Corpus Cavernosum Smooth Muscle Research Articles

MicroRNA-141 binds to the nerve growth factor receptor associated protein 1 gene and restores the erectile function of diabetic rats through down-regulating the nerve growth factor/neurotrophin receptor p75 (NGF/p75NTR) signaling.

Erectile dysfunction (ED) is one of the major complications in diabetes mellitus (DM). We have previously reported that the nerve growth factor (NGF)/tyrosine kinase receptor (TrkA) signaling is actively involved in DM-induced ED (DMED). Here, we investigate the effect of micro-RNA-141 (miR-141) on the NGF/p75 neurotrophin receptor (p75NTR) signaling and erectile function of diabetic rats. Sprague-Dawlay (SD) rats were used to establish a DMED model. The dual-luciferase reporter gene assay was first performed to identify the nerve growth factor receptor-associated protein 1 (NGFRAP1) gene as the target gene of miR-141. The regulatory mechanisms underlying miR-141 governing NGFRAP1 in vivo were then validated by modulating the expressions of miR-141 and knocking down NGFRAP1. The expressions of miR-141 were decreased while the expressions of NGFRAP1, NGF, and p75NTR were increased in DMED. miR-141 and downregulation of NGFRAP1, respectively, increased the density of corpus cavernosum smooth muscle and the ratio of intracavernosal pressure (ICP)/mean arterial blood pressure (MAP) and promoted the expression of α-actin and desmin as well. miR-141 also upregulated the expressions of NGFRAP1 in DMED, and knockdown of NGFRAP1 inhibited the productions of NGF and p75NTR. Furthermore, miR-141 suppressed the NGF/p75NTR signaling via binding to NGFRAP1. NGF/p75NTR signaling actively participates in the pathogenesis of DMED. miR-141 binds to NGFRAP1 and restores the erectile function of diabetic rats via downregulation of NGF/p75NTR signaling.

MSC-derived exosomes ameliorate erectile dysfunction by alleviation of corpus cavernosum smooth muscle apoptosis in a rat model of cavernous nerve injury

BackgroundThis study investigated the therapeutic effects of MSC-derived exosomes (MSC-Exos) on erectile function in a rat model of cavernous nerve injury (CNI).MethodsMSCs were isolated from rat bone marrow and exosomes were isolated from the supernatants by ultracentrifugation. The tissue explant adherent method was used to isolate and culture corpus cavernosum smooth muscle cells (CCSMCs). MSCs and CCSMCs were identified by flow cytometry, in vitro differentiation or immunofluorescence staining. Thirty-two 10-week-old male Sprague Dawley (SD) rats were divided into four groups: a sham operation group and bilateral CNI groups that received intracavernosal (IC) injection of either PBS, MSCs or MSC-Exos. Four weeks after CNI and treatment, the erectile function of the rats was measured by electrically stimulating the cavernous nerve. The penile tissues were harvested for blinded histologic analysis and western blotting. H2O2 was used to induce apoptosis in the CCSMCs, and a flow cytometer was used to measure the cell viability of the CCSMCs treated with or without exosomes in vitro.ResultsRecovery of erectile function was observed in the MSC-Exos group. The MSC-Exos treatment significantly enhanced smooth muscle content and neuronal nitric oxide synthase in the corpus cavernosum. The ratio of smooth muscle to collagen in the corpus cavernosum was significantly improved in the MSC-Exos treatment group compared to the PBS vehicle group. WB confirmed these biological changes. Cell viability of the CCSMCs was increased in the MSC-Exos-treated groups, and caspase-3 expression was decreased after the MSC-Exos treatment in vivo and in vitro.ConclusionsExosomes isolated from MSCs culture supernatants by ultracentrifugation could ameliorate CNI-induced ED in rats by inhibiting apoptosis in CCSMCs, with similar potency to that observed in the MSCs-treated group. Therefore, this cell-free therapy has great potential for application in the treatment of CNI-induced ED for replacing cell therapy.Graphical abstractMSC-derived exosomes ameliorate erectile dysfunction in a rat model of cavernous nerve injury

Islet transplantation improved penile tissue fibrosis in a rat model of type 1 diabetes

