Figure 5.

Cytotoxicity of the aerosolised engineered nanoparticles (ENP) (ATO, CeO₂ and ZrO₂) in polarised cultures of human alveolar epithelial cells at air-liquid interface (ALI) conditions. Lactate dehydrogenase release (LDH) was assessed immediately after (0 h) (A) and at 24 h (B) after exposure. (C) WST-1 reduction assay was carried out only in the recovery period (24 h after exposure). Data are expressed as mean ± standard deviation (n = 3). LDH values were normalised considering positive control (total LDH release; cells lysed with 2% Triton X-100), while WST-1 values were normalised considering the incubator control. Data was analysed by the one-way analysis of variance (ANOVA) test followed by the Dunnett’s post hoc test for multiple comparisons. * p ≤ 0.05, ** p ≤ 0.01 and *** p ≤ 0.001 vs. Inc. Ct; ^$ p ≤ 0.05, ^$$ p ≤ 0.01 and ^$$$ p ≤ 0.001 vs. Exp. Ct. Inc. Ct: Incubator control; Exp. Ct: Exposure control; Positive Ct: Positive control.