Adipose Tissue-Derived Stem Cell Therapy for Cavernous Nerve Injury-Induced Erectile Dysfunction in the Rat Model: A Systematic Review and Meta-Analysis Using Methodological Quality Assessment

BACKGROUND AND OBJECTIVES: Few studies were evaluated the effect of blindness on outcome in animal models, though a potential effect of blinding has been reported in clinical trials. We evaluated the effects of adipose tissue-derived stem cells (ADSCs) on cavernous nerve injury (CNI)-induced erectile dysfunction (ED) in the rat and examined how proper blinding of the outcome assessor affected treatment effect. METHODS AND RESULTS: We searched in Pubmed, EMBASE, Cochrane and Web of Science databases from inception to January 2019. We included CNI animal model, randomized controlled experiments, and ADSC intervention. Erectile function and structural changes were assessed by intracavernous pressure and mean arterial pressure (ICP/MAP) ratios, neuronal nitric oxide synthase (nNOS) levels, cavernous smooth muscle and collagen (CSM/collagen) ratios, and cyclic guanosine monophosphate (cGMP). RESULTS: Nineteen studies were included in the final meta-analysis. The ICP/MAP ratio of the ADSC treatment group increased compared to the control group (SMD=1.33, 95%CI: 1.11~1.56, I²=72%). The nNOS level (SMD=2.29, 95%CI: 1.74~2.84, I²=75%), CSM/collagen (SMD=2.57, 95%CI: 1.62~3.52; I²=85%), and cGMP (SMD=2.96, 95%CI: 1.82~4.10, I²=62%) were also increased in the ADSC treatment group. Preplanned subgroup analysis was conducted to explore the source of heterogeneity. Five studies with blinded outcome assessment were significantly less effective than the unblinded studies (SMD=1.33, 95%CI: 0.86~1.80; SMD=1.81, 95%CI: 1.17~2.46, respectively). CONCLUSIONS: ADSCs might be effective in improving erectile function and structural change in CNI-induced ED. However, non-blinded outcome assessors might cause detection bias and overestimate treatment efficacy. Therefore, the ADSC efficacy must be further evaluated with a rigorous study design to avoid bias.

C-Type Natriuretic Peptide/Natriuretic Peptide Receptor 2 Is Involved in Cell Proliferation and Testosterone Production in Mouse Leydig Cells

PURPOSE: This study investigated the role of natriuretic peptide receptor 2 (NPR2) on cell proliferation and testosterone secretion in mouse Leydig cells. MATERIALS AND METHODS: Mouse testis of different postnatal stages was isolated to detect the expression C-type natriuretic peptide (CNP) and its receptor NPR2 by quantitative reverse transcription polymerase chain reaction (RT-qPCR). Leydig cells isolated from mouse testis were cultured and treated with shNPR2 lentiviruses or CNP. And then the cyclic guanosine monophosphate production, testosterone secretion, cell proliferation, cell cycle and cell apoptosis in mouse Leydig cells were analyzed by ELISA, RT-qPCR, Cell Counting Kit-8, and flow cytometry. Moreover, the expression of NPR2, cell cycle, apoptosis proliferation and cell cycle related gene were detected by RT-qPCR and Western blot. RESULTS: Knockdown of NPR2 by RNAi resulted in S phase cell cycle arrest, cell apoptosis, and decreased testosterone secretion in mouse Leydig cells. CONCLUSIONS: Our study provides more evidences to better understand the function of CNP/NPR2 pathway in male reproduction, which may help us to treat male infertility.

