Calpain activation contributes to hyperglycemia-induced endothelial dysfunction and apoptosis. This study was designed to investigate the role of calpain inhibition in improving diabetic erectile dysfunction (ED) in mice. Thirty-eight-week-old male C57BL/6J mice were divided into three groups: (1) nondiabetic control group, (2) diabetic mice + vehicle group, and (3) diabetic mice + MDL28170 (an inhibitor of calpain) group. Type 1 diabetes was induced by intraperitoneal injection of streptozotocin at 60 mg kg^-1 body weight for 5 consecutive days. Thirteen weeks later, diabetic mice were treated with MDL28170 or vehicle for 4 weeks. The erectile function was assessed by electrical stimulation of the cavernous nerve. Penile tissues were collected for measurement of calpain activity and the endothelial nitric oxide synthase (eNOS)-nitric oxide (NO)-cyclic guanosine monophosphate (cGMP) pathway. Terminal deoxynucleotidyl transferase 2'-deoxyuridine 5'-triphosphate nick end labeling (TUNEL) staining was used to evaluate apoptosis. Caspase-3 expression and activity were also measured to determine apoptosis. Our results showed that erectile function was enhanced by MDL28170 treatment in diabetic mice compared with the vehicle diabetic group. No differences in calpain-1 and calpain-2 expressions were observed among the three groups. However, calpain activity was increased in the diabetic group and reduced by MDL28170. The eNOS-NO-cGMP pathway was upregulated by MDL28170 treatment in diabetic mice. Additionally, MDL28170 could attenuate apoptosis and increase the endothelium and smooth muscle levels in corpus cavernosum. Inhibition of calpain could improve erectile function, probably by upregulating the eNOS-NO-cGMP pathway and reducing apoptosis.
Animals ; Apoptosis/drug effects* ; Calpain/antagonists & inhibitors* ; Cyclic GMP/biosynthesis* ; Diabetes Complications/drug therapy* ; Diabetes Mellitus, Experimental/complications* ; Dipeptides/therapeutic use* ; Endothelium/metabolism* ; Enzyme Inhibitors/therapeutic use* ; Erectile Dysfunction/etiology* ; In Situ Nick-End Labeling ; Male ; Mice ; Mice, Inbred C57BL ; Muscle, Smooth/metabolism* ; Nitric Oxide Synthase Type III/biosynthesis* ; Penis/enzymology* ; Up-Regulation

Objective: To investigate whether androgens can regulate the expression of eNOS in rat corpus cavernosum through AKT3, PIK3CA, CALM, and CAV1 and influence erectile function. METHODS: Thirty-six 8-week-old male SD rats were randomly divided into groups A (4-week control), B (6-week control), C (4-week castration), D (6-week castration), E (4-week castration + testosterone replacement), and F (6-week castration + testosterone replacement). Both the testis and epididymis were removed from the rats in groups C, D, E and F, and on the second day after surgery, the animals of groups E and F were subcutaneously injected with testosterone propionate at 3 mg per kg of the body weight qd alt while all the others with isodose oil instead. At 4 weeks (for groups A, C and E) and 6 weeks (for groups B, D and F) after treatment, we detected the maximum intracavernous pressure (ICPmax), the mean carotid arterial pressure (MAP) and their ratio (ICPmax/MAP), measured the level of serum testosterone (T), and determined the expressions of eNOS, P-eNOS, AKT3, PIK3CA, CALM and CAV1 in the corpus cavernosum by Western blot and immunohistochemistry. RESULTS: No statistically significant differences were observed in the body weight and MAP among different groups. The serum T level and ICPmax/MAP were remarkably lower in groups C and D than in the other four groups (P<0.01) as well as in groups E and F than in A and B (P<0.05) but exhibited no significant differences either between E and F or between A and B. Immunohistochemistry showed that eNOS and P-eNOS were mainly expressed in the vascular endothelial cell membrane and cavernous vascular lumen, while AKT3, PIK3CA, CALM and CAV1 chiefly in the vascular endothelial cell cytoplasm and membrane, with a few in the smooth muscle cells. Western blot analysis manifested that the expressions of eNOS, P-eNOS, AKT3, PIK3CA, CALM and CAV1 were markedly lower in groups C and D than in A, B, E and F (P<0.01) as well as in D than in C (P<0.05) but those in groups E and F did not showed any significant difference from those in A and B, nor E from F or A from B. CONCLUSIONS Androgens can improve erectile function by upregulating the expressions of AKT3, PIK3CA, CALM and CAV1 protein molecules and activating eNOS after its phosphorylation, though the exact molecular mechanisms are yet to be further studied.
Animals ; Blood Pressure ; Blotting, Western ; Caveolin 1 ; metabolism ; Class I Phosphatidylinositol 3-Kinases ; metabolism ; Erectile Dysfunction ; Hormone Replacement Therapy ; Male ; Monomeric Clathrin Assembly Proteins ; metabolism ; Myocytes, Smooth Muscle ; Nitric Oxide Synthase Type III ; metabolism ; Orchiectomy ; Penile Erection ; physiology ; Penis ; enzymology ; metabolism ; Proto-Oncogene Proteins c-akt ; metabolism ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Testosterone Propionate ; administration & dosage

