[Aging-related change of erectile function and the expression of SIRT1].

OBJECTIVE: To explore aging-related changes in erectile function and the expressions of SIRT1 and other relevant factors in rats. METHODS: We divided 40 male SD rats into four age groups of equal number: 2-month-old (2 mo), 8-month-old (8 mo), 14-month-old (14 mo), and 20-month-old (20 mo), measured the intracavernous pressure (ICP), mean arterial pressure (MAP), and ICP/MAP ratio by electrostimulation of the cavernous nerve, evaluated fibrosis in the corpus cavernosum by Masson's trichrome staining, detected the expressions of SIRT1, P53, and FOXO3a by Western blot, and determined the levels of NO and cGMP using the NO/cGMP kit. RESULTS: Both the ICP/MAP ratio and the cGMP level were elevated with aging, reaching the peak at 8 months and then gradually decreased. Masson staining showed an aging-related increase of collagen fibers in the corpus cavernosum.The expression of SIRT1 was reduced while those of P53 and FOXO3a increased with aging. CONCLUSIONS: Aging-related erectile dysfunction may be attributed to the reduced activity of the NO/cGMP pathway, apoptosis and oxidative stress, and SIRT1 may play a role in aging-related erectile dysfunction.