Multi-omics analysis reveals polyethylene microplastics-induced gill damage, metabolic disruption and immune...

Microplastics (MPs) are emerging environmental pollutants that can induce physiological toxicity in aquatic organisms. This study investigated the toxicological effects of dietary exposure to polyethylene microplastics (PE-MPs) on gill tissues of Lateolabrax maculatus, using diets containing 0%, 4%, and 8% (w/w) PE-MPs. Histological, transcriptomic, and biochemical analyses were performed to assess structural damage, alterations in gene expression, and changes in antioxidant and immune parameters. Histological examination revealed structural abnormalities, including bending of gill lamellae and epithelial cell swelling, suggesting that gills may be sensitive to MP exposure. Transcriptomic analysis indicated that differentially expressed genes were enriched in pathways related to energy metabolism and immune response, including glycolysis/gluconeogenesis, oxidative phosphorylation, and phagosome. Key glycolytic enzymes (HK, PFK, PK) were upregulated, and the PPAR signaling pathway was activated, suggesting enhanced energy demands under stress conditions. Biochemical assays showed dynamic changes in antioxidant enzyme activities, with increased malondialdehyde (MDA) content in the high-concentration group, indicating oxidative stress. Immune-related genes associated with the NF-κB pathway (e.g., IL-1β, TNF-α) were upregulated, while TGF-β expression showed no significant changes. Following a 14-day depuration period without MP exposure, most antioxidant and immune parameters showed a trend toward recovery, indicating that the observed effects may be partially reversible. These findings suggest that MP exposure can contribute to gill structural impairment and perturbations in energy metabolism, redox homeostasis, and immune regulation in Lateolabrax maculatus, providing insights into the potential ecological risks of microplastic pollution in aquaculture environments.