Fig. 1

Bile acid induces phosphatidylserine externalisation in NP69 and TWO4 cells. NP69 cells were either left untreated or treated for 1 h with 0.5 mM of BA at pH 7.4 and pH 5.8. TWO4 cells were either left untreated or treated for 3 h with 0.5 mM of BA at pH 7.4 and pH 5.8. CPT was used as a positive control. After exposure, flow cytometric analysis of PS externalisation was performed in (a i) NP69 and (b i) TWO4 cells. Means and SD of three independent experiments performed in duplicate are shown. Data are expressed as fold increase normalised to the untreated control. Student’s t-test was used for statistical analysis to compare treated groups with the untreated control, * p < 0.05, ** p < 0.01. Representative dot plot diagrams showing the apoptotic populations of BA-treated (a ii) NP69 and (b ii) TWO4 cells detected by Annexin V-FITC and PI staining are shown. The lower left quadrants show viable cells; the lower right quadrants represent early apoptotic cells; the upper right quadrants show late apoptotic and necrotic cells