Differential organ-specific toxicity profiling of BDE-209 and its derivative DBDPE in zebrafish

Decabrominated diphenyl ether (BDE-209) and its alternative, decabromodiphenyl ethane (DBDPE), are widely used flame retardants in various industrial products. Due to their persistence and bioaccumulation properties, BDE-209 and DBDPE extensively exist in the environment and wild animals. While previous studies have reported their toxicities, a systematic comparison of their toxic effects remains limited. In this study, we comprehensively evaluated and compared the developmental toxicity of BDE-209 and DBDPE using the zebrafish model. Our results demonstrated that no developmental toxicity was observed for DBDPE even at concentrations up to 10 mg/L. In contrast, BDE-209 significantly reduced survival rates and hatching rates at 0.25 mg/L, although body length remained unaffected. While neither compound affected zebrafish heart rate or cardiac function, BDE-209 disrupts cardiac differentiation, as evidenced by abnormal morphology of the atria and ventricles. Additionally, both compounds showed no detectable toxicity on vascular development or hematopoiesis. Notably, DBDPE induced more severe hepatotoxicity than BDE-209 in zebrafish. Transcriptome sequencing indicated DBDPE and BDE 209 shared several enriched signaling pathways, while they both exhibit distinct pathway enrichment patterns. In summary, BDE-209 and DBDPE exhibit distinct toxicity profiles, as BDE-209 poses a greater risk to development and DBDPE exhibits more pronounced hepatotoxicity.