Interleukin-6 and IL-6 receptor cell expression in testis of rats with autoimmune orchitis

Oxytocin ameliorates lipopolysaccharide-induced acute orchitis model: interplay of oxidative stress and inflammatory pathways

Introduction

Lipopolysaccharide (LPS), a constituent of the outer membrane of Gram-negative bacteria, is a powerful inducer of systemic inflammation and has been extensively utilized in experimental models to simulate inflammatory responses and septic disorders. Recent research indicates that oxytocin (OXY), a neuropeptide typically linked to social bonding and reproductive functions, may influence inflammatory processes. This work examines the impact of OXY on LPS-induced testicular damage, aiming to elucidate its therapeutic potential in addressing inflammatory disorders and broadening the comprehension of its functions beyond conventional neuroendocrine roles.

Methods

Eighteen male albino rats were divided into three groups; the control group received no treatment; the LPS group received 0.5 mL of saline solution containing 5 mg/kg LPS intraperitoneally (orchitis model); and the LPS + OXY group received LPS and OXY (0.1 mg/kg) intraperitoneally every 12 h for 72 h.

Results and discussion

Animals subjected to LPS were found to have severe orchitis, as evidenced by increased oxidative stress and surging inflammatory mediators (TNF-α, IL-1β, and IL-6), with declined IL-10 levels. Besides, LPS increased the malondialdehyde (MDA) and decreased the glutathione (GSH) levels, inducing an oxidative stress cascade. In addition, there are dramatic increases in the TLR4, MyD88, NF-κB, and PK2/PKR1 protein expression levels. All these events could alter the sperm count, morphology, and testicular architecture.

Conclusion

Interestingly, OXY could mitigate LPS-induced oxidative damage and inflammation in testicular tissue alongside restoring the disrupted sperm count, motility, and morphology. This therapeutic potential of OXY might be accounted for by its anti-inflammatory, antioxidant, and antiapoptotic activities.

SARS-CoV-2-induced cytokine storm drives prolonged testicular injury and functional impairment in mice that are mitigated by dexamethasone

Compromised male reproductive health, including reduced testosterone and sperm count, is one of the long COVID symptoms in individuals recovering from mild-severe disease. COVID-19 patients display testicular injury in the acute stage and altered serum fertility markers in the recovery phase, however, long-term implications on the testis remain unknown. This study characterized the consequences of SARS-CoV-2 on testis function. The K18-hACE2 mice that survived SARS-CoV-2 infection were followed for one month after infection and the testicular injury and function markers were assessed at different stages of infection and recovery. The long-term impact of infection on key testes function-related hormones and male fertility was measured. The efficacy of inflammation-suppressing drug in preventing testicular injury was also evaluated. The morphological defects like sloughing of spermatids into the lumen and increased apoptotic cells sustained for 2-4 weeks after infection and correlated with testicular inflammation and immune cell infiltration. Transcriptomic analysis revealed dysregulation of inflammatory, cell death, and steroidogenic pathways. Furthermore, reduced testosterone levels associated with a transient reduction in sperm count and male fertility. Most testicular impairments resolved within one month of infection. Importantly, dexamethasone treatment attenuated testicular damage, inflammation, and immune infiltration. Our results implicate virus-induced cytokine storm as the major driver of testicular injury and functional impairments, timely prevention of which limits testis damage. These findings serve as a model for evaluating therapeutics in long COVID patients and may guide clinical strategies to improve male reproductive health outcomes post-SARS-CoV-2 infection.

Exploring the interplay between inflammation and male fertility

Male fertility results from a complex interplay of physiological, environmental, and genetic factors. It is conditioned by the properly developed anatomy of the reproductive system, hormonal regulation balance, and the interplay between different cell populations that sustain an appropriate and functional environment in the testes. Unfortunately, the mechanisms sustaining male fertility are not flawless and their perturbation can lead to infertility. Inflammation is one of the factors that contribute to male infertility. In the testes, it can be brought on by varicocele, obesity, gonadal infections, leukocytospermia, physical obstructions or traumas, and consumption of toxic substances. As a result of prolonged or untreated inflammation, the testicular resident cells that sustain spermatogenesis can suffer DNA damage, lipid and protein oxidation, and mitochondrial dysfunction consequently leading to loss of function in affected Sertoli cells (SCs) and Leydig cells (LCs), and the formation of morphologically abnormal dysfunctional sperm cells that lay in the basis of male infertility and subfertility. This is due mainly to the production and secretion of pro-inflammatory mediators, including cytokines, chemokines, and reactive oxygen species (ROS) by local immune cells (macrophages, lymphocytes T, mast cells) and tissue-specific cells [SCs, LCs, peritubular myoid cells (PMCs) and germ cells (GCs)]. Depending on the location, duration, and intensity of inflammation, these mediators can exert their toxic effect on different elements of the testes. In this review, we discuss the most prevalent inflammatory factors that negatively affect male fertility and describe the different ways inflammation can impair male reproductive function.

