A3 adenosine receptor allosteric modulator CF602 reverses erectile dysfunction in a diabetic rat model.

Adenosine plays a major role in erection by binding to its receptors and activating pathways resulting in increased arterial blood flow and intracavernosal pressure (ICP). CF602, an allosteric modulator of the A3 adenosine receptor (A3AR), increases the binding affinity of the endogenous adenosine to the receptor. We examined the effect of CF602 on resolving erectile dysfunction (ED) in a diabetic ED rat model (streptozotocin-induced diabetic rats that were screened for ED using the apomorphine test). ED was assessed by measuring ICP and main arterial pressure (MAP) during electrostimulation of the cavernosal nerve. A single dose of CF602 or placebo was applied either topically (100 µl from a 100 nM or 500 nM solution) or orally (100, 200 or 500 µg/kg) prior to erectile function assessment. A significant dose-dependent improvement in the ICP:MAP ratio without a change in MAP was recorded with the topical and oral CF602 treatments. A significant increase in smooth muscle:collagen ratio, vascular endothelial growth factor and endothelial nitric oxide synthase was also observed in both administration modes. In conclusion, topical and oral treatment with CF602 significantly improved erectile function, supporting its further evaluation as a treatment for ED.

[Hongjing-1 Recipe maintains the expression level of Connexin43 in the penile tissue of SD rats with bilateral cavernous nerve injury].

OBJECTIVE: To explore the effects of Hongjing-1 Recipe (HJ-1) on erectile function and the expression of the gap junction protein Connexin43 (Cx43) in the penile tissue in male rats with bilateral cavernous nerve injury (BCNI). METHODS: Fifty male SD rats were randomly divided into five groups of an equal number: sham operation, BCNI model control, and low-, medium- and high-dose HJ-1. The BCNI model was made in the latter four groups by clamping the bilateral cavernous nerves with hemostatic forceps. Three days after modeling, the rats in the sham operation and BCNI model control groups were treated intragastrically with pure water and those in the low-, medium- and high-dose HJ-1 groups with HJ-1 at 2.835, 5.67 and 11.34 g/kg/d, respectively, all for 28 successive days. Then, the animals were subjected to intracavernous pressure (ICP) measurement for evaluation of their erectile function and immunofluorescence staining and Western blot for determination of the Cx43 level in the penile tissue. RESULTS: The BCNI model controls, compared with the rats in the sham operation group, showed a dramatically decreased ratio of maximum ICP to mean arterial pressure (mICP/MAP) (0.40 ± 0.04 vs 0.83 ± 0.10, P < 0.01) and that of total ICP to MAP (tICP/MAP) (21.89 ± 2.16 vs 50.27 ± 4.45, P < 0.01), as well as a down-regulated expression of Cx43 in the penile tissue (P < 0.01). In comparison with the rats in the BCNI model control group, those in the medium- and high-dose HJ-1 groups exhibited significantly increased ratios of mICP/MAP (0.54 ± 0.05, P < 0.05; 0.61 ± 0.06, P < 0.01) and tICP/MAP (31.20 ± 3.85, P < 0.01; 37.82 ± 4.17, P < 0.01) and up-regulated expression of Cx43 (P<0.05 and P<0.01). CONCLUSIONS: Hongjing-1 Recipe can effectively improve ED in rats with bilateral cavernous nerve injury, which may be attributed to its effect of maintaining the expression level of the gap junction protein Cx43 in the penile tissue.

Effects of androgen on extracellular vesicles from endothelial cells in rat penile corpus cavernosum.

BACKGROUND: The explicit mechanism of erectile dysfunction caused by low androgen status is unknown. It was reported that eNOS was expressed in extracellular vesicles (EVs). Androgen may regulate erectile function by affect the release of EVs from endothelial cells. OBJECTIVES: To investigate whether androgen affects the production of EVs and nitric oxide (NO) in endothelial cells of rat penile corpus cavernosum. MATERIALS AND METHODS: Endothelial cells of rat penile corpus cavernosum were isolated and purified from 6-week-old healthy male Sprague Dawley (SD) rats. Endothelial cells were treated with different concentrations of dihydrotestosterone (DHT) in a cell culture medium as follows: no-androgen group (NA group, DHT 0 nmol/L), very-low androgen group (VLA group, DHT 0.1 nmol/L), low androgen group (LA group, DHT 1 nmol/L), and physiological concentrations androgen group (PA group, DHT 10 nmol/L). After 24 h, EVs of supernatant in each group were isolated and identified. The content of EVs and NO in the supernatant and the expression of CD9, CD63, TSG101, and eNOS in EVs were detected. RESULTS: Positive expression of CD9, CD63, TSG101, and eNOS was found in isolated EVs. The concentration of EVs was lower in the NA group compared with other groups (p < 0.01). The expression of eNOS and the concentration of NO was lower in the NA group than that in other groups (p < 0.05); it was lower in the VLA group than that in the LA group (p < 0.05) and lower in LA group than that in PA group (p < 0.05). When the concentration of DHT in endothelial cell culture medium ranged from 0 to 10 nmol/L, the concentration of DHT was positively correlated with the content of EVs and NO. CONCLUSION: Decrease in eNOS-expressing EVs is one mechanism of NO reduction in endothelial cells of rat corpus cavernosum caused by low androgen levels.

