes through interference with the expression of these genes.

Keywords: Polystyrene nanoplastics, Imidacloprid, enhanced toxicity, Misgurnus anguillicaudatus, liver and intestinal injuries