Fig. 5

Low potassium increased permeability in Caco-2 cell. A, B Caco-2 cell monolayers were treated with low potassium medium for indicated concentration and period, TEER were measure. C, D After treated with low potassium medium for indicated concentration and period, Lucifer yellow (LY) with concentrations of 100 µg/ml were added to the apical side of cells and incubated for 2 h, permeation of LY in the basal side of cell were measured. E Caco-2 cell monolayers were pretreated with low potassium (0.1 mM) for 48 h, followed by incubated with flourescent E. coli (K-12 strain, green) for 6 h, the number flourescent E. coli (green) per cross-section field in determined by inverted microscope. F Graphs display quantitation of the number of flourescent E. coli per cross-sectioned in the basal layer. Value are means ± SD, n = 3. *p < 0.05, **p < 0.01 vs. the control group