Macrophage response to silica nanoparticles. Mus musculus

Using a macrophage cell line, we demonstrate the ability of amorphous silica particles to stimulate inflammatory protein secretion and induce cytotoxicity. Whole genome microarray analysis of early gene expression changes induced by 10nm and 500nm particles showed that the magnitude of change for the majority of genes correlated more tightly with particle surface area than either particle mass or number. Gene expression changes that were size-specific were also identified, however the overall biological processes represented by all gene expression changes were nearly identical, irrespective of particle diameter. Our results suggest that on an equivalent nominal surface area basis, common biological modes of action are expected for nano- and supranano-sized silica particles. Keywords: Dose-response study Overall design: RAW 264.7 mouse macrophage cells were treated with two sizes of amorphous silica particles at three doses each for 2 hours. Cells were exposed to 10nm silica at 5 (low), 20 (mid), or 50 (high) ug/ml or 500nm silica at 250 (low), 500 (mid), or 1000 (high) ug/ml in serum-free medium.