Nuclear receptor disruption contributes to 2,4-dichlorophenol-induced developmental toxicity: Evidence from network toxicology and zebrafish analysis.

2,4-Dichlorophenol (2,4-DCP) is an environmental pollutant associated with developmental toxicity in zebrafish (Danio rerio) embryos and larvae, though its underlying mechanisms remain poorly understood. This study investigated 2,4-DCP-induced toxicity through integrated morphological, biochemical, computational and molecular analyses. Acute exposure (2.5-20 mg/L) yielded a 144-h LC50 of 13.94 mg/L. Intermediate concentrations (10-15 mg/L) induced severe malformations, including yolk sac retention, pericardial and yolk sac edemas, and craniofacial, spinal, and tail deformities. In contrast, lower concentrations (2.5-5 mg/L) elicited subtle morphological alterations alongside disruptions in defense antioxidant system (CAT, GST, GPx, MDA), neurotransmission (AChE), and metabolic activity (LDH). Network toxicology, gene ontology, and pathway analyses identified nuclear receptors (NCOA1, RXRA, PPARG, ESR1) as key mediators of 2,4-DCP toxicity, influencing energy metabolism, skeletal development, antioxidant responses, and neurotransmission. Molecular docking confirmed stable interactions between 2,4-DCP and these targets, while gene expression analysis revealed perturbations in PPAR (ppara, pparb, pparg) and estrogen (esr1) signaling pathways. These findings highlight nuclear receptor signaling as a critical mechanism in 2,4-DCP-induced developmental toxicity, providing a foundation for future environmental risk assessments.