Effects of Developmental Exposure to TiO2 Nanoparticles on Synaptic Plasticity in Hippocampal Dentate Gyrus Area: an In Vivo Study in Anesthetized Rats

With the increasing applications of titanium dioxide nanoparticles (TiO2 NPs) in industry and daily life, an increasing number of studies showed that TiO2 NPs may have negative effects on the respiratory or metabolic circle systems of organisms, while very few studies focused on the brain central nervous system (CNS). Synaptic plasticity in hippocampus is believed to be associated with certain high functions of CNS, such as learning and memory. Thus, in this study, we investigated the effects of developmental exposure to TiO2 NPs on synaptic plasticity in rats’ hippocampal dentate gyrus (DG) area using in vivo electrophysiological recordings. The input/output (I/O) functions, paired-pulse reaction (PPR), field excitatory postsynaptic potential, and population spike amplitude were measured. The results showed that the I/O functions, PPR, and long-term potentiation were all attenuated in lactation TiO2 NPs-exposed offspring rats compared with those in the control group. However, in the pregnancy TiO2 NPs exposure group, only PPR was attenuated significantly. These findings suggest that developmental exposure to TiO2 NPs could affect synaptic plasticity in offspring’s hippocampal DG area in vivo, which indicates that developmental brains, especially in lactation, are susceptible to TiO2 NPs exposure. This study reveals the potential toxicity of TiO2 NPs in CNS. It may give some hints on the security of TiO2 NPs production and application and shed light on its future toxicological studies.