Increased expression of interleukin-1α and interleukin-1β is associated with experimental varicocele

Effect of varicocele and varicocelectomy on sperm deoxyribonucleic acid fragmentation rates in infertile men with clinical varicocele

Varicocele is the leading cause of male infertility. It can affect sperm quantity and quality through various non-mutually exclusive pathophysiological mechanisms, mainly oxidative stress. Excessive production of reactive oxygen species may overwhelm the sperm's defenses against oxidative stress and harm the sperm's DNA. Excessive sperm DNA breaks, so-called sperm DNA fragmentation, result from the oxidative stress cascade and are commonly found in the ejaculates of men with varicocele and fertility-related issues. Measuring sperm DNA fragmentation can provide valuable information on the extent of harm and might help select candidates for surgical treatment. Varicocelectomy is beneficial for alleviating oxidative stress-associated infertility and improving sperm DNA integrity. However, reproductive outcomes of infertile men with elevated sperm DNA fragmentation rates and surgically treated varicoceles remain poorly studied, and there is a need for well-designed trials to determine the impact of sperm DNA fragmentation reduction on natural and medically assisted reproduction.

Varicocele and testicular cord torsion: immune testicular microenvironment imbalance

The main functions of the testis, steroidogenesis and spermatogenesis, depend on the endocrine axis and systemic and local tolerance mechanisms. Infectious or non-infectious diseases may disturb testicular immune regulation causing infertility. Literature has illustrated that bacterial and viral infections lead to autoimmune infertility: either sperm antibodies or autoimmune epidydimo-orchitis. However, little is known about the association between non-infectious testicular pathologic diseases and autoimmunity. Here we review the novel aspect of varicocele and testicular cord torsion pathology linked to inflammation and discuss how immune factors could contribute to or modulate autoimmunity in ipsi- and contralateral testis.

Insight into inflammation involvement in varicocele: A narrative review

BACKGROUND

Varicocele is one of the main causes of male infertility. Although the pathophysiology mechanism of varicocele is very well described and understood, there are some unanswered questions that remains unknown. Some studies have previously described the state of testicular inflammation and sperm in animal models, especially the mouse model, and the seminal plasma of men with varicocele, with or without changes in semen parameters.

METHODS OF STUDY

This review intended to verify the role of inflammatory mechanism in varicocele, using clinical studies as well as animal model studies on the effect of inflammation caused by varicocele on the function of testicular somatic and germ cells.

RESULTS

In-vivo studies confirmed whether anti-inflammatory molecules could treat the semen of men with varicocele and rats with varicocele. The use of different anti-inflammatory agents in mouse model studies provided a new perspective for future clinical studies to investigate the effect of concurrent treatment with surgery to improve surgical outcomes.

CONCLUSION

Similar to animal model studies, previously conducted clinical trials have demonstrated the effectiveness of anti-inflammatory therapy in varicocele patients. However, clinical trials using anti-inflammatory are needed to be conducted agents to evaluate different aspects of this therapeutical approach in varicocele patients.

Insight toward inflammasome complex contribution to male infertility

During the last decades, a wide range of factors involved in the physiopathology of male infertility disease have been discussed. The inflammation role in some of the main infertility-related diseases has been studied, such as varicocele, spinal cord injury and obesity. Inflammation is the main response of the immune system to infection or cell damage, leading to intense inflammatory cytokine release during the loss of homeostasis. One of the first steps toward pro-inflammatory cytokines release is the recognition of dangerous signals by the immune cells, including pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs). These molecules can activate an important multiprotein complex, called inflammasome. Although these complexes have been studied during the last decades, their participation in male infertility has gained attention recently. Considering the inflammasome complex's high potential to be targeted for drug therapy, this review tries to shed light on current literature. Therefore, in the current review paper, we aimed to discuss the inflammasome complex activation, involvement in different male infertility conditions, and localization in the male reproductive tract.

What is the impact of inflammasome mechanisms on male infertility?

BACKGROUND

Mechanisms to explain inflammation in male infertility of unknown cause are still being investigated. The inflammasome is a key regulator of innate immunity in the inflammatory response to infections. Our study aims to investigate the effects of varicocele on infertility, its relationship with antioxidant and inflammasome mechanisms, and how it could be guided in azoospermic or nonazoospermic patients.

