Erectile dysfunction drugs and oxidative stress in the liver of male rats

Mimosa pudica Linn. extract improves aphrodisiac performance in diabetes-induced male Wister rats

Male sexual dysfunction is considered one of the major consequences of diabetes mellitus. The medicinal plant, Mimosa pudica Linn. is believed to have numerous therapeutic effects, including anti-diabetic, anti-obesity, aphrodisiac, and a sexual behaviour-enhancing properties. In the present study, the significant effect of ethanolic extract of M. pudica L. to scavenge excessive free radicals and alleviate the deleterious effects of alloxan-induced diabetes on the male sexual system of rats was demonstrated. The rats treated with the M. pudica L. extract recovered their body weight, the weight of their reproductive organs, the characteristics of the sperm and the histocellular arrangement of the testes. In addition, significant levels of hormones (testosterone, follicle-stimulating hormone and luteinising hormone) increased in both serum and testicular homogenates of male diabetic rats treated with M. pudica L. extract. Further, antioxidant enzymes, SOD, CAT, GSH, and GPx levels are increased, and oxidative stress markers MDA and ROS are reduced in both serum and testicular homogenates of M. pudica L. extract treated male rats. Furthermore, an in silico molecular docking study was performed to predict high potential compounds of M. pudica L. extract against the PDE5 receptor. Two bioactive compounds, namely 3-Dibenzofuranamine (-11.1 kcal × mol-1), Stigmasta-7,16-dien-3-ol (-10.4 kcal × mol-1) showed the highest binding affinities with PDE5 enzyme, much higher than the reference drug sildenafil (-9.9 kcal × mol-1). According to these findings, bioactive compounds rich in ethanolic extract of M. pudica L. have significant aphrodisiac performance in diabetic rats.Communicated by Ramaswamy H. Sarma.

Potential and mechanisms of indigenous Indonesian medicinal plants in treating sexual dysfunction: A systematic review and pharmacological network overview

The epidemiology of Erectile Dysfunction (ED) continues to exhibit an increasing trend annually. The use of synthetic drugs in treating ED often leads to undesirable side effects and has limited efficacy. In Indonesia, several indigenous plants have been empirically utilized for ED remediation. This study aims to identify the latest scientific evidence on the potential of native Indonesian medicinal plants for ED treatment and elucidate the underlying molecular mechanisms using a systematic review and Pharmacological Network approach. There are 12 potential plants most commonly used by ethnic groups in Indonesia to treat erectile dysfunction (ED) as reviewed in this study. A systematic review search was conducted across three databases (PubMed, Scopus, and Springer) without limiting the publication years. Article screening was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flowchart. Determination of compound target genes was carried out using GeneCards, while disease target genes were analyzed using DisGeNET. Network topology was explored with Cytoscape 3.10, and the construction of Protein-Protein Interaction Networks was realized using STRING version 12.0. GO and KEGG analyses were subsequently conducted with SRplot. The systematic review findings indicated that 12 articles met the predefined inclusion criteria. The pharmacology network analysis demonstrated that the compounds present in Eurycoma longifolia, specifically stigmasterol, eurycomanone, and eurycomalactone, target 13 genes associated with erectile dysfunction (ED), which include BCL2, AKT1, SOAT1, PCSK9, ACHE, BDNF-AS, TMX2-CTNND1, GSK3B, LINCO1672, TP53, H19, HIF1A, and IL1B. These target genes are connected to the biological mechanisms underlying steroid hormone biosynthesis, which is essential for the formation of testosterone. Therefore, Eurycoma longifolia demonstrates significant potential for development as a promising phytopharmaceutical candidate in the treatment of sexual dysfunction.

Blockade of phosphodiesterase 5 by sildenafil reduces tumor growth and potentiates tumor-killing ability of cisplatin in vivo against T cell lymphoma: Implication of modulated apoptosis, reactive oxygen species homeostasis, glucose metabolism, and pH regulation

In the past years, PDE5 has emerged as a promising therapeutic target for many cancers due to its highly upregulated expression. Interestingly, a recent in vitro study by our group has shown the antitumor and chemopotentiating action of sildenafil against T cell lymphoma. Our study showed that lower doses of sildenafil (50 μM) and cisplatin (0.5 μg/mL) exhibited 4% and 23% cytotoxicity against HuT78 cells, respectively, which was dramatically increased up to 50% when treated with both. Hence, the present study was designed to evaluate the antitumor and chemo-potentiating action of sildenafil in a murine model of T cell lymphoma (popularly called as Dalton's lymphoma [DL]). In the present study, DL-bearing mice were administered with vehicle (PBS), sildenafil (5 mg/kg bw), cisplatin (5 mg/kg bw), and sildenafil and cisplatin followed by evaluation of their impact on tumor growth by analyzing various parameters. The apoptosis was assessed by Wright-Giemsa, annexin-V, and DAPI staining. Reactive oxygen species (ROS) level was examined through DCFDA staining. The expression of genes and proteins were estimated by RT-PCR and Western blotting, respectively. The experimental findings of the study demonstrate for the first time that sildenafil inhibits tumor growth and potentiates tumor inhibitory ability of cisplatin by altering apoptosis, glycolysis, ROS homeostasis, and pH regulation in T cell lymphoma-carrying host. In addition, our investigation also showed amelioration of tumor-induced liver and kidney damage by sildenafil. Overall, the experimental data of our study strongly advocate the use and repurposing of SDF in designing promising chemotherapeutic regimens against malignancies of T cells.

