Penile Cavernous Tissue Research Articles

Effect of chronic periodontitis on the endothelial glycocalyx of rat penile corpus cavernosum.

Chronic periodontitis may induce erectile dysfunction (ED), however, the specific mechanism involved is unclear. The endothelial glycocalyx (eGlx) is a structure that can regulate endothelial nitric oxide synthase (eNOS) phosphorylation on the cavity surface of vessels. To investigate whether chronic periodontitis leads to ED by affecting the eGlx. Twenty-four 4-week-old male Sprague‒Dawley rats were randomly divided into four groups (n=6): the control group, chronic periodontitis group, chronic periodontitis + heparin group (subcutaneous heparin 200 U/kg/day, 7 days), and control + heparin group. Four weeks after the induction of periodontitis in the rats, the maximum intra-cavernous pressure/mean arterial pressure (ICPmax/MAP), serum C-reactive protein (CRP), tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), nitric oxide (NO), heparin sulfate (HS), syndecan-1 (SDC-1), heparanase (HPSE), eNOS, and phosphor-eNOS (p-eNOS) concentration were measured, and the eGlx of the penile corpus cavernosum was observed by transmission electron microscopy (TEM). Chronic periodontitis can degrade eGlx on the rat penile corpus cavernosum by increasing serum CRP, TNF-α, and IL-6 levels, reducing the p-eNOS/eNOS ratio and the NO concentration in the penile corpus cavernosum, and resulting in the inhibition of the erectile function. Serum CRP, TNF-α, and IL-6 levels and HPSE expression in penile cavernous tissue were significantly greater in the chronic periodontitis group than in the control group and the chronic periodontitis + heparin group (P<0.05). The average thickness of the eGlx muscle in the penile corpus cavernosum in the chronic periodontitis group was significantly lower than those in the control group and chronic periodontitis + heparin group (P<0.05). The HS concentration, SDC-1 expression, p-eNOS/eNOS, NO concentration, and ICPmax/MAP in the chronic periodontitis group were significantly lower than those in the control group and chronic periodontitis+ heparin group (P<0.01). The eGlx on penile cavernosum vessels may be a new therapeutic target for the treatment of ED. This study revealed that chronic periodontitis promotes the decomposition of vascular eGlx in the rat penile corpus cavernosum, however, it is not clear whether chronic periodontitis inhibits the synthesis of eGlx. Chronic periodontitis can degrade eGlx on the rat penile corpus cavernosum by increasing serum CRP, TNF-α, and IL-6 levels, reducing the p-eNOS/eNOS ratio and the NO concentration in penile cavernous tissue, and resulting in the inhibition of the erectile function. Heparin inhibited eGlx decomposition and improved erectile function in rats with chronic periodontitis.

Nesfatin-1 regulates the phenotype transition of cavernous smooth muscle cells by activating PI3K/AKT/mTOR signaling pathway to improve diabetic erectile dysfunction.

This study aims to explore the impact of Nesfatin-1 on type 2 diabetic erectile dysfunction (T2DMED) and its underlying mechanism in regulating the phenotypic switching of corpus cavernosum smooth muscle cells (CCSMCs). Twenty-four 4-week-old male C57 wild-type mice were randomly assigned to the control group, model group, and Nesfatin-1 treatment group. Monitoring included body weight, blood glucose levels, and penile cavernous pressure (ICP). Histochemistry and Western blot analyses were conducted to assess the expressions of α-SMA, OPN, and factors related to the PI3K/AKT/mTOR signaling pathway. CCSMCs were categorized into the control group, high glucose and high oleic acid group (GO group), Nesfatin-1 treatment group (GO+N group), sildenafil positive control group (GO+S group), and PI3K inhibitor group (GO+N+E group). Changes in phenotypic markers, cell morphology, and the PI3K/AKT/mTOR signaling pathway were observed in each group. (1) Nesfatin-1 significantly ameliorated the body size, body weight, blood glucose, glucose tolerance, and insulin resistance in T2DMED mice. (2) Following Nesfatin-1 treatment, the ICP/MSBP ratio and the peak of the ICP curve demonstrated a significant increase. (3) Nesfatin-1 significantly enhanced smooth muscle and reduced collagen fibers in the corpus cavernosum. (4) Nesfatin-1 notably increased α-SMA expression and decreased OPN expression in CCSMCs. (5) Nesfatin-1 elevated PI3K, p-AKT/AKT, and p-mTOR/mTOR levels in penile cavernous tissue. Nesfatin-1 not only effectively improves body weight and blood glucose levels in diabetic mice but also enhances erectile function and regulates the phenotypic switching of corpus cavernosum smooth muscle. The potential mechanism involves Nesfatin-1 activating the PI3K/AKT/mTOR signaling pathway to induce the conversion of CCSMCs to a contractile phenotype.

Mode of cell death in the penile cavernous tissue of type 1 diabetes mellitus rats.

