Fig. 5. Effect of sildenafil on mitochondrial permeability transition in AGE-treated cells. A and B : Confocal microscopic images showing cells with intact mitochondria and cells with mitochondrial permeability transition. Intact mitochondria accumulate TMR and are discriminated as punctuated bright red spots, whereas mitochondria undergoing MPT get deprived of TMR, became permeable to calcein, and as a consequence, loose their visible contour. Arrows indicate cells undergoing MPT. C : Confocal microscopic analysis was performed after 48 hr incubation in media containing combinations of AGE, vehicle (Veh), sildenafil citrate (SC, 20 µM), Rp-8-Br-cGMP (RBcGMP, 20 µM). Data were represented as the mean±SEM of 6 experiments. ^*p<0.01 vs. control, ^†p<0.01 vs. Veh, ^‡p<0.01 vs. SC.