ABSTRACT

It has been reported that tadalafil, a specific phosphodiesterase-5 (PDE5) inhibitor, has an antioxidant effect besides its well-known vasoactive properties. This study aimed to determine the possible protective effects of tadalafil in managing renal oxidative stress induced by unilateral ureteral obstruction (UUO).

Male Sprague-Dawley rats aged 2.5-3 months were randomly divided into 5 groups (n=8) as sham (P), partial obstruction (P), P+tadalafil (PT), complete obstruction (C), and C+tadalafil (CT). Animals in the PT and CT groups were administered with tadalafil (10 mg/kg, ig) just before the anesthesia. Twenty-four hours after the obstruction surgery, the animals were sacrificed. In the kidney homogenates, MDA and AOPP levels were examined in addition to SOD and CAT activities. Serum creatinine levels were also measured.

Both partial and complete obstruction caused a significant increase in the serum creatinine, tissue MDA and tissue AOPP levels. Although unchanged SOD activity, renal CAT activity decreased significantly in P and C groups. In tadalafil treated animals, serum creatinine, tissue MDA and AOPP levels, or renal SOD activity did not change compared to obstructed groups. However, the renal CAT activity increased in tadalafil-treated groups. A single-dose tadalafil treatment significantly restored renal CAT activity to the range of controls in the PT group.

Although tadalafil did not affect renal oxidative stress induced by partial or complete UUO, elevation of CAT activity to control values in the PT group suggests that increasing doses or duration of tadalafil treatment might be protective for kidneys in UUO.

Keywords: PDE5, tadalafil, ureter, obstruction, oxidative stress