Neutralizing antibody to proNGF rescues erectile function by regulating the expression of neurotrophic and angiogenic factors in a mouse model of cavernous nerve injury.

BACKGROUND: Radical prostatectomy induces some degree of cavernous nerve injury (CNI) and causes denervation-induced pathologic changes in cavernous vasculature, regardless of the advances in surgical techniques and robotic procedures. The precursor for nerve growth factor (proNGF) is known to be involved in neuronal cell apoptosis and microvascular dysfunction through its receptor p75NTR . OBJECTIVES: To determine the expression of proNGF/p75NTR and the efficacy of proNGF neutralizing antibody (anti-proNGF-Ab) in a mouse model of ED induced by CNI. MATERIALS AND METHODS: Age-matched 12-week-old C57BL/6 mice were distributed into three groups: sham group and bilateral CNI group treated with intracavernous injections of PBS (20 µL) or of anti-proNGF-Ab (20 µg in 20 µL of PBS) on days -3 and 0. Two weeks after treatment, erectile function was measured by electrical stimulation of cavernous nerve. Penis tissues from a separate group of animals were harvested for further analysis. We also determined the efficacy of anti-proNGF-Ab on neural preservation in major pelvic ganglion (MPG) ex vivo. RESULTS: We observed increased penile expression of proNGF and p75NTR after CNI. Intracavernous administration of anti-proNGF-Ab increased nNOS and neurofilament expression probably by enhancing the production of neurotrophic factors, such as neurotrophin-3, NGF, and brain-derived neurotrophic factor. Anti-proNGF-Ab preserved the integrity of cavernous sinusoids, such as pericytes, endothelial cells, and endothelial cell-to-cell junctions, possibly by controlling angiogenic factors (angiopoietin-1, angiopoietin-2, and vascular endothelial growth factor) and induced endogenous eNOS phosphorylation in CNI mice. And finally, treatment with anti-proNGF-Ab rescued erectile function in CNI mice. Anti-proNGF-Ab also enhanced neurite sprouting from MPG exposed to lipopolysaccharide. DISCUSSION AND CONCLUSION: The preservation of damaged cavernous neurovasculature through inhibition of the proNGF/p75NTR pathway may be a novel strategy to treat radical prostatectomy-induced erectile dysfunction.

[Xiongcan Yishen Prescription upregulates the expressions of eNOS and cGMP in the penile tissue of ED rats with liver depression and kidney deficiency].

