Effect of SiO
NP on the phosphorylation of JNK1/2 and p38 in human lung epithelial cells. A549 cells were treated with 80 nm SiO2NP for multiple time points ranging from 15 min to 24 h or left untreated (N/T) and lysed. Cell lysates (20 μg each) were resolved by SDS-PAGE and after Western blotting probed with anti-phospho-JNK1/2 or JNK1/2 (A), or anti-phospho-p38 or p38 (B). Relative densitometric analysis of the individual bands was performed and presented. Data are mean ± S.E.M. of three independent experiments. 2-way ANOVA with Bonferroni post-test analysis was carried out on the experimental data, with respect to corresponding controls, and statistically significant data is reported by "*" symbol, for p < 0.05; "**" p < 0.01; "***" for p < 0.001.