TBBPA-BDBPE as a safer alternative? Comparative assessment of systemic toxicity with TBBPA in zebrafish

Tetrabromobisphenol A (TBBPA) and its derivative, TBBPA-bis (2,3-dibromopropyl ether) (TBBPA-BDBPE), are widely used brominated flame retardants (BFRs) that are frequently detected in environmental and human biological samples. Despite their widespread application, the potential toxicity of TBBPA-BDBPE is still not thoroughly assessed. In this study, we employed zebrafish as a model organism to systematically evaluate and compare the developmental toxicity of TBBPA and TBBPA-BDBPE. Our results demonstrated that TBBPA induced significant developmental toxicity at 1000 μg/L, as evidenced by reduced body length, decreased survival rates, and increased incidence of malformations. In contrast, TBBPA-BDBPE exhibited no observable developmental effects even at a substantially higher concentration (50,000 μg/L). While both compounds reduced heart rate without impairing cardiac function, only TBBPA disrupted early cardiac specification. Similarly, while TBBPA induced pronounced cardiovascular abnormalities-including cranial hemorrhage and caudal central vein (CV) expansion-TBBPA-BDBPE caused only mild hemorrhage and showed no detectable effects on vascular development. Lastly, neither compound induced significant hepatotoxicity at the tested concentrations. Taken together, these findings demonstrate that TBBPA-BDBPE exhibits markedly lower toxicity than TBBPA, supporting its safer use as a TBBPA derivative in industrial applications.