No Causal Link between Phosphodiesterase Type 5 Inhibition and Melanoma

PURPOSE: To examine the association between phosphodiesterase type 5 (PDE5) inhibitor use and melanoma by 1) conducting a systematic review of observational studies; and 2) determining if low PDE5A gene expression in human melanoma correlated with decreased overall survival. MATERIALS AND METHODS: A systematic search of observational studies examining the association between PDE5 inhibitor use and melanoma was performed through ClinicalTrials.gov, the Cochrane Library, EMBASE, PubMed, and Web of Science databases, and seven eligible studies were identified. PDE5A gene expression was analyzed with RNA sequencing data from 471 human melanoma samples obtained from The Cancer Genome Atlas. RESULTS: Four studies reported a positive association between PDE5 inhibitor use and melanoma, and three studies found no correlation. RNA sequencing data analysis revealed that under-expression of the PDE5A gene did not impact clinical outcomes in melanoma. CONCLUSIONS: There is currently no evidence to suggest that PDE5 inhibition in patients causes increased risk for melanoma. The few observational studies that demonstrated a positive association between PDE5 inhibitor use and melanoma often failed to account for major confounders. Nonetheless, the substantial evidence implicating PDE5 inhibition in the cyclic guanosine monophosphate (cGMP)-mediated melanoma pathway warrants further investigation in the clinical setting.

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/OBJECTIVES: This 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/METHODS: PCCSM 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. RESULTS: Both 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. CONCLUSIONS: The 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.

Acute exercise inhibits gastric emptying of liquids in rats: influence of the NO-cGMP pathway

We previously found that acute exercise inhibited the gastric emptying of liquid in awake rats by causing an acid-base imbalance. In the present study, we investigated the involvement of the nitric oxide-cyclic guanosine monophosphate (NO-cGMP) pathway, vasoactive intestinal peptide (VIP), and corticotropin-releasing factor (CRF) peptide in this phenomenon. Male rats were divided into exercise or sedentary group and were subjected to a 15-min swim session against a load (2.5 or 5% b.w.). The rate of gastric emptying was evaluated after 5, 10, or 20 min postprandially. Separate groups of rats were treated with vehicle (0.9% NaCl, 0.1 mL/100 g, ip) or one of the following agents: atropine (1.0 mg/kg, ip), the NO non-selective inhibitor Nω-nitro-L-arginine methyl ester hydrochloride (L-NAME; 10.0 mg/kg, ip), or the selective cGMP inhibitor 1H-(1,2,4)oxadiazole[4,3-a]quinoxalin-1-one (ODQ; 5.0 mg/kg, ip), the i-NOS non-specific inhibitor (aminoguanidine; 10.0 mg/kg, ip), the corticotropin-releasing factor receptor antagonist (astressin; 100 µg/kg, ip), or the vasoactive intestinal peptide (VIP) receptor antagonist Lys1, Pro2,5, Arg3,4, Tyr6 (100 µg/kg, ip). Compared to sedentary rats, both the 2.5 and 5% exercise groups exhibited higher (P<0.05) values of blood lactate and fractional gastric dye recovery. Corticosterone and NO levels increased (P<0.05) in the 5% exercised rats. Pretreatment with astressin, VIP antagonist, atropine, L-NAME, and ODQ prevented the increase in gastric retention caused by exercise in rats. Acute exercise increased gastric retention, a phenomenon that appears to be mediated by the NO-cGMP pathway, CRF, and VIP receptors.

The Effect of Alcohol Administration on the Corpus Cavernosum

PURPOSE: We studied the effects of alcohol administration on the corpus cavernosum (CC) using an animal model. MATERIALS AND METHODS: CC sections and the aortic ring of rabbits were used in an organ bath study. After acute alcohol administration, changes in blood alcohol concentration and electrical stimulation induced intracavernosal pressure/mean arterial pressure (ICP/MAP) percentage were compared in rats. Cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) levels in the CC were measured using immunoassays. After chronic alcohol administration, ICP/MAP percentage, cAMP and cGMP were compared in rats. Histological changes were examined using the Masson trichrome stain and the Sircol collagen assay. Endothelial nitric oxide synthase (eNOS) expression was examined using immunohistochemistry and Western blotting. RESULTS: Alcohol relaxed the CC in a dose-dependent manner, and the relaxation response was suppressed when pretreated with propranolol, indomethacin, glibenclamide, and 4-aminopyridine. In rats with acute alcohol exposure, the cAMP level in the CC was significantly greater than was observed in the control group (p<0.05). In rats with chronic alcohol exposure, however, changes in cAMP and cGMP levels were insignificant, and the CC showed markedly smaller areas of smooth muscle, greater amounts of dense collagen (p<0.05). Immunohistochemical analysis of eNOS showed a less intense response, and western blotting showed that eNOS expression was significantly lower in this group (p<0.05). CONCLUSIONS: Acute alcohol administration activated the cAMP pathway with positive effects on erectile function. In contrast, chronic alcohol administration changed the ultrastructures of the CC and suppressed eNOS expression, thereby leading to erectile dysfunction.