Withania somnifera ameliorates sexual arousal and impotence in stressed sexually sluggish male rats by modulating neurotransmitters and NO/cGMP/PDE5α pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Psychological stress is a growing global threat to male sexual potency and erection efficiency. Withania somnifera (L.) Dunal (WS), also known as Ashwagandha, is a well-known Ayurvedic herb. The roots of Withania somnifera improve the body's ability to handle stress, strengthen the immune system, promote healthy ageing, and have aphrodisiac properties with male sexual stimulation effects. Despite its widespread acceptance as an Ayurvedic stress-relieving drug with beneficial effects on male reproductive health, Withania somnifera has yet to be studied for its potential role in improving the sexual arousal and erectile dysfunction of psychologically stressed sexually sluggish males.

AIM OF THE STUDY

To investigate the therapeutic effects of purified root powder of Withania somnifera on sexual behaviour and erectile efficiency in stressed sexually sluggish male rats.

MATERIALS AND METHODS

Sexually sluggish male rats were screened by premating tests after being exposed to a psychological stressor, restraint stress, 3 h/day for 30 days. Subsequently, these rats were treated with purified root powder of WS (150 or 300 mg/kg/day-PO) or sildenafil (5 mg/kg/day-PO) for 30 days. The rats were sacrificed after 24 h of the last treatment, and the effects on various factors related to sexual behaviour, penile histomorphology, serum hormones, and neurotransmitters associated with sexual arousal and penile erection were examined.

RESULTS

WS treatment improves prosexual and sexual behaviour in psychologically stressed sexually sluggish male rats by increasing non-contact erections and mounts, intromission, and ejaculation frequencies, while decreasing sexual exhaustion by decreasing post-ejaculation intervals and latencies. WS also modulates neurotransmitters and hormones associated with sexual desire and stress, including dopamine, serotonin, corticosterone, and prolactin. Additionally, there was also a dose-dependent increase in serum LH, FSH, and testosterone levels. The administration of WS to sexually sluggish rats resulted in significant improvements in penile histomorphology, specifically by increasing the ratio of smooth muscle (SM) to collagen. Furthermore, in sexually sluggish rats, WS treatment increased the expression of markers associated with penile erection facilitation, such as nNOS, eNOS, p-Akt, nitric oxide, acetylcholine, and cGMP. Notably, WS treatment decreased the expression of penile PDE5α in these rats in a dose-dependent manner. Remarkably, the therapeutic effects of WS are comparable to those of sildenafil.

CONCLUSIONS

Purified root powder of Withania somnifera was found to improve sexual arousal and erection efficiency in stressed, sexually sluggish male rats. This improvement was achieved by modulating the HPG and HPA axes as well as the NO/cGMP/PDE5α pathway involved in penile erection. Thus, our findings strongly support the potent therapeutic potential of purified root powder of WS in improving the sexual health of stressed sexually sluggish rats.

Immunomodulatory, apoptotic and anti-proliferative potentials of sildenafil in Ehrlich ascites carcinoma murine model: In vivo and in silico insights

Sildenafil is a potent phosphodiesterase-5 (PDE5) inhibitor that effectively inhibits cGMP and increases the strength of nitric oxide. PDE5 was overexpressed in several carcinomas, including breast cancer, which inhibited tumor growth and cell division. The current research aims to investigate the in vivo sildenafil's immunomodulatory and antineoplastic potentials against Ehrlich Ascites Carcinoma. This study looked at the effects of sildenafil mono-treatment and co-treatment with cisplatin; tumor cell count, viability and the inhibition rate were determined. Apoptosis, cell cycle distribution, alterations in tumor cells and splenocytes proliferation, changes in splenocytes immunophenotyping using flowcytometry, plasma levels of malondialdehyde (MDA), reduced glutathione (GSH), interferone (IFN)-γ, granzyme B, alanine aminotransferase (ALT), aspartate aminotransferase (AST), urea, creatinine and hematological alterations were detected. Additionally, docking study was conducted to get further insights on how Sildenafil exerts its activity. Sildenafil mono-treatment and co-treatment with cisplatin markedly reduced tumor cell count, viability, growth rate and proliferative capability accompanied by apoptosis enhancement and G₀/G₁ and sub G₁ cells cycle arrest. Fortunately, sildenafil evoked efficient cellular immune response by increasing plasma levels of granzyme B and IFN-γ, proportion of splenic T cytotoxic (CD3⁺CD8⁺) and T helper (CD3⁺CD4⁺), accompanied by decrease in the proportion of splenic regulatory T cells. . Moreover, in silico data suggest LcK and MAPKs as the potential targets of sildenafil. Furthermore, sildenafil rebalanced the oxidant-antioxidant status by decreasing MDA and increasing GSH plasma levels. Sildenafil successfully retrieved various hematological values besides renal and hepatic functions in EAC-bearing animals. In conclusion, our results suggest that sildenafil could be potential safe anti-tumor agent with immuno-modulatory properties against Ehrlich ascites carcinoma.

