Figure 9. Delphinidin reduced ROS production in the aged myocardium through inhibiting NOX by activating AMPK. (A) Quantitative dihydroethidium (DHE) staining (n=8). (B) Statistical analysis of differences in nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity. A.U., arbitrary units. (C) Representative western blot analysis revealed AMPK phosphorylation levels (n=4). (D) Determination of rac1 activity. The cell lysates were affinity precipitated with GTP-PBD bound to glutathione-agarose beads. Precipitated GTP-Rac1 was detected by immunoblotting with anti-Rac1 antibody (n=4). (E) Expression of the NOX subunits p47phox, p40phox, p67phox, gp91phox, and p22phox (n=4). In A–D, *p<0.05, **p<0.01, ***p<0.001. In (E) *p<0.05 versus the young+DMSO group; **p<0.01 versus the young+DMSO group; ***p<0.001 versus the young+DMSO group; ns versus the aged+DMSO group; #p<0.05 versus the aged+DMSO group.