Diabetes mellitus commonly causes endothelial cell and smooth muscle cell death in penile cavernous tissue. The study sought to study the mode of cell death in the penile cavernous tissue in type 1 diabetic rats. A total of 36 Sprague Dawley rats 10 weeks of age were randomly divided into 2 groups: a normoglycemic group and type 1 diabetic group (intraperitoneal injection of Streptozotocin (STZ), 60mg/kg). We randomly selected 6 rats from each group for tests at the end of 11, 14, and 18weeks of age, respectively. All rats were able to eat and drink freely. The ratio of maximum intracavernous pressure to mean arterial pressure, concentration of serum testosterone, level of nitric oxide in the penile cavernosum, and expression of active caspase-1 (pyroptosis) and active caspase-3 (apoptosis) were determined. At the end of weeks 4 and 8 of type 1 diabetes, the proportions of endothelial cells and smooth muscle cells undergoing apoptosis and pyroptosis in penile cavernous tissue are different. The ratio of maximum intracavernous pressure to mean arterial pressure and nitric oxide levels were significantly lower in the 4- and 8-week diabetic groups than in the normoglycemic group (P < .01). Penile endothelial cell pyroptosis (5.67 ± 0.81%), smooth muscle cell apoptosis (23.72 ± 0.48%), total cell pyroptosis (9.67 ± 0.73%), and total apoptosis (10.52 ± 1.45%) were significantly greater in the 4-week diabetic group than in the normoglycemic group (P < .01). The proportion of endothelial cell pyroptosis (24.4 ± 3.69%), endothelial cell apoptosis (22.13 ± 2.43%), total cell pyroptosis (14.75 ± 0.93%), and total apoptosis (14.82 ± 1.08%) in the penile tissues of the 8-week diabetic group were significantly greater than those in the normoglycemic group (P < .01).The 8-week survival proportions of diabetic endothelial cells (38.86 ± 8.85%) and smooth muscle cells (44.46 ± 2.94%) was significantly lower than the 4-week survival proportions of endothelial cells (93.17 ± 8.07%) and smooth muscle cells (75.12 ± 4.76%) (P < .05). Inhibition of cell death by different methods at different stages may be the key to the treatment of type 1 diabetes-induced erectile dysfunction. The effect of type 1 diabetes on other types of cell death in penile cavernous tissue needs further study. The mode of death of endothelial cells in the cavernous tissue of the penis in the early stage in diabetic rats is dominated by pyroptosis, and the death of smooth muscle cells is dominated by apoptosis. Endothelial cell and smooth muscle cell death are not consistent at different stages of diabetes progression.

Nesfatin-1 regulates the phenotype transition of cavernous smooth muscle cells by activating PI3K/AKT/mTOR signaling pathway to improve diabetic erectile dysfunction

ObjectiveThis study aims to explore the impact of Nesfatin-1 on type 2 diabetic erectile dysfunction (T2DMED) and its underlying mechanism in regulating the phenotypic switching of corpus cavernosum smooth muscle cells (CCSMCs). MethodsTwenty-four 4-week-old male C57 wild-type mice were randomly assigned to the control group, model group, and Nesfatin-1 treatment group. Monitoring included body weight, blood glucose levels, and penile cavernous pressure (ICP). Histochemistry and Western blot analyses were conducted to assess the expressions of α-SMA, OPN, and factors related to the PI3K/AKT/mTOR signaling pathway. CCSMCs were categorized into the control group, high glucose and high oleic acid group (GO group), Nesfatin-1 treatment group (GO + N group), sildenafil positive control group (GO + S group), and PI3K inhibitor group (GO + N + E group). Changes in phenotypic markers, cell morphology, and the PI3K/AKT/mTOR signaling pathway were observed in each group. Results(1) Nesfatin-1 significantly ameliorated the body size, body weight, blood glucose, glucose tolerance, and insulin resistance in T2DMED mice. (2) Following Nesfatin-1 treatment, the ICP/MSBP ratio and the peak of the ICP curve demonstrated a significant increase. (3) Nesfatin-1 significantly enhanced smooth muscle and reduced collagen fibers in the corpus cavernosum. (4) Nesfatin-1 notably increased α-SMA expression and decreased OPN expression in CCSMCs. (5) Nesfatin-1 elevated PI3K, p-AKT/AKT, and p-mTOR/mTOR levels in penile cavernous tissue. ConclusionsNesfatin-1 not only effectively improves body weight and blood glucose levels in diabetic mice but also enhances erectile function and regulates the phenotypic switching of corpus cavernosum smooth muscle. The potential mechanism involves Nesfatin-1 activating the PI3K/AKT/mTOR signaling pathway to induce the conversion of CCSMCs to a contractile phenotype.

A low androgenic state inhibits erectile function by suppressing endothelial glycosides in the penile cavernous tissue of rats.