METHODS

A cross-sectional cohort study was conducted at the department of urology in our university hospital. Eightyeight randomly selected men aged 20-45 admitted to our hospital because of infertility between September 2019 and July 2020 were included in the study. Patients were divided into four equal groups according to their clinical status, those with/without azoospermia and with/without varicocele. Blood and semen samples were taken from the patients. NOD-like receptor pyrin domain-containing 3 (NLRP3) and interleukin-1 beta (IL1β) and total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI) levels were measured in serum and semen, and the groups were compared statistically.

RESULTS

Serum and semen NLRP3, IL1β, TAS, TOS, and OSI values of the patients with varicocele or azoospermia were significantlyhigher than those without either varicocele or azoospermia (p < 0.05). The oxidative stress markers TAS, TOS, and OSI values were significantly higher in the other groups than those without azoospermia and varicocele (p < 0.05).

DISCUSSION

Inflammasome mechanisms, such as NLRP3 and IL1-β molecules, may provide additional benefit in evaluating the need and benefit of surgical or medical treatment in infertility with and without vascular pathology and with and without azoospermia.

Microbiology and immune mechanisms associated with male infertility

Up to 50% of infertility is caused by the male side. Varicocele, orchitis, prostatitis, oligospermia, asthenospermia, and azoospermia are common causes of impaired male reproductive function and male infertility. In recent years, more and more studies have shown that microorganisms play an increasingly important role in the occurrence of these diseases. This review will discuss the microbiological changes associated with male infertility from the perspective of etiology, and how microorganisms affect the normal function of the male reproductive system through immune mechanisms. Linking male infertility with microbiome and immunomics can help us recognize the immune response under different disease states, providing more targeted immune target therapy for these diseases, and even the possibility of combined immunotherapy and microbial therapy for male infertility.

The NLRP3 inflammasome: molecular activation and regulation in spermatogenesis and male infertility; a systematic review

Background

Infertility related to varicocele, infections, metabolic dysfunctions, oxidative stress and environmental toxicants is also associated with inflammatory processes that ultimately lead to the activation of the inflammasome pathway (IP). IP is classically activated by DAMPs, MAMPs or LAMPs, which stand for Damage-, Microbe- or Lifestyle-Associated Molecular Patterns, respectively. The most important player in IP activation is the NLRP3 (NOD[Nuclear oligomerization domain]-, LRR[Leucine rich repeat]- and pyrin domain-containing protein 3) which functions as an intracellular sensor of D/M/L-AMPs resulting in activation of caspase-1, promotion of apoptosis, pyroptosis and generation of inflammatory cytokines. This review addresses the question of whether IP activation might be associated with male infertility situations.

Results & conclusions

We conducted a systematic review of articles published in the Google Scholar, and PubMed databases through October 2021. It turns out that inflammasome activation and its consequences including cytokine storms, apoptosis and pyroptosis could be associated with the reduced sperm count as well as the structural and functional sperm defects recorded in several situations associated with male infertility suggesting that anti-inflammatory therapeutic strategies could be possibly considered to restore male fertility in future research.

Long noncoding RNAs regulated spermatogenesis in varicocele-induced spermatogenic dysfunction

Objectives

To evaluate the expression, potential functions and mechanisms of long noncoding RNAs (lncRNAs) in the pathogenesis of varicocele (VC)‐induced spermatogenic dysfunction.

Materials and Methods

We established a rat model with left experimental VC and divided rats into the sham group, the VC group, and the surgical treatment group (each group, n = 10). Haematoxylin and eosin (HE) staining and sperm quality were analysed to evaluate spermatogenesis function. LncRNA expression profiles were analysed using lncRNA‐Seq (each group n = 3) and validated using quantitative real‐time polymerase chain reaction (each group n = 10). Correlation analysis and gene target miRNA prediction were used to construct competing endogenous RNA network. The regulated signalling pathway and spermatogenic dysfunction of differentially expressed lncRNAs (DE lncRNAs) were validated by Western blot.

Results

HE detection and sperm quality analysis showed that VC could induce spermatogenic dysfunction. Eight lncRNAs were upregulated and three lncRNAs were downregulated in the VC group compared with the sham group and surgical treatment group. The lncRNA of NONRATG002949.2, NONRATG001060.2, NONRATG013271.2, NONRATG022879.2, NONRATG023424.2, NONRATG005667.2 and NONRATG010686.2 were significantly negatively related to sperm quality, while NONRATG027523.1, NONRATG017183.2 and NONRATG023747.2 were positively related to sperm quality. The lncRNAs promote spermatogenic cell apoptosis and inhibit spermatogonia and spermatocyte proliferation and meiotic spermatocytes by regulating the PI3K–Akt signalling pathway.

