Chronic Ethanol Consumption Induces Cavernosal Smooth Muscle Dysfunction in Rats

doi:10.1016/j.urology.2009.04.043

Urology

Volume 74, Issue 6, December 2009, Pages 1250-1256

https://doi.org/10.1016/j.urology.2009.04.043 Get rights and content

Objectives

To investigate the effects of chronic ethanol consumption on nitric oxide (NO)–mediated relaxation in rat cavernosal smooth muscle (CSM).

Methods

Male wistar rats were divided into 2 groups: control and ethanol. CSM obtained from both groups were mounted in organ chambers for measurement of isometric tension. Contraction of the strips was induced by electrical field stimulation (EFS, 1-32 Hertz) and phenylephrine. We also evaluated the effect of ethanol consumption on the relaxation induced by acetylcholine (0.01-1000 μmol L⁻¹), sodium nitroprusside (SNP, 0.01-1000 μmol L⁻¹), or EFS (1-32 Hz) in strips precontracted with phenylephrine (10 μmol L⁻¹). Blood ethanol, serum testosterone levels, and basal nitrate generation were determined. Immunoexpression of endothelial NO synthase (eNOS) and inducible NO synthase (iNOS) was also accessed.

Results

Ethanol intake for 4 weeks significantly increased noradrenergic nerve-mediated contractions of CSM in response to EFS. The endothelium-dependent relaxation induced by acetylcholine decreased after the ethanol treatment. Ethanol consumption decreased serum testosterone levels but did not affect the nitrate levels on rat CSM. The mRNA and protein levels for eNOS and iNOS receptors were increased in CSM from ethanol-treated rats.

Conclusions

Ethanol consumption reduces endothelium-dependent relaxation induced by acetylcholine, but does not affect SNP or EFS-induced relaxation, suggesting that ethanol disrupts the endothelial function. Despite the overexpression of eNOS and iNOS in ethanol-treated rats, the impaired relaxation induced by acetylcholine may suggest that chronic ethanol consumption induces endothelial dysfunction.

Section snippets

Experimental Design

Male Wistar rats with body mass in the range 200-230 g were randomly divided into 2 groups (control and ethanol) at the start of the experiment. Rats in the control group received tap water ad libitum and those in the ethanol group received 20% vol/vol ethanol in their drinking water.¹² The ethanol-treated group was submitted to a brief and gradual adaptation period: the animals received 5% ethanol in their drinking water in the first week, 10% in the second week, and 20% in the third week. The

Effects of Chronic Ethanol Consumption on Mass Body Weight and KCl-induced Contraction

Before treatment, mean body masses of the rats were 220 ± 6 g (control) and 224 ± 5 g (ethanol-treated). After treatment for 4 weeks, no variation in body mass was observed in animals across the 2 experimental groups: 520 ± 11 g (control) and 478 ± 17 g (ethanol-treated) (Student's t-test).

When tissues were contracted with KCl at 80 mmol L⁻¹, the tensions were similar in both groups, with contractions of 2.4 ± 0.2 mN (n = 6) in ethanol-treated rats and 2.5 ± 0.3 (n = 5) in controls (Student's t

Comment

Chronic ethanol consumption significantly increased noradrenergic nerve-mediated contractions of CSM in response to EFS. This observation corroborates previous findings, namely, that treatment of rabbits for 6 weeks with an ethanol solution of 5% vol/vol induced increased responses of the CSM to EFS.¹⁰ Surprisingly, the contraction induced by phenylephrine—a selective α₁ agonist—was not affected by chronic ethanol consumption in our model. Similar results were previously described in the CSM

Conclusions

Despite the overexpression of eNOS and iNOS in ethanol-treated rats, the impaired relaxation induced by acetylcholine may suggest that chronic ethanol consumption induces endothelial dysfunction.

Acknowledgments

We thank Sonia Dreossi for technical support. We also thank Professor Margaret de Castro for testosterone measurements.