BackgroundGlycaemic control is one of the most effective strategies for the treatment of diabetes-related erectile dysfunction (DMED). Compared to conventional anti-diabetic drugs and insulin, islet transplantation is more effective in the treatment of diabetic complications. The aim of this study was to investigate the efficacy of islet transplantation for reversing advanced-stage DMED in rats and to observe its influence on corpus cavernosum fibrosis.MethodsWistar rats were intraperitoneally injected with streptozotocin to establish a diabetes model. After 12 weeks, the rats were divided into 4 groups: diabetic, insulin, islet transplantation, and normal control. Following supplementation, the changes in blood glucose and weight were determined sequentially. Penile erectile function was evaluated by apomorphine experiments in the fourth week, and the penile corpus cavernosum was also collected for assessment by Masson staining, immunohistochemistry and Western blot to observe the spongy tissue and the related cellular changes at the molecular level.ResultsIslet transplantation significantly ameliorated penile erectile function in advanced-stage diabetic rats. The ratio of corpus cavernosum smooth muscle cells to fibroblasts and the expression level of α-SMA in the islet transplantation group were significantly higher than those in the diabetic and insulin groups. In addition, the expression levels of TGF-β1, p-Samd2, and connective tissue growth factor (CTGF) in the islet transplantation and insulin groups were much lower than those in the diabetic group, while those in the islet transplantation group were significantly lower than those in the insulin group.ConclusionsOur findings strongly suggest that islet transplantation can promote the regeneration of smooth muscle cells and ameliorate corpus cavernosum fibrosis to restore its normal structure in advanced-stage diabetic rats. The possible mechanism of ameliorating corpus cavernosum fibrosis by islet transplantation may be associated with improvement of the hyperglycaemic status in diabetic rats, thereby inhibiting the TGF-β1/Samd2/CTGF pathway.

324 Characterization and functional roles of Kv7 Channels in corpus cavernosum smooth muscle

KCNQ-encoded voltage-gated potassium channels (Kv7) have recently been identified as key regulator of vascular and non-vascular smooth muscle tone. Kv7 channel subtypes (Kv7.1-Kv7.5) have a specific tissue distribution and pathophysiological role. Loss of function mutations in four of the five KV7 genes lead to distinct inherited diseases, such as cardiac arrhythmias, epilepsy and sensorineuronal deafness. However, their physiological role in corporal smooth muscle (CSM) remains to be fully elucidated. In this study, we examined the molecular expression and functional role of Kv7 channels in corporal smooth muscle. Expression of KCNQ isoforms in human corporal smooth muscle (hCSM) cells was examined using RT-PCR. Functional responses to Kv7 channel modulators were evaluated in normal and diabetic (DM) rabbit corporal smooth muscle (CSM) tissue. Isolated CSM strips were mounted in an organ-bath system, and the relaxation effects of the following Kv7 channel subtype selective activators: ML213 (Kv7.2/Kv7.4channels), ML277 (Kv7.1) and ICA 069673 (Kv7.2/7.3), Flupirtine (Kv7.2–7.5 channels) were evaluated by cumulative addition to strips pre-contracted with10-5 M phenylephrine (PE). Fluo-4 fluorescence techniques were used to monitor changes in [Ca2+]cyt.

325 Preserved erectile function in the hyperhomocysteinaemia transgenic rats harboring human tissue kallikrein 1

To investigate the detailed mechanism of erectile dysfunction (ED) induced by hyperhomocysteinaemia (HHcy) in rats and determine whether the Human Tissue Kallikrein 1 (hKLK1) might improve it, as we have proved the protective role of hKLK1 on erectile function in aged rats. We established a rat model of HHCy through dietary-rich methionine (Met) in male Sprague-Dawley (SD) rats. Male wild-type SD rats (WTR) and transgenic rats harboring the hKLK1 gene (TGR) were fed to 10 weeks of age. Then 24 WTRs were divided into control (n=8), the low-dose (4% Met, n=8), and the high-dose (7% Met, n=8). Another 8 age-matched TGRs with the high-dose formed the TGR+7%Met group. 30 days later, erectile function, level of total homocysteinaemia (tHcy), oxidative stress, endothelial function, cavernous nerve function and fibrosis of all groups were determined. hKLK1 in the TGR+7%Met group could greatly decrease the tHcy levels and improve ED induced by HHcy in rats. For the endothelial function, hKLK1 could preserve the endothelial cell-cell junction, enhance endothelial regeneration and activated the Akt/eNOS signaling pathway. Together with the promotion of hKLK1 on nNOS expression, the NO/cGMP signaling pathway activity was also increased. For the fibrosis, hKLK1 could preserve normal corpus cavernosum structure through inhibiting apoptosis and promoting autophagy on corpus cavernosum smooth muscle cells. In addition, hKLK1 also inhibited the fibrosis-related signaling pathway activity.

