Neurobehavioural Toxicity of Iron Oxide Nanoparticles in Mice.

Iron oxide nanoparticles (FeO-NPs) are widely used in various biomedical applications, extremely in neurotheranostics. Simultaneously, FeO-NP usage is of alarming concern, as its exposure to living systems causes deleterious effects due to its redox potential. However, study on the neurobehavioural impacts of FeO-NPs is very limited. In this regard, adult male mice were intraperitoneally administered with FeO-NPs (25 and 50 mg/kg body weight) once a week for 4 weeks. A significant change in locomotor behaviour and spatial memory was observed in FeO-NP-treated animals. Damages to blood-brain barrier permeability by FeO-NPs and their accumulation in brain regions were evidenced by Evan's blue staining, iron estimation and Prussian blue staining. Elevated nitric oxide, acetylcholinesterase, lactate dehydrogenase leakage and demyelination were observed in the FeO-NP-exposed brain tissues. Imbalanced levels of ROS generation and antioxidant defence mechanism (superoxide dismutase and catalase) cause damages to lipids, proteins and DNA. PARP and cleaved caspase 3 expression levels were found to be increased in the FeO-NP-exposed brain regions which confirms DNA damage and apoptosis. Thus, repeated FeO-NP exposure causes neurobehavioural impairments by nanoparticle accumulation, oxidative stress and apoptosis in the mouse brain.