Comparative Effects of Brominated Flame Retardants BDE-209, TBBPA, and HBCD on Neurotoxicity in Mice

Brominated flame retardants (BFRs) are ubiquitous industrial chemicals. In China, BFRs that are applied in large quantities include decabromodiphenyl ether (BDE-209), tetrabromobisphenol A (TBBPA), and hexabromocyclododecane (HBCD). Although findings are not always unequivocal, mounting evidence in vivo suggests that the BFRs have potential neurotoxicity. The present study aimed to assess and compare the neurotoxic effects of these three BFRs' exposure. Male mice were orally exposed to BDE-209, TBBPA, or HBCD at 50 and 100 mg/kg bw/day for 28 days. The cognitive behavior, oxidative stress (ROS, MDA, and GSH), apoptosis-related genes (caspase-3, bax, and bcl-2), memory-related proteins (BDNF and PSD-95), and neurotransmitters (AChE and ChAT) were detected comparatively. Results showed that high doses of BDE-209, TBBPA, and HBCD exposure impaired spatial memory of mice, elevated ROS and MDA and reduced GSH levels of hippocampus, upregulated caspase-3 and bax expressions, decreased BDNF and PSD-95 levels, and disordered AChE and ChAT levels. Notably, BDE-209 caused greater adverse effects > HBCD > TBBPA. This study confirms and extends that these three BFRs had similar neurotoxic effects at current concentrations, although they may be more or less toxic.