OBJECTIVE: To investigate the effect of Xiongcan Yishen Prescription (XYP) on the expressions of eNOS and cGMP in the penile tissue of ED rats with liver depression and kidney deficiency (LDKD). METHODS: The model of ED-LDKD was established in 30 eight-week-old SPF-class male SD rats by injecting hydrocortisone intramuscularly and binding the limbs for 14 days, and another 10 rats were taken as blank controls. Then, the model rats were randomized into six groups of equal number and treated intragastrically with distilled water (model control), tadalafil tablets at 0.52 mg/kg/d (tadalafil control), Shugan Yiyang Capsules 0.3125 g/kg/d (SYC control), and XYP at 10.4 g/kg/d (low-dose XYP), 20.8 g/kg/d (medium-dose XYP) and 41.6 g/kg/d (high-dose XYP), bid, for 28 successive days, respectively. Before and after modeling and after 28-day treatment, the animals were subjected to tail suspension and mating tests. The next day after medication, the penile tissues of the rats were harvested for determining the expression levels of eNOS and cGMP proteins by immunohistochemical analysis of the mean optical density. RESULTS: Compared with the model controls, the rats of the high-, medium- and low-dose XYP and SYC control groups all showed significant decreases in the tail suspension time (ï¼»3.17 ± 0.11ï¼½ vs ï¼»2.58 ± 0.25ï¼½, ï¼»2.52 ± 0.31ï¼½, ï¼»2.51 ± 0.3ï¼½ and ï¼»2.57 ± 0.29ï¼½ min, P < 0.05) and mount latency (ML) (ï¼»9.23 ± 0.11ï¼½ vs ï¼»1.21 ± 0.12ï¼½, ï¼»2.17 ± 0.16ï¼½, ï¼»2.26 ± 0.13ï¼½, ï¼»1.23 ± 0.15ï¼½ and ï¼»2.48 ± 0.18ï¼½ min, P < 0.05) but increases in mount frequency (MF) (ï¼»0.48 ± 0.18ï¼½ vs ï¼»3.29 ± 0.11ï¼½, ï¼»3.18 ± 0.11ï¼½, ï¼»3.05 ± 0.05ï¼½, ï¼»3.23 ± 0.12ï¼½ and ï¼»3.2 ± 0.28ï¼½ times, P < 0.05) and intromission frequency (IF) (ï¼»0.8 ± 0.84ï¼½ vs ï¼»11.8 ± 0.84ï¼½, ï¼»11.2 ± 1.48ï¼½, ï¼»9.4 ± 1.14ï¼½, ï¼»11.4 ± 1.14ï¼½ and ï¼»10 ± 1.22ï¼½ times, P < 0.05). The eNOS and cGMP proteins were mainly expressed in the nucleus and cytoplasm of the arterial and venous endothelial cells and sinusoidal endothelial cells of the cavernous, as brownish yellow particles in a scattered and focal pattern. Both the expressions of eNOS and cGMP in the penile tissue were remarkably upregulated in the high-, medium- and low-dose XYP and SYC control groups as compared with those in the model control (P < 0.05) but exhibited no statistically significant difference between the tadalafil and model control groups (P > 0.05). CONCLUSIONS: Xiongcan Yishen Prescription can relieve the depression symptoms, increase the mount frequency, activate the NO/cGMP pathway, and upregulate the expressions of eNOS and cGMP in the penile tissue of ED rats with liver depression and kidney deficiency.

Pfaffia glomerata hydroalcoholic extract stimulates penile tissue in adult Swiss mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Roots of Pfaffia glomerata are used in traditional medicine as aphrodisiacs and sexual stimulants. AIM OF THE STUDY: The aim of this study was to evaluate the action of the hydroalcoholic extract from the roots of Pfaffia glomerata on the Leydig cells, cavernous bodies and other penile constituents, as well as on serum testosterone and 17ß-estradiol levels of adult mice. MATERIALS AND METHODS: Mature male Swiss mice were divided into 6 groups: control (water), sildenafil citrate, 3 groups receiving daily doses of P. glomerata extract (100, 200 and 400 mg/kg) and one group receiving intermittent doses of P. glomerata (200 mg/kg/3-3d). RESULTS: The proportions of blood vessels, lymphatic space and estradiol levels were increased. On the other hand, reduction of testosterone levels due to Leydig cells death was observed. As for penile parameters, volumetric proportions of cavernous bodies, collagen and nitric oxide were increased, while smooth muscle content was decreased. CONCLUSIONS: Despite that the long term intake of P. glomerata extract was related to a stimulant action, reduction on Leydig cell viability induced decreased testosterone production.

Tangeretin ameliorates erectile and testicular dysfunction in a rat model of hypertension.

Tangeretin is a polymethoxyflavone concentrated in citrus peels and has several biological activities. This study examined whether tangeretin improved reproductive dysfunction in Nω-nitro-L-arginine methyl ester hydrochloride (L-NAME)-induced hypertensive rats. Male Sprague-Dawley rats received L-NAME to induce hypertension and reproductive dysfunction for 5 w and were treated with tangeretin (15 or 30 mg/kg) or sildenafil citrate (10 mg/kg) for the final two weeks. Mean arterial pressure (MAP), intracavernosal pressure (ICP) response to cavernous nerve stimulation, endothelial nitric oxide synthase (eNOS), Angiotensin II receptor type 1 (AT1R) and gp91phox protein expressions and malondialdehyde (MDA) level in penile tissues were measured. Sperm concentrations and motility, seminiferous tubule morphology, serum testosterone, testicular eNOS and steroidogenic acute regulatory protein (StAR) expression were evaluated. Aortic superoxide generation, plasma and testicular MDA and plasma nitrate/nitrite levels were determined. Tangeretin reduced blood pressure and increased the maximum ICP/MAP associated with suppression of AT1R/gp91phox and upregulation of eNOS expression in hypertensive rats (P < 0.05). Furthermore, improvement of sperm quality relevant to increased testicular eNOS and StAR expression was found in tangeretin treated rats (P < 0.05). Changes in seminiferous tubule morphology in hypertensive rats were recovered by tangeretin (P < 0.05). It increased testosterone levels and reduced oxidative stress biomarkers and raised plasma nitrate/nitrite levels in L-NAME rats (P < 0.05). In conclusion, tangeretin improved maximum ICP/MAP and testicular dysfunction and morphology in rats treated with L-NAME. The molecular mechanisms are mediated by modulations of penile eNOS and AT1R/gp91phox expressions and testicular eNOS and StAR expression.

