Evaluation of vitamin E in the treatment of erectile dysfunction in aged rats

AimsThe present study aims to elucidate the role of oxidative stress in erectile dysfunction associated with aging and to investigate the effect of treatment with vitamin E in this respect.Main methodsRats were divided into four groups: young (3-month-old), aged rats (18-month-old), aged rats given 80 IU of vitamin E/rat/day for 21-days, aged rats given 5 mg/kg of sildenafil/day for 21-days. Intracavernosal pressure/mean arterial pressure (ICP/MAP), nitric oxide production, TBARS, GSH levels and SOD activity in corpus cavernosum were measured.Key findingsSignificant decrease in ICP/MAP was observed in aged rats at both low and high frequency of stimulation. Significant increase in ICP/MAP was observed in aged rats treated with vitamin E over the range of 0.8 to 5 Hz but young control values were not restored. Percentage potentiation of ICP/MAP than aged group at 0.8 Hz was 326 ± 41.3% and 897 ± 72.2% for vitamin E and sildenafil respectively. Decreased levels of NO₂/NO₃ and SOD activity in the penile tissue observed with aging were elevated back to control by either vitamin E or sildenafil. Penile concentration of TBARS was 20.86 ± 0.83 for aged rats vs. 11.39 ± 0.79 nmol/g tissue for young controls. Both vitamin E and sildenafil reduced penile TBARS in aged rats.SignificanceThis study proves that antioxidant therapy with vitamin E ameliorates the age-associated erectile dysfunction. Sildenafil may exert some antioxidant properties which add to the advantages of its long-term use. The effect of combinations of low-dose sildenafil and vitamin E on age-associated erectile dysfunction merits to be studied.