Neonatal treatment with naloxone increases the population of Sertoli cells and sperm production in adult rats

Anti-inflammatory and anti-oxidant action of tadalafil in testicular regeneration process after heat stress

Tadalafil, a potent phosphodiesterase inhibitor 5 (PDE-5), is commonly used for the management of erectile dysfunction. However, its therapeutic potential extends beyond this indication. This study aimed to investigate the impact of tadalafil on the recovery of testicular parenchyma in male Wistar rats exposed to testicular thermal stress. Fifty-four Wistar rats were subjected to testicular thermal stress and randomly assigned to receive either tadalafil treatment (TAD) or no treatment (control). TAD was administered intraperitoneally at a dose of either 0.9 mg/kg or 1.8 mg/kg. Biometric parameters, histopathological assessment of the testis, serum testosterone levels, oxidative stress, and interleukin levels were evaluated on days 7, 15, and 30 after thermal shock. The animals were euthanized at the end of each experimental period, and samples were collected. TAD treatment maintained testicular weight and reduced the testicular degenerative process up to day 7 post-injury. However, despite TAD therapy, serum testosterone levels were decreased in the treated groups at days 7 and 15 post-thermal stress. TAD also decreased TNF-α and NO levels at different doses but had no effect on IL-6. The treatment with TAD after heat shock demonstrated anti-inflammatory and antioxidant properties but did not prevent the aggravation of testicular lesions in subsequent periods, even with the systematic reduction in TNF-α and NO levels. Therefore, this selective PDE-5 inhibitor, at the dosages used, did not have a positive impact on testosterone levels during the post-thermal stress period, which could compromise the resumption of the spermatogenic process.

Protective effect of exogenous melatonin on testicular histopathology and histomorphometry of adult rats with domperidone-induced hyperprolactinemia

Hyperprolactinemia is a pathological condition resulting from increased prolactin that directly affects reproduction, as this condition inhibits the release of LH, FSH and gonadal steroidogenesis, bringing several negative clinical associations in reproduction. In contrast, melatonin (MEL) plays an important role in the regulation of steroidogenesis and modulates damages to the process of spermatogenesis. The objective was to analyze the protective effects of exogenous melatonin on the testis of hyperprolactinemic adult rats. Forty-eight male rats were used, divided into two treatment periods: 30 and 60 days, each treatment was subdivided into three groups: Control, Hyper (hyperprolactinemia), and Hyper+MEL (hyperprolactinemia and melatonin). Treatment with melatonin was 200 μg/100 g, subcutaneously. Induction of hyperprolactinemia was obtained with a dose of 4 mg/kg of domperidone, subcutaneously. The results of the histopathology demonstrated that the animals in the Hyper group presented degeneration of germ cells when compared to the control. In addition, the degenerations were presented in smaller quantities in the Hyper+MEL, in both treatment periods, evidencing the benefits of the melatonin in gonadal regeneration. The Hyper group of both treatment periods showed a decrease in tubular diameter, epithelium height, and tubular area, in addition to a decrease in Sertoli cells, when compared to the control and the Hyper+MEL group. In conclusion, the hyperprolactinemia can affect the germinal epithelium and testicular microstructure; the exogenous melatonin has a protective effect against hyperprolactinemia, reducing testicular damage.

Supplementation of feedlot lambs with cactus cladodes as strategy to improve testicular function

The aim of this study was to evaluate the effects of diets containing cactus cladodes genotypes on plasma testosterone levels, testicular histopathological and histomorphometric parameters, and oxidative stress markers in lambs. Thirty-six male, intact Santa Inês lambs (22.0 ± 2.9 kg initial body weight), were to feedlot for 86 days. A completely randomized design was used with three dietary treatments (control diet with Tifton-85 hay as the only roughage; and two more diets with Miúda or OEM cactus cladodes partially replacing hay) and twelve replicates. There was no influence of the diets on the testicular weight (P = 0.414) and gonadosomatic index (P = 0.384) of lambs. The testosterone serum concentrations were almost twice as higher in lambs fed Miúda cactus cladodes compared to control treatment. There was greater incidence and severity of lesions in the testicular parenchyma of animals that received control diet: loosening of germ cell epithelium, germ cell desquamation and vacuolization of Sertoli cells. The seminiferous tubule diameter and height of the seminiferous epithelium were higher in lambs fed OEM cactus cladodes (P = 0.003). The tubular volume and Leydig cells volume were higher in animals fed with cactus cladodes (P < 0.05). The levels of malondialdehyde were higher in the lambs of control group compared to OEM group (P = 0.039) and the testicular concentration of nitric oxide was higher in control group (P = 0.009). The diet containing OEM cactus cladodes increased the levels of superoxide dismutase. Our results indicate that diets containing cactus cladodes promote antioxidant protection to the testicular parenchyma and preserve the spermatogenic process of lambs.