Chitosan Nanoparticles Alleviated the Adverse Effects of Sildenafil on the Oxidative Stress Markers and Antioxidant Enzyme Activities in Rats

Sildenafil (SF) is widely used for erectile dysfunction and other conditions, though with limitations regarding oral absorption and adverse effects. Despite nanotechnological improvements, the effect of nanocarriers on SF hepatotoxicity has not been documented to date. This study aimed at assessing the impact of chitosan nanoparticles either uncoated (CS NPs) or Tween 80-coated (T-CS NPs) on the effects of SF on oxidative stress markers and antioxidant enzyme activities in rats. Test SF-CS NPs prepared by ionic gelation were uniform positively charged nanospheres (diameter 178-215 nm). SF was administered intraperitoneally to male rats (1.5 mg/kg body weight) in free or nanoencapsulated forms as SF-CS NPs and T-SF-CS NPs for 3 weeks. Free SF significantly suppressed the activity of the antioxidant enzymes glutathione S-transferase (GST), glutathione peroxidase (GPx), glutathione reductase (GR), catalase (CAT), and superoxide dismutase (SOD), as well as the levels of glutathione (GSH) and thiobarbituric acid reactive substances (TBARS) as in an indirect measure of free radicals. Interestingly, SF-CS NPs and T-SF-CS-NPs treatments significantly attenuated the inhibitory effects of SF on the activity of these enzymes whereas, GST activity was inhibited. Moreover, the protein expression of GST was downregulated upon treatment of rats with free SF, SF-CS-NPs, and T-SF CS-NPs. In contrast, the activity and protein expression of GPx was induced by SF-CS NPs and T-SF-CS-NPs treatments. The histopathological study showed that SF induced multiple adverse effects on the rat liver architecture which were markedly suppressed particularly by T-SF-CS NPs. In conclusion, chitosan nanoencapsulation of SF counteracted the adverse effects of SF on the activity of antioxidant enzymes and liver architecture. Findings might have significant implications in improving the safety and efficacy of SF treatment of the widely expanding disease conditions.

Grapefruit peel extract mitigates paroxetine-induced erectile dysfunction in rats through stimulation of erectile response, antioxidant status, and inhibition of key enzymes related with impaired penile erection

Despite the antidepressant potency of paroxetine, its side effect of erectile dysfunction is burdensome. Grapefruit peels (GFPs) are underutilized cultivar wastes with wide range of therapeutic potentials which have been attributed to their antioxidant behavior and phenolic contents' abilities to effectively inhibit enzymatic activities and manage endothelial dysfunction in cardiovascular disorders. This study aims to investigate the erectogenic potentials of GFP extract in a rat model of paroxetine-induced ED. Experimental rats were sectioned into five groups: [1: control; 2: paroxetine (10 mg/kg); 3: paroxetine + sildenafil (5 mg/kg); 4: paroxetine + GFP (50 mg/kg); 5: paroxetine + GFP (100 mg/kg)] and treated for 28 days. Sexual behavior of rats was assessed and effect of GFP on ecto-5' nucleotidases, phosphodiesterase-5, and adenosine deaminase (ADA) activities was determined in rats' penile tissues. The levels of malondialdehyde, nitric oxide (NO) as well as superoxide dismutase (SOD) and catalase activities were also determined. HPLC-DAD analysis showed the presence of naringin, rutin, caffeic acid, quercitrin, quercetin, and kaempferol glycoside. Oral administration of paroxetine reduced erectile response as revealed by their low intromission and mounting numbers as well as high intromission and mounting latencies. Paroxetine caused a significant elevation of ADA and phosphodiesterase-5 activities and malondialdehyde levels with drastic reduction in levels of NO, SOD, and catalase activities in rats' penile tissues. However, GFP extract reversed PDE-5, ADA, and antioxidant activities to normal levels, raised the concentration of NO. These results suggest the erectogenic effects and protective potentials of GFP extract against paroxetine-induced erectile dysfunction. PRACTICAL APPLICATION: Grapefruit peels are an environmental menace in many countries and this study showed that the peels can be used in the prevention / management of erectile dysfunction. The therapeutic potentials of the peels are due to the presence of bioactive compounds such as flavonoids and phenolic acids. Therefore, exploring the erectogenic potentials of the peels will translate to conversion of the wastes to therapeutic products.