Conclusion

DE lncRNAs may be potential biomarkers for predicting the risk of spermatogenic dysfunction in VC and the effect of surgical repair. These DE lncRNAs promote spermatogenic dysfunction by regulating the PI3K–Akt signalling pathway.

Resveratrol benefits on sperm DNA, chromatin structure and reproductive outcomes of varicocelized rats

In varicocele, the main cause of sperm DNA damage is oxidative stress (OS). Resveratrol, a polyphenol with antioxidant properties, can protect cells from injuries caused by OS. We investigated the benefits of resveratrol against reproductive damage caused by experimental varicocele induced from peripuberty. Eighty peripubertal male rats were distributed into 4 groups: sham-control (S), varicocele (V), resveratrol (R) and varicocele treated with resveratrol (VR). Varicocele was induced through the partial ligature of the left renal vein. Resveratrol was given in a daily dose of 300 mg/kg body weight (gavage). Sperm samples were collected at 100 days of age for vitality, DNA fragmentation and chromatin protamination evaluations. OS analyses were carried out. Rats from all groups were mated with healthy primiparous females for evaluation of reproductive capacity and embryonic quality. The V group showed reduction of sperm vitality, altered chromatin protamination and sperm DNA integrity and high levels of OS. The VR group showed an improvement of oxidative status, sperm vitality, DNA integrity and chromatin structure, and an enhancement in the gestational index and embryonic quality. Therefore, we showed in this experimental model that resveratrol is a promising nutraceutical adjuvant and should be deeply studied to mitigate subfertility in varicocele.

Varicocele-Mediated Male Infertility: From the Perspective of Testicular Immunity and Inflammation

Background

Varicocele (VC) is present in 35 - 40% of men with infertility. However, current surgical and antioxidant treatments are not completely effective. In addition to oxidative stress, it is likely that other factors such as testicular immune microenvironment disorder contribute to irreversible testicular. Evidence suggests that VC is associated with anti-sperm antibodies (ASAs), spermatogenesis and testosterone secretion abnormalities, and testicular cytokine production. Moreover, inhibition of inflammation can alleviate VC-mediated pathogenesis. The normal function of the testis depends on its immune tolerance mechanism. Testicular immune regulation is complex, and many infectious or non-infectious diseases may damage this precision system.

Results

The testicular immune microenvironment is composed of common immune cells and other cells involved in testicular immunity. The former includes testicular macrophages, T cells, dendritic cells (DCs), and mast cells, whereas the latter include Leydig cells and Sertoli cells (SCs). In animal models and in patients with VC, most studies have revealed an abnormal increase in the levels of ASAs and pro-inflammatory cytokines such as interleukin (IL)-1 and tumor necrosis factor (TNF)-alpha in the seminal plasma, testicular tissue, and even peripheral blood. It is also involved in the activation of potential inflammatory pathways, such as the nucleotide-binding oligomerization domain-like receptor family pyrin domain containing (NLRP)-3 pathway. Finally, the development of VC-mediated infertility (VMI) may be facilitated by abnormal permeability of proteins, such as claudin-11, that constitute the blood-testis barrier (BTB).

Conclusions

The testicular immune response, including the production of ASAs and inflammatory factors, activation of inflammatory pathways, and destruction of the BTB may be involved in the pathogenesis of VMI it is necessary to further explore how patient outcomes can be improved through immunotherapy.

Seminal inflammasome activity in the adult varicocele

Varicocele has been hypothesized to lead to seminal inflammation, which in turn interferes with sperm function. Thus, the aim of this study was to investigate the role of inflammatory cytokines in the pathogenesis of decreased semen quality observed in adult men with varicocele, and to determine if varicocelectomy corrects these potential alterations. A prospective study was carried out including fifteen control men without varicocele and with normal semen quality and 15 men with varicocele with surgical indication. Men with varicocele grades II or III underwent microsurgical subinguinal varicocelectomy. Controls collected one semen sample and men with varicocele collected one before and one 6 months after the surgery. Semen analysis, sperm function, and seminal lipid peroxidation levels were assessed. Seminal plasma inflammasome activity was evaluated by ELISA assays for IL-1β, IL-18 and caspase-1 and by Western blotting for ASC (apoptosis-associated speck-like protein). Groups were compared by an unpaired Student's T test. Varicocelectomy samples were compared using a paired Student's T test (α = 5%). Men with varicocele had decreased semen quality, and increased seminal IL-1β levels, when compared to control men. Varicocelectomy decreased levels of caspase-1, IL-18, and IL1β. Thus, varicocelectomy improves sperm morphology and decreases seminal plasma inflammatory activity, after a six-month post-operative period.

