Fluoxetine-induced androgenic failure impairs the seminiferous tubules integrity and increases ubiquitin carboxyl-terminal hydrolase L1 (UCHL1): Possible androgenic control of UCHL1 in germ cell death?

Role of serotonin, estrogen, and TNF-α in the paroxetine-impaired steroidogenesis and testicular macrophages polarization

BACKGROUND

Paroxetine, a selective serotonin reuptake inhibitor (SSRI) antidepressant, has caused male sexual dysfunction; however, the paroxetine mechanisms of action in testes are still unclear.

OBJECTIVES

Paroxetine serotonergic effects in testes were evaluated, focusing on steroidogenesis and the correlation between macrophages population and possible TNF-α-derived oxidative stress. We also verified whether the changes are reversible following treatment interruption.

MATERIALS AND METHODS

Adult rats received paroxetine (PG35 and PG65) or tap water (CG) for 35 days. PG65 was maintained without treatment for 30 more days. Intratesticular testosterone (IT), nitrite, and malondialdehyde concentrations were measured. To confirm serotonergic and estrogenic effects, Htr1b and Esr1 expressions were analyzed. The daily sperm production (DSP), frequency of abnormal seminiferous tubules (ST), SC number, ST area, and Leydig cells nuclear area (LCnu) were evaluated. TUNEL+ germ cells, M1 (CD68+ ), and M2 (Perls+ ) macrophages were quantified. 17β-HSD7, CYP19A1, NDRG2, oxytocin, TNF-α, and iNOS were evaluated by immunoreactions. Oxytocin and NDRG2 protein levels as well as Tnfa mRNA expression were also analyzed.

RESULTS

The Htr1b downregulation in testes confirmed the paroxetine serotonergic effect. The testicular sections showed abnormal ST frequency, ST atrophy and reduction of DSP, LCnu, SC number and Perls+ macrophages. TUNEL+ germ cells and LC were associated with strong NDRG2 immunoexpression. Paroxetine reduced IT levels and 17β-HSD7 immunoexpression in parallel to increased CYP19A1, oxytocin, TNF-α and iNOS. Esr1 and Tnfa overexpression and increased number of CD68+ macrophages were also observed together with high nitrite and malondialdehyde levels. Most parameters were not recovered in PG65.

CONCLUSIONS

Paroxetine serotonergic effect impairs LC steroidogenesis, via aromatization, increasing estrogen/testosterone ratio, which in turn upregulate NDRG2, promoting apoptosis, and impairing sperm production. Serotonin-estrogen pathways may be responsible for M2/M1 polarization, Tnfa upregulation, and induction of oxidative stress. The unrecovered testicular changes after treatment discontinuation are due to persistent paroxetine serotonin/estrogen effects.

Fetal Ovarian Reserve: the Dynamic Changes in Ubiquitin C-Terminal Hydrolase L1

The regulation of protein turnover by the unique deubiquitinating enzyme ubiquitin C-terminal hydrolase L1 (UCHL1) is only seen in oocytes, spermatogonia, and neurons. Our objective was to investigate variation in expression of UCHL1 across fetal maturation of oocytes that result in lifelong ovarian reserve. We performed a retrospective cohort study of 25 fetal autopsy specimens from 21 to 36 weeks. This was an IRB-approved protocol with parental permission for use of tissues for research purposes. Tissues were stained for expression of the oocyte-specific protein UCHL1, and expression levels were evaluated using quantitative immunofluorescence across gestational ages after correction for the area and background absorbance. Corrected total cell fluorescence (CTCF) for expression of UCHL1 within human oocytes was compared across fetal gestational ages and oocyte size. Trends were analyzed using a locally weighted scatterplot smoothing algorithm. Local expression of UCHL1 increases in oocytes across ovarian development reaching a plateau at 27 weeks with the maintenance of elevated levels through 36 weeks gestational age. This maturation trend is also evidenced by the increase in protein expression as oocyte area increases (r = 0.5530, p ≤ 0.001) with the largest rise occurring as oocytes are enveloped into primordial follicles. The increase in expression as oocytes transition from oogonia into oocytes in primordial follicles and beyond may be part of the preparation of both oocytes and the surrounding somatic cells for the long-term maintenance of the ovarian reserve.