Influence of lemon (Citrus limon) and lime (Citrus aurantifolia) juices on the erectogenic properties of sildenafil in rats with L-NAME-induced erectile dysfunction

The use of lemon (Citrus limon) and lime (Citrus aurantifolia) juices for the treatment of erectile dysfunction (ED) is fast becoming common practice, even though there is dearth of information on the effect of such functional food and drug combination in the management of ED. This study evaluated the effect of lemon and lime juices on the erectogenic properties of sildenafil. ED was induced with L-NAME (40 mg/kg body weight). The rats were divided into 11 groups (n = 6) and given various doses of the test samples. Immediately after the sexual behavior studies, the animals were sacrificed and the penile and brain tissues were isolated. The results revealed that lime and lemon juices improved sexual behavior in rats by improving NO production and inhibiting the activities of PDE-5, arginase, ACE, MAO, ATPdase, AMPdase, and activated antioxidant enzymes. Furthermore, lime at 1.0 ml/kg significantly improved the therapeutic properties of sildenafil. While, lemon (0.5 and 1.0 ml/kg) and lime (0.5 ml/kg) did not show any synergistic effect. This study revealed that lime and lemon juices could improve erectile function and combining lime juice with sildenafil could be very effective in the management of ED. PRACTICAL APPLICATIONS: The therapeutic management of erectile dysfunction has involved maximizing NO production through the modulation of macromolecules such as phosphodiesterase-5 and arginase with the use of drugs such as sildenafil. Combining such drugs with functional foods such as lime and lemon juices is becoming common practice. However, there is dearth of report on the effect of lime and lemon juices on the erectogenic potentials of sildenafil. The present study shows that combining 1 ml/kg lime juice (got from 2 lime fruits) with sildenafil will boost the erectogenic properties of the drug. While combining lime (0.5 ml/kg) and lemon (0.5 and 1.0 ml/kg) juices with the drug did not have any synergistic effect.

Phytochemical Screening by LC-ESI-MS/MS and Effect of the Ethyl Acetate Fraction from Leaves and Stems of Jatropha macrantha Müll Arg. on Ketamine-Induced Erectile Dysfunction in Rats

Jatropha macrantha Müll Arg. L is also known as “huanarpo macho” and used in the Peruvian traditional medicine as an aphrodisiac and erectile dysfunction (ED). The aim of this study was to determine the phytochemical constituents in leaves and stems ethyl acetate fraction (LEAF and SEAF) of J. macrantha and to compare the antioxidant activity and the ameliorative effect on ketamine-induced erectile dysfunction in rats. The phytochemical constituents were determined by LC-ESI-MS/MS, the total phenolic compounds and total flavonoids (TPC and TF) by Folin-Ciocalteu and aluminum chloride, respectively. The antioxidant activity was determined by DPPH, ABTS, and FRAP assays. Experimental groups were divided as follows: I: negative control; II: positive control (ketamine at 50 mg/ kg/d); III: sildenafil 5 mg/kg; IV, V, VI: LEAF at 25, 50 and 100 mg/kg, respectively, and VII, VIII, IX: SEAF at 25, 50, and 100 mg/kg, respectively. The phytochemical analysis revealed the presence mainly of coumarins, flavonoids, phenolic acids, and terpenes. TPC of LEAF and SEAF were 359 ± 5.21 mg GAE/g and 306 ± 1.93 mg GAE/g, respectively; TF in LEAF and SEAF were 23.7 ± 0.80 mg EQ/g, and 101 ± 1.42 mg EQ/g, respectively. The DPPH, ABTS, FRAP in SEAF were 647 ± 3.27; 668 ± 2.30; and 575 ± 2.86 μmol TE/g, respectively, whilst LEAF showed 796 ± 3.15; 679 ± 0.85; and 806 ± 3.42 μmol TE/g, respectively. Regarding sexual behavior, LEAF showed a better effect in mount frequency, intromission frequency, ejaculation frequency, mount latency, intromission latency, ejaculatory latency, and post ejaculatory latency than SEAF. As conclusion, LEAF of J. macrantha at 50 mg/kg showed a better effect on sexual behavior in male rats with erectile dysfunction than SEAF but not higher than sildenafil.

