Investigating Polystyrene Nano-Plastic Effects on Largemouth Bass (Micropterus salmoides) Focusing on mRNA Expression: Endoplasmic Reticulum Stress and Lipid Metabolism Dynamics

Nano-plastics (NPs) have emerged as a pervasive global contaminant, posing significant threats to carnivorous fish, in recent years. The accumulation of polystyrene nano-plastics (PS-NPs) can cause endoplasmic reticulum (ER) stress. However, the concurrent impacts of PS-NPs on lipid metabolism and ER stress in largemouth bass have not been sufficiently investigated. To study this gap, we established a largemouth bass model exposed to PS-NPs in a culture environment. The exposure experiment focused on 100 μg/L PS-NPs (100 nm). Transcriptomics analysis revealed a significant enrichment of differentially expressed genes involved in a lipid metabolism pathway and ER process. The levels of biochemical parameters associated with lipid metabolism, including high-density lipoprotein cholesterol, total cholesterol, triglyceride, and low-density lipoprotein cholesterol, demonstrated that exposure to PS-NPs for nineteen days had an impact on lipid metabolism. Additionally, the expression levels of genes associated with fatty acid biosynthesis and ER stress exhibited a significant increase following exposure to PS-NPs for nineteen days, whereas these changes were not significant after a seven-day exposure period. The ER stress induced by PS-NPs exhibited a positive correlation with lipid metabolism disorder and the magnitude of damage caused by prolonged exposure to PS-NPs in largemouth bass. The present study provides novel insights into the health threats encountered by largemouth bass when exposed to NPs.