Manganese dioxide nanoparticle induces Parkinson like neurobehavioral abnormalities in rats

Manganese dioxide magnetic nanoparticle (MnO2-NP) with specific size range from 30 to 60 nm has widespread application in magnetic resonance imaging, medicine and drug delivery in exposed humans and animals. Manganese nanoparticles could affect hippocampus tissue and impose abnormal cognitive functions such as manganese ion. Therefore, to investigate whether MnO2-NP is damaging hippocampus tissue and inducing molecular and neurobehavioral abnormalities, we administrated different doses of synthesized nanoparticle to rats and measured behavioral, biochemical and histological parameters by standard methods.

Results showed that the treatment of rats with MnO2-NP during 15 days induced oxidative stress and reduced catecholamine content in hippocampus tissue. MnO2-NP affected hippocampus tissue appearance by increasing the number of apoptotic and necrotic cells suggested that approved nanoparticle penetrated blood brain barrier and reached the hippocampal cells. Interestingly, all biochemical and histological effects of MnO2-NP were dose dependent.

By considering that hippocampus plays an important role in cognitive function, behavioral abnormalities in intoxicated rats were predictable and nanoparticle administrated rats showed depression like behavioral signs dose dependently. Based on our results and previous studies that confirmed neurotoxicity of MnO2-NP in µg dose rang, the application of this nanoparticles should be limited and their waste should be neutralized before their release to the environment (Fig. 4, Ref. 31).