Role of mitochondrial pathway in deoxycholate-induced apoptosis of human normal esophageal mucosal epithelial cells

Objective: To study the role of mitochondrial pathway in deoxycholate (DCA)-induced apoptosis of human normal esophageal mucosal epithelial cells. Methods: Cultured normal human esophageal mucosal epithelial cells were treated with deoxycholate. We used flow cytometry to determine mitochondrial membrane potential (ΔΨm) and its permeability. Expressions of caspase-3, cytochrome c and poly (ADP-ribose) polymerase (PARP) were detected with Western blotting. Caspase-3 inhibitor DEVD-FMK was used to explore the role of caspase in deoxycholate-induced apoptosis of human normal esophageal epithelial cells. Results: Esophageal epithelial cells treated with 100 μmol/Lof DCA, Pi-negative but low Rh123 stained cells in the control group (1.8± 0.6)%, 48 h was (30.5±1.7)% ; after 200 μmol/L of DCA treatment, PI negative but low Rh123 stained cells numbered up (43.1±0.2)% at 36 h (P<0.05). PI-negative but low Rh123 stained cells began to appear, and gradually increased, DCA induced apoptosis when the mitochondrial membrane potential decreased, indicating that apoptotic cells gradually increased. Cyt.c and activation of Caspase-3 antibody showed that with the decline in ΔΨm of mitochondria, cleavage of Cyt.c, Caspase-3 and poly (ADP-ribose) polymerase (PARP) of Casapse-3 substrate also occurred in the degradation activation. Caspase-3 specific inhibitor DEVD-FMK could partially inhibit the DCA-induced apoptosis of cells, but did not affect the decrease in mitochondrial membrane potential. Conclusion: DCA induces the apoptosis of esophageal mucosal epithelial cells through the mitochondrial pathway. Mitochondria, caspase-3 and activation of PARP cleavage are also involved in the apoptosis.