Administration of Goji (Lycium chinense Mill.) Extracts Improves Erectile Function in Old Aged Rat Model

PURPOSE: This study investigated the effect of goji (Lycium chinense Mill.) on erectile dysfunction in old-aged rats. MATERIALS AND METHODS: Twenty-four 18-month-old male Sprague-Dawley rats (defined as old-aged rats) were used. Treatment groups contained eight rats each: a control group, goji extract of 150 mg/kg/day group, and goji extract of 300 mg/kg/day group. Treatment was by orogastric tube once daily for 6 weeks. After 6 weeks of treatment, testes weight, serum testosterone, superoxide dismutase, nitric oxide (NO)-cyclic guanosine monophosphate (cGMP)-related parameters, intracavernous pressure/mean arterial pressure, and histological changes were examined. RESULTS: Treatments with goji extracts increased serum testosterone level, increased the expression of endothelial NO synthase, neuronal NO synthase, and cGMP, improved the oxidative stress marker, and decreased corporal fibrosis. CONCLUSIONS: Our results indicate that goji extract may have a positive effect on erectile dysfunction via its antioxidant effects.

Effects of Next-Generation Low-Energy Extracorporeal Shockwave Therapy on Erectile Dysfunction in an Animal Model of Diabetes

PURPOSE: Gene therapy, stem cell therapy, and low-energy extracorporeal shockwave therapy (ESWT) have been investigated as treatments for refractory erectile dysfunction (ED), but inconclusive evidence has been obtained. We investigated the effect of a next-generation electromagnetic cylinder ESWT device on an animal model of ED. MATERIALS AND METHODS: Diabetes mellitus (DM)-induced rats were divided into 3 groups: group 1, control; group 2, DM; and group 3, DM+ESWT. Rats were treated with ESWT 3 times a week for 2 weeks. After the treatment course, intracavernous pressure was measured and the corpus cavernosum and cavernous nerve were evaluated. RESULTS: In the DM group, all parameters predicted to be significantly lower in the ED model had statistically significantly decreased (p < 0.01). As a measurement of erectile function, intracavernous pressure was evaluated. The DM+ESWT group exhibited significantly restored erectile function compared to the DM group (p < 0.05). Moreover, ESWT treatment restored smooth muscle content, as assessed by Masson's trichrome staining (p < 0.05). Finally, corporal tissue and the dorsal nerve were evaluated by immunohistochemistry, Western blotting, and ELISA. After ESWT treatment, vascular endothelial growth factor (VEGF), endothelial nitric oxide synthase (eNOS), platelet endothelial cell adhesion molecule-1, cyclic guanosine monophosphate, and neuronal nitric oxide synthase (nNOS) expression levels were restored to levels in the DM group (p < 0.05). CONCLUSIONS: Electromagnetic cylinder ESWT device resulted in increased VEGF, nNOS, and eNOS expression; reduced smooth muscle atrophy; and increased endothelial cell regeneration in a DM-associated ED model. Our data suggest that safe and effective application could be possible in future clinical studies.

Penile Erection Induced by Scoparone from Artemisia capillaris through the Nitric Oxide-Cyclic Guanosine Monophosphate Signaling Pathway

