Figure 2. Cell viability (neutral red uptake assay) at 24 h (gray bars) and 48 h (black bars). The results were expressed as percentages (means±SD) of the 100% of control DMEM. When compared to DMEM, significant cytotoxic effects (p<0.001) were observed in HO conditions in an HO-dependent manner, and in BAK solutions in a BAK concentration- and time-dependent manner after 24 h and 48 h, except for the lowest concentration of BAK10−4%; the associations of both stresses in all experiments were more cytotoxic than their respective HO or BAK conditions. The following letter codes were used for statistical comparisons with (b) all BAK concentrations, (b1) BAK10−4%, (b3) BAK5.10−4%, (b5) BAK3.10−4%, (h) all HO solutions, (h50) HO50 mM, (h60) HO60 mM, (h90) HO90 mM, corresponding to a statistically significant difference at p<0.001.