030 Light-controlled relaxation of rat penile corpus cavernosum by a novel NO donor, NO-Rosa

Phosphodiesterase-5 inhibitors are not always effective for patients with erectile dysfunction (ED) who also have diabetes mellitus or have had a radical prostatectomy, because of the reduction in nitric oxide (NO) production. The control of NO production may be useful as a therapy for ED. In this study, we focused on a light-controllable NO releaser. Previously, we developed a blue (470–500 nm) light-controllable NO releaser, NOBL-1. Subsequently, we improved NOBL-1, because blue light has low tissue permeability. We have now succeeded in the development of a yellow-green (530–590 nm) light-controllable NO releaser, NO-Rosa. We investigated whether we could control the relaxation of the corpus cavernosum smooth muscle by using an NO-Rosa derivative and light irradiation. Fluorescence imaging of the NO release from NO-Rosa in HEK-293 cells was performed using DAF-FM. Adult male Wistar-ST rats were used for the isometric tension study. The corpus cavernosum was treated by the addition of L-NAME (100 μM) to inhibit endogenous NO production and pre-contracted with noradrenaline (10 μM). The response of the corpus cavernosum smooth muscle to irradiation with yellow-green light, before and after the addition of an NO-Rosa derivative (10 μM), was measured and recorded.

Adipose-derived stem cells improve erectile function partially through the secretion of IGF-1, bFGF, and VEGF in aged rats.

Adipose-derived stem cells (ADSCs) have recently been considered as a promising therapy for erectile dysfunction (ED). However, the mechanism of ADSC-based therapy is unclear. Insulin-like growth factor-1 (IGF-1), basic fibroblast growth factor (bFGF), and vascular endothelial growth factor (VEGF) secreted by ADSCs were assessed invitro. Sixteen 24-month-old male Sprague-Dawley rats were used for comparative analysis of 2-week treatment with labeled ADSCs or PBS. Eight additional 5-month-old rats were used as a young rat group. At 2weeks post-transplantation, all rats were analyzed for erectile function, cavernous IGF-1, bFGF and VEGF levels, and penile histology. Conditioned medium and co-culture systems were used in cell experiments to detect how growth factors act on corpus cavernosum smooth muscle cells (CCSMCs) under oxidative stress conditions via crystal violet staining and immunofluorescence staining. We found that ADSCs secreted significantly higher IGF-1, bFGF, and VEGF levels in culture medium compared with basal medium. Compared with young rats, untreated aged rats had significantly lower Max ICP/MAP and ADSC treatment significantly increased the ratio. Immunofluorescence staining demonstrated a small number of labeled ADSCs in the corpus cavernosum. The untreated aged rats showed significantly decreased cavernous IGF-1, bFGF, and VEGF levels and significantly decreased contents of cavernous smooth muscle and endothelium compared with young rats. ADSC treatment partially normalized these alterations. In cell experiments, the groups receiving growth factor neutralizing antibody separately or combined had significantly decreased numbers of CCSMCs compared with control groups. These results indicated that ADSC treatment may improve aging-related ED partially through the secretion of IGF-1, bFGF, and VEGF.