PURPOSE: The objective of this study was to evaluate the relaxant effect of scoparone from Artemisia capillaris on rabbit penile corpus cavernosum smooth muscle (PCCSM) and to elucidate the mechanism of action of scoparone for the treatment of erectile dysfunction (ED). MATERIALS AND METHODS: PCCSM that had been precontracted with phenylephrine was treated with 3 Artemisia herbs (A. princeps, A. capillaris, and A. iwayomogi) and 3 fractions (n-hexane, ethyl acetate, and n-butanol) with different concentrations (0.1, 0.5, 1.0, and 2.0 mg/mL). Four components (esculetin, scopoletin, capillarisin, and scoparone) isolated from A. capillaris were also evaluated. The PCCSM was preincubated with Nω-nitro-L-arginine methyl ester hydrochloride (L-NAME) and 1H-[1,2,4] oxadiazolo [4,3-a]quinoxalin-1-one (ODQ). Cyclic nucleotides in the perfusate were measured by a radioimmunoassay. The interactions of scoparone with udenafil and rolipram were also evaluated. RESULTS: A. capillaris extract relaxed PCCSM in a concentration-dependent manner. Scoparone had the highest relaxant effect on PCCSM among the 4 components (esculetin, scopoletin, capillarisin, and scoparone) isolated from the ethyl acetate fraction. The application of scoparone on PCCSM pretreated with L-NAME and ODQ led to significantly less relaxation. Scoparone also increased the cyclic guanosine monophosphate (cGMP) levels in the perfusate in a concentration-dependent manner. Furthermore, scoparone enhanced udenafil- and rolipram-induced relaxation of the PCCSM. CONCLUSIONS: Scoparone relaxed the PCCSM mainly by activating the nitric oxide-cGMP signaling pathway, and it may be a new promising treatment for ED patients who do not completely respond to udenafil.

Ginsenoside Re Enriched Fraction (GS-F3K1) from Ginseng Berries Ameliorates Ethanol-Induced Erectile Dysfunction via Nitric Oxide-cGMP Pathway

Erectile dysfunction (ED) is a highly prevalent disorder that affects millions of men and considered to be an early symptom of atherosclerosis and a precursor of various systemic vascular disorders. The aim of the present study was to prepare ginsenoside Re enriched fraction (GS-F3K1, ginsenoside Re 10%, w/w) from ginseng berries flesh and to investigate the enhanced activities of GS-F3K1 on alcohol-induced ED. GS-F3K1 was prepared by the continuous liquid and solid separating centrifugation and circulatory ultrafiltration from ginseng berries flesh. GS-F3K1 was administered for 5 weeks in ethanol-induced ED rat by oral administration of 20% ethanol. To investigate the effects of GS-F3K1 on ED model, the levels of nitrite expression, cyclic guanosine monophosphate (cGMP) and erectile response of the penile corpus cavernosum of rat were measured. The erectile response of the corpus cavernosum was restored after GS-F3K1 administration, to a level similar to the normal group. The level of nitrite and cGMP expression in the corpus cavernosum of GS-F3K1-administered male rats was increased significantly compared to positive control group. GS-F3K1 from ginseng berries should effectively restore ethanol-induced ED in male rats and could be developed as a new functional food for the elderly men.

Water soluble tomato concentrate regulates platelet function via the mitogen-activated protein kinase pathway

Tomato extract has been shown to exert antiplatelet activity in vitro and to change platelet function ex vivo, but with limitations. In this study, antiplatelet activity of water soluble tomato concentrate (Fruitflow I) and dry water soluble tomato concentrate (Fruitflow II) was investigated using rat platelets. Aggregation was induced by collagen and adenosine diphosphate and granule-secretion, [Ca2+]i, thromboxane B2, cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) levels were examined. The activation of integrin αIIbβ3 and phosphorylation of signaling molecules, including mitogen-activated protein kinase (MAPK) and PI3K/Akt, were investigated by flow cytometry and immunoblotting, respectively. Prothrombin time (PT) and activated partial thromboplastin time (aPTT) were examined. Moreover, in vivo thrombus weight was tested by an arteriovenous shunt model. Fruitflow I and Fruitflow II significantly inhibited agonist induced platelet aggregation, adenosine triphosphate and serotonin release, [Ca2+]i, and thromboxane B2 concentration, while having no effect on cAMP and cGMP levels. Integrin αIIbβ3 activation was also significantly decreased. Moreover, both concentrates reduced phosphorylation of MAPK pathway factors such as ERK, JNK, P38, and PI3K/Akt. In vivo thrombus formation was also inhibited. Taken together, these concentrates have the potential for ethnomedicinal applications to prevent cardiovascular ailments and can be used as functional foods.