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Expression of MicroRNAs (miR-15b, miR-16, miR-138, miR-221, and miR-222) as Biomarkers of Endothelial Corpus Cavernosum Dysfunction in a Diabetic Alcoholic Murine Model
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Citation Excerpt :
Diabetes patients who are at-risk drinkers are likely to have poor diabetes treatment adherence, leading to increased morbidity and mortality.8 Interestingly, clinical and experimental studies have also associated alcoholism with endothelial dysfunction, impaired corpus cavernosum smooth muscle (CSM) relaxation capacity, hypertension, oxidative stress and release of inflammatory mediators.9-13 MicroRNAs (MiRNAs) are small noncoding RNAs of 19 to 25 nucleotides that have emerged in recent decades as important regulators of gene expression, since a single miRNA is able to modulate the expression of hundreds of genes.14
MicroRNAs (miRNAs) are short noncoding RNA molecules that regulate gene expression and are related to endothelial dysfunction (EnD). Recently, miRNAs have also been explored as potential biomarkers and target molecular therapy of erectile dysfunction (ED). Could the miRNAs be the tip of the iceberg of chronic arterial disease foreshadowed by the ED?
To investigate the expression of miR-15b, miR-16, miR-138, miR-221, and miR-222 in corpus cavernosum (CC) and peripheral blood in a rat model of endothelium dysfunction secondary to diabetes (DM) and alcohol consumption to assess potential endothelial lesion biomarkers.
Twenty males Wistar rats were divided into 4 groups: control group (C), alcohol consumption group (A), diabetic group (D), diabetic-alcohol consumption group (D + A). DM was alloxan-induced and alcohol consumption was through progressive increase of ethanol concentration in drinkable water. After 7 weeks, miRNAs expressions from CC and blood sample were evaluated by real-time PCR. Functional assessment of CC was performed in an acetylcholine endothelium-dependent relaxation pharmacological study.
miRNA expression in CC and blood were evaluated; pharmacological study in CC strips was conducted to validate EnD.
We found that 3 miRNAs (miR-16, miR-221, and miR-222) were downregulated in the CC in the D+A group, while all 5 miRNAs were downregulated in the blood of D and D + A groups. The endothelium-dependent relaxation induced by acetylcholine was significantly decreased in groups A, D, and D + A. Diagnostic accuracy estimated by AUC, to discriminating groups A, D, and D + A from controls, was superior to >0.9 in all plasmatic miRNAs.
miRNAs downregulation was identified in both CC and blood notably in DM associated with alcohol consumption animals (D + A), the greatest endothelial injury potential group. Serum miRNAs have also demonstrated high diagnostic accuracy properties in predicting CC relaxation dysfunction labeling EnD. RB Tiraboschi, FSL Neto, DP da Cunha Tirapelli, et al. Expression of MicroRNAs (miR-15b, miR-16, miR-138, miR-221, and miR-222) as Biomarkers of Endothelial Corpus Cavernosum Dysfunction in a Diabetic Alcoholic Murine Model. Sex Med 2021;9:100326.
Role of Risk Factors Such as Smoking, Alcohol, and Substance Abuse on Sexual Health of Brazilian Men
2018, Bioenvironmental Issues Affecting Men's Reproductive and Sexual Health
The association between alcohol and tobacco is well described in the literature. Recent studies suggest that alcohol and nicotine have interactive pharmacological effects that motivate their combined use, in addition to maintenance, and dependency on both substances [1,2]. Nearly one in five individuals with nicotine dependence also meets criteria for alcohol dependence, and conversely, half of individuals with alcohol dependence are dependent on nicotine [2,3]. Erectile dysfunction, defined as the inability to attain and maintain penile erection, is a common medical disorder, which decreases the quality of life of the couples and is related with hypertension, metabolic syndrome, diabetes mellitus, dyslipidemia, sedentary lifestyle, obesity, and alcoholism [4].
The Epidemiology and Pathophysiology of Erectile Dysfunction and the Role of Environment-Current Updates
2018, Bioenvironmental Issues Affecting Men's Reproductive and Sexual Health
Erectile dysfunction (ED), the inability to attain or maintain a sufficient penile erection for satisfactory sexual intercourse, is a major health issue predicted to affect 322 million people worldwide by year 2025. This chapter reviews well-known risk factors of ED including aging, vasculopathy, neuropathy, neurologic diseases, psychogenic problems, metabolic and endocrine dysregulation, and medications. Commonly consumed toxins such as tobacco, alcohol, and marijuana are also discussed as are environmental factors implicated in ED ranging from chemicals used in agriculture (pesticides and DDT), industrial chemicals, lead, bisphenol A, and 4,4′-diaminostilbene-2,2′-disulfonic acid to arsenic. Although how these compounds cause ED is unclear, this chapter reviews the available research and current theories on how they are thought to be endocrine disrupters with antiandrogenic or estrogenic properties and neurotoxins. The chapter concludes with a discussion of what are believed to be natural solutions for sexual dysfunction (aphrodisiacs) including commonly used cooking ingredients such as honey and potentially lethal plant derivatives such as yohimbine.
The Epidemiology and Pathophysiology of Erectile Dysfunction and the Role of Environment—Current Updates
