Various nanoparticles are produced with development of nanotechnology; however, the safety is not confirmed precisely at present. Influence on brain of offspring that exposed to various nanoparticles (titanium dioxide; TiO₂, carbon black, carbon nanotube, fullerene; C₆₀ and nanoparticles from diesel engine; DEP) in fetal period was examined pathologically.

Brains from ICR mice born from each nanoparticle-exposed and normal mothers were examined under light and electron microscope. To detect apoptosis, immunohistochemical staining for caspase-3 was performed, and to detect metal particle (TiO₂) transferred from mother to the fetus, brains of offspring were observed by energy-dispersive X-ray spectroscopy (EDS). The storage of abnormal structures (amyloid β and phosphorylayed tau), which are characteristic of neurodegenerative diseases, was detected with immunohistochemical staining.

All mice with nanoparticles exposure showed swelling of astrocytes’ endfoot, apoptosis of endothelial cells. In brain of TiO₂-exposed groups, EDS detected TiO₂. Many apoptosis and storage of abnormal structures were showed in characteristic parts of brain. Some capillaries were stenosis and the neighboring parenchyma had degenerative changes.

These findings indicate that nanoparticles transferred from pregnant mice has a severe impact on fetal brain, carries the multiple infarctions and atrophy, a great risk of dementia in offspring. Moreover, appearance of apoptosis and abnormal structures may relate to some mental neurological disorders. Our result should be a grave warning that nonparticles exposure is one of risk factors on neurological diseases, in which various psychic symptoms occur.