Tetrabromobisphenol A: a neurotoxicant or not?

Although some regulatory agencies have claimed that consumer exposures to tetrabromobisphenol A (TBBPA) are not likely to cause adverse health effects in humans or the environment, the safety of tetrabromobisphenol A (TBBPA) has been questioned. Here, we summarize the literature concerning in vivo and in vitro neurotoxicity of TBBPA over the past decades. Most laboratory rodent studies reported that gavage administration of TBBPA at doses below 1000 mg/kg/day generally exerted no or limited effects on neuropathology and locomotor behaviors, but increased anxiety and auditory impairments were observed in several studies. In fish and amphibians, waterborne exposure to TBBPA was generally reported to disrupt neurodevelopment and lead to neurobehavioral alterations. Moreover, in vitro studies support the observations that TBBPA could exert neurotoxic effects in vertebrates. Thus, we suggest that TBBPA could have adverse effects on the nervous system in vertebrates. Given rapid excretion and low availability of TBBPA in laboratory rodents following single gavage administration, we speculate that single-daily gavage could result in an underestimation of the neurotoxic effects of TBBPA in rodents. Thus, we propose to employ multiple-daily administration routes (such as dermal, inhalation, and drinking water), to further assess the neurotoxic effects of TBBPA in mammals.