Figure 3.

Effect of sildenafil on inducible nitric oxide synthase (iNOS) immunohistochemical staining of gentamicin-treated rat kidney (×400). Localization of iNOS immunoreactivity in the kidney cortex of (a) and (b) control and sildenafil treated groups, respectively, showing negative immunoreactivity, (c) gentamicin-treated group showing high cytoplasmic expression within the renal tubules (arrow), and (d) gentamicin and sildenafil treated group showing faint cytoplasmic expression within few renal tubules (arrow).