Protective Effects of KH-204 in the Bladder of Androgen-Deprived Rats

PURPOSE: We investigated the protective effects of the herbal formulation KH-204 in the bladder of androgen-deprived rats. MATERIALS AND METHODS: Male rats aged eight weeks were randomly divided into four groups, containing eight rats each: sham operation only (normal control group), androgen-deprived only (androgen-deprived control group), and androgen-deprived followed by treatment with 200 mg/kg or 400 mg/kg of KH-204. After 0.5 mg/kg of leuprorelin was subcutaneously injected in the androgen-deprived groups, the oral administration of either distilled water in the two control groups or KH-204 in the treatment group was continued for four weeks. Serum testosterone levels, RhoGEF levels, nitric oxide (NO)-cyclic guanosine monophosphate (cGMP)-related parameters, oxidative stress, and histologic changes were evaluated after treatment. RESULTS: Treatment with the herbal formulation KH-204 (1) increased serum testosterone levels; (2) restored the expression of RhoGEFs, endothelial NO synthase, and neuronal NO synthase; (3) increased the expression of superoxide dismutase; and (4) decreased bladder fibrosis. CONCLUSIONS: Our results suggest that the positive effects of KH-204 on the urinary bladder may be attributed to its antioxidant effects or to an elevation in NO-cGMP activity.

Role of Cyclic GMP-AMP Synthase in Sensing Human Immunodeficiency Virus

Cyclic guanosine monophosphate adenosine monophosphate (cGAMP) synthase (cGAS) detects human immunodeficiency virus (HIV) and produces cGAMP to induce cytokines. Reverse transcribed DNA of HIV is critical for triggering innate immune responses as inhibitor of HIV reverse transcriptase blocked the induction of interferon-beta by the virus. Furthermore, knockout of cGAS in human or mouse cell lines abrogated the production of cytokines by HIV infection highlighting the essential role of cGAS in detection of HIV and other retroviruses.

Protective Effects of Inducible HO-1 on Oxygen Toxicity in Rat Brain Endothelial Microvessel Cells

BACKGROUND: Reperfusion in ischemia is believed to generate cytotoxic oxidative stress, which mediates reperfusion injury. These stress conditions can initiate lipid peroxidation and damage to proteins, as well as promote DNA strand breaks. As biliverdin and bilirubin produced by heme oxygenase isoform 1 (HO-1) have antioxidant properties, the production of both antioxidants by HO-1 may help increase the resistance of the ischemic brain to oxidative stress. In the present study, the survival effect of HO-1 was confirmed using hemin. METHODS: To confirm the roles of HO-1, carbon monoxide, and cyclic guanosine monophosphate further in the antioxidant effect of HO-1 and bilirubin, cells were treated with cycloheximide, desferoxamine, and zinc deuteroporphyrin IX 2,4 bis glycol, respectively. RESULTS: HO-1 itself acted as an antioxidant. Furthermore, iron, rather than carbon monoxide, was involved in the HO-1-mediated survival effect. HO-1 activity was also important in providing bilirubin as an antioxidant. CONCLUSION: Our results suggested that HO-1 helped to increase the resistance of the ischemic brain to oxidative stress.

Effects and Mechanism of Action of a Tribulus terrestris Extract on Penile Erection

PURPOSE: Tribulus terrestris has been used as an aphrodisiac. However, little is known about the effects and mechanism of action of T. terrestris on penile erection. Therefore, the effect of a T. terrestris extract and the mechanism of action of the extract on relaxation of the corpus cavernosum (CC) were investigated. The erectogenic effects of an oral preparation of the extract were also assessed. MATERIALS AND METHODS: The relaxation effects and mechanism of action of the T. terrestris extract on rabbit CC were investigated in an organ bath. The intracavernous pressure (ICP) was calculated after oral administration of the extract for 1 month to evaluate whether the relaxation response of the CC shown in the organ bath occurred in vivo. Additionally, cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) were measured in the CC by immunoassay. Smooth muscle relaxation was expressed as the percentage decrease in precontraction induced by phenylephrine. The ICP was also assessed in rats after oral administration of the extract for 1 month, and changes in concentrations of cGMP and cAMP were monitored. RESULTS: Concentration-dependent relaxation effects of the extract on the CC were detected in the organ bath study. Relaxation of the CC by the T. terrestris extract was inhibited in both an endothelium-removed group and an L-arginen methyl ester pretreatment group. The ICP measured after oral administration of the T. terrestris extract for 1 month was higher than that measured in the control group, and a significant increase in cAMP was observed in the T. terrestris extract group. CONCLUSIONS: The T. terrestris extract induced concentration-dependent relaxation of the CC in an organ bath. The mechanism included a reaction involving the nitric oxide/nitric oxide synthase pathway and endothelium of the CC. Moreover, in an in vivo study, the T. terrestris extract showed a significant concentration-dependent increase in ICP. Accordingly, the T. terrestris extract may improve erectile function.