Paroxetine treatment in an animal model of depression improves sperm quality

Depression in mammals is known to be associated with poor reproductive capacity. In males, it has been associated with decreased efficiency of spermatogenesis as well as the production of spermatozoa of reduced structural and functional integrity. Although antidepressants are effective in correcting depressive states, there is controversy regarding their effectiveness in restoring male reproductive function. Here, using an animal model of depression induced by a forced swim test, we confirmed that depression is accompanied by impaired male reproductive function. We further show that administration of a conventional antidepressant of the serotonin reuptake inhibitor class (paroxetine) impairs male reproductive performance in terms of sperm production and quality when administered to healthy animals. Intriguingly, when paroxetine is administered to "depressed" animals, it resulted in a complete restoration of the animal's ability to produce sperm that appears to be as capable of meeting the parameters evaluated here as those of control animals. The one-carbon cycle (1CC) is one of the most important metabolic cycles that include the methionine and folate cycles and plays a major role in DNA synthesis, amino acids, and also the production of antioxidants. Our results show that depression affects the main components of this cycle and paroxetine on healthy mice increases homocysteine levels, decreases glycine and vitamin B12, while in depressed mice, it increases folate levels and decreases vitamin B12. Thus, paroxetine exerts negative impacts on male reproductive function when administered to healthy animals and it well correlate with the altered sperm parameters and functions of depressed animals, and its mechanism remains to be explored.

Connexin 43: insights into candidate pathological mechanisms of depression and its implications in antidepressant therapy

Major depressive disorder (MDD), a chronic and recurrent disease characterized by anhedonia, pessimism or even suicidal thought, remains a major chronic mental concern worldwide. Connexin 43 (Cx43) is the most abundant connexin expressed in astrocytes and forms the gap junction channels (GJCs) between astrocytes, the most abundant and functional glial cells in the brain. Astrocytes regulate neurons' synaptic strength and function by expressing receptors and regulating various neurotransmitters. Astrocyte dysfunction causes synaptic abnormalities, which are related to various mood disorders, e.g., depression. Increasing evidence suggests a crucial role of Cx43 in the pathogenesis of depression. Depression down-regulates Cx43 expression in humans and rats, and dysfunction of Cx43 also induces depressive behaviors in rats and mice. Recently Cx43 has received considerable critical attention and is highly implicated in the onset of depression. However, the pathological mechanisms of depression-like behavior associated with Cx43 still remain ambiguous. In this review we summarize the recent progress regarding the underlying mechanisms of Cx43 in the etiology of depression-like behaviors including gliotransmission, metabolic disorders, and neuroinflammation. We also discuss the effects of antidepressants (monoamine antidepressants and ketamine) on Cx43. The clarity of the candidate pathological mechanisms of depression-like behaviors associated with Cx43 and its potential pharmacological roles for antidepressants will benefit the exploration of a novel antidepressant target.

The effects of selective serotonin reuptake inhibitors on male and female fertility: a brief literature review

Objective: The aim of this review was to determine whether selective serotonin reuptake inhibitors (SSRIs) affect the ability to conceive in men and women of reproductive age, as well as to find out whether there are certain differencies between them in terms of effects on fertility. Methods: Our review was based on systematic search of literature in four online databases: Medline (PubMed), Scopus, Web of Science and SCIndex (Serbian Citation Index). Results: Several clinical studies reported that SSRIs can decrease the number and viability of sperm, and cause a disruption of their morphological structure. Regarding the effect of these antidepressants on female fertility, some experimental findings suggest that paroxetine and escitalopram may have a negative effect on the ability to conceive due to their stimulatory effect on fallopian tube motility. However, several observational studies favor the use of SSRIs in women with depression/anxiety undergoing in vitro fertilization (IVF) given their efficiency in suppressing these unpleasant symptoms without a relevant negative impact on IVF outcomes. Conclusions: SSRIs should be avoided male patients of reproductive age who wish to conceive, while the use of these antidepressants seems to be justified in women with depression or anxiety who have undergone IVF.Key pointsSSRIs could cause dose and duration-dependent reversible adverse effects on male fertility parameters.In depressed or anxious male patients of reproductive age who wish to conceive mirtazapine or bupropion should be used because of their lower potential to cause sexual side effects.The results of certain experimental studies indicate that paroxetine and escitalopram may have a negative effect on the fertility of female patients.The use of SSRIs in women with depression or anxiety who have undergone IVF seems to be justified, because these psychiatric disorders reduce the likelihood of becoming pregnant.

What Does Androgen Receptor Signaling Pathway in Sertoli Cells During Normal Spermatogenesis Tell Us?