2017, Bioenvironmental Issues Affecting Men's Reproductive and Sexual Health
Erectile dysfunction (ED), the inability to attain or maintain a sufficient penile erection for satisfactory sexual intercourse, is a major health issue predicted to affect 322 million people worldwide by year 2025. This chapter reviews well-known risk factors of ED including aging, vasculopathy, neuropathy, neurologic diseases, psychogenic problems, metabolic and endocrine dysregulation, and medications. Commonly consumed toxins such as tobacco, alcohol, and marijuana are also discussed as are environmental factors implicated in ED ranging from chemicals used in agriculture (pesticides and DDT), industrial chemicals, lead, bisphenol A, and 4,4′-diaminostilbene-2,2′-disulfonic acid to arsenic. Although how these compounds cause ED is unclear, this chapter reviews the available research and current theories on how they are thought to be endocrine disrupters with antiandrogenic or estrogenic properties and neurotoxins. The chapter concludes with a discussion of what are believed to be natural solutions for sexual dysfunction (aphrodisiacs) including commonly used cooking ingredients such as honey and potentially lethal plant derivatives such as yohimbine.
Role of Risk Factors Such as Smoking, Alcohol, and Substance Abuse on Sexual Health of Brazilian Men
2017, Bioenvironmental Issues Affecting Men's Reproductive and Sexual Health
The association between alcohol and tobacco is well described in the literature. Recent studies suggest that alcohol and nicotine have interactive pharmacological effects that motivate their combined use, in addition to maintenance, and dependency on both substances [1,2]. Nearly one in five individuals with nicotine dependence also meets criteria for alcohol dependence, and conversely, half of individuals with alcohol dependence are dependent on nicotine [2,3]. Erectile dysfunction, defined as the inability to attain and maintain penile erection, is a common medical disorder, which decreases the quality of life of the couples and is related with hypertension, metabolic syndrome, diabetes mellitus, dyslipidemia, sedentary lifestyle, obesity, and alcoholism [4].
Ethanol-induced erectile dysfunction and increased expression of pro-inflammatory proteins in the rat cavernosal smooth muscle are mediated by NADPH oxidase-derived reactive oxygen species
2017, European Journal of Pharmacology
Citation Excerpt :
The erectile response was calculated using the maximum ICP response normalized to MAP at the time of maximum ICP. The CSM was isolated and placed in 5-ml organ chamber containing Krebs solution at 37 °C as previously described (Lizarte et al., 2009). The strips of CSM were stretched to a resting tension of 3 mN and allowed to equilibrate for 60 min.
Ethanol consumption is associated with an increased risk of erectile dysfunction (ED), but the molecular mechanisms through which ethanol causes ED remain elusive. Reactive oxygen species are described as mediators of ethanol-induced cell toxicity/damage in distinctive tissues. The enzyme NADPH oxidase is the main source of reactive oxygen species in the endothelium and vascular smooth muscle cells and ethanol is described to increase NADPH oxidase activation and reactive oxygen species generation. This study evaluated the contribution of NADPH oxidase-derived reactive oxygen species to ethanol-induced ED, endothelial dysfunction and production of pro-inflammatory and redox-sensitive proteins in the rat cavernosal smooth muscle (CSM). Male Wistar rats were treated with ethanol (20% v/v) or ethanol plus apocynin (30 mg/kg/day; p.o. gavage) for six weeks. Apocynin prevented both the decreased in acetylcholine-induced relaxation and intracavernosal pressure induced by ethanol. Ethanol increased superoxide anion (O₂^-) generation and catalase activity in CSM, and treatment with apocynin prevented these responses. Similarly, apocynin prevented the ethanol-induced decreased of nitrate/nitrite (NOx), hydrogen peroxide (H₂O₂) and SOD activity. Treatment with ethanol increased p47phox translocation to the membrane as well as the expression of Nox2, COX-1, catalase, iNOS, ICAM-1 and p65. Apocynin prevented the effects of ethanol on protein expression and p47phox translocation. Finally, treatment with ethanol increased both TNF-α production and neutrophil migration in CSM. The major new finding of this study is that NADPH oxidase-derived reactive oxygen species play a role on chronic ethanol consumption-induced ED and endothelial dysfunction in the rat CSM.

View all citing articles on Scopus

: This work was supported by CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior).

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Male Sexual DysfunctionChronic Ethanol Consumption Induces Cavernosal Smooth Muscle Dysfunction in Rats

Objectives

Methods

Results

Conclusions

Section snippets

Experimental Design

Effects of Chronic Ethanol Consumption on Mass Body Weight and KCl-induced Contraction

Comment

Conclusions

Acknowledgments

J Urol.

Urol Clin North Am.

J Urol.

J Substance Abus Treat.

Neurosci Lett.

Reprod Toxicol.

Gastroenterology

Biochem Biophys Res Commun.

Local control of penile erectionNerves, smooth muscle, and endothelium

Urol Clin North Am.

Nitric oxide: a physiologic mediator of penile erection

Science

Physiology of penile erection

Physiol Rev.

Erectile dysfunction

N Engl J Med.

ImpotenceNIH Consensus Development Panel on Impotence

JAMA

Male Sexual Dysfunction
Chronic Ethanol Consumption Induces Cavernosal Smooth Muscle Dysfunction in Rats