Effects of icariin on improving erectile function in streptozotocin-induced diabetic rats.

Icariin has been shown to improve penile hemodynamics in animal models of erectile dysfunction from cavernous nerve injury and castration. The effects of icariin on penile hemodynamics in diabetic animals remain to be determined. Transforming growth factor β1 (TGFβ1) has been implicated in the pathogenesis of diabetes-related erectile dysfunction. The aim of this study was to investigate the effects of icariin in the penis of streptozotocin (STZ)-induced diabetic rat. Two-month-old Sprague-Dawley male rats received one-time intraperitoneal (IP) STZ (60 mg/kg) or vehicle injection after a 16-hour fast. Three days later, the STZ-induced diabetic rats were randomly divided into four groups and were treated with daily gavage feedings of a 50:50 mix of normal saline and dimethyl sulfoxide (DMSO) or icariin dissolved in DMSO at doses of 1, 5, and 10 mg/kg for 3 months. A positive control group underwent IP injection of saline followed by daily gavage of saline/DMSO solution. Treatment was stopped 1 week prior to functional assay and euthanasia. Penile hemodynamics was assessed by electrical stimulation of the cavernous nerves with real-time intracavernous pressure (ICP) measurement. After euthanasia, penile tissue was studied using immunohistochemistry, Western blot, and enzyme-linked immunosorbent assay (ELISA) to assess the nitric oxide-cyclic guanosine monophosphate (NO-cGMP) and TGFβ1/Smad2 signaling pathway. Diabetes attenuated ICP response in control animals. Untreated diabetic animals had decreased smooth muscle/collagen ratio and endothelial cell content in the corpora cavernosa; treatment with icariin partially attenuating these effects. Icariin-treated animals also had a significantly greater expression of nicotinamide adenine dinucleotide phosphate-positive nerves and the endothelial cell markers, von Willebrand factor (vWF), and platelet endothelial cell adhesion molecule-1 (PECAM). TGFβ1/Smad2 signaling pathway was down-regulated in the penis from icariin-treated models relative to what was observed in negative control animals. Icariin treatment preserved penile hemodynamics, smooth muscle and endothelial integrity, and neuronal nitric oxide synthase expression in the penis of diabetic rats. Down-regulation of TGFβ1/Smad2 signaling pathway might mediate this effect.

Liu T ，Xin H ，Li WR ，Zhou F ，Li GY ，Gong YQ ，Gao ZZ ，Qin XC ，Cui WS ，Shindel AW ，Xin ZC ... -  《-》

Effects of icariside II on improving erectile function in rats with streptozotocin-induced diabetes.

Zhou F ，Xin H ，Liu T ，Li GY ，Gao ZZ ，Liu J ，Li WR ，Cui WS ，Bai GY ，Park NC ，Xin ZC ... -  《-》

Ginsenoside Rg3 improves erectile function in streptozotocin-induced diabetic rats.

Ginsenoside Rg3 is one of the active ingredients isolated from Panax ginseng C.A. Meyer. Previous studies demonstrated that Rg3 has antioxidant and neuroprotective abilities. The purpose of this study was to evaluate the protective effect of Rg3 on erectile function in streptozotocin (STZ)-induced diabetic rats. Two-month-old Sprague-Dawley male rats received a one-time intraperitoneal (IP) STZ (60 mg/kg) or vehicle injection after a 16-hour fast. Three days later, rats were randomly divided into four groups and were treated with daily gavage feedings of a mix of distilled saline water and 0.5% carboxymethylcellulose or Rg3 dissolved in the mix at doses of 10 mg/kg and 100 mg/kg for 3 months. A sham group underwent IP injection of saline followed by daily gavage of the above mix for 3 months. Erectile function was assessed by cavernosal nerve electrostimulation at 3 months. The penis was then harvested and deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) was performed. Western blot was performed to examine cleaved caspase-3, platelet endothelial cell adhesion molecule (PECAM)-1, and smooth muscle actin (SMA). Neural regeneration was measured by nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase staining. Superoxide dismutase (SOD) and malondialdehyde (MDA) levels were detected by colorimetry. In the negative control group, the functional evaluation showed a lower mean intracavernosal pressure (ICP) with cavernosal nerve stimulation than in the sham group; there was a significant change in the expression of cleaved caspase-3, bcl-2, bcl-xl, PECAM-1, and SMA, as well as in the SOD and MDA production in the corpus cavernosum. Histological analysis of specimens stained for NADPH showed a significant change in the staining quality of the neurons in the dorsal nerves; TUNEL showed a greater apoptotic index in corpus cavernosum cells. With daily oral gavage with 100 mg/kg Rg3, the ICP/mean arterial pressure value was significantly higher than in the controls. The level of cleaved caspase-3, bcl-2, bcl-xl, PECAM-1, and SMA and the number of positively stained nerve fibers tended to revert to normal after Rg3 treatment. The apoptotic index in corpus cavernosum cells was lowered. Oral gavage with Rg3 appears to both prevent degeneration of neurons in the dorsal nerves and exert an antioxidant effect in the corpus cavernosum of rats.