Androgen receptor signaling pathway is necessary to complete spermatogenesis in testes. Difference between androgen binding location in Sertoli cell classifies androgen receptor signaling pathway into classical signaling pathway and non-classical signaling pathway. As the only somatic cell type in seminiferous tubule, Sertoli cells are under androgen receptor signaling pathway regulation via androgen receptor located in cytoplasm and plasma membrane. Androgen receptor signaling pathway is able to regulate biological processes in Sertoli cells as well as germ cells surrounded between Sertoli cells. Our review will summarize the major discoveries of androgen receptor signaling pathway in Sertoli cells and the paracrine action on germ cells. Androgen receptor signaling pathway regulates Sertoli cell proliferation and maturation, as well as maintain the integrity of blood-testis barrier formed between Sertoli cells. Also, Spermatogonia stem cells achieve a balance between self-renewal and differentiation under androgen receptor signaling regulation. Meiotic and post-meiotic processes including Sertoli cell - Spermatid attachment and Spermatid development are guaranteed by androgen receptor signaling until the final sperm release. This review also includes one disease related to androgen receptor signaling dysfunction named as androgen insensitivity syndrome. As a step further ahead, this review may be conducive to develop therapies which can cure impaired androgen receptor signaling in Sertoli cells.

Venlafaxine-induced adrenergic signaling stimulates Leydig cells steroidogenesis via Nur77 overexpression: a possible role of EGF

Venlafaxine, a norepinephrine and serotonin reuptake inhibitor, impairs rat sperm parameters, spermatogenesis and causes high intratesticular estrogen and testosterone levels, indicating that Leydig cells (LCs) may be a venlafaxine target. We evaluated the effect of venlafaxine treatment on LCs in vivo, focusing on adrenergic signaling, EGF immunoexpression and steroidogenesis. Germ cells mitotic/meiotic activity and UCHL1 levels were also evaluated in the seminiferous epithelium. Adult male rats received venlafaxine (30 mg/kg) or distilled water. In testicular sections, the seminiferous tubules, epithelium and the LCs nuclear areas were measured, and the immunoexpression of Ki-67, UCHL1, StAR, EGF, c-Kit and 17β-HSD was evaluated. UCHL1, StAR and EGF protein levels and Adra1a, Nur77 and Ndrg2 expression were analyzed. MDA and nitrite testicular levels, and serum estrogen and testosterone levels were measured. Venlafaxine induced LCs hypertrophy and Ndrg2 upregulation, in parallel to increased number of Ki-67, c-Kit- and 17β-HSD-positive interstitial cells, indicating that this antidepressant stimulates LCs lineage proliferation and differentiation. Upregulation of Adra1a and Nur77 could explain the high levels of StAR and testosterone levels, as well as aromatization. Enhanced EGF immunoexpresion in LCs suggests that this growth fact is involved in adrenergically-induced steroidogenesis, likely via upregulation of Nur77. Slight tubular atrophy and weak Ki-67 immunoexpression in germ cells, in association with high UCHL1 levels, indicate that spermatogenesis is likely impaired by this enzyme under supraphysiological estrogen levels. These data corroborate the unchanged MDA and nitrite levels. Therefore, venlafaxine stimulates LCs steroidogenesis via adrenergic signaling, and EGF may be involved in this process.

Impaired macrophages and failure of steroidogenesis and spermatogenesis in rat testes with cytokines deficiency induced by diacerein

The role of cytokines in testicular function under normal conditions has not been completely understood. Here, we evaluated testicular macrophages (TM), steroidogenesis by Leydig cells (LC) and seminiferous tubules integrity in cytokines-deficient rat testes induced by diacerein, an anti-inflammatory drug that inhibits interleukin-1 (IL-1) and tumor necrosis factor-alpha (TNF-α). Male rats received daily 100 mg/kg of diacerein (DIAG; n = 8) or saline (CG; n = 8) for 30 days. Serum testosterone (T) levels were measured and the seminiferous tubule (ST) area, epithelial area (EA), frequency of damaged ST and number of Sertoli cells (SC) were evaluated. TUNEL method and immunoreactions for detection of pro-IL-1β, TNF-α, steroidogenic acute regulatory protein (StAR), 17β-hydroxysteroid dehydrogenase (17β-HSD), androgen receptor (AR) and scavenger receptor for hemoglobin-haptoglobin complexes (CD163), a TM marker, were performed. Testicular AR, 17β-HSD and IL-1β levels were detected by Western blot. Data were submitted to Student t test (p ≤ 0.05). In DIAG, T and testicular AR, 17β-HSD and IL-1β levels decreased significantly (p < 0.05). The number of TUNEL-positive interstitial cells increased and LC showed weak StAR, 17β-HSD and AR immunoexpression in association with reduced IL-1β immunoexpression and number of CD163-positive TM in the interstitial tissue from diacerein-treated rats. Numerous damaged ST were found in DIAG, and reduction in the EA were associated with germ cells death. Moreover, the number of SC reduced and weak AR and TNF-α immunoexpression was observed in SC and germ cells, respectively. The cytokines deficiency induced by diacerein impairs TM, LC and spermatogenesis, and points to a role of IL-1β in steroidogenesis under normal conditions. In the ST, the weak AR and TNF-α immunoexpression in SC and germ cells, respectively, reinforces the idea that TNF-α plays a role in the SC androgenic control.