Objective: To investigate the safety and efficacy of pancreatic kininogenase combined with sildenafil in the treatment of erectile dysfunction(ED) in type 2 diabetes mellitus (DM) patients in the high-altitude area. METHODS: This study included 93 ED patients with type 2 DM, all residents of the Xining area 1500 meters above sea level. We randomly divided them into an experimental group (n = 48) and a control group (n = 45), the former treated with pancreatic kininogenase(120 u, tid) and sildenafil (25 mg, qd at bedtime), while the latter with sildenafil only (25 mg, qd at bedtime).After 4 and 8 weeks of medication, we obtained the penile hemodynamic parameters,IIEF-5 scores, and sexual intercourse satisfaction(SIS) scores and compared them between the two groups of patients. RESULTS: There were no statistically significant differences in age or DM course between the two groups of patients (P >0.05).Compared with the baseline, both the experimental and control groups showed remarkably improvement inthe IIEF-5 score (8.81 ± 2.06 vs 11.54 ± 7.72 and 8.29 ± 1.91 vs 9.37± 1.65, P <0.05), SIS score (3.35 ± 2.43vs6.83± 2.61and 3.41 ± 2.38 vs 4.92± 2.49, P <0.05), and penile hemodynamic parameters obtained by color duplex Doppler ultrasonography(P <0.05), with significant differences between the two groups in the IIEF-5 score (11.54 ± 7.72 vs 9.37± 1.65, P <0.05) and SIS score (6.83± 2.61 vs 4.92± 2.49, P <0.05) but not in the penile hemodynamic parameters (P >0.05). Even more remarkable improvement was observed at 8 weeks in the experimental and control groups in the IIEF-5 score (19.29± 1.85 and 15.43± 1.74)(P <0.05), SIS score (11.73 ± 2.57 and 6.55± 2.71) (P <0.05), and penile hemodynamic parameters(P <0.05), all with significant differences between the two groups (P <0.05). CONCLUSIONS Pancreatic kininogenase combined with sildenafil has a better clinical effect than sildenafil alone on ED in type 2 DM patientsin the high-altitude area.
Aged ; Altitude ; Coitus ; Diabetes Mellitus, Type 2 ; complications ; Drug Therapy, Combination ; Erectile Dysfunction ; etiology ; therapy ; Humans ; Kallikreins ; therapeutic use ; Male ; Pancreas ; enzymology ; Penile Erection ; drug effects ; physiology ; Penis ; physiology ; Phosphodiesterase 5 Inhibitors ; therapeutic use ; Sildenafil Citrate ; therapeutic use ; Treatment Outcome