Histomorphometric and oxidative evaluation of the offspring's testis from type 2 diabetic female rats treated with metformin and pentoxifylline

Type 2 diabetes mellitus (T2D) during pregnancy is characterized by high levels of reactive oxygen species and pro-inflammatory factors in the placenta. Once these reactive species reach the foetus, they trigger physiological adaptations that allow the foetus to survive, but programme the organism to develop metabolic disorders in adulthood. The male reproductive system is highly susceptible to foetal programming. This study aimed to investigate the effects of intrauterine exposure to T2D on testicular histomorphometry and redox homeostasis of adult rats and evaluate the effects of maternal treatment with metformin and pentoxifylline. Female rats were induced to T2D, then treated with metformin and pentoxifylline, or co-treated with both drugs. The females were mated, the male offspring were sacrificed on postnatal day 90, and the testicles were collected for analysis. Metformin protected the tubular compartment, with the maintenance of the Sertoli cell population and daily sperm production. Pentoxifylline attenuated the effects of diabetes on Leydig cells, in addition to stimulating testosterone production and lowering lipid peroxidation. Intrauterine exposure to T2D results in important testicular alterations that compromise gonadal function, and the co-treatment with metformin and pentoxifylline may represent a promising therapy that attenuates these effects by combining the positive influences in both the tubular and interstitial compartments of the testicular parenchyma.

Effects of Dietary Crude Glycerin Concentration on Testicular Morphology and Oxidative Stress Markers and on Plasma Testosterone Concentrations

We evaluated the effects of feeding 6%, 12% or 18% crude glycerin, containing 80.5% glycerol, on testicular histomorphometry and markers of oxidative stress and on plasma testosterone concentrations in lambs. Body weight, testicular biometric measurements, gonadosomatic index and net weight of the testicles were higher for the treated groups (P <0.05) compared with a control group that did not receive dietary glycerin. The mean total length of seminiferous tubules was higher in the 6% group (P <0.05), while the mean total tubular and seminiferous epithelium volumes increased in all treated groups (P <0.05). The volume of Leydig cells increased in the 12% group, while their number per gram of testicle decreased (P <0.05). There was a decrease in mean nuclear diameter and mean volume of Leydig cells, and an increase in the mean number of these cells per gram of testicle, in the 18% group (P <0.05). Plasma testosterone concentrations were unaffected. There was desquamation of seminiferous epithelium and vacuolation of Sertoli cells in the treated groups. Variable degrees of spermatocyte necrosis and the presence of giant cells were seen in all groups and there was intense vacuolation of Sertoli cells in the 12% and 18% groups. Superoxide dismutase and catalase production increased most in the 12% and 18% groups (P <0.05), while glutathione production was higher in the 18% group (P <0.05). Mean nitric oxide concentration decreased in all treated groups (P <0.05), while malondialdehyde production was higher in the 18% group than in the control and 6% groups (P <0.05). We conclude that the inclusion of 6% glycerin in the diet of lambs results in changes in testicular morphology that have been previously associated with improved reproductive function, but without evidence of oxidative stress.

Protective action of melatonin on diabetic rat testis at cellular, hormonal and immunohistochemical levels

The aim of the present study was to analyze the effects of melatonin treatment on diabetic rat testes. Fifty albino rats were divided into the following groups: CG: control group; GD: placebo-induced and placebo-treated mice; GDI: insulin-induced and post-confirmation diabetes-induced rats; GDM: diabetes-induced and melatonin-treated post-confirmation mice and GDMS: diabetes-induced and melatonin-treated mice simultaneously. Melatonin was administered at a dose of 10 mg/kg in drinking water every day for 20 days at night. Diabetes was induced by streptozotocin (60 mg/kg) and confirmed after the fifth day of induction. Insulin was administered at 5 IU (international units)/day at different times of the day for 20 days. The testes were submitted to histopathological, morphometric, immunohistochemical and oxidative stress analysis. Melatonin moderately decreased glycemic levels, protected weight loss and morphometric changes in the testicles, increased antioxidant enzyme levels and stabilized plasma testosterone and androgen receptor levels and decreased inflammatory markers in the testicles. Showing its potential to mitigate diabetes effects.