Venlafaxine-induced damage to seminiferous epithelium, spermiation, and sperm parameters in rats: A correlation with high estrogen levels

BACKGROUND

Venlafaxine (selective serotonin and norepinephrine reuptake inhibitor) use has increased worldwide. However, the impact of venlafaxine on testes and sperm parameters has not been investigated.

OBJECTIVES

We evaluated venlafaxine impact on testicular and sperm parameters and verified whether the changes are reversible.

METHODS

Animals from venlafaxine-35 days and venlafaxine-65 days groups received 30 mg/kg of venlafaxine for 35 days. Control-35 days and control-65 days received distilled water. In control-65 days and venlafaxine-65 days, the treatment was interrupted for 30 days. Sperm concentration, morphology, motility, and mitochondrial activity were analyzed. Number of step 19 spermatids (NLS), frequency of tubules with spermiation failure, Sertoli cells number, and TUNEL-positive germ cells were quantified. Testicular aromatase, connexin 43 (Cx43) immunoexpression, Cx43 protein levels, and Cx43 expression were evaluated. Either intratesticular testosterone or estrogen levels were measured.

RESULTS

Venlafaxine impaired sperm morphology, reduced sperm concentration, mitochondrial activity, and sperm motility. The frequency of tubules with spermiation failure and NLS increased in parallel to increased Cx43 immunoexpression; mRNA and protein levels; and aromatase, testosterone, and estrogen levels. An increase in germ cell death and decreased Sertoli cells number were observed. In venlafaxine-65 days, except for sperm motility, mitochondrial activity, Sertoli cells number, and germ cell death, all other parameters were partially or totally recovered.

CONCLUSION

Venlafaxine increases testosterone aromatization and Cx43. This drug, via high estrogen levels, disturbs Sertoli cells, induces germ cell death, and impairs spermiation and sperm parameters. The restoration of spermiation associated with the decreased Cx43 and hormonal levels in venlafaxine-65 days reinforces that high estrogen levels are related to venlafaxine-induced changes. The presence of damaged Sertoli cells, germ cell death, and low sperm motility in venlafaxine-65 days indicates that interruption of treatment for 30 days was insufficient for testicular recovery and points to a long-term estrogen impact on the seminiferous epithelium.

Effect of fluoxetine on the testes of adult albino rats and the possible protective role of curcumin

Fluoxetine (FLX) is extensively used for the treatment of a diversity of psychiatric disorders, mainly depression. However, it can adversely affect male fertility. This study was done to clarify the changes which take place in the testes after the oral administration of FLX and to evaluate the possible preventative role of curcumin. Seventy-six adult male albino rats were randomly divided into four equal groups. Control group: kept without any treatment. Curcumin group: received daily dose of curcumin (150 mg/kg body weight) through oral gavage for 8 weeks. FLX group. They were given daily dose of FLX (10 mg/kg body weight) given through oral gavage for 8 weeks. FLX and curcumin group. They were given FLX together with curcumin with the same previous doses through oral gavage daily for 8 weeks. By the end of the experiment, blood samples were collected for the biochemical study of testosterone. All the animals were anaesthetized by ether inhalation, and the testis specimens were dissected out and weighed. The specimens were subjected to histopathological, immunohistochemical, and morphometrical evaluation. FLX decreased serum testosterone, diminished both epithelial height and diameter of seminiferous tubules, increased collagen fiber deposition in testicular tissue and induced positive immune reaction to B-cell lymphoma-2-associated X protein. In the FLX and curcumin group, the FLX-induced changes were less remarkable. Exposure to FLX led to pronounced testicular alterations. Co-administration of curcumin with FLX ameliorated these changes.

Ubiquitin carboxy-terminal hydrolase L1 - physiology and pathology

Ubiquitin C-terminal hydrolase 1 (UCHL1) is an enzyme unique for its multiple activity - both ligase and hydrolase. UCHL1 was first identified as an abundant protein found in the brain and testes, however its expression is not limited to the neuronal compartment. UCHL1 is also highly expressed in carcinomas of various tissue origins, including those from brain, lung, breast, kidney, colon, prostate, pancreas and mesenchymal tissues. Loss-of-function studies and an inhibitor for UCHL1 confirmed the importance of UCHL1 for cancer therapy. So far biological significance of UCHL1 was described in the following processes: spermatogenesis, oncogenesis, angiogenesis, cell proliferation and differentiation in skeletal muscle, inflammation, tissue injury, neuronal injury and neurodegeneration.