Hepatic multi-level responses to polyethylene microplastics in Lateolabrax maculatus: Insights from transcriptomics, antioxidant enzyme activity, and histopathology

Microplastic (MP) contamination in aquaculture feeds and rearing environments has raised increasing concerns regarding fish health and food safety. Polyethylene microplastics (PE-MPs), one of the most common synthetic polymers in aquaculture environments, may pose chronic risks to economically important fish species. In this study, Lateolabrax maculatus was exposed to experimental diets containing 0% (CK), 4% (LM), and 8% (HM) PE-MPs for 45 days, followed by a 14-day depuration phase to evaluate hepatic recovery. Comprehensive analyses including transcriptome sequencing, antioxidant enzyme assays, immune-related gene expression profiling, and histopathological examinations were performed to elucidate the hepatic responses to PE-MPs. KEGG enrichment revealed significant alterations in multiple metabolic pathways, such as cytochrome P450, PPAR signaling, oxidative phosphorylation, amino acid metabolism, and purine metabolism. PE-MP exposure induced oxidative stress (increased SOD, CAT, MDA levels), activated inflammatory responses via NF-κB signaling (up-regulated IL-1β, IL-8, TNF-α, IFN-γ), and caused hepatic vacuolation. Most physiological parameters recovered partially after microplastic withdrawal; however, persistent IL-8 elevation indicated incomplete inflammation resolution. This integrated study on PE-MP hepatotoxicity and post-exposure recovery in Lateolabrax maculatus shows that hepatic damage is partially reversible after a 14-day depuration. The coexistence of repairable and persistent impairments implies that recovery trials may need to be considered in long-term risk assessment frameworks. These findings contribute to a scientific basis for evaluating microplastic risks in aquaculture and offer reference evidence for the potential inclusion of depuration periods in sustainable farming practices. • Dietary exposure to PE MPs for 45 days disrupts hepatic metabolism in Lateolabrax maculatus . • Transcriptomics reveals altered xenobiotic metabolism, oxidative phosphorylation, and lipid oxidation. • Biochemical assays confirmed oxidative stress, lipid peroxidation, and NF-κB–mediated immune activation. • Histopathology showed dose-dependent hepatocellular vacuolation and structural damage. • Recovery trials show partial antioxidant restoration but persistent IL-8 elevation, indicating ongoing inflammation.