Galanin Administration Partially Restores Erectile Function After Cavernous Nerve Injury and Mediates Endogenous Nitrergic Nerve Outgrowth In Vitro

BackgroundPreviously, we found that the neuropeptide galanin was strongly upregulated soon after bilateral cavernous nerve injury (BCNI) and that galanin and its receptors were expressed in nitrergic erectile innervation. Galanin has been observed to exert neuroregenerative effects in dorsal root ganglion neurons, but evidence for these effects in the major pelvic ganglion (MPG) after BCNI is lacking. AimTo evaluate the neurotropic effects of galanin receptor agonists and antagonists in vitro in nitrergic neurons and MPG and in vivo in rats after BCNI. MethodsMale Sprague-Dawley rats underwent BCNI and sham surgery. Organ culture and single-cell neuron culture of the MPG were performed. Osmotic pump treatment with the galanin agonist in vivo and measurement of erectile response to electrostimulation after BCNI, immunohistochemical localization of galanin and receptors in the human neurovascular bundle, and myographic analysis of rat corpus cavernosum smooth muscle relaxation to galanin receptor agonists were investigated. OutcomesNeurite outgrowth in vitro and erectile response to electrostimulation after BCNI in vivo, immunohistochemical localization of galanin and receptors, and penile muscle relaxation in vitro. ResultsGalanin showed neurotrophic action in vitro and inhibition of endogenous galanin significantly impaired neurite outgrowth in nitrergic but not in sympathetic MPG neurons. In vivo administration of a selective galanin receptor-2 agonist, M1145, resulted in partial recovery of erectile function (EF) after BCNI. Galanin did not act as a direct vasodilator on corpus cavernosum muscle strips. Clinical TranslationEndogenous neurotrophins such as galanin could be used as a strategy to improve EF for patients after BCNI from radical prostatectomy. Strengths and LimitationsWe evaluated the effect of galanin on nerve regeneration and EF recovery in vivo and in vitro. Limitations include the lack of washout period for the in vivo experiment and absence of differences in the expression of neuronal markers between treatment groups. ConclusionsWe identified galanin as a potential endogenous mechanism for nerve regeneration after BCNI, which could play a physiologic role in EF recovery after radical prostatectomy. In vivo treatment with exogenous galanin was beneficial in enhancing EF recovery after BCNI, but further research is necessary to understand the underlying mechanisms.Weyne E, Hannan JL, Gevaert T, et al. Galanin Administration Partially Restores Erectile Function After Cavernous Nerve Injury and Mediates Endogenous Nitrergic Nerve Outgrowth In Vitro. J Sex Med 2018;15:480–491.

Effects of Schisandra chinensis fruit extract and gomisin A on the contractility of penile corpus cavernosum smooth muscle: a potential mechanism through the nitric oxide - cyclic guanosine monophosphate pathway.

BACKGROUND/OBJECTIVESThis study evaluated the effects and molecular mechanisms of the Schisandra chinensis fruit extract (SC) and its major compound gomisin A (GA), on the contractility of rabbit penile corpus cavernosum smooth muscle (PCCSM).MATERIALS/METHODSPCCSM was exposed to SC or GA after appropriate pretreatment with nitric oxide synthase (NOS) blocker, guanylate cyclase blocker, adenylyl cyclase blocker or protein kinase A blocker. Subsequently, we evaluated the cyclic nucleotide in the perfusate by radioimmunoassay, protein expression level of neuronal NOS (nNOS) and endothelial NOS (eNOS) by western blot, and the interaction of SC or GA with udenafil and rolipram.RESULTSBoth SC and GA induce PCCSM relaxations in a concentration-dependent manner. Pretreatment with NOS blocker, guanylate cyclase blocker, adenylyl cyclase blocker or protein kinase A blocker result in significantly decreased relaxation. SC and GA also induce the levels of cyclic nucleotide in the perfusate in a concentration-dependent manner. Perfusion with GA also showed significantly higher levels of eNOS protein. Furthermore, the udenafil and rolipram induced relaxations of PCCSM were enhanced after exposure to SC and GA. Our results indicate that SC and GA induce the relaxation of PCCSM via the nitric oxide (NO)-cGMP and cAMP signaling pathways.CONCLUSIONSThe SC and GA are potential alternative treatments for men who want to consume natural products to ameliorate erectile function, or who do not respond to the commercially available medicines.

