[Toxicity of nano silica particles on rat type I-like alveolar epithelial cells].

Objective To access rat lung toxicity of nano silica particles. Methods 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, 20.0μg/ml of two silica nano particles were detected by spectrophotometric method; protein car- bonylation and MIP-2 release of R3/1 cells after 24 h incubation with 2.5, 5.0, 10.0, 20.0 μg/ml of two silica nano particles were measured using ELISA kits. Results 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 bad similar size in water and RPMI 1640 containing 1% FBS, respectively. Both nano silica particles in 2.5-20.0 μg/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）.Conclusion Two nano silica particles do not have lung toxicity in 2.5-20.0 μg/ml dose range. Key words: Silicon dioxide Epithelial cells;  Toxicity tests;  Lactate dehydrogenase