Endocytosis, endoplasmic reticulum, actin cytoskeleton affected in tilapia liver under polystyrene microplastics and BDE153 acute co-exposure

Abstract

Studies showed that contaminants adhered to the surface of nano-polystyrene microplastics (NPs) have a toxicological effect. Juveniles tilapia were dispersed into four groups: the control group A, 75 nm NPs exposed group B, 5 ng·L⁻¹ 2,2′,4,4′,5,5′-hexabromodiphenyl ether group C (BDE₁₅₃), and 5 ng·L⁻¹ BDE₁₅₃ + 75 nm MPs group D, and acutely exposed for 2, 4 and 8 days. The hepatic histopathological change, enzymatic activities, transcriptomics, and proteomics, have been performed in tilapia. The results showed that the enzymatic activities of anti-oxidative (ROS, SOD, EROD), energy (ATP), lipid metabolism (TC, TG, FAS, LPL, ACC), pro-inflammatory (TNFα, IL-1β) and apoptosis (caspase 3) significantly increased at 2 d in BDE₁₅₃ and the combined group and together in BDE₁₅₃ group at 8 d. Histological slice showed displaced nucleus by BDE₁₅₃ exposure and vacuoles appeared in the combined groups. KEGG results revealed that pathways associated with endocytosis, protein processing in endoplasmic reticulum and regulation of actin cytoskeleton were significantly enriched. The selected genes associated with neurocentral development (ganab, diaph3/baiap2a/ddost decreased and increased), lipid metabolism (ldlrap1a decreased, stt3b increased), energy (agap2 decreased, uggt1 increased) were affected under co-exposure, and fibronectin significantly increased via proteome. Our study indicated that endocytosis, protein processing in endoplasmic reticulum, regulation of actin cytoskeleton were affected in tilapia liver under NPs and BDE₁₅₃ co-exposure.