D-(+)-Galactose-induced aging: A novel experimental model of erectile dysfunction

Erectile dysfunction (ED) is defined as the inability to achieve and/or maintain penile erection sufficient for satisfactory sexual relations, and aging is one of the main risk factors involved. The D-(+)-Galactose aging model is a consolidated methodology for studies of cardiovascular aging; however, its potential for use with ED remain unexplored. The present study proposed to characterize a new experimental model for ED, using the D-(+)-Galactose aging model. For the experiments, the animals were randomly divided into three groups receiving: vehicle (CTL), D-galactose 150 mg/kg (DGAL), and D-(+)-galactose 150 mg/Kg + sildenafil 1.5 mg/Kg (DGAL+SD1.5) being administered daily for a period of eight weeks. All of the experimental protocols were previously approved by the Ethics Committee on the Use of Animals at the Federal University of Paraíba n° 9706070319. During the treatment, we analyzed physical, molecular, and physiological aspects related to the aging process and implicated in the development of ED. Our findings demonstrate for the first time that D-(+)-Galactose-induced aging represents a suitable experimental model for ED assessment. This was evidenced by an observed hyper-contractility in corpora cavernosa, significant endothelial dysfunction, increased ROS levels, an increase in cavernous tissue senescence, and the loss of essential penile erectile components.

The effect of selected drugs on the mitigation of myocardial injury caused by gamma radiation

Radiation damage of healthy tissues represents one of the complications of radiotherapy effectiveness. This study is focused on the screening of potentially effective drugs routinely used in medical practice and involved in the mechanism of radiation injury, namely for radiation-induced production of free radicals in the body. Experiments in rats revealed significant reduction of oxidative stress (malondialdehyde) and inflammatory marker (tumor necrosis factor α) in 10 Gy irradiated groups after administration of atorvastatin and a slight decrease after tadalafil administration, which indicates that one of the possible mechanisms for mitigation of radiation-induced cardiac damage could be the modulation of nitric oxide (NO) in endothelium and phosphodiesterase 5. In addition, miRNAs were analyzed as potential markers and therapeutically effective molecules. Expression of miRNA-21 and miRNA-15b showed the most significant changes after irradiation. Atorvastatin and tadalafil normalized changes of miRNA (miRNA-1, miRNA-15b, miRNA-21) expression levels in irradiated hearts. This screening study concludes that administration of specific drugs could mitigate the negative impact of radiation on the heart, but more detailed experiments oriented to other aspects of drug effectiveness and their exact mechanisms are still needed.

Comparative efficacy of Gum Arabic (Acacia senegal) and Tribulus terrestris on male fertility

In this study the effect of Gum arabic (Acacia Senegal) was systemically targeted at male fertility with two experiments, the first comparing the effectiveness of Gum arabic (GA) and Tribulus terrestris (TT). For the first experiment, 27 adult mice Balb / c (18 females, 9 males) were divided into 3 in each group, one male and two females, group one had the usual tap water as power, group two had 5% (w / v) GA and group three had 5% (w / v) of TT for 21 days. The results showed, the number of offspring was more with GA treated when compared to TT treated. Blood measurements of testosterone showed significant increase in the GA group as compared to other groups, also Histopathological analysis showed the dose dependent 5% GA had normal seminiferous tubules with increase spermatogenesis. In this study the enhanced fertility in GA-treated mice Balb/c was observed and the experimental studies also show that GA fertility was increased.

Erectile dysfunction drugs altered the activities of antioxidant enzymes, oxidative stress and the protein expressions of some cytochrome P450 isozymes involved in the steroidogenesis of steroid hormones

OBJECTIVES

Infertility is a global health problem with about 15 percent of couples involved. About half of the cases of infertility are related to male-related factors. A major cause of infertility in men is oxidative stress, which refers to an imbalance between levels of reactive oxygen species (ROS) and antioxidants. Erectile dysfunction drugs (EDD), known as phosphodiesterase inhibitors (PDEIs), have been used for the treatment of ED. It has been shown that oxidative stress plays an important role in the progression of erectile dysfunction. Oxidative stress can be alleviated or decreased by non-antioxidants and antioxidant enzymes. The present study was undertaken to determine if these compounds could have a role in the incidence of infertility, especially after long-term use. Therefore, the present study aims to investigate the effect of EDD on the activities of antioxidant enzymes, free radical levels as well as the protein expression of different cytochrome P450 isozymes involved in the steroidogenesis of different hormones. In addition, the activity of both 17β-hydroxysteroid dehydrogenase and 17-ketosteroid reductase were assayed. The architectures of both livers and testes cells were investigated under the influence of EDD.

METHODS

A daily dose of Sildenafil (1.48 mg/kg), Tadalafil (0.285 mg/kg) and Vardenafil (0.285 mg/kg) were administered orally to male rabbits for 12 week. Western immunoblotting, ELISA, spectrophotometric and histopathological techniques were used in this study.