The endothelial glycocalyx is an important barrier that protects the structure and function of endothelial cells. Androgen deficiency is a common factor that causes structural and functional impairment of endothelial cells. To investigate changes in the endothelial glycocalyx in the penile corpus cavernosum of the rat with low androgen status and its relationship with erection function. Eighteen 10-week-old Sprague-Dawley male rats were randomly divided into 3 groups (n = 6 each): sham operation, castration, and castration + testosterone replacement. The maximum intracavernosal pressure/mean arterial pressure of the penis was measured after modeling for 4weeks. The expression levels of endothelial nitric oxide synthase (eNOS), phospho-eNOS, syndecan 1, heparanase, and nitric oxide in penile cavernous tissue and the serum levels of heparan sulfate, hyaluronic acid, tumor necrosis factor α, and interleukin 6 were determined. Transmission electron microscopy was used to observe the ultrastructure of the endothelial glycocalyx in penile tissue. The thickness of the endothelial glycocalyx in the penile corpus cavernosum of castrated rats was significantly lower than that of the control group. In the castrated rats, the endothelial glycocalyx thickness, syndecan 1 level, ratio of phospho-eNOS to eNOS, nitric oxide level, and maximum intracavernosal pressure/mean arterial pressure (3V, 5V) were significantly lower than those in the sham group (P < .05). The expression of heparanase and the serum levels of tumor necrosis factor α and interleukin 6 were significantly higher in the castrated group than in the sham group (P < .05). Upregulating the expression of the endothelial glycocalyx in the penile corpus cavernosum may be a new method for treating erectile dysfunction caused by low androgen levels. This study confirms that low androgen status promotes the breakdown of the endothelial glycocalyx. However, further research is needed to determine whether androgens are related to the synthesis of the endothelial glycocalyx. Low androgen status may suppress the level of nitric oxide in the cavernous tissue of the penis via impairment of the endothelial glycocalyx, resulting in inhibited erection function in rats.

Uncovering the Penile Clock: Expression of Molecular Clock Proteins in Human Penile Cavernous Tissue.

To evaluate the expression of core molecular clock genes/proteins in penile cavernous tissue from healthy male subjects and to determine whether their expression has circadian variation. Corpus cavernosum biopsy samples were obtained from 10 healthy males with penile deviation or fracture who underwent surgical intervention during the day and night. The daytime group (n=5) underwent corpus cavernosum tissue sampling during zeitgeber time (ZT) 8-12, while the nighttime group (n=5) underwent sampling during ZT 20-24. The expression and localization of BMAL1, CLOCK, PER1, PER2, PER3, CRY1, and CRY2 proteins were analyzed using immunohistochemistry and quantified using H-score analysis. RT-qPCR analysis was performed to assess the expression of core molecular clock genes in the corpus cavernosum tissue of 5 additional daytime patients. The expression of core molecular clock proteins was detected in vascular endothelial cells (VECs) and smooth muscle cells (SMCs) in corpus cavernosum during daytime and nighttime. BMAL1 exhibited the most significant nuclear expression during daytime in both cell types, whereas its expression decreased significantly at night. In VECs, a significant decrease in the nuclear expression of CRY1 was observed at night. In SMCs, a significant decrease in the cytoplasmic expression of PER3 was observed at night. The expression patterns of the core molecular clock genes were ascertained through a RT-qPCR analysis. Our research provides compelling evidence that core molecular clock genes are distinctly expressed in penile tissue in humans. Furthermore, we observed the expression of molecular clock proteins within the VECs and SMCs of the corpus cavernosum, with BMAL1 being the most prominently expressed. The discovery of core molecular clock genes in penile tissue, as well as proteins within the SMCs and VECs of the corpus cavernosum, introduces the potential significance of the molecular clock mechanism in the physiology of penile erection.

Effect of hypoandrogenism on expression of transient receptor potential vanilloid channels in rat penile corpus cavernosum and erectile function.

Hypoandrogenism is a cause of erectile dysfunction (ED). Vascular smooth muscle cell contraction and relaxation are regulated by TRPV1-4 channels. However, the influence of hypoandrogenism on TRPV1-4 and its relationship with erectile function remain unclear. To reveal whether hypoandrogenism affects erectile function by influencing TRPV1-4 expression in the corpus cavernosum of rats. Male Sprague-Dawley rats (N = 36) aged 8 weeks were assigned to 6 groups at random (n = 6): sham operation, castrated, castrated + testosterone replacement, sham operation + transfection, castrated + transfection, and castrated + empty transfection. Four weeks after castration, 20μL of lentiviral vector (1 × 108 TU/mL) carrying the TRPV4 gene was injected into the penile cavernous tissue of the transfection groups. One week after transfection, the maximum intracavernous pressure (ICPmax)/mean arterial pressure (MAP) and the content of TRPV1-4, phosphorylated eNOS (p-eNOS)/eNOS, and nitric oxide (NO) in penile cavernous tissue of each group were measured. Under low androgen conditions, TRPV4 expression in endothelial cells in the rat penile cavernosum was sharply reduced, resulting in a decrease in p-eNOS/eNOS and NO content, which could inhibit erectile function. In rat penile cavernous tissue, TRPV1-4 was expressed in the cell membranes of endothelial cells and smooth muscle cells. The ICPmax/MAP and the content of TRPV4, p-eNOS/eNOS, and NO end product nitrite level in rat penile cavernous tissue was markedly reduced in the castrated group as compared with the sham group (P < .05). The ICPmax/MAP and the content of TRPV4, p-eNOS/eNOS, and NO end product nitrite level in rat penile cavernous tissue were markedly improved in the castrated + transfection group vs the castrated group (P < .01). Upregulation of TRPV4 expression in penile cavernosum tissue might be a viable therapeutic for ED caused by hypoandrogenism. The specific mechanism of TRPV4 in ED needs to be further verified by androgen receptor or TRPV4 gene knockout experiments. Hypoandrogenism may cause ED by reducing the expression of TRPV4 in rat penile cavernous tissue. Upregulation of TRPV4 expression in penile cavernous tissue can increase the ratio of p-eNOS/eNOS and NO levels and ameliorate the erectile function of castrated rats.