A Study of the Correlation between Angiotensin (1-7) and the Histopathological Changes in the Penises of Experimentally Diabetic Rats

Background: Diabetes mellitus is an important risk factor for erectile dysfunction. Renin-angiotensin system with its branches Angiotensin II and Angiotensin 1-7 [Ang-(1-7)] are altered in diabetes and could affect erection. So, in this study we determine the level of Ang-(1-7), nitrite (the major nitric oxide metabolite) and histopathological changes in penile tissues of type I diabetic rats. A total of 60 male albino rats were divided into two groups: group I (control) and group II (diabetic) for either 4 weeks in group IIa, or 8 weeks in group IIb. Diabetes was induced by intraperitoneal injection of streptozotocin (60 mg/kg). Penile levels of Ang-(1-7), nitrite and histopathological examination were assessed at 4 and 8 weeks after diabetes induction. Results: Ang-(1-7) and nitrite were decreased in diabetic rats at 4 weeks and continued to be lower at 8 weeks for Ang-(1-7) only. Loss of corpus cavernosum smooth muscle was present in 25% and 85% of rats at 4 and 8 weeks of diabetes respectively (P < 0.001). The loss of smooth muscle was replaced by dense fibrous tissue and was correlated positively with the reduced Ang-(1-7). Conclusion: Diabetes induced progressive decrease in the release of Ang-(1-7) and nitric oxide from the corpora cavernosa in a time-dependent manner with concomitant fibro-muscular changes that end by corporal fibrosis affecting subsequently erectile functions.

Structural-Activity Relationship of Ginsenosides from Steamed Ginseng in the Treatment of Erectile Dysfunction.

Ginseng has been reported to have diverse pharmacological effects. One of the therapeutic claims for ginseng is to enhance sexual function. Ginsenosides are considered as the major active constituents. A steaming process can alter the ginsenoside profile of ginseng products. The structure-function relationship of ginsenosides in the treatment of erectile dysfunction (ED) has not been investigated yet. In this work, 15 different processed ginsengs are produced by steaming, and 13 major ginsensosides are quantified by liquid chromatography with UV detection, including Rg1, Re, Rf, Rb1, Rc, Rb2, Rf, Rk3, Rh4, 20S-Rg3, 20R-Rg3, Rk1, and Rg5. Their anti-ED activities are screened using hydrocortisone-induced mice model (Kidney Yang Deficiency Syndrome in Chinese Medicine) and primary corpus cavernosum smooth muscle cells (CCSMCs). A processed ginseng with steaming treatment at 120[Formula: see text]C for 4[Formula: see text]h and five times possesses abundant ginsenosides Rk1, Rk3, Rh4 and Rg5 transformed via deglycosylation and dehydroxylation, and produces optimal activity against ED. The number of sugar molecules, structure of hydroxyl groups and stereoselectivity in ginsenosides affect their anti-ED activity. Among the 13 ginsenosides, Rk1, Rk3, Rh4 and Rg5 are the most efficient in decreasing intracellular calcium levels by inhibiting phosphodiesterase 5A (PDE5A) to reduce the degradation of cyclic guanosine monophosphate (cGMP) in CCSMCs. Rg5 also restrain hypoxia inducible factor-1[Formula: see text] (HIF-1[Formula: see text] expression in hypoxia state, and increase endothelial nitric oxide synthase (eNOS) expression in isolated rat cavernous tissue. These observations suggest a role for steamed ginseng containing two pairs of geometric isomers (i.e., Rk1/Rg5 and Rk3/Rh4) in the treatment of ED.

Effect of lysyl oxidase (LOX) on corpus cavernous fibrosis caused by ischaemic priapism.