Folic acid supplementation improves erectile function in patients with idiopathic vasculogenic erectile dysfunction by lowering peripheral and penile homocysteine plasma levels: a case-control study.

BACKGROUND: Erectile dysfunction (ED) has common risk factors with many cardiovascular (CV) impairments. In view of these facts, hyperhomocysteinemia (HHcys) has been postulated for involvement in endothelial dysfunction. OBJECTIVES: We evaluated peripheral and penile homocysteine (Hcys) plasma levels before and after folic acid supplementation in idiopathic vasculogenic erectile dysfunction (ED) patients. MATERIALS AND METHODS: This study included 50 consecutive patients and 50 consecutive healthy controls that were recruited from December 2017 to December 2018. The patients received folic acid (FA) daily for 3 months and were evaluated by the abridged 5-item International Index of Erectile Function (IIEF-5) and penile duplex before and after therapy, in addition to plasma Hcys levels. RESULTS: Our study showed improvement in the severity of ED in our patients as all of them became mild to moderate ED after folic acid administration. Additionally, the median scores of IIEF-5 significantly increased from 6 to 14, respectively (p < 0.001). Furthermore, the median peripheral and penile Hcys plasma levels (µmol/l) significantly decreased after folic acid administration as 39 patients with moderate ED and 11 patients with severe ED were 0.62, 0.34, 5.37, 0.37, respectively, became mild to moderate ED with their median peripheral and penile Hcys plasma levels became 0.19, 0.15, p < 0.001, <0.001, respectively. Peripheral Hcys level correlates significantly with penile Hcys before and after folic acid administration (r: -0.06 p: 0.8, r: 0.9, p < 0.001, respectively). DISCUSSION AND CONCLUSION: Recently, an emerging body of evidence suggests a role for Hcys and folate in erectile function. Interestingly, our interventional study is one of the first that evaluated the effect of folic acid supplementation on HHcys where it demonstrated a significant decrease in peripheral and penile Hcys plasma levels after folic acid administration. Thus, FA should be prescribed concomitantly with phosphodiesterase type 5 inhibitors in ED patients.

Effects of Chaga Medicinal Mushroom Inonotus obliquus (Agaricomycetes) Extracts on NOS-cGMP-PDE5 Pathway in Rat Penile Smooth Muscle Cells.

Some medicinal mushrooms have effects on sexual dysfunctions. Nitric oxide synthase (NOS)-cyclic gua-nosine monophosphate (cGMP)-phosphodiesterase 5 enzyme (PDE5) pathway is one of the pathophysiological basis of erectile dysfunction (ED). The normal erectile function involves the synthesis of nitric oxide (NO), and the subsequent accumulation of cGMP, whereas cGMP degradation is specifically controlled by PDE5, which promotes corporal smooth muscle cell (SMC) tone and terminates erection. The antioxidant activities of Inonotus obliquus (chaga) water extracts (IO1) and water extraction and alcohol precipitation extracts (IO2) were compared using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging assay and oxygen radical absorbance capacity (ORAC) method. Three subtypes of NOS (nNOS, iNOS, and eNOS) and PDE5 protein expressions were tested by Western blotting, and cGMP was determined by ELISA on a rat corporal primary SMC. The results revealed that IO2, which had a significantly higher polysaccharide content than IO1, showed a significantly higher ORAC value and a significantly lower half inhibitory concentration for DPPH scavenging activity than IO1. We observed that both IO1 and IO2 increased the expression of eNOS and iNOS significantly compared with the control. Furthermore, when compared with the control, IO1 increased PDE5 expression significantly, while IO2 showed no effect. The different impacts on PDE5 might be the reason that IO2, not IO1, showed significant inducible effect on cGMP compared with the control. This is to our knowledge, the first study exploring the effect of I. obliquus on NOS-cGMP-PDE5 pathway on SMC. The results provide a possible selection of I. obliquus for the treatment of ED.

