Reproductive Toxicity and Transgenerational Effects of Anesthetic Etomidate in Zebrafish: PCOS-like Ovarian Changes, Oxidative Stress, and Metabolism Disruption

Etomidate (ETO), a benzodiazepine commonly used by pregnant women with anxiety disorders, has been increasingly detected in aquatic environments. However, its reproductive toxicity and intergenerational effects have not been adequately assessed. In this study, adult female fish were employed to investigate the reproductive toxicity after ETO exposure. After 4 weeks of exposure, zebrafish ovaries exhibited polycystic ovary syndrome (PCOS)-like changes, including polycystic ovaries, reduced spawning rates, and elevated androgen levels. Moreover, ETO was transmitted to offspring via maternal ovaries, significantly increasing larval mortality and deformity rates while reducing their locomotor activity. Transcriptomic and metabolomic profiling revealed oxidative stress responses, disrupted unsaturated fatty acid and glutathione metabolism, and damage to ovarian granulosa cells and the zona pellucida, as confirmed by reactive oxygen species (ROS) fluorescence staining. Combined multiomics analysis demonstrated that ETO exposure exacerbated ovarian oxidative stress, impaired the functional structure of ovaries, and disrupted follicular cell maturation via hyperactivation of the mechanistic target of the rapamycin complex 1 (mTORC1) pathway. These changes culminated in PCOS-like effects in zebrafish. This study provides critical insights into the mechanisms of ETO-induced reproductive toxicity and transgenerational impacts, offering a foundation for more comprehensive risk assessments and potential interventions.