Identification of mechanisms involved in the relaxation of rabbit cavernous smooth muscle by a new nitric oxide donor ruthenium compound

PURPOSE: The aim of this study was to evaluate the relaxation in vitro of cavernous smooth muscle induced by a new NO donor of the complex nitrosil-ruthenium, named trans-[Ru(NH3)4(caffeine)(NO)]C13 (Rut-Caf) and sodium nitroprusside (SNP). MATERIALS AND METHODS: The tissues, immersed in isolated bath systems, were pre-contracted with phenilephrine (PE) (1 µM) and then concentration-response curves (10-12 - 10-4 M) were obtained. To clarify the mechanism of action involved, it was added to the baths ODQ (10 µM, 30 µM), oxyhemoglobin (10 µM), L-cysteine (100 µM), hydroxicobalamine (100 µM), glibenclamide, iberotoxin and apamine. Tissue samples were frozen in liquid nitrogen to measure the amount of cGMP and cAMP produced. RESULTS: The substances provoked significant relaxation of the cavernous smooth muscle. Both Rut-Caf and SNP determined dose-dependent relaxation with similar potency (pEC50) and maximum effect (Emax). The substances showed activity through activation of the soluble guanylyl cyclase (sGC), because the relaxations were inhibited by ODQ. Oxyhemoglobin significantly diminished the relaxation effect of the substances. L-cysteine failed to modify the relaxations caused by the agents. Hydroxicobalamine significantly diminished the relaxation effect of Rut-Caf. Glibenclamide significantly increased the efficacy of Rut-Caf (pEC50 4.09 x 7.09). There were no alterations of potency or maximum effect of the substances with the addition of the other ion channel blockers. Rut-Caf induced production of significant amounts of cGMP and cAMP during the relaxation process. CONCLUSIONS: In conclusion, Rut-Caf causes relaxation of smooth muscle of corpus cavernosum by means of activation of sGC with intracellular production of cGMP and cAMP; and also by release of NO in the intracellular environment. Rut-Caf releases the NO free radical and it does not act directly on the potassium ion channels.

Efeitos do sildenafil pela via intraperitoneal na viabilidade de retalhos cutâneos de ratos / Effects of intraperitoneal application of sildenafil on the viability of mice’s skin flap

Introdução: o sildenafil pertence a uma classe relativamente nova de medicamentos, cujo mecanismo de ação ocorre por inibição da fosfodiesterase-5, que é responsável pela degradação intracelular da guanosina monofosfato cíclica (GMPc). A GMPc promove vasodilatação, alteração no perfil de granulação plaquetária e angiogênese. Nesse contexto, seus efeitos vasoativos podem aumentar o fluxo sanguíneo de retalhos, melhorando a sua viabilidade. Este estudo tem como objetivo avaliar a viabilidade de retalhos cutâneos de ratos à McFarlane após a administração de sildenafil pela via intraperitoneal. Métodos: 20 ratos Wistar foram distribuídos em dois grupos - controle (confecção do retalho cutâneo dorsal, aplicação intraperitoneal de solução salina a 0,9%) e estudo (confecção do retalho cutâneo dorsal, aplicação intraperitoneal de sildenafil). Sete dias após a operação, os retalhos foram fotografados e representados graficamente, para serem analisados com o programa AutoCad. Três biópsias (cranial, média e caudal) foram coletadas de cada retalho, para análise histológica. Resultados: à análise macroscópica, o uso do sildenafil pela via intraperitoneal esteve associado à maior contração tecidual (p=0,019). O estudo histológico evidenciou menos granulação associada a polimorfonucleares no terço distal dos retalhos (p=0,001) e mais necrose interpondo os locais de granulação no terço médio dos retalhos (p=0,011). Conclusão: o sildenafil intraperitoneal não se mostrou eficaz para melhorar a viabilidade de retalhos à McFarlane em ratos. Outros estudos talvez possam esclarecer o seu mecanismo de ação para a contração tecidual.