RESULTS

The present study showed that Sildenafil, Vardenafil, and Tadalafil treatments significantly decreased the levels of glutathione and free radicals in both livers and testes of rabbits. Also, Vardenafil and Sildenafil induced the activity of superoxide dismutase and catalase whereas, glutathione S-transferase, glutathione reductase, and glutathione peroxidase activities inhibited in livers of rabbits. The protein expression of cytochrome P450 isozymes (CYP 11A1, 21A2, and 19C) which are involved in the steroidogenesis was markedly changed in both livers and testes of rabbits after their treatments for 12 weeks. After the treatment of rabbits with these medication, the protein expression of CYP11A1 was slightly down-regulated in both livers and testes except Sildenafil up-regulated such protein expression. In addition, the protein expressions of CYP11A1 and CYP 19C in both livers and testes were down-regulated after treatment of rabbits with Sildenafil, Vardenafil, and Tadalafil for 12 weeks. Also, these drugs inhibited the activity of both 17β-hydroxysteroid dehydrogenase and 17-ketosteroid reductase in testes of rabbits. Moreover, Sildenafil, Vardenafil, and Tadalafil-treated rabbits showed a decrease in spermatocytes and the number of sperms in the testes.

CONCLUSIONS

It is concluded that ED drugs induced the activities of both SOD and catalase which consequently decreased MDA level. Decrement in MDA levels and oxidative stress could therefore sustain the erection for a long period of time. On the other hand, it is not advised to use these drugs for a long-term since the protein expressions of CYP isozymes involved in steroidogenesis as well as the numbers of spermatocytes in testes were decreased.

The Phosphodiesterase-5 Inhibitor Vardenafil Improves the Activation of BMP Signaling in Response to Hydrogen Peroxide

PURPOSE

The pleiotropic roles of phosphodiesterase-5 inhibitors (PDE5is) in cardiovascular diseases have attracted attention. The effect of vardenafil (a PDE5i) is partly mediated through reduced oxidative stress, but it is unclear whether vardenafil protects against hydrogen peroxide (H₂O₂)-induced endothelial cell injury, and the molecular mechanisms that are involved remain unknown. We determined the protective role of vardenafil on H₂O₂-induced endothelial cell injury in cultured human umbilical vein endothelial cells (HUVECs).

METHODS AND RESULTS

Vardenafil decreased the number of TUNEL-positive cells, increased the Bcl2/Bax ratio, and ameliorated the numbers of BrdU-positive cells in H₂O₂-treated HUVECs. The bone morphogenetic protein receptor (BMPR)/p-Smad/MSX2 pathway was enhanced in response to H₂O₂, and vardenafil treatment could normalize this pathway. To determine whether the BMP pathway is involved, we blocked the BMP pathway using dorsomorphin, which abolished the protective effects of vardenafil. We found that vardenafil improved the H₂O₂-induced downregulation of BMP-binding endothelial regulator protein (BMPER), which possibly intersects with the BMP pathway in the regulation of endothelial cell injury in response to oxidative stress.

CONCLUSIONS

We demonstrated for the first time that exogenous H₂O₂ activates BMPR expression and promotes Smad1/5/8 phosphorylation. Additionally, vardenafil can attenuate H₂O₂-induced endothelial cell injury in HUVECs. Vardenafil decreases apoptosis through an improved Bcl-2/Bax ratio and increases cell proliferation. Vardenafil protects against endothelial cell injury through ameliorating the intracellular oxidative stress level and BMPER expression. The protective role of vardenafil on H₂O₂-induced endothelial cell injury is mediated through BMPR/p-Smad/MSX2 in HUVECs.

Potential activity of Aframomum daniellii (Zingiberaceae) dry seeds: A case study of its action mechanism on the Wistar rat strain with testicular deficiency

This work was undertaken to evaluate the biological activity of the aqueous extract of the dry seeds of Aframomum daniellii seeds on the copulatory performance of rats with testicular deficiency. Hypogonadal adult male rats (30) were divided into 6 groups: group I received distilled water (10 ml/kg), group II received sildenafil citrate (5 mg/kg), group III received intramuscular injections of testosterone enanthate (3. 6 mg/kg), group IV, V, and VI received the aqueous extract of A. daniellii at the respective doses of 100, 200, and 400 mg/kg/po/day for 14 days. The copulatory performance of the animals were assessed on days 1, 7 and 14 through the following copulation parameters: Mount, intromission, and ejaculation latency (ML, IL, and EL) and frequency (MF, IF and EF), average interval of copulation (AIC) and post-ejaculatory interval (PEI)). We noticed a significant decrease of ML (p < 0.05), IL (p < 0.01), EL (p < 0.001) and the increase of MF, IF and EF (p < 0.01) particularly at doses of 100 and 400 mg/kg when compared to group I and II. In addition, we noticed a significant increase of AIC from day 7 (p < 0.05) to day 14 (p < 0.001) at the same two doses while the PEI significantly decreased from the 1st (p < 0.01) to the 14th day (p < 0.001) when compared to group I and II. These findings demonstrated that A. daniellii aqueous extract of seeds enhanced pro-sexual potential and pro-sexual desire in male rats with testicular deficiency.