Downregulation of the expression of galanin impairs erectile function in hypoandrogenic rats

Abstract Background The relationship between galanin and erectile function under low androgen levels is still unclear. Aim To explore whether a low testosterone level damages the erection of a rat by regulating the expression of galanin and GalR in penile cavernous tissue. Methods Thirty-six male Sprague-Dawley rats, 8 weeks of age, were randomly grouped as follows (n = 6): control, castration, castration + testosterone replacement, control + transfection, castration + transfection, and castration + empty transfection. At 4 weeks after castration, rats in the transfection group were injected with lentivirus carrying the targeting galanin gene (2 × 108 TU/mL, 10 μL) in the corpus cavernosum. After 1 week of injection, the intracavernosal pressure (ICP), mean arterial blood pressure (MAP), nitric oxide (NO), serum testosterone concentration, galanin, GalR1-3, ROCK1, ROCK2, and p-eNOS/eNOS in the rat penile tissues were evaluated. Outcomes ICPmax/MAP and the expression of galanin in the corpus cavernosum in castrated rats were obviously decreased as compared with those in the control rats. Results The castrated rats showed remarkably lower ICPmax/MAP, galanin, GalR1-3, p-eNOS/eNOS, and NO content and markedly higher ROCK1 and ROCK2 in penile tissues than the control group (P &amp;lt; .05). The transfected rats administrated with LV Gal had obviously higher ICPmax/MAP, p-eNOS/eNOS, and NO content and less ROCK1 and ROCK2 protein expression in the corpus cavernosum when compared with the castration group (P &amp;lt; .05). Clinical Translation Upregulating the expression of galanin in the penile corpus cavernosum might be a novel method of treating erectile dysfunction caused by a low androgen level. Strengths and Limitations The conclusions obtained in the animal experiments need to be confirmed in human data. Conclusion The erectile function of hypoandrogen rats might be inhibited by downregulating the level of galanin and GalR1-3, upregulating ROCK1 and ROCK2 levels, and inhibiting the eNOS/NO signaling pathway in penile corpus cavernosum.

Methylation of eNOS in the rat penile corpus cavernosum under different pathological states and its relationship with erectile function.

It has been shown that methylation in the promoter region of eNOS can downregulate eNOS expression resulting in the endothelial dysfunction. However, it is unclear whether low androgen levels and type 1 diabetes cause ED by methylating the promoter region of eNOS in the penile corpus cavernosum. To clarify the effects of type 1 diabetes and hypo-androgen status on the methylation level of the promoter region of the eNOS gene in penile cavernous tissue and their relationship with the erectile function. Fifty-eight eight-week-old male Sprague-Dawley rats were randomly divided into six groups (n=6): sham operation group, castration group, castration+testosterone (cast+T) group, normoglycemia group, diabetic group, and diabetic+methyltransferase inhibitor (5-aza-dc, 1.5mg/kg) group. The ICPmax/MAP, serum T, the concentration of nitric oxide (NO), the expression of DNMT1, DNMT3a, DNMT3b, and eNOS, and the methylation level of the eNOS promoter region in penile corpus cavernosum of rat were examined 4weeks after surgery in the sham-operated group, the castration group, and the castration + testosterone replacement group. Those tests were examined after 6weeks using of methylation inhibitors in the normoglycemic group, the diabetic group, and the diabetic + methylation inhibitor group. ICPmax/MAP, DNMT1, DNMT3a, DNMT3b, eNOS, and NO levels were significantly lower in castrated rats than in sham and cast+T rats (P<0.05). ICPmax/MAP, eNOS, and NO levels were lower, and DNMT1, DNMT3a, and DNMT3b expression levels were significantly increased in the diabetic group compared with the normoglycemic and diabetic+methyltransferase inhibitor groups (P<0.05). There was no significant difference in the methylation level of the promoter region of eNOS in penile cavernous tissue of castrated rats compared with the sham group or the testosterone replacement group. The methylation level of the promoter region of eNOS in penile cavernous tissue was significantly higher in the diabetic group than in the normoglycemic group and diabetic+methyltransferase inhibitor group (P<0.05). Although low androgen status inhibited the level of methyltransferase in rat penile cavernous tissue, did not affect the level of methylation in the promoter region of eNOS. Hyperglycemia inhibits the NO level in the penile cavernous tissue and the erectile function of rats by upregulating the methyltransferase level in the penile cavernous tissue and the methylation level in the promoter region of eNOS. Methylation inhibitors can partly improve the erectile function in type 1 diabetic rats.

Low testosterone state inhibits erectile function by downregulating the expression of GIT1 in rat penile corpus cavernosum.