Liu T ，Peng YF ，Jia C ，Yang BH ，Tao X ，Li J ，Fang X ... -  《-》

Probucol Improves Erectile Function by Restoring Endothelial Function and Preventing Cavernous Fibrosis in Streptozotocin-induced Diabetic Rats.

To investigate the effects of probucol on erectile function in streptozotocin-induced diabetic rats and explore the underlying mechanisms. A total of thirty 12-week-old Sprague-Dawley male rats received a 1-time intraperitoneal streptozotocin (60 mg/kg) or vehicle injection after a 12-hour fast. Three days later, the streptozotocin-induced diabetic rats were randomly divided into 2 groups and were treated with daily gavage feedings of probucol at doses of 0 and 500 mg/kg for 12 weeks. A positive control group underwent intraperitoneal injection of saline followed by daily gavage of saline solution. Erectile function was assessed by electrical stimulation of the cavernous nerves with real-time intracavernous pressure measurement. After euthanasia, penile tissue was investigated using immunohistochemistry, Western blot, and ELISA to assess the protein arginine-N-methyltransferase 1/dimethylarginine dimethylaminohydrolase/asymmetric dimethylarginine/nitric oxide synthase metabolism pathway. Superoxide dismutase activity and malondialdehyde levels were detected by colorimetry. We also evaluated penile histological changes such as smooth muscle contents and Masson's trichrome stain. Significant recovery of erectile function was observed in the probucol-treated rats than the untreated diabetic rats. The protein expression of dimethylarginine dimethylaminohydrolase and nitric oxide synthase, cyclic guanosine monophosphate concentrations, and superoxide dismutase activity in cavernous tissue of probucol-treated rats were significantly higher than the untreated diabetic rats. The protein expression of protein arginine-N-methyltransferase 1, asymmetric dimethylarginine concentrations, and malondialdehyde levels in cavernous tissue of probucol-treated rats were significantly lower than the untreated diabetic rats. In addition, probucol treatment markedly augments the cavernous smooth muscle content. Probucol treatment improves erectile function by restoring endothelial function and preventing cavernous fibrosis in streptozotocin-induced diabetic rats.

Zhang KQ ，Chen D ，Sun DQ ，Zhang H ，Li B ，Fu Q ... -  《-》

Effect of icariin in combination with daily sildenafil on penile atrophy and erectile dysfunction in a rat model of bilateral cavernous nerves injury.

The commonly utilized phosphodiesterase type 5 inhibitors do not lead to satisfactory penile erection after radical prostatectomy mainly because of insufficient nitric oxide drive from the damaged cavernous nerves. The aim of this study was to assess the efficacy and mechanisms of icariin in combination with daily sildenafil on neurogenic erectile dysfunction and penile atrophy in a rat model of bilateral cavernous nerves injury. Sixty male Sprague-Dawley rats injected with 5-ethynyl-2-deoxyuridine (50 mg/kg) at postnatal day 1 for the purpose of tracking endogenous stem cells in penis. Forty-eight rats of bilateral cavernous nerves injury were randomized equally into gavage feeding of vehicle, sildenafil (10 mg/kg), icariin (1.5 mg/kg) and sildenafil + icariin, respectively. Twelve sham-operated rats served as control. The intracavernous pressure and mean arterial pressure was measured and mid-penile cross sections were histologically examined 5 weeks after surgery. Western blotting of cavernous tissue protein was also performed. Animals treated with sildenafil + icariin had significantly higher mean intracavernous pressure/mean arterial pressure ratio relative to other rats with bilateral cavernous nerves injury (p < 0.05). The circumference and mean cross-sectional area of the paired corpus cavernosum were effectively preserved in the sildenafil + icariin. Treatment with sildenafil + icariin significantly increased the cavernous cyclic guanosine monophosphate concentration compared with the icariin group (p < 0.05). In addition, the numbers of neuronal nitric oxide synthase-positive nerves and 5-ethynyl-2-deoxyuridine-positive cells co-expressing S100 in the icariin-treated groups were greater compared with the bilateral cavernous nerves injury control group (p < 0.05). These data suggest that the combined use of icariin and daily sildenafil holds promise as a potential therapy for neurogenic erectile dysfunction in the future. The underlying mechanisms appears to involve two aspects: (i) icariin promotes differentiation of endogenous stem cells to Schwann cells, which help to repair the damaged neural pathway for erection; (ii) on this basis, sildenafil can further improve penile engorgement through the cyclic guanosine monophosphate-dependent smooth muscle relaxation.

Xu Y ，Xin H ，Wu Y ，Guan R ，Lei H ，Fu X ，Xin Z ，Yang Y ... -  《-》