2.9. Inflammatory Stress Protection Induced by Lactobacillus Strains

The protection effect of Lactobacillus strains on inflammatory stress was evaluated by Presti, et al. [27]. The inflammatory stress on Caco-2 cells was induced with SDS (Sigma, Darmstadt, Germany) at a concentration of 0.05% prepared in DMEM. Each one of the Lactobacillus strains was added to the wells at a concentration of 10⁷ CFU/mL following incubation of 24 h. The cell viability was evaluated using the 3- (4,5-bromide dimethylthiazol-2-yl) -2,5-diphenyltetrazole (MTT) assay (Sigma, Darmstadt, Germany) at a concentration of 0.05% MTT in DMEM, followed by incubation for 4 h at 37 °C under a 5% CO₂ atmosphere in the dark. After the medium was removed, 100 µL of dimethyl sulfoxide (DMSO; Sigma, Darmstadt, Germany) was added to each well and the reduction of MTT was measured at an absorbance of 570 nm using a microplate reader Fluoroskan Ascent FL (Thermo Fisher Scientific, Waltham, MA, USA) with DMSO alone serving as the blank control.