Sildenafil restores DNA integrity of the stenotic kidney cells in renovascular hypertensive mice. Panel A: Typical comets showing higher DNA fragmentation in the 2K1C hypertensive mice compared with the Sham mice and the beneficial effects of sildenafil in decreasing the DNA fragmentation. Levels of genotoxicity according to the comet tail size: 0 (intact comets), 1 (1% - 25% damage), 2 (26% - 45% damage), 3 (46% - 70% damage) and 4 (more than 70% damage). Scale bar: 10 μm. Bar graphs showing the mean percentage of DNA in tail (panel B) and the mean of the tail moment (panel C). Values are the means ± SEM, n = 10 per group. *p < 0.05 (ANOVA).