Effects of low-intensity shock wave therapy (LiST) on the erectile tissue of naturally aged rats

Low-intensity shock wave therapy (LiST) improves erectile function in patients with erectile dysfunction (ED), probably by promoting angiogenesis as suggested by studies on animals with comorbidities as disease associated ED models. We aim to investigate the effects of LiST on erectile tissue of healthy, naturally aged rats. Twelve naturally aged male rats were randomized into two groups: control group (n = 6) and LiST-treatment group (n = 6). Young rats (8 weeks) (n = 6) was also used as control. Each rat in treatment group received 300 shock waves with an energy flux density of 0.09 mJ/mm² at 2 Hz. Sessions were repeated three times/week for 2 weeks, followed by a 2-week washout period. Real-time RT-PCR for the expressions of vascular endothelial growth factor (VEGF), endothelial nitric oxide synthase (eNOS), nerve growth factor (NGF), neuronal NOS (nNOS), as well as α1 and α2-adrenergic receptors (α1AR, α2AR) was performed, followed by immunohistochemical analysis (IHC) to evaluate protein expression. The expressions of VEGF, eNOS, and α2AR/α1AR ratio were increased after LiST (p = 0.039, p = 0.008, and p = 0.006 respectively). The increase of VEGF, eNOS, and α2AR was confirmed in IHC (p = 0.013, p = 0.092, and p = 0.096, respectively). The increase of VEGF and eNOS seem to play key role in the mechanism of action of LiST, apparently by inducing angiogenesis. The altered expression of α1/α2-adrenergic receptors could indicate a decrease in sympathetic activity. LiST showed to partially reverse changes associated with aging in erectile tissue of rats, which supports future research for ED prevention.