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

摘要

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.