Low-intensity Pulsed Ultrasound Improves Erectile Function in Streptozotocin-induced Type I Diabetic Rats

Abstract

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). Seventy male Sprague-Dawley rats were randomly assigned to 2 cohorts: a normal control (NC) group and an STZ-induced DM group, which was further subdivided 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, and 300mW/cm(2)) for 3minutes, and animals in the LESWT group received 300 shocks at 0.09mJ/mm(2). All procedures were repeated 3 times per week for 2weeks. 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. 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 downregulation of the TGF-β1/Smad/CTGF signaling pathway in penile tissue, whose activation is correlated with ED pathology. LIPUS therapy improved erectile function and reversed pathologic changes in penile tissue of STZ-induced diabetic rats. LIPUS therapy has potential as a noninvasive therapy for diabetic ED in the clinic.