Penile fibrosis caused by ischemic priapism (IP) adversely affects patients’ erectile function. We explored the role of lysyl oxidase (LOX) in rat and human penes after ischemic priapism (IP) to verify the effects of anti‐LOX in relieving penile fibrosis and preventing erectile dysfunction caused by IP in rats. Seventy‐two rats were randomly divided into six groups: control group, control + β‐aminopropionitrile (BAPN) group, 9 hrs group, 9 hrs + BAPN group, 24 hrs group, and 24 hrs + BAPN group. β‐aminopropionitrile (BAPN), a specific inhibitor of LOX, was administered in the drinking water. At 1 week and 4 weeks, half of the rats in each group were randomly selected for the experiment. Compared to the control group, the erectile function of IP rats was significantly decreased while the expression of LOX in the corpus cavernosum was significantly up‐regulated in both 9 and 24 hrs group. Proliferated fibroblasts, decreased corpus cavernosum smooth muscle cells/collagen ratios, destroyed endothelial continuity, deposited abnormal collagen and disorganized fibers were observed in IP rats. The relative content of collage I and III was not obviously different among the groups. β‐aminopropionitrile (BAPN) could effectively improve the structure and erectile function of the penis, and enhance recovery. The data in this study suggests that LOX may play an important role in the fibrosis of corpus cavernosum after IP and anti‐LOX may be a novel target for patients suffering with IP.

In vitro and in vivo aphrodisiac properties of the seed extract from Allium tuberosum on corpus cavernosum smooth muscle relaxation and sexual behavior parameters in male Wistar rats

BackgroundAllium tuberosum is a well-known spice as well as a herb in traditional Chinese medicine, used for increasing libido and treating erectile dysfunction. However, not many studies have been done to evaluate the sexual enhancing properties of A. tuberosum. The aim of this study was to evaluate the aphrodisiac and vasorelaxant properties of A. tuberosum on corpus cavernosum smooth muscle (CCSM) as well as checking the effect on enhancing male rat sexual behavior, libido, potency as well as its spermatogenic properties.MethodThe seeds were powdered and sequentially extracted with hexane, ethyl acetate and butanol. Male Wistar rats were administered with graded doses of the n-BuOH extracts (ATB) of A. tuberosum (50, 100, 200 and 400 mg/kg) and Viagra was used as the positive control drug. The extract/drug was administered by gastric probe once daily for 45 days and the sexual behavior was analyzed by exposing the male rats to female rats in the estrus period.ResultsATB relaxed corpus cavernosum smooth muscle (68.9%) at a concentration of 200 μg/ml. The results obtained from the animal studies indicated that ATB significantly increased mount frequency (MF), intromission frequency (IF), ejaculation frequency (EF), ejaculation latency (EL) and markedly reduced post ejaculatory interval (PEI), mount latency (ML), and intromission latency (IL). Furthermore, a remarkable increase in the test for potency was observed as witnessed by marked increase in erections, quick flips, long flips and total reflex. In addition, ATB significantly improved the sperm viability and count as well as increased the concentrations of testosterone, follicle stimulating hormone (FSH), and phosphatases in the treated animals.ConclusionThus our results suggest that A. tuberosum could stimulate sexual arousal and enhance sexual execution in male rats, thus providing valuable experimental evidence that A. tuberosum possesses sexual enhancing properties.

PDGF-mediated PI3K/AKT/β-catenin signaling regulates gap junctions in corpus cavernosum smooth muscle cells

Erectile dysfunction (ED) is the most common sexual disorder that men report to healthcare providers. Gap junctions (GJs) are thought to be responsible for synchronous shrinkage of corpus cavernosum smooth muscle cells (CCSMCs), and play thus an important role in the maintenance of an erection. Hypoxia has been suggested as a pathological mechanism underlying ED. Here we demonstrate that hypoxia increased the expression of platelet-derived growth factor (PDGF) and the main GJ component connexin (Cx)43 in CCSMCs. Inhibiting PDGF receptor (PDGFR) activity decreased Cx43 expression. Treatment with different concentrations of PDGF increased the levels of phosphorylated protein kinase B (AKT), β-catenin, and Cx43, whereas inhibition of PDGFR or activation of phosphatidylinositol 3 kinase (PI3K)/AKT signaling altered β-catenin and Cx43 expression. Meanwhile, silencing β-catenin resulted in the downregulation of Cx43. These results demonstrate that PDGF secretion by CCSMCs and vascular endothelial cells is enhanced under hypoxic conditions, leading to increased Cx43 expression through PI3K/AKT/β-catenin signaling and ultimately affecting GJ function in ED. Thus, targeting this pathway is a potential therapeutic strategy for the treatment of ED.

Stimulators and activators of soluble guanylate cyclase for urogenital disorders.