Alkaloid extracts from Bitter leaf (Vernonia amygdalina) and Black nightshade (Solanum nigrum) inhibit phosphodiesterase-5, arginase activities and oxidative stress in rats penile tissue.

The erectogenic potential of alkaloids extracted from Bitter leaf (Vernonia amygdalina) and Black nightshade (Solanum nigrum) was investigated in this study. Fresh leaves obtained from Bitter leaf and Black night shade were air-dried, pulverized, and extracted for alkaloids. The inhibitory potential of the alkaloid extracts on arginase and phosphodiesterase-5 (PDE-5) activities in rats penile tissue was determined in vitro. The antioxidant properties were also evaluated and the constituent alkaloids quantified using GC-MS. The alkaloid extracts inhibited arginase (0-30.51 µg/ml) and PDE-5 (0-133.69 µg/ml) activities in a concentration-dependent pattern. Similarly, the alkaloid extracts inhibited Fe2+ -induced lipid peroxidation in rats penile tissues, scavenged DPPH, OH, and NO radicals as a function of concentration. GC-MS characterization revealed over 20 alkaloid compounds. The inhibition of PDE-5-, arginase-, pro-oxidant-induced lipid peroxidative-, and free radicals-scavenging activities by the alkaloids is suggestive of putative mechanisms underlying their therapeutic use for managing erectile dysfunction in folklore medicine. PRACTICAL APPLICATIONS: Alkaloids extracted from Black nightshade (Solanum nigrum) and Bitter leaf (Vernonia amygdalina) were characterized and investigated by standard procedures for inhibitory action against key erectile dysfunction-linked enzymes and antioxidant activity. The alkaloids inhibited erectile dysfunction-linked enzymes (arginase and PDE-5) and showed considerable antioxidant activity in a concentration-dependent manner. In view of this, we suggest the application of these results in the development of erectile dysfunction drugs in the pharmaceutical industry, with probable minimal or no adverse effect.

Anogeissus leiocarpus attenuates paroxetine-induced erectile dysfunction in male rats via enhanced sexual behavior, nitric oxide level and antioxidant status.

Sexual dysfunction is a side effect of the antidepressant drug paroxetine. Anogeissus leiocarpus is a medicinal plant with a wide range of biological activities which include antioxidant and antiulcer properties. With these in mind, we investigated the effect of Anogeissus leiocarpus stem bark extract on paroxetine-induced sexual dysfunction in male Wistar rats. Forty-two adult male Wistar rats were divided into seven experimental groups: normal control, PAR (10 mg/kg), PAR + sildenafil (5 mg/kg), ALE (50 and 100 mg/kg) and PAR + ALE (50 and 100 mg/kg). The experiment lasted for 21 days, after which the rats were subjected to sexual behavioral test. Various biochemical assays (phosphodiesterase-5, arginase, acetylcholinesterase, nitric oxide and MDA) were carried out on the penile tissue homogenate. From our findings, paroxetine significantly altered sexual behavior in male rats and increased phosphodiesterase-5, arginase and acetylcholinesterase activities with a concomitant decrease in nitric oxide level. Furthermore, paroxetine altered antioxidant status which revealed by increased MDA level and reduced thiol level. However, treatment with Anogeissus leiocarpus stem bark extract reversed the altered sexual behavior in male rats and boosted antioxidant status. In addition, administration of Anogeissus leiocarpus stem bark extract resulted in a significant attenuation of phosphodiesterase-5, arginase and acetylcholinesterase activities in paroxetine-induced rats. In view of the aforementioned findings, Anogeissus leiocarpus could be considered a promising natural agent in erectile dysfunction management.

Optimization of Extraction Technology of Majun Mupakhi Ela and its Effect on Hydrocortisone-induced Kidney Yang Deficiency in Mice.

We used Box-Behnken design-based (BBD) response surface methodology (RSM) in this research to optimize the extraction process of Traditional medicine Majun Mupakhi Ela (MME) and evaluate its effect on hydrocortisone-induced kidney yang deficiency. Three independent parameters were applied to evaluate the maximum phosphodiesterase type 5 (PDE5) inhibition activity of MME extracts in vitro. The optimal processing conditions (extraction time 2 h, solid-liquid ratio 1:16, extraction once) gave a maximum PDE5 inhibition rate of 84.10%, flavonoid content of 0.49 mg/ml, icariin content of 0.028 mg/ml and targeted extraction yield of 26.50%. In animal experiments, MME extracts significantly increased the adrenal mass index, semen weight index, preputial gland weight index, and penis weight index in mice; in the middle and high dose group, the level of serum testosterone increased by 7664.29% and 14207.14% respectively, compared with the model group, and the level of PDE5 decreased by 67.22% and 74.69% respectively compared with the control group. These results indicate that MME has a significant positive effect on the hypothalamus-pituitary-gonadal axis, improve mating ability and not only has inhibits PDE5 activity but also significantly inhibits the expression of PDE5 in penile tissues, potential to become erectile dysfunction (ED) therapies for the clinical management of patients with kidney yang deficiency.

