on some Enzymatic and Non- enzymatic Antioxidants in

Sildenafil citrate, a specific phosphodiesterase-5 (PDE-5) inhibitor drug currently used for the treatment of erectile dysfunction in men. The present study investigates the effects of Sildenafil citrate on antioxidant defense systems of testes and brain tissues of male rats by measuring the GSH, SOD, and CAT activity. Lipid peroxidation was also estimated by measuring the MDA levels, a Thiobarbituric Acid Reactive Substrate (TBARS) as biomarker of oxidative stress. Sildenafil citrate was orally administered at the different dose levels of 20 mg/kg body weight per 30 days in four divided doses of 50, 100, 150 and 200 mg/kg body weight while control rats were given distilled water. The result revealed that Sildenafil citrate significantly increased MDA levels in testes. Conversely, the MDA levels in brain tissue was significantly reduced P<0.05. However, a significant increase in GSH content of testes and brain was observed. Similarly, superoxide dismutase (SOD) and catalase (CAT) activities for both tissues increased significantly (p<0.05) compared to their corresponding control. The histological examination of the testicular tissues revealed no visible lesions. Collectively, the results suggest that therapeutic dose of Sildenafil citrate elicits modulatory roles by stabilizing/boosting antioxidant defense systems in male rat