Lower urinary tract symptoms (LUTS), comprising storage (such as urinary incontinence and urinary frequency), voiding, and postmicturition symptoms, are highly prevalent conditions that affect millions of people worldwide. LUTS have a profound effect on quality of life and are a considerable cost to health care systems. In men specifically, BPH commonly leads to LUTS. Clinical studies also show an association of LUTS with erectile dysfunction (ED). Nitric oxide (NO) has long been recognized as an important nonadrenergic, noncholinergic (NANC) transmitter in bladder, urethra, prostate, and corpus cavernosum smooth muscle. Data from clinical and basic research show that oxidation and degradation of soluble guanylate cyclase (sGC; also known as GCS) and reduced cyclic GMP (cGMP) levels are involved in the physiopathology of genitourinary diseases. The NO-sGC-cGMP signalling pathway has a role in disease pathophysiology of the bladder, urethra, prostate, and corpus cavernosum in animal models and humans. Advances in targeting sGC directly to enhance cGMP production independently of endogenous NO have been made using NO-independent stimulators and activators of sGC. These molecules are potential therapeutics in the treatment of LUTS and ED.

Activation of the NGF/TrkA signaling pathway attenuates diabetic erectile dysfunction.

Erectile dysfunction (ED) is a common complication of diabetes mellitus (DM). The exact role of the NGF/TrkA signaling pathway in the pathogenesis of diabetic ED is largely unknown. In the present study, we investigated the role of the NGF/TrkA signaling pathway in Sprague-Dawley rats with diabetic ED. Animals were divided into 2 groups: the normal group and the DM ED model group. The model group included the blank subgroup, the negative control (NC) subgroup, the TrkA subgroup and the TrkA + NGF subgroup. Erectile function, intracavernous pressure (ICP) and mean arterial pressure were measured respectively. Immunohistochemistry was used to examine the number of neuronal nitric oxide synthase (nNOS) expressing nerve fibers. The quantitative real-time polymerase chain reaction was applied to detect the mRNA expressions of NGF and TrkA in the cavernous tissue. Further, Western blotting was conducted to detect the expressions of NGF, TrkA and its downstream ERK pathway-related proteins. Higher erectile frequency, ICP values and diastolic function, more nNOS-positive nerve fibers, and decreased systolic function of the corpus cavernosum smooth muscle were found in the TrkA and TrkA+NGF groups when compared with the blank and the NC groups. Moreover, significantly higher mRNA expressions of NGF and TrkA, and upregulated protein expressions of NGF, TrkA, c-raf, ERK1/2 and CREB1 were found in the TrkA and the TrkA + NGF groups. In conclusion, downregulation in the NGF/TrkA signaling pathway may contribute to the pathogenesis of diabetic ED.

Relaxant Effect of Rhynchophylline from the Hooks and Stems of Uncaria sinensis on Penile Corpus Cavernosum Smooth Muscle in a rabbit

The relaxant effect of ethanol extract and its active indole alkaloid, rhynchophylline, from the hooks and stems of Uncaria sinensis was evaluated on...

The role of Ca2+-activated Cl- current in tone generation in the rabbit corpus cavernosum.

Rabbit corpus cavernosum smooth muscle (RCCSM) cells express ion channels that produce Ca2+-activated Cl- (IClCa) current, but low sensitivity to conventional antagonists has made its role in tone generation difficult to evaluate. We have reexamined this question using two new generation IClCa blockers, T16Ainh-A01 and CaCCinh-A01. Isolated RCCSM cells were studied using the perforated patch method. Current-voltage protocols revealed that both L-type Ca2+ current and IClCa T16Ainh-A01 and CaCCinh-A01 (10 μM) reduced IClCa by ~85%, while 30 μM abolished it. L-type Ca2+ current was unaffected by 10 μM CaCCinh-A01 but was reduced by 50% at 30 μM CaCCinh-A01, 46% at 10 μM T16Ainh-A01, and 78% at 30 μM T16Ainh-A01. Both drugs reduced spontaneous isometric tension in RCCSM strips, by 60-70% at 10 μM and >90% at 30 μM. Phenylephrine (PE)-enhanced tension was also reduced (ED50 = 3 μM, CaCCinh-A01; 14 μM, T16Ainh-A01). CaCCinh-A01 at 10 μM had little effect on 60 mM KCl contractures, though they were reduced by 30 μM CaCCinh-A01 and T16Ainh-A01 (10 μM and 30 μM) consistent with their effects on L-type Ca2+ current. Both drugs also reversed the stimulatory effect of PE on intracellular Ca2+ waves, studied with laser scanning confocal microscopy in isolated RCCSM cells. In conclusion, although both drugs were effective blockers of IClCa, the effect of T16Ainh-A01 on L-type Ca2+ current precludes its use for evaluating the role of IClCa in tone generation. However, 10 μM CaCCinh-A01 selectively blocked IClCa versus L-type Ca2+ current and reduced spontaneous and PE-induced tone, suggesting that IClCa is important in maintaining penile detumescence.

