Developmental toxicity and transcriptome analysis of zebrafish (Danio rerio) embryos exposed to anesthetic esketamine

Esketamine (ESK), a novel intravenous general anesthetic, extensively utilized in obstetric and pediatric anesthesia. However, the potential in vivo toxicity of ESK to growth and development has not been comprehensively evaluated. In this study, we employed a zebrafish model to investigate the developmental toxicity and behavioral alterations induced by ESK in zebrafish embryos. Based on the 24-h lethal concentration 50 % (LC₅₀) value of 271.9 μg/mL, fertilized embryos were exposed to ESK at concentrations of 50, 100, 150, 200, and 250 μg/mL for a duration of 24 h (from 2 to 26 h post-fertilization). The findings indicated that ESK exposure resulted in delayed hatching, increased mortality, and elevated malformation rates. Developmental anomalies, such as reduced body length, delayed yolk absorption, decreased heart rate, and an increased distance between the sinus venosus and bulbus arteriosus (SV-BA) were observed in zebrafish embryos and larvae following ESK exposure. Moreover, Exposure to ESK resulted in notable behavioral alterations, including decreased movement distance and average speed at 96 h post-fertilization (hpf). Histopathological analyses further demonstrated impaired brain development. RNA sequencing data revealed significant disruptions in the cell cycle, neuroactive ligand-receptor interaction, adrenergic signaling in cardiomyocytes, and calcium signaling pathways. These findings indicate that ESK induces both cardiotoxicity and neurotoxicity in zebrafish larvae. This study elucidates the potential mechanisms underlying the developmental toxic effects of embryonic exposure to ESK in zebrafish larvae, offering valuable insights for ecological risk assessment and potential implications for human health.