Abstract:
Objectives To study the effects of nano silica (nm-SiO2) and micro silica (μm-SiO2) particles on the cytotoxicity and secretion of inflammatory factors in human lung adenocarcinoma cells (A549 cells).
Methods A549 cells were exposed to three sizes of nm-SiO2 (20, 60 and 100nm) and μm-SiO2 (0.1~5 μm) particles for 24 h at different doses (0, 12.5, 25, 50, 100 and 200 μg/mL) The cytotoxicity of nm-SiO2 and μm-SiO2 on A549 cells was measured by MTT method, the activity of LDH and the levels of IL-8 and TNF-α were measured by micro ELISA method
Results The viability of cells was inhibited and the activity of LDH was increased with a dose response relationship in all nm-SiO2 groups The cytotoxicity of cells in 20-nm-SiO2 group was most serious, even in a lower dose of 25μg/mL; the viability of cells in 20-nm-SiO2 group was significantly lower than that of control group (P < 0.01) The activity of LDH in 20-nm-SiO2 group was significantly higher than that of 60-nm-SiO2 group, and the activity of LDH in 60-nm-SiO2 group was higher than that of 100-nm-SiO2 group (P < 0.05);but the viability of cells in μm-SiO2 groups was reduced only in the highest dose group (P < 0.05 or P < 0.01) The secretion of IL-8 in cells was increased in 3-nm-SiO2 groups, but no significant changes in the secretion of TNF-α from cells, the secretion of IL-8 from cells in 20-nm-SiO2 group was significantly higher than that in 100-nm-SiO2 group (P < 0.01) However, the secretion of IL-8 and TNF-α was not increased significantly in μm-SiO2 groups
Conclusions Three nanometer sized SiO2 particles could cause cytotoxicity and increase the secretion of IL-8 in A549 cells; and the smaller size of nm-SiO2 particles were, the stronger of its toxic effects; but no significant change was observed in the secretion of TNF-α in the cell in nm-SiO2 groups However, μm-SiO2 particles could not cause significant cytotoxicity in A549 cells