Evaluation of epithelial integrity (TEER) (panel A) and viability (resazurin assay) (panel B) for tissue cells in the MucilAi model, as a function of HTO activity levels. Measurements are carried out at the end of the 24-h exposure (day 1), after four days (day 4) and seven days (day 7). Data (mean ± SD) are shown normalized to control conditions (C neg = no administration of HTO) at the same time point. Statistical significance was determined using one-way ANOVA followed by Dunnett's multiple comparisons test: *P < 0.05 and ***P < 0.001 (n = 2–20).