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 ... -  《-》

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 ... -  《-》

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 ... -  《-》

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 ... -  《-》

AGE-breaker ALT-711 plus insulin could restore erectile function in streptozocin-induced type 1 diabetic rats.

The interaction between advanced glycation end-products (AGEs) and its receptors for AGEs (RAGEs) elicits oxidative stress and mediates the development of erectile dysfunction (ED). ALT-711, an AGE cross-link breaker, has the therapeutic potential for ED but has been less intensively investigated. The aim of this study was to investigate the effects of an AGEs breaker 3-phenacyl-4,5-dimethylthiazolium chloride (ALT-711) plus insulin on erectile function in streptozocin (STZ)-induced type 1 diabetic rats. Fifty 8-week-old Sprague-Dawley rats were randomly distributed into five groups: normal control (C), diabetic (D), insulin-treated diabetic (D + I), ALT-711-treated diabetic (D + ALT-711) and insulin plus ALT-711-treated diabetic (D + I + ALT-711) rats. Diabetes was induced by a single intraperitoneal injection of STZ. Eight weeks after induction of diabetes, ALT-711 was administered by intraperitoneal injection. Two to six units of intermediate-acting insulin were utilized to achieve normal levels of glycemic control. After treatment for 6 weeks, erectile function was determined via measurement of intracavernous pressures (ICPs) following electrostimulation of the cavernous nerve. The deposition of AGEs, expression of RAGEs, superoxide dismutase activity, and lipid peroxidation were measured. We also evaluated penile histological changes such as smooth muscle contents, endothelial cells contents, and apoptotic activity. The main outcome measures were the ratio of ICP/mean arterial pressure (MAP), penile endothelial cells, smooth muscle cells, neuronal nitric oxide synthase, AGE and RAGE expression, malondialdehyde concentration, SOD activity, and apoptosis index. Diabetic rats demonstrated significantly reduced ICP/MAP ratio, penile endothelial cells, smooth muscles cells, increased AGEs and RAGE expression, and increased apoptosis. Insulin and ALT-711 monotherapy partially restored erectile function and histological changes. However, the combination therapy group showed erectile parameters and components similar to those in C. ALT-711-treated group demonstrated less deposition of AGEs and lower expression of RAGE than those in insulin-treated group. These results suggest that although insulin can effectively control glycemic levels, it does not completely alter the pathological changes in erectile tissues. Better efficacy could be expected with tight glycemic control plus ALT-711, an AGEs cross-link breaker. The combination therapy might have the potential to eliminate metabolic memory by down-regulating the AGEs-RAGE oxidative stress axis.

Wang L ，Tian W ，Uwais Z ，Li G ，Li H ，Guan R ，Gao Z ，Xin Z ... -  《-》