Presence of The NLRP3 Inflammasome Components in Semen of Varicocele Patients

Background

Varicocele is a common cause of male infertility with multifactorial etiology. Inflammation is a characteristic pathological event that occurs in the testis tissue following the varicocele. The aim of this study was to investigate expression of nod-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome components and cytokines in semen of varicocele and control subjects.

Materials and Methods

In this case-control study, seminal plasma was collected from 32 varicocele patients (with grades 2 and 3) and 20 fertile men as control group. Semen analysis was performed in all subjects. Concentrations of interleukin-1b (IL-1b), IL-18 and caspase-1 in seminal plasma were measured by enzyme-linked immunosorbent assay (ELISA). Apoptosis-associated speck-like protein containing a caspase activation and recruitment domain, in addition to NALP3 were identified in seminal plasma by Western blot. Statistical significance between the mean values was determined by student’s t test.

Results

According to our data, the level of IL-1b was significantly (P=0.03) increased in the seminal plasma of varicocele patients, compared to the control subjects. We analyzed amount of IL-18 in the both groups. The level of this interleukin was markedly (P=0.002) decreased in varicocele patients. No change was observed in the level of caspase-1 in both groups. Western blot analysis revealed that apoptosis associated speck-like protein (ASC, P=0.0002) and NLRP3 (P=0.005) were significantly elevated in the semen of varicocele patients.

Conclusion

This study provides the first evidence of activation of NLRP3 components in semen of men with varicocele.

The effect of experimental varicocele on the apelin and APJ expressions in rat testis tissue

Varicocele, which is one of the causes of infertility in men, can be defined as the expansion of spermatic cord veins. The presence of apelin and apelin receptor (APJ) in many tissues and the effects of apelin have been reported in several studies. There is no study showing apelin and APJ protein expressions in normal and varicocele-induced testicular tissues. In this study, we aimed to demonstrate varicocele-induced changes in apelin and APJ expressions in testicular tissue by immunohistochemical and western blotting techniques. In our study, Wistar male rats were randomly divided into three groups as control, varicocele, and sham. While the control group rats were not subjected to any treatment, the unilateral varicocele model was created under anesthesia in the varicocele group. In the sham group, the left abdominal region was opened and closed to exclude the effect of the surgical procedure. At the 13th postoperative week, the left testes were obtained under anesthesia in all groups, and the immunohistochemistry and Western blotting techniques were used to detect apelin and APJ expressions. In our study; apelin and APJ were significantly expressed in control group's testicular tissue; apelin in testicular tissues of varicocele groups increased compared to the control group, whereas APJ expression decreased. In conclusion, the presence of apelin/APJ system in normal testis and the increased expression of apelin in varicocele-induced testicular tissue suggested that apelin may have a role in the varicocele etiopathogenesis.

The Effect of Schisandra chinensis Baillon on Cross-Talk between Oxidative Stress, Endoplasmic Reticulum Stress, and Mitochondrial Signaling Pathway in Testes of Varicocele-Induced SD Rat

