ABSTRACT
<p><b>OBJECTIVE</b>To access rat lung toxicity of nano silica particles.</p><p><b>METHODS</b>Transmission electron microscope was used to observe size, shape and dispersibility of two silica particles; Size of two particles in water and RPMI 1640 containing 1% FBS were measured using Zeta Potential Analyzer. LDH activities of rat type I-like alveolar epithelial cell line R3/1 cells after 6, 24 and 48 h incubation with 2.5, 5.0, 10.0, 20.0 microg/ml of two silica nano particles were detected by spectrophotometric method; protein carbonylation and MIP-2 release of R3/1 cells after 24 h incubation with 2.5, 5.0, 10.0, 20.0 microg/ml of two silica nano particles were measured using ELISA kits.</p><p><b>RESULTS</b>TEM image showed nano silica particles were round and dispersed evenly; the average sizes of the two silica particles were (43+/-4.2) and (68+/-5.7) nm. Two silica particles had similar size in water and RPMI 1640 containing 1% FBS, respectively. Both nano silica particles in 2.5 approximately 20.0 microg/ml dose range did not cause significant increase of LDH activities (P>0.05), did not elevate protein carbonylation and MIP-2 levels in R3/1 cells (P>0.05).</p><p><b>CONCLUSION</b>Two nano silica particles do not have lung toxicity in 2.5 approximately 20.0 microg/ml dose range.</p>