The mechanism of erectile dysfunction (ED) caused by a low androgen level is still not clear. To explore the influence of the low testosterone state on G protein-coupled receptor kinase interactor 1 (GIT1) and its contact to erectile function. Thirty male Sprague-Dawley rats aged 8 weeks were distributed at random into 5 groups: control (sham operated), castration, testosterone supplement after castration, castration + vacant lentiviral transfection, and castration + lentiviral transfection. The testis and epididymis were removed through a scrotal incision to develop castrated rats. Four weeks after castration, a lentivirus carrying the GIT1 gene was injected into the middle of rat penile corpus cavernosum. One week after transfection, maximum intracavernous pressure/mean arterial pressure (ICPmax/MAP), serum testosterone, nitric oxide, GIT1, endothelial nitric oxide synthase (eNOS), phospho-eNOS (p-eNOS), p-eNOS/eNOS, and the interaction between eNOS and GIT1 were assessed in the rats. The levels of GIT1 in the penile cavernous tissue of castrated rats are significantly lower than that of controls. GIT1 was expressed in the cytoplasm and cell membrane of vascular endothelial cells and smooth muscle cells in rat penile tissue. In comparison with normal rats, the castrated rats showed lower levels of GIT1 expression, GIT1 and eNOS interaction, p-eNOS/eNOS, nitric oxide, and ICPmax/MAP (P < .01). Overexpression of GIT1 can intensively enhance the expression level of GIT1, the interaction between GIT1 and eNOS, p-eNOS/eNOS, nitric oxide, and ICPmax/MAP in rats (P < .01). Modulating the interaction between eNOS and GIT1 might be a novel method of treating ED caused by a low androgen level. The impact of GIT1 phosphorylation on the activity of eNOS and its possible mechanisms affecting erectile function require further study. A low testosterone state inhibits erectile function in rats by reducing the expression of GIT1 and the protein interaction between GIT1 and eNOS.

Icariin inhibits the formation of mitochondria-associated membranes (MAMs) and improves erectile function in rats treated with prostate radiation.

Erectile function is usually impaired after radiation therapy in prostate cancer patients. eNOS is a key enzyme in the process of erection. Mitochondria-associated membranes (MAMs) are closely contacted with the production and bioactivity of eNOS. To study the mechanism of icariin improves the erectile function of rats treated with prostate radiation by controling the expression of MAMs in penile corpus cavernosum. Twenty 8-week-old healthy male SD rats were randomized to four groups: control group, radiation therapy (RT) group, icariin (10mg/kg/d gavage) group, and RT + icariin (10mg/kg/d gavage) group (n=5). In RT group and RT + icariin group, rats were irradiated with X-rays to the prostate region (total dose 37.5 gray; 7.5 gray/day for 5 days). The maximum intracavernous pressure/mean arterial pressure (ICPmax/MAP), NO concentration and the level of IP3 R1, PACS2, FACL4, nNOS, p-eNOS, and eNOS in rats' penile cavernous tissue was determined 9weeks after radiation therapy. Compared with the control group and the RT + icariin group, the ICPmax/MAP of the RT group was remarkably reduced (p<0.05). The levels of p-eNOS/eNOS, nNOS and the concentration of NO in the penile cavernous tissue of the penis in the RT group were remarkably decreased compared to the control group and the RT + icariin group (p<0.05). The levels of IP3 R1, PACS2, and FACL4 in penile cavernous tissue of the RT group were significantly higher than those in the control group and the RT + icariin group (p<0.05). After prostate X-ray radiotherapy in rats, the formation of MAMs may be increased by increased expression of IP3 R1, PACS2, and FACL4 in penile cavernous tissue, resulting in impaired erectile function. Icariin might increase p-eNOS/eNOS and improve erectile function in rats after prostate radiotherapy by inhibiting the expression of IP3 R1, PACS2, and FACL4.

Low androgen level impairs erectile function of rat by regulating the Ng/CaN/AKT/eNOS pathway in penile corpus cavernosum.

The mechanism by which low androgen status inhibit erectile function has not yet been clearly elucidated. Neurogranin (Ng) is a Ca2+ -sensitive calmodulin binding protein that is expressed in endothelial cells and regulates eNOS function. To investigate whether low androgen status inhibit erectile function by regulating the Ng/CaN/AKT/eNOS pathway in the penile cavernous tissue of rats. Thirty-six 8-week-old male Sprague-Dawley rats were randomly divided into six groups as follows (n=6): 4-week control group (4w-control), 4-week castration group (4w-cast), 4-week castration+testosterone replacement group (4w-cast+T), 8-week control group (8w-control), 8-week castration group (8w-cast), and 8-week castration+testosterone replacement group (8w-cast+T). Four weeks and eight weeks after surgery, the ratio of the maximum intracavernous pressure/mean arterial pressure (ICPmax/MAP) was examined. The level of NO and the expression of Ng, calcineurin (CaN), AKT, p-AKT(S473), eNOS, and p-eNOS(Ser1177) in the penile cavernous tissue of each group were determined. Ng and CaN were mainly expressed in the membrane and cytoplasm of endothelial cells and smooth muscle cells in the penile cavernous tissue of rats. The ICPmax/MAP and the concentration of NO in the cast group were significantly lower than those in the control group and cast+T replacement group (p<0.01). The expression of Ng and the ratios of p-AKT/AKT and p-eNOS/eNOS in the penile cavernous tissue of rats in the cast group were significantly lower than those in the control group and cast+T replacement group (p<0.01). The expression of CaN in the penile cavernous tissue of rats in the cast group was significantly increased compared with that in the control group and the cast+T replacement group (p<0.01). Inhibiting the expression of Ng and subsequently upregulating the expression of CaN in the rat penile cavernous tissue was one of the upstream mechanisms of low androgen status inhibiting erectile function by inhibiting the AKT/eNOS signaling pathway.

