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Tetrabromobisphenol A (TBBPA) is a brominated flame retardant that is commonly used in commercial and household products, such as, computers, televisions, mobile phones, and electronic boards. TBBPA can accumulate in human body fluids, and it has been reported that TBBPA possesses endocrine disruptive activity. However, the neurotoxic effect of TBBPA on hippocampal neurogenesis has not yet been investigated. Accordingly, the present study was undertaken to evaluate the effect of TBBPA on adult hippocampal neurogenesis and cognitive function. Male C57BL/6 mice were orally administrated vehicle or TBBPA (20 mg/kg, 100 mg/kg, or 500 mg/kg daily) for two weeks. TBBPA was observed to significantly and dose-dependently reduce the survival of newly generated cells in the hippocampus but not to affect the proliferation of newly generated cells. Numbers of hippocampal BrdU and NeuN positive cells were dose-dependently reduced by TBBPA, indicating impaired neurogenesis in the hippocampus. Interestingly, glial activation without neuronal death was observed in hippocampi exposed to TBBPA. Furthermore, memory retention was found to be adversely affected by TBBPA exposure by a mechanism involving suppression of the BDNF-CREB signaling pathway. The study suggests high dose TBBPA disrupts hippocampal neurogenesis and induces associated memory deficits. [ABSTRACT FROM AUTHOR]

Abstract: Bisphenol A (BPA) is used as a monomer during the manufacture of polycarbonate plastics and epoxy resins. However, BPA adversely affects reproductive organ growth and development, and it has been proposed that the detrimental effects of BPA could extend to future generations. The present study was conducted to evaluate the transgenerational effects of BPA on hippocampal neurogenesis and neurocognitive function. Pregnant female C57BL/6 mice (F0) were exposed to BPA (0.1–10mg/kg) from gestation day 6 to 17, and female offspring (F2) from F1 generation mice were prepared. It was found that exposure of F0 mice to BPA at 10mg/kg decreased the number of newly generated cells in the hippocampi of F2 female mice. Passive avoidance testing revealed that high-doses BPA (1mg/kg and 10mg/kg) decreased cross-over latency time in F2 mice, suggesting a BPA-mediated neurocognitive deficit in terms of memory retention. Furthermore, it was found that levels of phospho-ERK, brain-derived neurotrophic factor (BDNF), and phospho-CREB in hippocampi were significantly lower in F2 mice. Interestingly, the effects of BPA on hippocampal neurogenesis were found to be correlated with altered DNA methylation. In particular, high-dose BPA exposure increased DNA methylation of the CREB regulated transcription coactivator 1 (Crtc1) generated in F2 mice. These findings suggest that BPA exposure of pregnant mothers could adversely affect hippocampal neurogenesis and cognitive function in future generations by modulating the ERK and BDNF–CREB signaling cascades. [Copyright &y& Elsevier]

Abstract: Bisphenol A (BPA) is widely used in the manufacture of plastics and epoxy resins, and is known to affect reproductive organ growth and development. However, the effects of BPA on hippocampal neurogenesis are unclear in young adult mice. Therefore, the present study was conducted to examine the effects of BPA on hippocampal neurogenesis and learning as well as memory performance in young adult mice. BPA (1, 5, and 20mg/kg/day) was administered orally to mice for 2weeks. It was found that high-dose BPA (20mg/kg/day) decreased the number of newly generated cells in hippocampus, but that low-dose BPA (1mg/kg) increased the survival of newly generated cells in hippocampi of young mice. Furthermore, high-dose BPA (20mg/kg/day) was found to impair learning and memory performance significantly. However, no significant differences were observed between high- and low-dose treated mice in terms of levels of brain-derived neurotrophic factor (BDNF) or reactive oxygen species production in hippocampus. In addition, BPA treatment did not induce neuronal loss or damage or astrocyte activation. These data suggest that exposure to BPA causes fluctuations in hippocampal neurogenesis in young adult mice that result in spatial learning and memory impairment via a BDNF-independent pathway. [Copyright &y& Elsevier]