Nano-TiO₂ enhanced bioaccumulation and developmental neurotoxicity of bisphenol a in zebrafish larvae

The titanium dioxide nanoparticles (n-TiO₂) could enhance the bioavailability and toxicity of the coexisted organic toxicants in aquatic phase. Parental co-exposure to n-TiO₂ and bisphenol A (BPA) could generate developmental neurotoxicity in unexposed zebrafish offspring. However, it remains unexplored regarding the developmental neurotoxicity in larvae fish after co-exposure during the early developmental stage. In present study, fertilized zebrafish eggs were exposed to TiO₂ nanoparticles (100 μg/L), BPA (1, 4 and 20 μg/L) or their binary mixtures until 6 days post fertilization (dpf). No significant change was observed in hatching, malformation, survival and weight of the larvae among all groups. However, n-TiO₂ significantly increased the body burden of BPA in the 4 and 20 μg/L co-exposure groups, depressed expression of neurodevelopment marker genes (α1-tubulin, mbp and syn2a) as well as the locomotor behavior. The current results indicate that n-TiO₂ could strengthen the developmental neurotoxicity and inactive locomotion in co-exposed zebrafish larvae by promoting the bioaccumulation and bioavailability of BPA, which highlighted the similar toxic risks of developmental neurotoxicity after co-exposure at early developmental stage to that of the parental co-exposure.