[Differentially expressed proteins in the penile tissue of rats with compound stress-induced ED after intervention with Yimusake Tablets: A bioinformatics analysis].

OBJECTIVE: To search for specific protein makers and target proteins for intervention with Yimusake Tablets (YT) in the penile tissue of rats with ED induced by compound cold stress and explore the molecular mechanisms underlying the development and progression of ED. METHODS: Eighty adult male rats were screened and divided into three groups, normal control (n = 10), ED model control (n = 15) and YT intervention (n = 15). The model of compound cold stress-induced ED was established in the latter two groups, and meanwhile the animals in the YT intervention group were treated with oral YT for 2 weeks. After that, proteins were extracted from the penile tissues of the rats for screening and identification by iTRAQ labeling combined with LC-MS-MS proteomics, and the IPA bioinformatics software was used for analysis of differentially expressed proteins. RESULTS: A total of 48 differentially expressed proteins were identified from the penile tissue of the ED model controls, of which 18 were associated with endothelial function, 5 with smooth muscle activity and 4 with inflammation, involving the biological processes of glucose metabolism and alcohol catabolism and the signaling pathways of glucose metabolism, calcium and RXR activation. In comparison, 29 differentially expressed proteins were identified from the rats in the YT intervention group, of which 5 were associated with endothelial function, 1 with smooth muscle activity and 4 with inflammation, involving the biological processes of glucose metabolism, vasodilation and acute-phase response and the signaling pathways glucose metabolism, RXR activation and acute-phase response. Seven ED-associated candidate biomarkers were obtained from the differentially expressed proteins in the ED model control and YT intervention group, including Collagen alpha-1(III) chain（COL3α1）, Collagen alpha-1(I) chain（COL1α1）, Collagen alpha-2(I) chain（COL1α2）, Glyceraldehyde-3-phosphate dehydrogenase（GAPDH）, T-kininogen 1（MAP1）,Biglycan（BGN）, and Myosin-11（MYH11）. CONCLUSIONS: Changes of vascular endothelial and smooth muscle functions in the penile tissue are likely to be the key mechanisms underlying the development and progression of compound stress-induced ED, which is also associated with inflammation as well as the interaction of the identified differentially expressed proteins and their participation in the relevant signaling pathways. The 7 proteins obtained can be used as the markers of compound stress-induced ED in the rat penile tissue, of which MAP1, GAPDH, BGN and MYH11 may serve as target proteins for YT intervention.

Protective effects of Danshen injection against erectile dysfunction via suppression of endoplasmic reticulum stress activation in a streptozotocin-induced diabetic rat model.

BACKGROUND: Erectile dysfunction (ED) is a common complication of diabetes. This study aimed to explore the beneficial effect of Danshen injection on ED in a streptozotocin (STZ)-induced diabetic rat model and the underlying mechanism. METHODS: The diabetic rat model was established by an intraperitoneal injection of 60 mg/kg STZ in male Sprague-Dawley rats. The diabetic rats were intraperitoneally injected with Danshen solution (0.5 or 1 mL/kg/day) or the same volume of saline for 6 weeks. Age-matched rats served as controls. After 6 weeks, erectile function and histological morphology of the corpora cavernosum were assessed. Oxidative stress indicators, including superoxide dismutase (SOD) activity, malondialdehyde (MDA) content, and reactive oxygen species (ROS) levels, were measured in penile tissues. The expression levels of glucose-regulated protein 78 (Grp78), growth arrest and DNA damage-inducible gene 153 (GADD153/CHOP) were determined by immunohistochemistry, immunoblotting, and RT-PCR. Apoptosis was detected by a TUNEL assay. RESULTS: The erection times of diabetic rats were significantly less than those of control rats. Danshen injection could improve erectile function via increased erection times. Danshen injection was also found to ameliorate the morphological abnormalities of the corpora cavernosum, to reduce the number of apoptotic cells, and to suppress caspase-3 activation in penile tissue, accompanied by downregulation of the endoplasmic reticulum stress biomarkers Grp78 and CHOP. Danshen injection could increase SOD activity as well as reduce ROS and MDA levels in diabetic rats, indicating suppression of oxidative stress. CONCLUSION: Danshen injection could rescue diabetes-associated ED, possibly via suppressing the oxidative stress and endoplasmic reticulum (ER) stress-induced apoptosis pathways.