Objective: To explore the effects of immediate and delayed intracavernous injection of bone marrow mesenchymal stem cells (BM-MSCs) on neurogenic erectile dysfunction (NED) induced by bilateral cavernous nerve injury in Sprague-Dawley (SD) rats. METHODS: BM-MSCs isolated from male SD rats were cultured and identified. Twenty-eight 8-week-old male SD rats were randomly divided into four groups, sham operation, NED model control, BM-MSCs immediate, and BM-MSCs delayed, and NED models were established in the latter three groups by crushing the bilateral cavernous nerves. The rats in the sham operation and model control groups were injected intracavernously with placebo while those in the latter two with BM-MSCs immediately or 2 weeks after modeling. At 12 weeks after operation, the penile function of the rats was assessed according to the penile intracavernous pressure (ICP), mean arterial pressure (MAP), and ICP/MAP ratio obtained from different groups of rats. Then, all the animals were sacrificed and the penile cavernosal tissue collected for histological analysis. RESULTS: At 12 weeks after modeling, both ICP and ICP/MAP were significantly increased in the BM-MSCs immediate and delayed groups as compared with those in the model control (P <0.05), and so were the ratio of smooth muscle to collagen (P <0.05) and the smooth muscle content in the corpus cavernosum (P <0.05), and the number of neurofilament (NF)-positive nerve fibers (P <0.05) and the expression of neuronal nitric oxide synthase (nNOS) in the dorsal nerves of the midshaft penis (P <0.05). CONCLUSIONS Intracavernous injection of BM-MSCs can improve erectile function in rats with bilateral cavernous nerve injury by elevating the smooth muscle-collagen ratio and smooth muscle content in the corpus cavernosum and thus preventing its fibrosis as well as by increasing the number of NF-positive nerve fibers and expression of nNOS in the penile dorsal nerves.
Animals ; Disease Models, Animal ; Erectile Dysfunction ; enzymology ; etiology ; therapy ; Male ; Mesenchymal Stem Cell Transplantation ; methods ; Muscle, Smooth ; Nitric Oxide Synthase Type I ; metabolism ; Penile Erection ; physiology ; Penis ; enzymology ; innervation ; Pudendal Nerve ; Random Allocation ; Rats ; Rats, Sprague-Dawley

UNLABELLEDOCTOBER: To explore the effects of the glucagon-like peptide 1 (GLP-1) liraglutide on the penile erectile function of rats with diabetic erectile dysfunction (DED) by observing the impact of liraglutide on the expression of eNOS in the corpus cavernosum of diabetic rats.

METHODSWe randomly divided 30 six-week-old male SD rats into a normal control (n = 10) and an experimental group (n = 20) , established models of diabetes mellitus (DM) in the experimental rats, and subdivided them into a DM (n = 8) and a GLP-1 group (n = 8) to receive intramuscular injection of normal saline and liraglutide at 5 mg per kg of the body weight per day, respectively. After 12 weeks of intervention, we obtained the levels of FPG, FINS, TG, TC, HDL-C, LDL-C, testosterone, and IL-6 and the indexes of Homa-IR and Homa-β, detected the expressions of Akt/p-Akt and eNOS/p-eNOS in the corpus cavernosum by Western blot, and compared the erectile function between different groups.

RESULTSThe frequency and rate of penile erection were significantly lower in the DM group than in the GLP-1 and normal control groups (P < 0.05) and also lower in the GLP-1 group than in the normal controls (P < 0.05). Immunofluorescence staining showed the expression of eNOS mainly in the cytoplasm of the cavernosal vessels and sinusoidal endothelial cells, markedly lower in the DM and GLP-1 groups than in the normal rats (P < 0.05), but higher in the GLP-1 than in the DM group (P < 0.05). The level of eNOS/p-eNOS in the penile tissue was significantly decreased in the DM and GLP-1 groups in comparison with the normal controls (P < 0.01 or P < 0.05), while that of p-eNOS was markedly increased in the GLP-1 group as compared with the DM group (P < 0.05). No statistically significant differences were observed in the Akt level among the three groups of animals (P > 0.05). The expression of p-Akt was remarkably reduced in the DM and GLP-1 groups in comparison with the control rats (P < 0.01 or P < 0.05), but higher in the GLP-1 than in the DM group (P < 0.05).

CONCLUSIONGLP-1 can protect the function of endothelial cells in the corpus cavernosum and improve the erectile function of DED rats by regulating the Akt/ eNOS signaling pathway, which indicates that GLP-1 could be an important option for the treatment and prevention of DED.

