Astrocytes Are More Vulnerable than Neurons to Silicon Dioxide Nanoparticle Toxicity in Vitro

Some studies have shown that silicon dioxide nanoparticles (SiO(2)-NPs) can reach different regions of the brain and cause toxicity; however, the consequences of SiO(2)-NPs exposure on the diverse brain cell lineages is limited. We aimed to investigate the neurotoxic effects of SiO(2)-NP (0–100 µg/mL) on rat astrocyte-rich cultures or neuron-rich cultures using scanning electron microscopy, Attenuated Total Reflection-Fourier Transform Infrared spectroscopy (ATR-FTIR), FTIR microspectroscopy mapping (IQ mapping), and cell viability tests. SiO(2)-NPs were amorphous particles and aggregated in saline and culture media. Both astrocytes and neurons treated with SiO(2)-NPs showed alterations in cell morphology and changes in the IR spectral regions corresponding to nucleic acids, proteins, and lipids. The analysis by the second derivative revealed a significant decrease in the signal of the amide I (α-helix, parallel β-strand, and random coil) at the concentration of 10 µg/mL in astrocytes but not in neurons. IQ mapping confirmed changes in nucleic acids, proteins, and lipids in astrocytes; cell death was higher in astrocytes than in neurons (10–100 µg/mL). We conclude that astrocytes were more vulnerable than neurons to SiO(2)-NPs toxicity. Therefore, the evaluation of human exposure to SiO(2)-NPs and possible neurotoxic effects must be followed up.