Antioxidative response induced by SiO2 nanoparticles in MRC5 cell line

Amorphous SiO2 nanoparticles may be harmful to humans and also ecotoxic. In our study, the effect of these nanoparticles on some antioxidant scavenging enzymes belonging to MRC-5 cells was investigated. The cells were exposed to 6.3 x 10(5) SiO2 nanoparticles (3-14 nm) per individual cell for 24, 48 and 72 hours, respectively. The treatment resulted in the appearance of a significant number of cells with modified shape. In more detail, the variation of SOD specific activity showed an increase of 88% only after 72 hours, whereas CAT activity significantly increased with 15% and 30% after 48 and 72 hours respectively. The enhancement of the GPX and GST specific activity with 56% and 43%, respectively, after 72 hours suggested that important lipid peroxidation occurred. In conclusion, it appeared that tip to 72 hours of exposure, MRC-5 cells can counteract the SiO2 nanoparticles induced oxidative stress.