Animals ; Blotting, Western ; Diabetes Mellitus, Experimental ; Erectile Dysfunction ; drug therapy ; enzymology ; Hypoglycemic Agents ; pharmacology ; Liraglutide ; pharmacology ; Male ; Nitric Oxide Synthase Type III ; metabolism ; Penile Erection ; drug effects ; Penis ; drug effects ; enzymology ; physiopathology ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Testosterone ; blood

OBJECTIVETo study the expression of nNOS and ultrastructural changes in the penile tissue of rats with prolactinoma-induced erectile dysfunction (ED).

METHODSWe established the model of prolactinoma in 20 male Westar rats by peritoneal injection of diethylstilbestrol (DES) and treated the control rats with normal saline (n = 10) or sterilized arachis oil (n = 10). After 8 weeks, we performed the apomorphine test and measured the weight of the pituitary gland and the levels of serum prolactin (PRL) and testosterone (T) to confirm the successful construction of the prolactinoma-induced ED model. Then we determined the expression of nNOS in the penile tissue by immunohistochemistry and examined the ultrastructural changes of the penile cavernosum under the transmission electron microscope.

RESULTSThe prolactinoma-induced ED model was successfully established in 15 rats. The weight of the pituitary gland was significantly increased in the rats treated with DES as compared with the normal saline and sterilized arachis oil controls ([46.7 ± 15.5] vs [11.7 ± 2.4] and [12.4 ± 2.3] mg, both P < 0.05). The level of serum PRL was markedly higher while that of T remarkably lower in the former than in the latter two groups ([1,744.9 ± 304.5] vs [11.5 ± 2.4] and [10.6 ± 1.9] ng/ml, both P < 0.0l; [1.54 ± 0.46] vs [3.11 ± 1.08] and [3.04 ± 1.11] ng/ml, both P < 0.05). The rate of penile erection was significantly reduced in the prolactinoma-induced ED model rats in comparison with the normal saline and arachis oil controls (16.7% vs 100% and 87.5%, both P < 0.05), and so was the expression of nNOS in the penile tissue (0.024 ± 0.011 vs 0.066 ± 0.019 and 0.058 ± 0.021, both P < 0.05). Transmission electron microscopy manifested significant ultrastructural changes in the endothelial and smooth muscle cells of the cavernous tissue in the prolactinoma-induced ED models.

CONCLUSIONThe ultrastructural changes of the penile cavernous tissue and the reduced expression of nNOS in penile tissue may be the most important mechanisms of prolactinoma-induced ED in rats.

Animals ; Apomorphine ; Carcinogens ; Diethylstilbestrol ; Erectile Dysfunction ; etiology ; Humans ; Male ; Myocytes, Smooth Muscle ; ultrastructure ; Nitric Oxide Synthase Type I ; metabolism ; Organ Size ; Penile Erection ; Penis ; enzymology ; ultrastructure ; Pituitary Neoplasms ; chemically induced ; complications ; Prolactin ; blood ; Prolactinoma ; chemically induced ; complications ; Rats ; Rats, Wistar ; Testosterone ; blood

OBJECTIVETo investigate the expressions of cystathionine gamma-lyase (CSE) and cystathionine beta-synthase (CBS) in the corpus cavernosum of spontaneous hypertensive rats (SHR) and their relationship with erectile dysfunction.

METHODSThis study included 10 male SHRs and 10 healthy male Wistar-Kyoto (WKY) rats as controls, all aged 12 weeks. We applied a series of electric stimuli to the major pelvic ganglions of the rats, observed changes in the ratio of intracavernosal to mean arterial blood pressure (ICP/MAP), measured the levels of serum testosterone (T) and endogenous H2S, and determined the expressions of CSE and CBS in the corpus cavernosum by Western blot and immunohistochemistry.

