IN VITRO TOXICITY OF METAL NANOPARTICLES IN NEURONAL AND GLIAL CELLS

Several in vitro studies have indicated the potential toxicity of NPs to various types of neuronal and glial cells. SH-SY5Y neuroblastoma cell line has already been used to assess NP-induced neurotoxicity. Exposure of SH-SY5Y cells to Fe2O3, CuO and ZnO NPs was found to decrease cell viability showing a dose-dependent toxic response [3]. Similarly human glioblastoma U87MG cell line was studied to evaluate the effect of silicon dioxide nanoparticles [4]. The results showed a decreased mitochondrial energy production and an altered cell survival/proliferation signaling. At present little is known concerning the potential adverse effects of the NPs on neuronal cells, thus it seems urgent to investigate a possible NPs role in neurotoxicity. U87MG cells showed a decrease in cell viability following treatment with NPs of iron, cobalt oxide and cerium oxide at both 48 and 72h. Cobalt NPs reduced the cell viability of approximately 21% after 48 hours of exposure and the effect remained the same even after 72h. NPs of cerium oxide showed a decrease in cell viability comparable to that of cobalt NPs (21%) but only at the longer incubation time (72h). On the contrary, gold particles did not show any modulation of cell viability. In SH-SY5Y cells all the NPs tested showed a decrease of cell viability after 48 and 72 hours of exposure. Indeed, after 72h the NPs of gold and iron oxide showed a decrease of cell viability by over 16% relative to the control, whereas cobalt and of cerium oxide NPs reduced the cell viability by approximately the 32%. Rat primary cells showed no significant decline in cell viability after 72h of exposure to gold and iron oxide NPs in both sub population (glial cells and neurons). Instead cobalt and cerium oxide NPs led to a decrease of cell viability in glial cells and neurons of 56% and 23% respectively after 72h. Interestingly glial cells, as verified by ESEM imaging, internalized most of the particles but the cell mitochondrial metabolism seemed to be less affected than the neuronal one.