Microplastics Enhance the Toxic Effects of Tetracycline on the Early Development of Zebrafish in a Dose-Dependent Manner

Microplastic pollution in the environment has greatly increased due to the widespread use of plastics. Antibiotics and microplastic are common contaminants, especially in aquaculture. Microplastics could act as antibiotic vectors that raise the potential of their ecotoxicological effects. In this work, we conducted several analyses of biomarker responses to examine the developmental toxicity and toxicological endpoints that polyethylene microplastics (PE-MPs) and tetracycline antibiotics (TC) induced in zebrafish (Danio rerio) embryos/larvae. The results suggested that TC-PE-MPs induced significant physiological perturbations, including attenuated spontaneous cardiac contractions, cardiotoxicity, a dose-dependent elevation in mortality, and a marked reduction in body length, accompanied by morphological alterations. The mechanistic analysis revealed that ROS accumulation triggered enzymatic activity changes, which further induced aberrant vascular development, robust inflammatory responses, and dysregulated gene expression. These findings demonstrate that PE coexistence potentiates TC’s toxicological effects, with combined exposure inducing developmental toxicity during critical organogenesis stages in zebrafish. Overall, the current research demonstrated the detrimental effects of TC-PE-MPs on early fish development, suggesting potential environmental risks.