Molecular Mechanisms and Signaling Pathways Involved in Sertoli Cell Proliferation

Sertoli cells are somatic cells present in seminiferous tubules which have essential roles in regulating spermatogenesis. Considering that each Sertoli cell is able to support a limited number of germ cells, the final number of Sertoli cells reached during the proliferative period determines sperm production capacity. Only immature Sertoli cells, which have not established the blood-testis barrier, proliferate. A number of hormonal cues regulate Sertoli cell proliferation. Among them, FSH, the insulin family of growth factors, activin, and cytokines action must be highlighted. It has been demonstrated that cAMP/PKA, ERK1/2, PI3K/Akt, and mTORC1/p70SK6 pathways are the main signal transduction pathways involved in Sertoli cell proliferation. Additionally, c-Myc and hypoxia inducible factor are transcription factors which participate in the induction by FSH of various genes of relevance in cell cycle progression. Cessation of proliferation is a pre-requisite to Sertoli cell maturation accompanied by the establishment of the blood-testis barrier. With respect to this barrier, the participation of androgens, estrogens, thyroid hormones, retinoic acid and opioids has been reported. Additionally, two central enzymes that are involved in sensing cell energy status have been associated with the suppression of Sertoli cell proliferation, namely AMPK and Sirtuin 1 (SIRT1). Among the molecular mechanisms involved in the cessation of proliferation and in the maturation of Sertoli cells, it is worth mentioning the up-regulation of the cell cycle inhibitors p21Cip1, p27Kip, and p19INK4, and of the gap junction protein connexin 43. A decrease in Sertoli cell proliferation due to administration of certain therapeutic drugs and exposure to xenobiotic agents before puberty has been experimentally demonstrated. This review focuses on the hormones, locally produced factors, signal transduction pathways, and molecular mechanisms controlling Sertoli cell proliferation and maturation. The comprehension of how the final number of Sertoli cells in adulthood is established constitutes a pre-requisite to understand the underlying causes responsible for the progressive decrease in sperm production that has been observed during the last 50 years in humans.

The mu (μ) and delta (δ) opioid receptors modulate boar sperm motility

Endogenous and exogenous opioids modulate reproductive functions in target cells via opioid receptors (μ, δ, and κ). Sperm motility is a metric of gamete functionality, and serves as a suitable parameter for in vitro drug-induced toxicity assays. This study identifies the presence and location of opioid receptors in pig spermatozoa as well as their functional response after in vitro challenge with known agonists (morphine [μ]; [D-Pen 2,5]-enkephanile [δ]; and U 50488 [κ]) and antagonists (naloxone [μ]; naltrindole [δ]; and nor-binaltrorphimine [κ]). Only the μ- and δ-opioid receptors were present in the boar sperm plasma membrane, overlying the acrosome, neck, and principal piece. Challenge experiments with agonists and antagonists identified both μ- and δ-opioid receptors as regulators of sperm kinematics, wherein μ maintains or increases sperm movement whereas δ decreases sperm motility over time. Mol. Reprod. Dev. 83: 724-734, 2016 © 2016 Wiley Periodicals, Inc.

Fluoxetine induces changes in the testicle and testosterone in adult male rats exposed via placenta and lactation