Effect of low androgen levels on transient receptor potential channels expression in rat penile corpus cavernosum tissue and its relationship with erectile function.

The exact mechanism by which testosterone deficiency causes ED has not yet been elucidated. TRPC is involved in the process of smooth muscle cell contraction and relaxation. The effect of androgens on TRPCs and their relationship with erectile function are currently unclear. Thirty male SD rats were randomly divided into six groups: control group, castration group, castration + testosterone (T) group (cast + T), control + transfection group (control + trans), control + empty transfection group and castration + transfection group (cast + trans). The transfection group rats were given with lentivirus (1 × 108 TU/mL, 15 μl) carrying the siRNA targeting TRPC4 gene in the rat penile cavernous tissue at 4 weeks after castration. The tests were performed at 5 weeks after castration. Comparing the cast group with the control, the ICPmax/MAP, p-eNOS/eNOS and NO levels in the rat penile tissue were significantly lower (p < 0.01) and the level of TRPC3, TRPC4 and TRPC6 in the rat penile tissue was significantly increased (p < 0.01). When the cast + trans group was compared to the cast group, ICPmax/MAP was markedly higher (p < 0.05), and the level of the TRPC4 was remarkably lower (p < 0.05). Low androgen levels might inhibit an erectile function through up-regulation of the expression of TRPC3, TRPC4 and TRPC6 in rat penile cavernous tissue. Inhibition the level of TRPC4 in rat penile tissue may improve the erectile function in low androgen levels.

Inhibition of MicroRNA-92a Improved Erectile Dysfunction in Streptozotocin-Induced Diabetic Rats via Suppressing Oxidative Stress and Endothelial Dysfunction.

To determine whether microRNA could be a therapy target of erectile dysfunction (ED) and the underlying mechanisms. Eight-week-old fasting male SD rats were intraperitoneally injected with streptozotocin to construct diabetic rat models. Diabetic ED rats were treated with miRNA-92a inhibitor. The cavernous nerves were electrically stimulated to measure the intracavernous pressure and mean arterial pressure of rats in each group. After the detection, the penile cavernous tissues are properly stored for subsequent experiments. Rat aortic endothelial cells were used in in vitro studies. The expression of miR-92a was significantly increased in the corpus cavernosum of Streptozocin (STZ)-induced diabetic rats and injection of miR-92a antagomir into the corpus cavernosum of diabetic rats significantly increased eNOS/NO/cGMP signaling pathway activities, cavernous endothelial cell proliferation, endothelial cell-cell junction protein expression and decreased the levels of oxidative stress. These changes restored erectile function in STZ-induced diabetic rats. Moreover, in vitro study demonstrated that the miR-92a expression increased significantly in endothelial cells treated with high glucose, inhibiting AMPK/eNOS and AMPK/Nrf2/HO-1 signaling pathways in rat aortic endothelial cells via targeting Prkaa2, causing endothelial dysfunction and overactive oxidative stress, miR-92a inhibitor can improve the above parameters. miRNA-92a inhibitor could exert an inhibition role on oxidative stress and endothelial dysfunction to improve diabetic ED effectively.

Mechanism of Huoxue Tongluo Decoction in treatment of erectile dysfunction caused by ischemic stroke based on network pharmacology

ObjectiveTo study the therapeutic effect of Huoxue Tongluo Decoction (HXTLD) on erectile dysfunction caused by ischemic stroke and identify the mechanisms involved. MethodsNetwork pharmacology was used to predict the key active ingredients and targets of HXTLD. Surgical methods were used to create a rat model of ischemic stroke. The rats were then given a suspension of HXTLD by ig administration. Erectile function was evaluated by Apomorphine (APO) induction. Real-time fluorescence quantitative reverse transcription-polymerase chain reaction (Real-time PCR) and Western blotting were used to detect the expression of related mRNAs and proteins in rat penile corpus cavernous tissue and brain tissue. Hematoxylin & Eosin (HE) staining was used to investigate structural changes in the penile cavernous tissue. ResultsNetwork pharmacology showed that tumor necrosis factor (TNF), nitric oxide synthase 3 (eNOS), and vascular endothelial growth factor (VEGF) were the key targets of HXTLD in the treatment of erectile dysfunction caused by ischemic stroke. Experimental studies showed that HXTLD improved erectile dysfunction caused by ischemic stroke. HE results showed that HXTLD improved the structure of the corpus cavernosa. HXTLD also inhibited the expression of TNF and VEGF proteins in penile tissue (P < 0.05) and enhanced the expression of eNOS protein in penile tissue (P < 0.05). ConclusionHXTLD improved the erectile function of rats with erectile dysfunction caused by ischemic stroke by regulating the mRNA and protein levels of TNF, eNOS and VEGF.

Mesenchymal stem cells-derived exosomal microRNA-21-5p downregulates PDCD4 and ameliorates erectile dysfunction in a rat model of diabetes mellitus.