Phosphodiesterase-5 inhibitors ameliorate structural kidney damage in a rat model of contrast-induced nephropathy

The aim of the study was to investigate the potential of sildenafil and tadalafil to ameliorate structural kidney damage in contrast-induced nephropathy (CIN). A rat model of CIN was developed by dehydration, administration of a nitric oxide inhibitor and a prostaglandin synthesis inhibitor (L-NAME/indomethacin) and contrast media exposure to iopromide. The effect of pre-treatment with sildenafil, tadalafil or N-acetyl cysteine (NAC) for 7 days prior to CIN induction was investigated. All animals were sacrificed at 24 h after CIN induction and both kidneys were collected. Histopathological examination was performed under light microscopy in serial tissue sections stained with hematoxylin and eosin. CIN group showed hydropic changes of the renal tubules (proximal and distal convoluted tubules and Henle's loop), an increased Bowman space with lobulated glomerulus and alteration of macula densa region of distal convolute tubules. The groups pretreated with sildenafil and tadalafil showed nearly normal histological aspects of renal tissue. The group pretreated with NAC showed similar but less intense histopathologic changes compared to CIN group. Sildenafil and tadalafil pre-treatment ameliorates CIN-related structural kidney damage and the protective potential of these agents is superior to NAC.

Sildenafil for the Treatment of Alzheimer's Disease: A Systematic Review

Nitric oxide/cyclic guanosine monophosphate (cGMP) signaling is compromised in Alzheimer’s disease (AD), and phosphodiesterase 5 (PDE5), which degrades cGMP, is upregulated. Sildenafil inhibits PDE5 and increases cGMP levels. Integrating previous findings, we determine that most doses of sildenafil (especially low doses) likely activate peroxisome proliferator-activated receptor-γ coactivator 1α (PGC1α) via protein kinase G-mediated cyclic adenosine monophosphate (cAMP) response element binding protein (CREB) phosphorylation and/or Sirtuin-1 activation and PGC1α deacetylation. Via PGC1α signaling, low-dose sildenafil likely suppresses β-secretase 1 expression and amyloid-β (Aβ) generation, upregulates antioxidant enzymes, and induces mitochondrial biogenesis. Plus, sildenafil should increase brain perfusion, insulin sensitivity, long-term potentiation, and neurogenesis while suppressing neural apoptosis and inflammation. A systematic review of sildenafil in AD was undertaken. In vitro, sildenafil protected neural mitochondria from Aβ and advanced glycation end products. In transgenic AD mice, sildenafil was found to rescue deficits in CREB phosphorylation and memory, upregulate brain-derived neurotrophic factor, reduce reactive astrocytes and microglia, decrease interleukin-1β, interleukin-6, and tumor necrosis factor-α, decrease neural apoptosis, increase neurogenesis, and reduce tau hyperphosphorylation. All studies that tested Aβ levels reported significant improvements except the two that used the highest dosage, consistent with the dose-limiting effect of cGMP-induced phosphodiesterase 2 (PDE2) activation and cAMP depletion on PGC1α signaling. In AD patients, a single dose of sildenafil decreased spontaneous neural activity, increased cerebral blood flow, and increased the cerebral metabolic rate of oxygen. A randomized control trial of sildenafil (ideally with a PDE2 inhibitor) in AD patients is warranted.

Sex-related differences in oxidative stress and neurodegeneration

Oxidative stress has been implicated in a number of neurodegenerative diseases spanning various fields of research. Reactive oxygen species can be beneficial or harmful, depending on their concentration. High levels of reactive oxygen species can lead to oxidative stress, which is an imbalance between free radicals and antioxidants. Increased oxidative stress can result in cell loss. Interestingly, sex differences have been observed in oxidative stress generation, which may underlie sex differences observed in neurodegenerative disorders. An enhanced knowledge of the role of sex hormones on oxidative stress signaling and cell loss can yield valuable information, leading to sex-based mechanistic approaches to neurodegeneration.

Moringa oleifera extract (Lam) attenuates Aluminium phosphide-induced acute cardiac toxicity in rats

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Aluminium phosphide (AlP) affects many organs especially heart.

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Antioxidant activities of Moringa was investigated after acute AlP intoxication.

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Moringa preventive effects were determined histopathologically.

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Moringa significantly re-equilibrates antioxidant parameters back near to their normal values.

Background

Moringa oleifera extract (Lam) has many antioxidant and protective properties. Objective: to investigate the antioxidant activities of Lam in counteracting the high oxidative stress caused by acute sub-lethal aluminium phosphide (AlP) intoxication in rat heart. These activities will be detected by histopathological examination and some oxidative stress biomarkers.