Fluoxetine is a selective serotonin reuptake inhibitor used to treat depression in pregnant and nursing women. However, recent studies have shown adverse effects in the male reproductive system after fluoxetine treatment. Aiming to analyze the extent of damage caused by fluoxetine in the testicle and safe doses for treatment during the perinatal period, the present study analyzed the effects of in utero exposure and exposure during lactation to fluoxetine in spermatogenesis of male rat offspring in adulthood. Wistar rat dams were orally treated with fluoxetine (5, 10, and 20 mg/kg) from 13 days of gestation to lactation day 21 and their offspring were analyzed at 90 days old. Results showed a reduction in the weight of testes (16%), epididymis (28%), and seminal glands (18%) in animals exposed to fluoxetine 20 mg/kg compared to the control. Seminal gland weight was also reduced 25% and 30% in animals exposed to 5 mg/kg and 10 mg/kg fluoxetine, respectively. Body weight of animals exposed to 20 mg/kg fluoxetine was reduced from post-natal day 9 to 36 compared to controls but from the post-natal day 9 to 36 there was no statistical difference. The volume of seminiferous epithelium reduced 17% and the total volume of Leydig cells reduced 30% in the group exposed to fluoxetine at 20 mg/kg. Furthermore, Leydig cells volume reduced 29% in the 5 mg/kg group. The length of the seminiferous tubules reduced 17% and daily sperm production per testicle also reduced 18% in animals exposed to the highest dose of fluoxetine compared to controls. The individual area of Leydig cells increased 7% and plasma testosterone increased 49% in animals exposed to fluoxetine at 20 mg/kg. In conclusion, exposure to 20 mg/kg fluoxetine via the placenta and during lactation may change testosterone and testicular parameters important for sperm production and male fertility in adulthood.

Testicular testosterone: estradiol ratio in domestic cats and its relationship to spermatogenesis and epididymal sperm morphology

The phenomenon of teratozoospermia in felids is not fully understood. In this study, we investigated the testicular androgen:estrogen balance in domestic cats and correlated these data with epididymal sperm morphology and the degree of spermatogenic activity. During spring and summer, testes and blood samples were obtained from 37 mixed-breed domestic cats (12 to 48 mo). The epididymal sperm were harvested and evaluated for sperm counts, motility, and morphology. Distal cytoplasmic droplets were not considered a defect, and samples were considered normozoospermic if they contained more than 60% normal sperm (N = 25) or teratozoospermic if they contained less than 45% normal sperm (N = 12). The testicular and serum concentrations of testosterone (T) and 17β-estradiol (E2) were determined with an enzyme immunoassay. The gonadosomatic index and epididymal sperm numbers and motility did not differ between groups. The percentage of normal sperm was higher in normozoospermic (74.3 ± 2.0, mean ± SEM) than in teratozoospermic samples (43.1 ± 1.4). The most prevalent sperm defects in the teratozoospermic group were abnormal acrosomes (9.7 ± 2.0) and bent midpieces (12.2 ± 2.0) or tails (24.0 ± 2.7) with cytoplasmic droplets. Histomorphometric data were similar between groups, although there was a lower Leydig cell nuclear volume in teratozoospermic samples. Normozoospermic samples contained a higher percentage of haploid cells and had a higher index of total spermatogenic transformation than teratozoospermic samples. Serum concentrations of T (0.5 ± 0.1 vs. 0.8 ± 0.4 ng/mL) and E2 (9.5 ± 1.2 vs. 11.4 ± 2.3 pg/mL) and testicular T concentrations (471.6 ± 65.3 vs. 313.4 ± 57.6 ng/g) were similar between groups. However, compared with normozoospermic samples, teratozoospermic samples had higher testicular E2 concentrations (8.5 ± 3.6 vs. 5.4 ± 0.5 ng/g) and a lower T:E2 ratio (31.8 ± 4.1 vs. 87.2 ± 11.6). There were significant correlations between testicular E2 values and percentages of normal sperm (r = -0.55) as well as those with primary sperm defects (r = 0.58) or abnormal acrosomes (r = 0.64). The T:E2 ratio was also correlated with meiotic index (r = 0.45) and percentage of normal sperm (r = 0.58). In conclusion, a high testicular E2 concentration and a reduced T:E2 ratio were significantly associated with higher ratios of abnormal sperm types, suggesting that the balance between androgens and estrogens is an important endocrine component in the genesis of teratozoospermia in felids.