RESULTSNo obvious difference was found in the serum T level between the two groups. Compared with the WKY rats, the SHRs showed significant reduction in the ICP/MAP ratio, the contents of plasma H2S ([21.92 +/- 2.75] micromol/L vs [10.49 +/- 1.35] micromol/L, P < 0.05) and endogenous corpus cavernosal H2S ([87.67 +/- 2.12] nmol/mg prot vs [52.60 +/- 3.44] nmol/mg prot, P < 0.05), the level of endogenous H2S synthesis ([4.35 +/- 0.32] nmol/mg per min vs [1.14 +/- 0.07] nmol/mg per min, P < 0.05) and the expressions of CBS and CSE (P < 0.05). Immunohistochemistry showed that CSE and CBS were distributed mainly in the smooth muscle cells and vascular endothelial cells of the corpus cavernosum. The ICP/MAP ratio was highly positively correlated with the expressions of CSE (r = 0.977, P < 0.05) and CBS (r = 0.955, P < 0.05) in the corpus cavernosal tissue.

CONCLUSIONHypertension inhibits endogenous H2S synthesis by suppressing the expressions of CSE and CBS in the corpus cavernosum, which might be related with hypertension-induced reduction of erectile function.

Animals ; Cystathionine beta-Synthase ; metabolism ; Cystathionine gamma-Lyase ; metabolism ; Gene Expression Regulation ; Hydrogen Sulfide ; blood ; Hypertension ; metabolism ; Male ; Penis ; enzymology ; Rats ; Rats, Inbred SHR ; Rats, Inbred WKY

OBJECTIVETo investigate the effect of salidroside on hypoxia-induced apoptosis of corpus cavernosum smooth muscle cells (CCSMCs) in rats.

METHODSRat CCSMCs were cultured in vitro by the enzyme digestion method and identified by immunofluorescent staining of anti-alpha-SMA and anti-Desmin. The non-toxic dose of salidroside was determined by MTT assay. Low-oxygen mixed gas (1% O2, 5% CO2, and 94% N2) was piped into a modular incubator chamber to induce hypoxia. The CCSMCs were divided into a normal, a hypoxia, and a 32 microg/mL salidroside intervention group. The apoptosis of the CCSMCs was detected by flow cytometry and the expression of the caspase-3 protein determined by Western blot.

RESULTSThe majority of the CCSMCs were positive for alpha-SMA and Desmin at immunofluorescent staining. Salidroside at < 32 microg/ml produced no obvious toxicity to CCSMCs. Compared with the normal control group, the rates of early and late apoptosis of CCSMCs were both increased significantly in the hypoxia group ([12.77 +/-1.41]% vs [18.69 +/- 1.29]%, P < 0.01 and [14.63 +/- 2.00]% vs [21.03 +/- 1.530]% , P < 0.05). Western blot showed a markedly increased expression of cleaved caspase-3 (P < 0.01). Intervention with 32 microg/ml salidroside significantly reduced hypoxia-induced early apoptosis of CCSMCs ([13.46% +/- 1.87]%, P < 0.01) and decreased the expression of cleaved caspase-3 (P < 0.01).

CONCLUSIONSalidroside can reduce the expression of cleaved caspase-3 and inhibit hypoxia-induced apoptosis of CCSMCs in rats.

Animals ; Apoptosis ; drug effects ; physiology ; Caspase 3 ; metabolism ; Cell Hypoxia ; physiology ; Cells, Cultured ; Glucosides ; pharmacology ; Humans ; Male ; Myocytes, Smooth Muscle ; cytology ; drug effects ; enzymology ; Penis ; cytology ; drug effects ; Phenols ; pharmacology ; Rats

OBJECTIVETo investigate the impact of hyperglycemia on the hydrogen sulfide (H2S) signaling pathway in rat penile tissue and its relationship with erectile function.

METHODSTwenty healthy male Sprague Dawley (SD) rats aged 8 weeks were randomly divided into groups A (4-week healthy control), B (4-week diabetes mellitus model), C (6-week healthy control) and D (6-week diabetes mellitus model). The rats in groups B and D were injected intraperitoneally with streptozotocin at 50 mg/kg to induce diabetes mellitus, while those in groups A and C with the same volume of normal saline. The animals were killed at 4 (groups A and B) and 6 weeks (groups C and D) after treatment for measurement of the maximal intracavernous pressure/mean arterial blood pressure (ICP(max)/MAP) by electrostimulation, determination of the H2S concentration in the plasma and penile tissue, and detection of the expressions of cystathionine-beta-synthetase (CBS) and cystathionine-gamma-lyase (CSE) in the penile corpus cavernosum by immunohisto- chemistry and Western blot.

