AB172. Low-intensity pulsed ultrasound recovers erectile function in streptozotocin-induced type I diabetic rats

OBJECTIVE: To investigate the effect of low-intensity pulsed ultrasound (LIPUS) as a treatment for erectile dysfunction (ED) in a rat model of type I diabetes mellitus (DM) induced by streptozotocin (STZ). METHODS: Seventy male Sprague-Dawley rats were randomly assigned to two cohorts: a normal control (NC) group and a STZ-induced DM group, which was further sub-divided into DM, DM + LIPUS 100, DM + LIPUS 200 and DM + LIPUS 300 groups and a DM+LESWT (low-energy shock wave therapy) 300 positive control group. Animals in the LIPUS subgroups were treated at different energy levels (100, 200, 300 mW/cm(2)) for 3 min, and animals in the LESWT group received 300 shocks at 0.09 mJ/mm(2). All procedures were repeated 3 times per week for 2 weeks. After a 2-week wash-out period, intracavernous pressure (ICP) was measured; the midpenile region was examined histologically; and VEGF, αSMA, eNOS and nNOS expression, and activity of the TGF-β1/Smad/CTGF signaling pathway were examined in penile tissue by Western blot analysis. RESULTS: LIPUS therapy significantly improved erectile function in diabetic rats, as evidenced by enhanced ICP levels, increased endothelial and smooth muscle content, a higher collagen I/collagen III ratio, increased quantity of elastic fibers, and elevated eNOS and nNOS expression. Interestingly, LIPUS was also associated with down-regulation of the TGF-β1/Smad/CTGF signaling pathway in penile tissue, whose activation is correlated with ED pathology. CONCLUSIONS: LIPUS therapy improved erectile function and reversed pathological changes in penile tissue of STZ-induced diabetic rats. LIPUS therapy has potential as a non-invasive therapy for diabetic ED in the clinic.