Glyphosate impairs male offspring reproductive development by disrupting gonadotropin expression

Sexual differentiation in the brain takes place from late gestation to the early postnatal days. This is dependent on the conversion of circulating testosterone into estradiol by the enzyme aromatase. The glyphosate was shown to alter aromatase activity and decrease serum testosterone concentrations. Thus, the aim of this study was to investigate the effect of gestational maternal glyphosate exposure (50 mg/kg, NOAEL for reproductive toxicity) on the reproductive development of male offspring. Sixty-day-old male rat offspring were evaluated for sexual behavior and partner preference; serum testosterone concentrations, estradiol, FSH and LH; the mRNA and protein content of LH and FSH; sperm production and the morphology of the seminiferous epithelium; and the weight of the testes, epididymis and seminal vesicles. The growth, the weight and age at puberty of the animals were also recorded to evaluate the effect of the treatment. The most important findings were increases in sexual partner preference scores and the latency time to the first mount; testosterone and estradiol serum concentrations; the mRNA expression and protein content in the pituitary gland and the serum concentration of LH; sperm production and reserves; and the height of the germinal epithelium of seminiferous tubules. We also observed an early onset of puberty but no effect on the body growth in these animals. These results suggest that maternal exposure to glyphosate disturbed the masculinization process and promoted behavioral changes and histological and endocrine problems in reproductive parameters. These changes associated with the hypersecretion of androgens increased gonadal activity and sperm production.

Evaluation of testicular degeneration induced by low-frequency electromagnetic fields

The population exposure to electromagnetic fields (EMF) has been growing in recent decades. The generation, distribution and use of electric energy can generate low-frequency electromagnetic fields. The present study investigates the effects of EMF (60 Hz and 1 mT) on spermatogenesis of rats during different periods of maturation. Wistar rats were exposed to EMF from day 13 of gestation to postnatal day 21 or 90 in three daily applications of 30 min. Plasma testosterone concentration was not changed by EMF exposure; however, histopathological and histomorphometrical analyses of the testes showed testicular degeneration in a subset of animals exposed to EMF. The magnitude of the degenerative process varied between those individuals affected, indicating different individual sensitivity to EMF. The main alterations observed through transmission electron microscopy were highly electron-dense mitochondria with loss of their organization and cristae. Exposure to 60 Hz and 1 mT EMF can disturb spermatogenesis and may produce subfertility or infertility.

Regulation of male fertility by the opioid system

Endogenous opioid peptides are substances involved in cell communication. They are present in various organs and tissues of the male and female reproductive tract, suggesting that they may regulate some of the processes involved in reproductive function. In fact, the opioid system that operates as a multi-messenger system can participate in the regulation of reproductive physiology at multiple levels, for example, at the levels of the central nervous system, at the testes level and at sperm level. A better understanding of the implication of the opioid system in reproductive processes may contribute to clarifying the etiology of many cases of infertility and the effect of opiate abuse on fertility. Indeed, a novel biochemical tool for the diagnosis and treatment of male infertility could be based upon components of the opioid system. The presence of the opioid system in sperm cells also represents a novel opportunity for reproductive management, for either enhancing the probability of fertilization or reducing it through the development of novel targeted contraceptives.

Pode a atividade física materna modular a programação fetal induzida pela nutrição?

Existe considerável evidência para a indução de diferentes fenótipos em reposta às variações no ambiente fetal e neonatal. O aporte inadequado de nutrientes no período crítico do desenvolvimento está associado ao risco alto de doenças metabólicas na vida adulta, este fenômeno biológico é chamado de programação. A atividade física durante a gestação resulta em adaptações fisiológicas da mãe e no aumento da disponibilidade de nutrientes e oxigênio no espaço feto-placentário. Este trabalho tem como objetivo discutir os mecanismos da indução de programação fetal pela nutrição e o provável efeito modulador da atividade física durante a gestação. Foram utilizadas as bases de dados do Medline Pubmed, Lilacs e Bireme, com publicações entre 1990 até 2008. Os termos de indexação utilizados foram: nutrition, fetal programming, gestation, physical activity, physical exercise, metabolism. Em conclusão, o aporte inadequado de nutrientes programa o aparecimento de doenças metabólicas na vida adulta, enquanto que a atividade física durante a gestação aumenta a disponibilidade de nutrientes e oxigênio, repercutindo positivamente no crescimento fetal e no peso ao nascer.

Endogenous opiates and behavior: 2006

This paper is the 29th consecutive installment of the annual review of research concerning the endogenous opioid system, now spanning 30 years of research. It summarizes papers published during 2006 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurological disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); and immunological responses (Section 17).