Resveratrol treatment may preserve the erectile function after radiotherapy by restoring antioxidant defence mechanisms, SIRT1 and NOS protein expressions.

Radiotherapy (RT) for prostate cancer (PC) can cause erectile dysfunction (ED) by damaging neurovascular structures with oxidative stress. In this study, we evaluated the effects of resveratrol, an antioxidant, on post-RT ED. Fifty rats in five groups were evaluated; control (C), prostate-confined radiotherapy with short- and long-term vehicle or resveratrol treatment. Cavernosal tissues were obtained to analyze glutathione (GSH), nitric oxide (NO), cyclic guanosine monophosphate (cGMP), 8-hydroxy-2'-deoxy-guanosine (8-OHdG) levels and superoxide dismutase (SOD), caspase-3 activities, sirtuin-1, Foxo-3, nNOS, and eNOS protein expressions. Intracavernosal pressures (ICP) were measured for the long-term treatment group. In the RT + long-term vehicle treatment group, tissue GSH, NO, cGMP, and SOD activity were decreased while 8-OHdg levels and caspase-3 activities were increased. Radiotherapy caused a decrease in sirtuin-1, nNOS, and eNOS protein expressions. These parameters were reversed by resveratrol treatment. Foxo-3 protein expressions were unaltered in the RT + short-term vehicle treatment group and started to increase as a defense mechanism in the RT + long-term vehicle group; however, resveratrol treatment caused a significant increase in Foxo-3 expressions. Resveratrol preserved the metabolic pathways involved in erectile function and provided functional protection. Resveratrol can be used as a supplementary agent in patients undergoing radiotherapy to preserve erectile function.

Phenolic-rich extracts of Eurycoma longifolia and Cylicodiscus gabunensis inhibit enzymes responsible for the development of erectile dysfunction and are antioxidants.

BACKGROUND: Herbs have been used from ages to manage male sexual dysfunction. Hence, this study sought to investigate the effects of Eurycoma longifolia (EL) and Cylicodiscus gabunensis (CG) stem bark extracts on some enzymes implicated in erectile dysfunction in vitro. METHODS: The extracts were prepared, and their effects on phosphodiesterase-5 (PDE-5), arginase, and angiotensin-1-converting enzyme (ACE) as well as pro-oxidant-induced lipid peroxidation were assessed. Furthermore, phenolic contents were determined, and their components were characterized and quantified using high-performance liquid chromatography with diode array detector (HPLC-DAD). RESULTS: The results revealed that the extracts inhibited PDE-5, arginase, and ACE in a concentration-dependent manner. However, IC50 values revealed that CG had higher inhibitory potential on PDE-5 (IC50=204.4 µg/mL), arginase (IC50=39.01 µg/mL), and ACE (IC50=48.81 µg/mL) than EL. In addition, the extracts inhibited pro-oxidant-induced lipid peroxidation in penile tissue homogenate. HPLC-DAD analysis showed that CG is richer in phenolic compounds than EL, and this could be responsible for higher biological activities observed in CG than EL. CONCLUSIONS: Hence, the observed antioxidant property and inhibitory action of CG and EL on enzymes relevant to erectile dysfunction in vitro could be part of possible mechanisms underlying their involvement in traditional medicine for the management of male sexual dysfunction.

Dietary supplementation of tiger nut alters biochemical parameters relevant to erectile function in l-NAME treated rats.

Tiger nut tubers have been reportedly used for the treatment of erectile dysfunction (ED) in folk medicine without scientific basis. Hence, this study evaluated the effect of tiger nut on erectile dysfunction by assessing biochemical parameters relevant to ED in male rats by nitric oxide synthase (NOS) inhibitor, Nω-nitro-l-arginine methyl ester hydrochloride (l-NAME) treatment. Rats were divided into five groups (n = 10) each: Control group; l-NAME plus basal diet; l-NAME plus Sildenafil citrate; diet supplemented processed tiger nut (20%) plus l-NAME;diet supplemented raw tiger nut (20%) plus l-NAME. l-NAME pre-treatment (40 mg/kg/day) lasted for 14 days. Arginase, acetycholinesterase (AChE) and adenosine deaminase (ADA) activities as well as nitric oxide levels (NO) in serum, brain and penile tissue were measured. l-NAME increased the activity of arginase, AChE and ADA and reduced NO levels. However, dietary supplementation with tiger nut caused a reduction on the activities of the above enzymes and up regulated nitric oxide levels when compared to the control group. The effect of tiger nut supplemented diet may be said to prevent alterations of the activities of the enzymes relevant in erectile function. Quercetin was revealed to be the most active component of tiger nut tuber by HPLC finger printing.

