In vitro neurotoxic potential of emerging flame retardants on neuroblastoma cells in an acute exposure scenario

Since 2004, some legacy flame retardants (FRs) were restricted or removed from the European markets due to their concern on human health. Both organophosphorus FRs (OPFRs) and novel brominated FRs (NBFRs) have replaced them because they are presumably safer and less persistent emerging FRs (EFRs) and their exposure is currently occurring in indoor environments at high levels. Little is known about the neurotoxic potential risk of these EFRs in humans. The present study was aimed at assessing the acute neurotoxicity potential of Tris(1, 3-dichloro-2-propyl)phosphate (TDCPP), triphenyl phosphate (TPhP), Bis(2-ethylhexyl)tetrabromophthalate (BEH-TEBP) and 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EH-TBB) on human neuroblastoma cells (SH-SY5Y). SH-SY5Y were exposed to these EFRs at low concentrations -ranging 2.5-20 μM. during 2-24 h. We investigated viability, mitochondrial function, oxidative stress, inflammatory response, as well as neural plasticity and development. The results have demonstrated that selected EFRs (TDCPP, TPhP, EH-TBB and BEH-TBP) did not impair neural function on SH-SY5Y as acute response. To the best of our knowledge, this has been the first study focused on evaluating the neural affection of TPhP on SH-SY5Y cells and of EH-TBB and BEH-TBP on neural cells. We also assessed for the first time almost all endpoints after FR exposure on neural cell lines.