RESULTSWith electrostimulation of the pelvic ganglia at 5V and 7 V, ICP(max)/MAP was significantly reduced in groups B (0.19 +/- 0.03 and 0.29 +/- 0.04) and D (0.14 +/- 0.04 and 0.25 +/- 0.04) as compared with A (0.46 +/- 0.07 and 0.68 +/- 0.09) and C (0.43 +/- 0.07 and 0.65 +/- 0.16) (P < 0.05). No statistically significant differences were found in the level of serum testosterone either between groups A and B ([469.19 +/- 126.46] ng/dl vs [359.08 +/- 60.06] ng/dl, P > 0.05) or between C and D ([470.44 +/- 209.28] ng/dl vs [297.01 +/- 96.58] ng/dl, P > 0.05). Groups B and D showed remarkable reduction in the H2S concentration (P < 0.05) and the expressions of CBS and CSE (P < 0.05) in comparison with A and C, and the CBS and CSE expressions were even more significantly decreased in D than in B (P < 0.05).

CONCLUSIONThe reduced concentration of H2S and decreased expressions of CBS and CSE in the penile corpus cavernosum of the diabetic rats suggested that the H2S signaling pathway might be involved in hyperglycemia-induced erectile dysfunction.

Animals ; Blood Pressure ; physiology ; Cystathionine gamma-Lyase ; metabolism ; Diabetes Mellitus, Experimental ; chemically induced ; metabolism ; Electric Stimulation ; methods ; Erectile Dysfunction ; etiology ; Humans ; Hydrogen Sulfide ; metabolism ; Hyperglycemia ; metabolism ; Lyases ; metabolism ; Male ; Penis ; enzymology ; physiology ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Signal Transduction ; Testosterone ; metabolism

OBJECTIVETo study the expressions of cystathionine-beta-synthase (CBS) and cystathionine-gamma-lyase (CSE) in the corpus cavernosum smooth muscle of castrated rats and their roles in erectile dysfunction after castration.

METHODSWe randomly assigned 40 eight-week-old male SD rats to groups A (2-week sham-operation), B (4-week sham-operation), C (2-week castration) and D (4-week castration). We determined the level of serum testosterone (T) and the expressions of CBS and CSE in the corpus cavernosum smooth muscle of the rats after operation using immunohistochemistry and RT-PCR.

RESULTSThe T level was significantly decreased in groups C ([11.85 +/- 6.73] nmol/L) and D ([1.96 +/- 1.23] nmol/L) as compared with A ([89.65 +/- 17.13] nmol/L) and B ([106.75 +/- 19.68] nmol/L) (P < 0.05). CBS and CSE were expressed in all groups of rats, but the relative expressions of CBS and CSE mRNA were significantly lower in groups C (0.93 +/- 0.14 and 0.87 +/- 0.20) and D (0.79 +/- 0.17 and 0.71 +/- 0.12) than in A (2.13 +/- 0.65 and 1.93 +/- 0.15) and B (2.07 +/- 0.53 and 1.89 +/- 0.45) (P < 0. 05), so were the optical density values (IA) of the CBS and CSE proteins, 130.35 +/- 23.56 and 93.56 +/- 36.64 in group C and 80.29 +/- 29.65 and 58.56 +/- 19.95 in group D, as compared with 310.57 +/- 130.56 and 269.56 +/- 116.76 in group A and 349.68 +/-112.35 and 298.35 +/- 100.76 in group B (P < 0.05). The androgen level was positively correlated with the expressions of CBS and CSE in the corpus cavernosum smooth muscle of the rats.

CONCLUSIONAndrogen regulates erectile function via the expressions of CBS and CSE.

Animals ; Cystathionine beta-Synthase ; metabolism ; Cystathionine gamma-Lyase ; metabolism ; Male ; Muscle, Smooth ; enzymology ; Orchiectomy ; Penis ; enzymology ; Rats ; Rats, Sprague-Dawley ; Testosterone ; blood