Neurotoxicity of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) during embryonic zebrafish development

Polybrominated diphenyl ethers (PBDEs) were widely used as flame retardants in consumer products but have become pervasive environmental contaminants. We investigated the developmental toxicity of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) using zebrafish embryos exposed to control, vehicle, low (5 µM), or high (20 µM) concentrations from 6 h post-fertilization to 6 days post-fertilization. Consistent with previous reports, BDE-47 induced abnormal body curvature and hindbrain flexion. Using a transgenic line expressing GFP in branchiomotor neurons, we found significant reductions in rhombomere 1-8 length, disrupted branchiomotor neuron patterning, and loss of pax2 expression in the hindbrain. BDE-47 also caused concentration-dependent disruption of muscle myofibrils. Although primary motor neuron patterning remained intact despite spinal curvature, treated embryos exhibited reduced motor neuron signal. Together, these findings demonstrate that BDE-47 disrupts hindbrain development and muscle organization, highlighting its developmental neurotoxic effects in zebrafish embryos.