α-Lipoic Acid Inhibits Helicobacter pylori-Induced Oncogene Expression and Hyperproliferation by Suppressing the Activation of NADPH Oxidase in Gastric Epithelial Cells
Figure 4
Effect of α-LA on ROS levels, NADPH oxidase activity, and levels of NADPH oxidase subunits in H. pylori-infected AGS cells. The cells were pretreated with α-LA for 2 h and cultured in the presence or absence of H. pylori. (a) ROS levels were determined by DCF fluorescence after 30 min of H. pylori infection. The levels of ROS trapped in the cells treated without DPI and cultured in the absence of H. pylori are considered as 100%. (b) NADPH oxidase activity was determined by lucigenin assay using membrane extracts of the cells. NADPH oxidase activity was also monitored by addition of cytosolic extracts to the reaction mixture as a negative control. (c), Protein levels of NADPH oxidase subunits (p47, p67) in cytosolic and membrane extracts were determined by Western blotting. Aldolase A and Nox1 were used as indices for cytosol and membrane, respectively. versus none (the cells cultured in the absence of H. pylori); + versus control (the cells cultured in the presence of H. pylori and treated without α-LA).