Effect of ginger, Paullinia cupana, muira puama and l- citrulline, singly or in combination, on modulation of the inducible nitric oxide- NO-cGMP pathway in rat penile smooth muscle cells.

INTRODUCTION: COMP-4 is a natural compound-based dietary supplement consisting of the combination of ginger, Paullinia cupana, muira puama and l-citrulline, which when given long-term has been shown in the aged rat to a) upregulate iNOS in the penile smooth muscle cells (SMC), b) reverse the corporal SMC apoptosis and fibrosis associated with corporal veno-occlusive dysfunction (CVOD), and c) improve resulting erectile function. To elucidate the mechanism of how COMP-4 and its individual components modulate the iNOS-cGMP pathway, an in vitro study was conducted using a rat corporal primary SMC culture to determine its effect on NOS, soluble guanylate cyclase (sGC), cGMP and the phosphodiesterase 5 enzyme (PDE5). MATERIALS AND METHODS: Primary SMC cultures using the explant technique were initiated by cutting small pieces of corporal tissue from 8 week old Sprague-Dawley rats. The SMC were grown in Dulbecco media with 20% fetal calf serum. The SMC were then incubated with or without COMP-4 (0.69 mg/ml) or its ingredients alone (ginger: 0.225 mg/ml; muira puama, Paullinia cupana and l-citrulline each at 0.9 mg/ml) for up to 24 h mRNA and protein were extracted and used for the determination of NOS, sGC and PDE5 content. cGMP content was determined by ELISA. L-NIL (4 µM) was used as an inhibitor of iNOS activity. RESULTS: Compared to the control values, COMP-4 upregulated expression of cGMP by 85%, induced a 42 fold increase in sGC as well as a 15 fold increase in both iNOS protein and mRNA content while it decreased both PDE5 mRNA and protein content each by about 50%. L-NIL completely inhibited the effect of COMP-4 on cGMP production. When compared with each of the individual four components of COMP-4, it appears that COMP-4 itself had the most profound effect in modulating each one the specific steps within the iNOS-cGMP pathway. CONCLUSIONS: This in vitro study demonstrates that COMP-4 is capable of activating the endogenous cellular iNOS-cGMP pathway within the CSM cells, which is theorized to be responsible for reducing the fibrosis and apoptosis as well as the CVOD observed in the aging rat penis. Further studies will be necessary in order to determine whether supplementation of COMP-4 on a daily basis may be beneficial in halting or reversing this aging related erectile dysfunction in the clinical setting.

Icariin improves the sexual function of male mice through the PI3K/AKT/eNOS/NO signalling pathway.

We aimed to investigate the effect and mechanism of icariin on male sexual function. Forty-eight Crl:CD1(ICR) male mice were randomly divided into control, low-, medium- and high-dose icariin group (intragastric administration of 50, 100 and 200 mg/kg/d for 21 days). Mating experiment was then performed at a ratio of 1: 3 (male: female). The mating behaviours of male mice were recorded. The genital indexes and serum testosterone, nitric oxide (NO), hypothalamic dopamine (DA) and 5- hydroxy tryptophan (5-HT) concentrations were measured. The expression of endothelial nitric oxide (eNOS), phosphatidylinositol tallow alcohol 3-kinase (PI3K) and phosphorylated protein kinase (p-AKT) in penile tissue was detected by Western blot. All icariin groups exhibited shorter capture latency and ejaculation latency, increased number of capture and ejaculation, higher capture and ejaculation rate, and higher testicular and prostate indexes compared with controls (p < .001). These groups had higher serum testosterone and NO concentrations (p < .001), hypothalamic DA and 5-HT levels, and eNOS, PI3K and phosphorylated AKT expressions in penile tissue (p < .05). The effect of icariin was dose-dependently increased. Our study suggests that icariin improves the sexual function of male mice, which might be associated with the hypothalamic-pituitary-gonadal axis and the PI3K/AKT/eNOS/NO signalling pathway.