The effects of miRNA-145 on the phenotypic modulation of rat corpus cavernosum smooth muscle cells.

To investigate the effect of miR-145 on the phenotypic modulation in rat corpus cavernosum smooth muscle cells. Corpus cavernosum smooth muscle cells were treated with either miR-145 mimics or miR-145 negative control. Cell proliferation were analyzed by the MTS assay and colony formation assay. Wound healing assay were performed to detect the effect of miR-145 on cell migration. The mRNA and protein levels of phenotype marker proteins were assessed by quantitative real-time polymerase chain reaction and western blotting. The intracavernosal pressure and mean arterial pressure were measured to assess erectile function at one month after the injection of platelet-derived growth factor-BB and miR-145. Our results showed that miR-145 inhibited the proliferation and migration of cavernosal smooth muscle cells. Smooth muscle cell phenotypic markers were also affected by overexpression of miR-145, as indicated by the increase in α-smooth muscle actin, calponin and smooth muscle myosin heavy chain expression. Moreover, significantly attenuated erectile function was observed in the platelet-derived growth factor-BB group as compared with the platelet-derived growth factor-BB+miR-145 group. These findings indicated that miR-145 regulate phenotypic modulation of corpus cavernosum smooth muscle cells.

Short hairpin RNA silencing the expression of insulin-like growth factor binding protein 3 in corpus cavernosal smooth muscle cell in rat

Objective To screen the most effective short hairpin RNA (shRNA) which down-regulate the insulin-like growth factor binding protein 3 (IGFBP-3) in corpus cavernosal smooth muscle cell (CCSMC) in vitro. Methods 4 pair IGFBP-3 small interfering RNA (siRNA), and plasmid constructs for U6 promoter plasmid vector (pGPU6/GFP/Neo-IGFBP-3-shRNA) and negative control vector were constructed. Corpus cavernosal smooth muscle cells (CCSMC) were primary cultured and divided into 6 groups: the CCSMCs-only, transfection pGPU6/GFP/Neo-IGFBP-3 (611) group, transfection pGPU6/GFP/Neo-IGFBP-3 (526) group, transfection pGPU6/GFP/Neo-IGFBP-3 (866) group, transfection pGPU6/GFP/Neo-IGFBP-3 (710) group and the negative control group (transfection with pGPU6/GFP/Neo-shNC). The silencing effection was determined by real-time quantitative polymerase chain reaction (Real-time PCR) and Western blotting. Results CCSMCs transfected with shRNA showed an obviously decrease of IGFBP-3 in mRNA and protein levels compared with CCSMCs transfected with negative control vector and the CCSMCs-only in transfection pGPU6/GFP/Neo-IGFBP-3 (611) group, pGPU6/GFP/Neo-IGFBP-3 (526) group and pGPU6/GFP/Neo-IGFBP-3 (866) group. The most inhibiting effective were observed in trasnfection pGPU6/GFP/Neo-shIGFBP3-526 group. The 72% and 79% inhibiting effection were determined in real-time PCR and Western blotting. Conclusion shRNA can obviously silence the expression of IGFBP-3 in CCSMCs. It may be an effective methods to improved erection in vivo. Key words: Erectile dysfunction; Insulin-like growth factor binding protein 3; Gene Therapy; siRNA Technology; Rats