Methods

a single sub-lethal dose of Alp (2 mg/kg body weight) was administered orally, and Lam was given orally at a dose (100 mg/kg body weight) one hour after receiving AlP to rats.

Results

aluminium phosphide caused significant cardiac histopathological changes with a significant increase in malondialdehyde (MDA); lipid peroxidation marker; and a significant depletion of antioxidant enzymes (catalase and glutathione reductase). However, treatment with Lam protected efficiently the cardiac tissue of intoxicated rats by increasing antioxidants levels with slight decreasing in MDA production compared to untreated group.

Conclusions

This study suggested that Moringa oleifera extract could possibly restore the altered cardiac histopathology and some antioxidant power in AlP intoxicated rats, and it could even be used as adjuvant therapy against AlP-induced cardiotoxicity.

Effects of phosphodiestrase type 5 inhibitors in epinephrine-induced arrhythmia in rats: Involvement of lactate dehydrogenase and creatine kinase downregulation and adiponectin expression

Cardiac arrhythmia is a common cause of mortality, and its progression may be due to abnormal sympathetic nerve activity and catecholamine release. Besides, lactate dehydrogenase (LDH) and creatine kinase (CK) downregulation and adiponectin expression play important roles in promoting coronary artery disease. The study aimed to examine the possible cardioprotective effect of members of phosphodiesterase type 5 (PDE-5) inhibitors in epinephrine-induced arrhythmia in rats. Arrhythmia was induced by cumulative boluses of epinephrine (4, 8, 16, 32, 64, and 128 mg/kg) given at 10-min intervals. Rats were randomly allocated into five groups. Group I: Normal control group received only saline. Group II: Rats injected with epinephrine and served as arrhythmia group. Groups III, IV, and V: Rats received daily oral sildenafil (0.5 mg/kg), vardenafil (3 mg/kg), and tadalafil (10 mg/kg), respectively, for 30 days prior to epinephrine injections. Injection of epinephrine to rats decreased heart rate and QTc interval but increased RR interval and duration of arrhythmia. Epinephrine group had lower serum reduced glutathione (GSH) and adiponectin levels and higher serum malondialdehyde (MDA), nitric oxide (NO), heart LDH, and CK contents. Histopathological investigations of epinephrine group provoked necrotic changes with strong positive immunoreactivity for caspases-3. While pretreatment of rats with PDE-5 inhibitors improved GSH and adiponectin contents, ameliorated serum MDA and NO levels and heart LDH and CK contents and corrected epinephrine-induced histopathological changes. PDE-5 inhibitors may delay epinephrine-induced arrhythmia through expression of adiponectin and downregulation of heart LDH and CK.

Chemotherapeutic efficacy of phosphodiesterase inhibitors in chagasic cardiomyopathy

Molecular mechanisms of Trypanosoma cruzi (Tc)-induced Chagasic cardiomyopathy (CCM) are not well understood. The NO-cGMP-PKG1α pathway maintains cardiac homeostasis and inotropy and may be disturbed due to phosphodiesterase (PDE5)-mediated cGMP catabolism in CCM. To test this, C57BL/6 mice were infected with T. cruzi, and after the control of acute parasitemia (∼45 days post-infection), given sildenafil (SIL) (1 mg/kg) treatment for 3 weeks that ended long before the chronic disease phase (∼150 days post-infection). The PDE5 was increased and cGMP/PKG activity was decreased in chagasic myocardium. Transthoracic echocardiography revealed left ventricular (LV) systolic function, that is, stroke volume, cardiac output, and ejection fraction, was significantly decreased in chagasic mice. SIL treatment resulted in normal levels of PDE5 and cGMP/PKG activity and preserved the LV function. The cardioprotective effects of SIL were provided through inhibition of cardiac collagenosis and chronic inflammation that otherwise were pronounced in CCM. Further, SIL treatment restored the mitochondrial DNA–encoded gene expression, complex I–dependent (but not complex II–dependent) ADP-coupled respiration, and oxidant/antioxidant balance in chagasic myocardium. In vitro studies in cardiomyocytes verified that SIL conserved the redox metabolic state and cellular health via maintaining the antioxidant status that otherwise was compromised in response to T. cruzi infection. We conclude that SIL therapy was useful in controlling the LV dysfunction and chronic pathology in CCM.

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Mice infected with T. cruzi control acute parasitemia but develop chronic chagasic cardiomyopathy.

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Treatment with SIL (a phosphodiesterase inhibitor) during a therapeutic window of indeterminate phase provided powerful cardioprotective effects against chronic development of cardiomyopathy and LV dysfunction.

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SIL normalized the cGMP-dependent protein kinase activity and mitochondrial oxidative metabolism, and established the oxidant/antioxidant balance in chagasic myocardium.

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SIL prevented the oxidative/inflammatory adducts that precipitate cardiomyocytes death and cardiac remodeling in CCM.