Schisandra chinensis Baillon (SC) has been utilized for its antioxidants and anti-inflammatory activities in a broad variety of medical applications. However; SC uses for improving fertility in males and related disorders with proper scientific validation remain obscure. The present study aimed to investigate the effects of SC on varicocele (VC)-induced testicular dysfunction and the potential molecular mechanism associated with VC-induced germ cell apoptosis. The male Sprague–Dawley rats were equally divided into four groups consisting of 10 rats in a normal control group (CTR), a control group administered SC 200 mg/kg (SC 200), a varicocele-induced control group (VC), and a varicocele-induced group administered SC 200 mg/kg (VC + SC 200). Rats were administrated 200 mg/kg SC once daily for 28 days after induction of varicocele rats and sham controls. At the end of the treatment period, body and reproductive organ weight, sperm parameters, histopathological damages, proinflammatory cytokines, apoptosis markers, biomarkers of oxidative stress, endoplasmic reticulum (ER) stress, and steroidogenic acute regulatory protein (StAR) were evaluated. The effects of SC extract on human sperm motility were also analyzed. SC treatment reduces VC-induced testicular dysfunction by significantly increasing testicular weight, sperm count and sperm motility, serum testosterone level, Johnsen score, spermatogenic cell density, testicular superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase level, and steroidogenic acute regulatory protein (StAR) level. Furthermore, the effects of SC on malondialdehyde (MDA) level, reactive oxygen species (ROS)/reactive nitrogen species (RNS) level, apoptotic index, serum luteinizing hormone (LH) and follicle stimulating hormone (FSH) levels, Glucose-regulated protein-78 (Grp 78), phosphorylated c-Jun-N-terminal kinase (p-JNK), phosphorylated inositol-requiring transmembrane kinase/endoribonuclease 1α (p-IRE1α), cleaved caspase 3, and Bax:Bcl2 in VC-induced rats were significantly decreased. Treatment with SC extracts also increased sperm motility in human sperm. Our findings suggest that the SC ameliorate testicular dysfunction in VC-induced rats via crosstalk between oxidative stress, ER stress, and mitochondrial-mediated testicular germ cell apoptosis signaling pathways. SC promotes spermatogenesis by upregulating abnormal sex hormones and decreasing proinflammatory cytokines (interleukin-6; TNF-α).

Alteration of testicular regulatory and functional molecules following long-time exposure to 900 MHz RFW emitted from BTS

The aim of this investigation was to evaluate changes in testosterone and some of the functional and regulatory molecules of testis such as P450scc, steroidogenic acute regulatory protein (StAR), tumour necrosis factor-α (TNF-α), interleukin-1α (IL-1α), interleukin-1β (IL-1β) and nerve growth factor (NGF) following exposure to 900 MHz radio frequency (RF). Thirty adult male Sprague Dawley rats (190 ± 20 g BW) were randomly classified in three equal groups, control (sham, without any exposure), short-time exposure (2 hr) (STE) and long-time exposure (4 hr) (LTE). The exposure was performed for 30 consecutive days. The testosterone level in both exposed groups was significantly less than control (p < .05). Level of TNF-α in both exposed groups was significantly greater than control (p < .05). IL-1α and NGF levels in LTE were significantly higher than the STE and control groups (p < .05). Level of IL-1β in LTE was significantly higher than control (p < .05). Expression of both P450scc and StAR mRNA was significantly down-regulated in both exposed groups compared to control (p < .05). Our results showed that RFW can affect testis and reproductive function through changes in factors, which are important during steroidogenesis, and also through changes in inflammatory factors, which regulate Leydig cell functions.

With a new clip technique surgically inducing varicocele in Sprague-Dawley rats

BACKGROUND

We introduced and recreated a more consistent and effective experimental varicocele rat model by a new clip technique.

METHODS

A total of 40 rats were numbered and randomly assigned to 5 groups of 8 each, including sham surgery (Group I), conventional (Group II) and clip groups with 0.7, 0.8, 0.9 mm gap widths, respectively (Group III, IV, V). All of the rats in each group were sacrificed at 8 weeks after initial surgery, and the rats forming out with less than 1 mm diameter of left spermatic vein or no presence of the pampiniform plexus dilation were excluded from the experimental groups. The left spermatic vein (LSV) diameter, testicular weight, left kidney weight to body weight coefficients, kidney and testicular histology were determined.

RESULTS

The baseline mean diameter of the LSV in Group I, II and III was 0.22 ± 0.02, 0.23 ± 0.02 and 0.22 ± 0.03 mm, respectively (P = 0.7504). At 8 weeks after initial surgery, varicocele was successfully created in 6/8 (75%), 7/8 (87.5%), 3/8 (37.5%), 3/8 (37.5%) in GroupII-V, no varicocele was observed in Group I. In Group I, II and III, no pathological changes were observed and the left kidney weight to body weight coefficients showed no significant differences. The diameter of LSV was remarkably increased both in Group II and III compared to Group I (1.72 ± 0.13, 1.57 ± 0.19 and 0.25 ± 0.02, respectively), and Group II and III had a smaller testicular weight than the rats in Group I (1.67 ± 0.05, 1.62 ± 0.06, and 1.92 ± 0.12, respectively).

