Figure 2.

Effects of silica nanoparticles on lung inflammation after instillation. A) C57Bl/6j mice were intranasally instilled with FITC-SiO₂ or unlabelled SiO₂ nanoparticles (5 mg/kg;100 μg/mice) or vehicle. 5 h or 24 h after, concentration of pro-inflammatory cytokines were measured in BALs (2 ml) (left panels). B) Cells present in BALs were cytospined and stained with Diff-Quick to identify macrophages and neutrophils. A representative image of BAL cells in a control mice (upper panel) or SiO₂ NPs treated mice are shown (lower panels). Neutrophils (red arrow) were found in some NP treated mice 24 h post-instillation and represented less than 10% of total cells in BALs. Mean ± SEM is represented from 4 to 6 mice per group. *p < 0.05 vs. Vehicle, Mann–Whitney test.