Search

As standard therapy for prostate cancer, radical prostatectomy causes cavernous nerve (CN) injury and increases fibrosis and hypoxia-induced penile structural alterations. This study aimed to determine the potential beneficial effects of adipose-derived stem cells (ADSCs) and l-arginine alone or in combination on the penile erection in a rat model of erectile dysfunction caused by bilateral cavernous nerve transection (CNT). Male rats (n = 35) were randomized into five groups: Sham-operated; CNT (4-weeks); CNT plus ADSCs (1 × 106 cells by intracavernosal injection); CNT plus l-arginine (4 weeks, 10 mg/kg/day, oral); and ADSCs combined with l-arginine in CNT. In vivo erectile responses and in vitro relaxant responses were measured. Western blot and immunohistochemistry analyses were used to determine the expression and localization of endothelial nitric oxide synthase, neuronal nitric oxide synthase, transforming growth factor-beta 1, hypoxia-inducible factor-1 alpha (HIF-1α), and apoptosis markers (Bax and Bcl-2). The ratio of smooth muscle to collagen and nerve regeneration were calculated using Masson's trichrome and nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase staining. The combined treatment restored diminished erectile responses, endothelium-dependent acetylcholine, and electrical field stimulation-induced relaxation of the corpus cavernosum in rats with CNT, whereas either monotherapy produced only partial improvements. All treatment regimens restored increases in the protein expression of HIF-1 and Bax in rats with CNT. The decrease in smooth muscle mass and NADPH-diaphorase-positive nerve fibers was partially ameliorated by monotherapy, whereas combined therapy led to recovery. These findings indicate that combined treatment with ADSCs and l-arginine may restore erectile function in rats with CNT by inhibiting hypoxia-induced neurotoxicity and preserving endothelium function and smooth muscle content. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to identify the effect of trimetazidine (TMZ), an antianginal drug, on detrusor smooth muscle (DSM) contractility and its possible mechanisms of action. Methods: We performed in-vitro contractility studies on isolated mouse DSM strips and investigated the effect of TMZ on Ca2+ levels in fura-2-loaded A7r5 cells. Key findings: TMZ (300 or 1000 µM) inhibited carbachol (CCh)- and KCl-induced contractions and produced a concentration-dependent (10–1000 µM) relaxation in KCl-precontracted DSM strips. TMZ-induced relaxation was markedly decreased by BaCl2, an inward-rectifying K+ channel blocker, but was not altered by preincubation with tetraethylammonium, glibenclamide, 4-aminopyridine, propranolol, L-NAME or methylene blue. TMZ (300 or 1000 µM) reduced both the CaCl2-induced contraction of depolarized DSM strips under Ca2+-free conditions and the CCh-induced contraction of DSM strips preincubated with nifedipine in Ca2+-containing Krebs solution. Furthermore, TMZ (1000 µM) significantly decreased the Ca2+ levels in fura-2-loaded A7r5 cells. Conclusions: TMZ decreased DSM contractility and caused a concentration-dependent relaxation of the tissue possibly through its actions on Ca2+ transients and K+ channels. Our results provide preclinical evidence that TMZ would be a potential candidate to treat disorders related to the overactivity of the bladder. [ABSTRACT FROM AUTHOR]

Background Diabetes mellitus-induced erectile dysfunction (DMED) is a common urological complication of diabetes, and current drugs often fail to provide an effective treatment. Smad2/3 signaling-mediated corporal fibrosis has a critical role in the molecular basis of DMED. Aim We investigated the effect of Niclosamide (Nic), an antihelmintic drug with antifibrotic effects, on erectile function in a rat DMED model. Methods Male Sprague Dawley rats were injected intraperitoneally (i.p) with streptozotocin (75 mg/kg) to induce diabetes. At week 8, both diabetic and nondiabetic rats were treated with Nic (10 mg·kg−1/day; i.p) or vehicle for 4 weeks. At week 12, erectile function was evaluated as intracavernous pressure (ICP) response to the electrical stimulation of the cavernous nerve (CN). Penile tissues were harvested for Masson's trichrome staining or western blotting to determine corporal fibrosis and Smad2/3 pathway-related protein expression, respectively. Outcomes At the end of the experimental protocol, in vivo erectile function was assessed by measuring the ratio of ICP/ mean arterial pressure (MAP) and total ICP following CN stimulation. Smooth muscle content and collagen fibers were evaluated by Masson's trichrome staining of the penile tissues. The expressions of fibrosis-related proteins (Smad2, Smad3, fibronectin) were determined using western blotting in the penile tissues. Results Erectile function, as determined by the maximum ICP/MAP and total ICP/MAP ratios, was drastically decreased in diabetic rats. Corporal tissues of diabetic rats were severely fibrotic with a significant increase in collagen fibers and a marked reduction in smooth muscle content. Also, the protein expressions of phosphorylated (p-)Smad2, p-Smad3 and fibronectin were significantly increased in the penis of diabetic rats. Both functional and molecular alterations in DMED were effectively reversed by Nic-treated diabetic rats without a glycemic alteration. Clinical Implications Nic could be a promising candidate for the treatment of DMED due to its antifibrotic effects. Strengths and Limitations The present study provides the first evidence that Nic has beneficial effect on erectile dysfunction by attenuating corporal fibrosis in a rat model of DMED. The effect of Nic on penile endothelial function and the other potential underlying mechanisms needs to be further elucidated. Conclusions Nic improved erectile function in DMED rats possibly suppressing penile fibrosis by inhibiting Smad2/3 signaling. These results suggest a potential therapeutic repurposing of Nic as an adjuvant treatment in DMED. [ABSTRACT FROM AUTHOR]