CONCLUSIONS

With a new clip technique, surgically inducing varicocele rat model becomes convenient and safe. This appears to improve the effectiveness of the model and this innovation may allow us to further understand the pathophysiology of varicocele.

The protective effects of GYY4137 on ipsilateral testicular injury in experimentally varicocele-induced rats

The aim of the present study was to evaluate whether morpholin-4-ium 4 methoxyphenyl (morpholino) phosphonodithioate (GYY4137) exhibits a protective effect on ipsilateral testicular injury in experimentally varicocele (VC)-induced rats. A total of 48 rats were randomly divided into the following 6 groups (n=8 each): Group A (control group); group B (sham group); group C (VC group); group D (VC group administered 5 mg/kg/day GYY4137); group E (VC group administered 10 mg/kg/day GYY4137) and group F (VC group administered 20 mg/kg/day GYY4137). Indicators of oxidative stress, apoptosis and inflammation were measured to evaluate the effect of GYY4137 on ipsilateral testicular injury. Compared with groups A and B, rats in group C exhibited severe histological changes and an increase in oxidative stress, apoptosis and inflammation. By contrast, amelioration of testicular damage was evident in the group D, E and F that were treated with GYY4137. These results demonstrate that GYY4137 may be a promising therapy to treat VC as it alleviates oxidative stress, apoptosis and inflammation in experimentally VC-induced rats.

Comparative Expression Analysis of HSP70, HSP90, IL-4, TNF, KITLG and KIT-receptor Gene between Varicocele-Induced and Non-Varicocele Testes of Dog

Background

This study was designed to create an experimental varicocele model by a simple surgical procedure in dog with minimum invasion and to investigate the effect of varicocele-induced infertility on the expression of six related genes (HSP90, HSP70, IL-4, TNF, KITLG and KIT receptor).

Materials and Methods

In this experimental study, the proximal part of the pampini-form plexus of dog testes was partially occluded without abdominal incision which was confirmed by venographic examination. To evaluate varicocele in its acute form, dogs were castrated after 15 days and testes were dissected. Histopathologic evaluation was undertaken and the relative expression of the six genes was assessed by quantitative realtime polymerase chain reaction (PCR).

Results

Microscopic changes showed tubule degeneration. The Johnson score was significantly decreased in the varicocele testes when compared with non-varicocele testes. Expressions of HSP90, TNF, KITLG and the KIT-receptor gene were significantly downregulated (P=0.029, 0.047, 0.004 and 0.035 respectively) in varicocele-induced testes while HSP70 was upregulated (P=0.018). IL-4 did not show differential expression (P=0.377).

Conclusion

We conclude that partial occlusion of the proximal part of the pampiniform plexus induces varicocele in the testis of dog. Differential expression of the mentioned genes may be responsible for the pathophysiology of varicocele and related subfertility.

Insight into oxidative stress in varicocele-associated male infertility: part 1

Varicocele is recognized as the leading cause of male infertility because it can impair spermatogenesis through several distinct pathophysiological mechanisms. Current evidence supports oxidative stress as a key element in the pathophysiology of varicocele-related infertility, although these mechanisms have not yet been fully described. Measurement of the reactive oxygen species and other markers of oxidative stress, including the levels of the antioxidant enzymes catalase and superoxide dismutase, can provide valuable information on the extent of oxidative stress and might guide therapeutic management strategies. The testis can respond to varicocele-associated cell stressors, such as heat stress, ischaemia or production of vasodilators (for example, nitric oxide) at the expense of the generation of excessive reactive oxygen species. These responses have their own implications in exacerbating the underlying oxidative stress and on the subsequent infertility.