Erectile dysfunction (ED) is a common comorbidity in males with diabetes mellitus (DM), whose pathogenesis might be induced by dysregulation of corpus cavernosum smooth muscle cells (CCSMCs). Gene Expression Omnibus repository-based analysis identified the differentially expressed PDCD4 in DM rats. PDCD4 has also been determined as a putative gene under the regulatory control of microRNA-21-5p (miR-21-5p). This study aimed to further determine the functional role of miR-21-5p in CCSMCs in a rat model of diabetes mellitus-induced erectile dysfunction (DMED). CCSMCs were isolated from penile cavernous tissue and cultured in high glucose (HG) medium. The expression of miR-21-5p and/or PDCD4 was altered in CCSMCs, as directly or indirectly measured by CCK-8 assay, flow cytometry, and TUNEL assays. Furthermore, exosomes were isolated from mesenchymal stem cells (MSCs) transfected with miR-21-5p mimic or miR-21-5p inhibitor and co-cultured with CCSMCs. DMED rats were injected with lentivirus carrying PDCD4/siRNA-PDCD4 plasmids, or exosomes from MSCs containing miR-21-5p-agomir to explore their roles in vivo. The experimental data validated that PDCD4 was upregulated in cavernous tissue of DMED rats. miR-21-5p targeted and inhibited PDCD4. miR-21-5p was enriched in MSC-exosomes. Moreover, PDCD4 downregulation, miR-21-5p elevation or MSC-derived exosomal miR-21-5p reduced apoptosis and enhanced proliferation of CCSMCs cultured in HG medium. PDCD4 silencing or miR-21-5p-containing MSC-exosomes improved erectile function and smooth muscle density in DMED rats. Collectively, our findings suggested that MSC-derived exosomal miR-21-5p suppressed PDCD4 expression and ED in rats with DM.

Icariin modulates eNOS activity via effect on post-translational protein-protein interactions to improve erectile function of spontaneously hypertensive rats.

Type 5 phosphodiesterase inhibitor (PDE5I) has become the first-line treatment for erectile dysfunction (ED). However, its effective rate for hypertension ED is only 60%-70%. How to improve the efficacy of ED treatment is the focus of current research. To explore whether icariin can improve the erectile function of spontaneously hypertensive rats (SHR) by affecting post-translational protein-protein interactions to regulate endothelial nitric oxide synthetase (eNOS) activity. Twelve-week-old healthy male SHR rats and Wistar-Kyoto rats (WKY) were randomly divided into four groups: SHR control group, SHR+icariin (10mg/kg·d gavage) treatment group, WKY control group, and WKY+icariin (10mg/kg·d gavage) treatment group (n=5). After 4weeks, the maximum penile intracavernous pressure/mean arterial pressure (ICPmax/MAP), the expression of heat-shock protein 90 (Hsp90), caveolin-1, calmodulin, p-eNOS, and eNOS in penile cavernous tissue and the content of nitric oxide (NO) and cGMP were measured. The interaction between eNOS and Hsp90, caveolin-1, and calmodulin were detected by immunoprecipitation. The ICPmax/MAP in the SHR+icariin treatment group (0.08±0.01, 0.23±0.07, 0.40±0.05) was significantly higher than the SHR group (0.03±0.01, 0.13±0.03, 0.21±0.02) under 3V and 5V electrical stimulations (P<.05). Compared with the SHR group, the expression of HSP90, calmodulin, P-eNOS, eNOS, and P-eNOS/eNOS in the penile cavernous tissue of rats in the WKY group and the SHR+icariin treatment group were significantly increased (P<.05), and the expression of caveolin-1 was significantly decreased (P<.05). The NO content (2.16±0.22μmol/g) and cGMP concentration (3.69±0.12pmol/mg) in the SHR+icariin treatment group were significantly higher than those in the SHR group (1.01±0.14μmol/g, 2.31±0.22pmol/mg) (P<.05). Compared with the SHR group, the interaction between eNOS and HSP90 in the cavernosa of the rats in the SHR+icariin treatment group was significantly increased (P<.05), the interaction between eNOS and caveolin-1 was significantly decreased (P<.01), and the interaction between eNOS and calmodulin did not significantly change. Up-regulating the expression of HSP90 and calmodulin and inhibiting caveolin-1 in SHR corpus cavernosum, promoting the interaction between eNOS and HSP90, inhibiting the interaction between eNOS and caveolin-1, increasing p-eNOS/eNOS, may be the mechanism of icariin that improves SHR erectile function.

Exogenous hydrogen sulfide improves erectile dysfunction by inhibiting apoptosis of corpus cavernosum smooth muscle cells in rats with cavernous nerve injury