Sildenafil belong to a relatively new class of drugs. Its mechanism of action consists of inhibiting phosphodiesterase-5, which is responsible for the intracellular degradation of cyclic monophosphate guanosine (CMPG). CMPG leads to vasodilation, platelet granulation change, and angiogenesis. CMPG vasoactive effects can increase the blood flows of the flaps, improving their viability. This study aims to assess the viability of McFarland skin flaps after intraperitoneal sildenafil administration. Methods: In total, 20 Wistar mice were distributed in two groups: control (production of dorsal skin flap, intraperitoneal applicatdion of 0.9 % salt solution), and study (production of dorsal skin flap with intraperitoneal application of sildenafil). Skin flaps were photographed seven days after operation and represented graphically with a view to AutoCad-based analysis. Three biopsies (cranial, middle, and caudal) were collected for histological analysis of each flap. Results The macroscopic analysis showed that intraperitoneal application of sildenafil was associated with stronger tissue contraction (p=0.019). The histological study showed less granulation associated with polymorphonuclears in the distal third of the flaps (p=0.001) and more necrosis in granulation sites in the middle third of the flaps (p=0.011). Conclusion: The intraperitoneal application of sildenafil was not effective in improving the viability of McFarlane skin flaps in mice. Other studies may shed light into its mechanism of action for tissue contraction.

Altered Regulation of Renal Nitric Oxide and Atrial Natriuretic Peptide Systems in Lipopolysaccharide-induced Kidney Injury

Nitric oxide (NO) and atrial natriuretic peptide (ANP) may induce vascular relaxation by increasing the production of cyclic guanosine monophosphate (cGMP), an important mediator of vascular tone during sepsis. This study aimed to determine whether regulation of NO and the ANP system is altered in lipopolysaccharide (LPS)-induced kidney injury. LPS (10 mg.kg-1) was injected in the tail veins of male Sprague-Dawley rats; 12 hours later, the kidneys were removed. Protein expression of NO synthase (NOS) and neutral endopeptidase (NEP) was determined by semiquantitative immunoblotting. As an index of synthesis of NO, its stable metabolites (nitrite/nitrate, NOx) were measured using colorimetric assays. mRNA expression of the ANP system was determined by real-time polymerase chain reaction. To determine the activity of guanylyl cyclase (GC), the amount of cGMP generated in response to sodium nitroprusside (SNP) and ANP was calculated. Creatinine clearance decreased and fractional excretion of sodium increased in LPS-treated rats compared with the controls. Inducible NOS protein expression increased in LPS-treated rats, while that of endothelial NOS, neuronal NOS, and NEP remained unchanged. Additionally, urinary and plasma NOx levels increased in LPS-treated rats. SNP-stimulated GC activity remained unchanged in the glomerulus and papilla in the LPS-treated rats. mRNA expression of natriuretic peptide receptor (NPR)-C decreased in LPS-treated rats, while that of ANP and NPR-A did not change. ANP-stimulated GC activity reduced in the glomerulus and papilla. In conclusion, enhancement of the NO/cGMP pathway and decrease in ANP clearance were found play a role in the pathogenesis of LPS-induced kidney injury.

Transplantation of Muscle-Derived Stem Cells into the Corpus Cavernosum Restores Erectile Function in a Rat Model of Cavernous Nerve Injury

PURPOSE: Muscle-derived stem cells (MDSCs) harvested from skeletal muscles have the advantage of providing easier access and do not pose the immunogenic risks of embryonic stem cells. We investigated the effect of intracavernosal transplantation of MDSCs on erectile function in rats with bilateral cavernous nerve injury. MATERIALS AND METHODS: Adult male white rats underwent experimentation in 3 groups: group I, sham operation; group II, bilateral cavernous nerve injury; group III, bilateral cavernous nerve injury with MDSC injection. MDSCs were harvested from the femoral muscle of rats and were then injected into the cavernosum. Survival of MDSCs and measurement of erectile function was studied after 4 weeks. We checked the intracavernosal pressure (ICP) and obtained penile tissue. The expression of cyclic guanosine monophosphate (cGMP) was analyzed. RESULTS: Four weeks after transplantation, PKH-26-labeled MDSCs were identified in the cavernosal tissues of group III. Peak ICP and the drop rate of group II were 52+/-8.7 mmHg and 34+/-6.5 mmHg/min, respectively, whereas peak ICP and the drop rate of group III were 97+/-15.6 mmHg and 17+/-4.9 mmHg/min, respectively, showing that erectile function improved after MDSC transplantation (p<0.05). The expression of cGMP was significantly lower in group II (21.9+/-5.8 fmol/well) than in group I and group III (70.2+/-10.3 and 58.9+/-10.5 fmol/well, respectively). CONCLUSIONS: In a cavernous nerve injury rat model, intracavernosal transplantation of MDSCs showed acceptable survival of MDSCs as well as improvement of erectile function.

