Toxicological mechanisms and molecular impacts of tire particles and antibiotics on zebrafish

Tire microplastics (TMPs) and antibiotics are emerging pollutants that widely exist in water environments. The coexistence of these pollutants poses severe threats to aquatic organisms. However, the toxicity characteristics and key molecular factors of the combined exposure to TMPs in aquatic organisms remain unknown. Therefore, the joint toxicity of styrene-butadiene rubber TMPs (SBR-TMPs) and 32 antibiotics (macrolides, fluoroquinolones, β-lactams, sulfonamides, tetracyclines, nitroimidazoles, highly toxic antibiotics, high-content antibiotics, and common antibiotics) in zebrafish was investigated using a full factorial design, molecular docking, and molecular dynamics simulation. Sixty-four combinations of antibiotics were designed to investigate the hepatotoxicity of the coexistence of SBR-TMPs additives and antibiotics in zebrafish. Results indicated that low-order effects of antibiotics (e.g., enoxacin-lomefloxacin and ofloxacin-enoxacin-lomefloxacin) had relatively notable toxicity. The van der Waals interaction between additives and zebrafish cytochrome P450 enzymes primarily affected zebrafish hepatotoxicity. Zebrafish hepatotoxicity was also affected by the ability of SBR-TMPs to adsorb antibiotics, the relation between antibiotics, the affinity of antibiotics docking to zebrafish cytochrome P450 enzymes, electronegativity, atomic mass, and the hydrophobicity of the antibiotic molecules. This study aimed to eliminate the joint toxicity of TMPs and antibiotics and provide more environmentally friendly instructions for using different chemicals.