To explore the effects of exogenous hydrogen sulfide (H2S) on apoptosis of corpus cavernosum smooth muscle cells (CCSMCs) and erectile dysfunction (ED) in rats with bilateral cavernous nerve injury (BCNI). Twentyfour male SD rats were randomly divided into 3 groups (n=8):sham operation group, bilateral cavernous nerve injury group (BCNI group) and H2S intervention group (BCNI+NaHS group). In BCNI and BCNI+NaHS groups, BCNI was induced by clamp injury of the bilateral cavernous nerves, and the rats were subjected to daily intraperitoneal injection of normal saline and 100 μmol/kg NaHS solution for 4 weeks, respectively. After the treatment, the intracavernous pressure (ICP) and mean arterial pressure (MAP), ) of the rats were measured. Western blotting was used to detect the expressions of cystathionine β synthetase (CBS), cystathionine γ lyase (CSE), α-SMA, collagen-I, caspase-3, Bax and Bcl-2 in the penile cavernous tissue, and the expressions of CBS and CSE were also detected immunohistochemically. The ratio of cavernous smooth muscle to collagen was detected using Masson's Trichrome staining. The apoptosis level of CCSMC was detected by TUNEL + α-SMA immunofluorescence double staining. After 4 weeks of treatment, the rats in BCNI+NaHS group showed a significantly higher ICP/MAP ratio than those in BCNI group (P < 0.05). The results of Masson's Trichrome staining showed that the ratio of cavernous smooth muscle/collagen was significantly higher in BCNI + NaHS group than in BCNI group (P < 0.05). Western blotting showed a significantly higher expression of α-SMA protein but a lower expression of collagen-I protein in BCNI + NaHS group than in BCNI group (P < 0.05). TUNEL+α-SMA immunofluorescence double staining revealed a significantly lower number of apoptotic CCSMCs in BCNI+NaHS group than in BCNI group (P < 0.05). Compared with those in BCNI group, the rats in BCNI+NaHS group had significantly decreased expressions of caspase-3 and Bax proteins (P < 0.05) with significantly enhanced Bcl-2 protein expression and an increased Bcl-2/Bax ratio (P < 0.05). The expressions of CBS and CSE were significantly lower in BCNI group than in the other two groups (P < 0.05). Exogenous H2S enhance the expression of the classic apoptotic protein Bcl-2 and reduces apoptosis of CCSMC to improve the erectile function in rats with BCNI.

Novel noninvasive quantification of penile corpus cavernosum lesions in hyperlipidemia-induced erectile dysfunction in rabbits by two-dimensional shear-wave elastography.

Structural alterations in fibroelastic components of the penile corpus cavernousum (CC) may impair its compliance, resulting in venous leakage and erectile dysfunction (ED). Our study evaluated the effectiveness of noninvasive two-dimensional shear-wave elastography (2-D SWE) in quantifying penile CC lesions in rabbits with hyperlipidemia-induced ED. A total of 12 New Zealand white rabbits were randomly divided into two groups. Six were fed a high-cholesterol diet containing 2% cholesterol and 8.5% lard for 10 weeks and the other six were fed normal diet as controls. We measured the shear-wave elastic quantitative (SWQ) value of penile CC by 2-D SWE. Erectile function was investigated by intracavernous injection of papaverine, and immunohistochemical (IHC) staining and the western blot analysis to determine the penile CC lesions. After 10 weeks, the SWQ values obtained from penile CC were remarkably higher in the high-cholesterol-fed compared with the control group, and the ΔICP (ICP plateau minus ICP baseline)/MAP (ICP: intracavernous pressure, MAP: mean arterial pressure) was markedly decreased. The IHC staining and western blot revealed extracellular matrix (ECM) accumulation in penile cavernous tissues, and the smooth muscle cell (SMC) phenotypic transition was affected, as indicated by reduced alpha-smooth muscle actin and calponin-1 expression and increased phospho-myosin light chain20 (p-MLC20)/MLC20 and osteopontin expression. Hyperlipidemia resulted in ECM accumulation accompanied with SMC phenotypic transition in penile CC and impaired the erectile function eventually. These might, in turn, lead to variations in the SWQ values. It suggests that 2-D SWE may be a novel, noninvasive and effective approach that distinguishes penile CC lesions secondary to hyperlipidemia from normal.

Effects of Fine Particulate Matter on Erectile Function and Its Potential Mechanism in Rats

To investigate whether the exposure to fine particulate matter (PM2.5) in a rat model can impair erectile function and the possible mechanism. Sprague-Dawley rats were distributed into 4 groups (n = 9 each): 1 control group and 3 groups exposed to different levels of PM2.5. Rats were exposed to PM2.5 (0.0 [saline control], 0.8, 1.6, and 3.2 mg/rat). After exposure period, the ratio of maximum intracavernosal pressure to mean arterial pressure, molecular-biological indicators in corpus cavernosum tissue and plasma, and the pathologic changes of the lung tissue and penile tissue were detected and compared between the control group and the 3 exposure groups. The ratio of maximum intracavernosal pressure to mean arterial pressure in 2 groups exposed to PM2.5 was significantly lower than that of the control group only (P <.05). Exposure to PM2.5 could trigger the significant increase of plasma malondialdehyde, vascular endothelial growth factor, C-reactive protein, and tumor necrosis factor-α in experimental groups than that of the control group (P <.05). Expression of endothelial nitric oxide synthase (NOS), neuronal NOS, cyclic guanosine monophosphate, NOS activity, and content of reactive oxygen species in penile tissue were higher than that of the control group in a dose-response way (P <.05). The function of penile erection is impaired by exposure to PM2.5. The decrease in the expression of endothelial NOS and NOS activity in penile cavernous tissue caused by systemic inflammatory and oxidative stress status induced by exposure to PM2.5 may be one of the important risk factors of erectile dysfunction.