Glia cells are selectively sensitive to nanosized titanium dioxide mineral forms

Nanosized titanium dioxide is widely used by the industry e.g. in pigments, suncreams and food colors. Its environmental and biological effects have been investigated in the past, however, few studies have focused on its crystal structure-specific effects. In our experiments, the toxicity of two types of nanoparticles was examined on primary neural cultures with different cell-compositions, using MTT and LDH assays. Primary murine cell cultures containing only astroglia cells originated from two brain regions, as well as mixed neurons and glia cells or microglia cells exclusively, were treated with anatase and rutile TiO 2 nanoparticles at varying concentrations for 24 or 48 hours. Our results show that neither anatase nor rutile nanoparticles reduced viability in cell cultures containing a mixture of neurons and glial cells, independently of the applied concentration and treatment time. Rutile but not anatase form induced cell death in cortical astroglia cultures already at 24 hours of treatment above 10 μg/mL, while hippocampus-derived glial cultures were much less sensitive to rutile. The rutile form also damaged microglia. These findings suggest that products containing rutile-form nano-titanium particles may pose a targeted risk to astroglia and microglial cells in the central nervous system.