Protective effect of vitamin E against ischemia: reperfusion induced oxidative stress in isolated hearts from hyperthyroid rabbits

Hyperthyroidism either clinical or experimentally induced is associated with cardiac problems such as sinus tachycardia and atrial fibrillation in addition to reduction in ventricular contractility which is due to increased free radicals. It is now generally accepted that free radical-lipid peroxidation in biological membranes is associated with variety of important pathological events and aging. Vitamin E is one of the well known antioxidants used in clinical practice. The objective of this work is to study the effect of vitamin E on the functional recovery from in vitro induced ischemia-reperfusion of isolated hearts in hyperthyroid rabbits compared to euthyroid and vitamin E treated hyperthyroid ones. In the present study 40 normal male New Zealand rabbits, weighing 2.0-2.25 kg, were used and randomly divided into 4 groups, 10 rabbits each. Group-1 [euthyroid "E"]: rabbits received intramuscular [i.m.] injection of saline [1 ml/kg/day] for 8 days and oral corn oil vehicle [1 ml/kg/day] orally for 10 days, Group-II [hyperthyroid "H"]: as group-I but rabbits received i.m. injection of 1-thyroxin "T[4]" [200 micro g/kg/day] instead of saline, Group-III [vitamin E-treated "VE"]: rabbits received i.m. injection of saline [1 ml/kg/day] and oral vitamin E [200 micro g/kg/day] in corn oil vehicle for 10 days and Group-IV [hyperthyroid vitamin E-treated "HVE"]: as group-Ill but rabbits received i.m. injection of T[4] [200 micro g/kg/day] instead of saline. At the end of therapy, hearts were isolated, weighed and exposed to 30 min. no flow ischemia followed by 25 min. reperfusion. Pre-ischemic and after 25 min. reperfusion coronary effluent, heart rate [HR] and contractility parameters [amplitude of contractions, LVDP and dP/dt[max]] were assessed then hearts of each group were homogenized to measure the malondialdehyde [MDA] and guanosine 3',5'-cyclic monophosphate [cGMP]. The mean heart weight/BW ratio in [H] and [HVE] groups significantly increased after T4 therapy by +32.4% and +35.1% respectively compared to [E] group. Except for the mean coronary effluent, which showed insignificant changes, all other tested parameters significantly increased in [H] and [HVE] groups compared to corresponding pre-ischemic values of [E] group. All pre-ischemic values of [HVE] group insignificantly changed compared to that of [H] group. The mean coronary effluent significantly increased in [HVE] by +19.4% compared to [H] group after 25 min. reperfusion. However, the mean HR was significantly reduced in [HVE] by -34.7%; compared to [H] group after 25 min. reperfusion. The mean contractility parameters "amplitude of contractions, LVDP and dP/dt[max]" significantly increased in [HVE] by "+41.1%, +106%; and +40%;" respectively compared to [H] group after 25 min. reperfusion. The mean MDA and cGMP was significantly reduced in [HVE] by -45.7%- and -39.5%- respectively compared to [H] group. These results suggested that after exposure of isolated hyperthyroid rabbits' hearts to ischemia-reperfusion, as a model for oxidative stress, oral vitamin E could improve the contractility parameters, coronary flow as well as tachycardia response to reperfusion in addition to the improvement of the cardiac capability to face oxidative stresses in hyperthyroidism. This might need a further clinical study to prove the role of vitamin E in preventing ischemic cardiac dysfunction in patients with thyrotoxicosis