The hypoxic testicle: physiology and pathophysiology

Mammalian spermatogenesis is a complex biological process occurring in the seminiferous tubules in the testis. This process represents a delicate balance between cell proliferation, differentiation, and apoptosis. In most mammals, the testicles are kept in the scrotum 2 to 7°C below body core temperature, and the spermatogenic process proceeds with a blood and oxygen supply that is fairly independent of changes in other vascular beds in the body. Despite this apparently well-controlled local environment, pathologies such as varicocele or testicular torsion and environmental exposure to low oxygen (hypoxia) can result in changes in blood flow, nutrients, and oxygen supply along with an increased local temperature that may induce adverse effects on Leydig cell function and spermatogenesis. These conditions may lead to male subfertility or infertility. Our literature analyses and our own results suggest that conditions such as germ cell apoptosis and DNA damage are common features in hypoxia and varicocele and testicular torsion. Furthermore, oxidative damage seems to be present in these conditions during the initiation stages of germ cell damage and apoptosis. Other mechanisms like membrane-bound metalloproteinases and phospholipase A2 activation could also be part of the pathophysiological consequences of testicular hypoxia.

The comparison of two experimental rat varicocele models and their effect on sperm quality

OBJECTIVE

To develop a modified rat varicocele model.

METHODS

300 male Sprague-Dawley rats were selected. In 82 rats (classic group, CG), this was achieved by dissecting the left renal vein and ligating it using a 0.8-mm metal clip and 3-0 silk suture proximal to the inferior vena cava, followed by removal of the bar. In 118 rats (modified group, MG), in addition to the partial ligation of the left renal vein, the communicating branch was fully ligated. In 100 rats (sham operation group, SG), the left renal vein and communicating branches were dissected, but not ligated. The seminal fluid was aspirated and the diameters of the left spermatic veins were analyzed. Three months later, the examination was performed again.

RESULTS

The diameters were 0.16 ± 0.1 mm and 1.88 ± 0.1 mm before and after operation, respectively, in the CG (p < 0.01), and 0.15 ± 0.05 mm and 2.0 ± 0.1 mm in the MG (p < 0.01). Postsurgical diameters in the CG and MG were 1.88 ± 0.1 mm and 2.0 ± 0.1 mm (p > 0.5), and 0.16 ± 0.1 mm and 0.16 ± 0.11 mm in the SG (p > 0.5). Semen parameters in the CG had significant differences before and after the operation (p < 0.01), were significantly lower in the MG (p < 0.01), and had no significant differences in the SG (p > 0.5).

CONCLUSION

Simple partial ligation of the renal vein combined with ligation of the communicating branch leads to acceptable models for varicocele.

Intratesticular expression of mRNAs of both interferon γ and tumor necrosis factor α is significantly increased in experimental autoimmune orchitis in mice

Experimental autoimmune orchitis (EAO) is one of the models of immunological male infertility. Murine EAO is CD4+T cell-dependent and classically induced by immunization with a testicular homogenate and adjuvants. We previously established that immunization with viable syngeneic testicular germ cells (TGC) can also induce murine EAO with no use of any adjuvant. Analyses of this EAO model have already revealed that cultured spleen cells of immunized mice secreted interferon (IFN)-γ and that treatment of the immunized mice with anti-IFN-γ monoclonal antibodies significantly suppressed the EAO. It is known that both IFN-γ and tumor necrosis factor (TNF)-α are representative cytokines of Th1 cells and exhibit local toxicity toward the seminiferous epithelium in vivo. However, changes in these two cytokines in EAO-affected testes have not yet been investigated. Therefore, in the present study, we investigated the expression of intratesticular IFN-γ and TNF- α mRNAs in TGC-induced EAO using real-time RT-PCR. The results demonstrated that the intratesticular mRNAs for both IFN-γ and TNF-α significantly increased, while other cytokines such as IL-1α, IL-1β, IL-6 and TGF-β did not show dramatic changes in the immunized mice. These results suggest that secretion of significant amounts of IFN-γ and TNF-α in situ contributes to the spermatogenic disturbance in EAO.

TNF-alpha and IL-6 affect human sperm function by elevating nitric oxide production

Many studies have reported the effects of cytokines on human sperm function, even though their role and the mechanisms involved remain unclear. The effects of increasing concentrations of the cytokines TNF-alpha and IL-6 on human sperm motility and viability were assessed, and the possible mechanisms involved were investigated. TNF-alpha and IL-6 significantly reduced progressive motility at higher concentrations in a dose- and time-dependent manner. No differences were observed in cell viability. Both cytokines increased nitric oxide production in a dose-dependent manner. TNF-alpha and IL-6 did not statistically differ in their detrimental effects on human spermatozoa. These results indicate that TNF-alpha and IL-6 have an effect on sperm function. This effect is possibly mediated via an increase in nitric oxide production.