Oxidative stress in arteriogenic erectile dysfunction: prophylactic role of antioxidants

PURPOSE: We searched for markers of oxidative stress in cavernous ischemia and examined the effect of long-term antioxidant intake on arteriogenic erectile dysfunction (ED) in the rabbit. MATERIALS AND METHODS: Antioxidant activity of known antioxidant beverages, such as pomegranate juice (PJ), red wine, blueberry juice, cranberry juice, orange juice and green tea, was examined spectrophotometrically. PJ demonstrated the highest free radical scavenging capacity. The effect of long-term PJ intake on intracavernous blood flow and penile erection was then examined in the rabbit model. Erectile tissues were processed to assess oxidative stress and smooth muscle relaxation, immunohistochemical staining of nitric oxide synthase (NOS) and histomorphometry. RESULTS: On spectrophotometric analysis PJ showed the highest capacity to decrease low density lipoprotein oxidation and inhibit cellular oxidative stress in macrophages. The rabbit model of arteriogenic ED demonstrated decreased intracavernous blood flow, erectile dysfunction, loss of smooth muscle relaxation, decreased endothelial NOS and neuronal NOS, increased inducible NOS expression, diffused cavernous fibrosis and increased cavernous levels of the oxidative product isoprostane 8-epi-prostaglandin F2alpha. Long-term PJ intake increased intracavernous blood flow, improved erectile response and smooth muscle relaxation in ED and control groups while having no significant effect on NOS expression. PJ intake prevented erectile tissue fibrosis in the ED group. CONCLUSIONS: Arteriogenic ED accumulates oxidative products in erectile tissue, possibly via an intrinsic mechanism. Oxidative stress may be of great importance in the pathophysiology of arteriogenic ED. Antioxidant therapy may be a useful prophylactic tool for preventing smooth muscle dysfunction and fibrosis in ED.