The Role of Cells and Cytokines in Male Infertility Induced by Orchitis

Recent studies on male infertility reveal a growing worry: more infertile men are dealing with inflammation in the testis. Analyzing testicular biopsies from infertile men highlights a significant presence of inflammation. This connection, supported by clinical and pathological evidence, emphasizes that testicular inflammation hampers sperm production, leading to lasting declines in sperm count and quality. However, the exact reasons behind male infertility due to orchitis, a type of testicular inflammation, are still uncertain. Understanding these fundamental aspects of molecular signals and cellular mechanisms in testicular inflammation is crucial. Our review delves into recent literature with a dual objective: elucidating potential mechanisms involving immune cells, non-immune cells, and cytokines that link orchitis to male infertility, while also paving the way for precise interventions and solutions to address the challenges of male infertility.

Testicular fibrosis pathology, diagnosis, pathogenesis, and treatment: A perspective on related diseases

Testicular fibrosis is a chronic and progressive condition characterized by the excessive deposition of extracellular matrix proteins. This process leads to fibrotic remodeling, damage to testicular tissue, and the irreversible loss of male reproductive function. However, there is currently a lack of comprehensive reviews systematically elucidating the pathology, diagnosis, pathogenesis, and treatment of testicular fibrosis from the perspectives of different related diseases. This review addresses these aspects of testicular fibrosis, with a particular emphasis on elucidating the underlying mechanisms of testicular cells. It provides insights that can be relevant for future research and clinical interventions.

Comparison of the therapeutic effect of platelet-rich plasma and injectable platelet-rich fibrin on testicular torsion/detorsion injury in rats

Testicular torsion is a common disorder in males and results in blockage of testicular circulation with subsequent damage of testicular germ cells. The current work aimed to compare the therapeutic effect of platelet-rich plasma (PRP) and injectable platelet-rich fibrin (i-PRF) on torsion/detorsion (T/D) injury in rats. Forty mature male Wister rats were arranged into 4 groups; (1) Control, (2) T/D, (3) T/D + PRP, and (4) T/D+ i-PRF. The right testis was twisting 1080° clockwise for 3 h in groups 2, 3 and 4, then 10 μl of PRP or i-PRF was injected intra-testicular 3 h after detorsion in groups 3 and 4, respectively. After 30 days postoperatively, the semen quality and hormonal assay were improved in PRP and i-PRF-treated groups with superiority of i-PRF (P < 0.001). High significance of Catalase, Glutathione Peroxidase (GPx), Superoxide Dismutase, Interleukin-1β (IL-1β), Caspase-3 and Tumor necrosis factor-α (TNF-α) was reported in treated rats with PRP and i-PRF (P < 0.001) with superiority to i-PRF-treated rats (P < 0.001). Testicular histoarchitectures were improved in PRP and i-PRF-treated rats with superiority of i-PRF-treated rats. It was concluded that PRP and i-PRF have regenerative efficacy on testicular damage after induced T/D injury with a superior efficacy of i-PRF.

Comprehensive analysis of differentially expressed mRNAs, circRNAs, and miRNAs and their ceRNA network in the testis of cattle-yak, yak, and cattle

Cattle-yak is a hybrid offspring resulting from the crossbreeding of yak and cattle, and it exhibits substantial heterosis in production performance. However, male sterility in cattle-yak remains a concern. Reports suggest that noncoding RNAs are involved in the regulation of spermatogenesis. Therefore, in this study, we comprehensively compared testicular transcription profiles among cattle, yak, and cattle-yak. Numerous differentially expressed genes (DEGs), differentially expressed circRNAs (DECs), and differentially expressed miRNAs (DEMs) were identified in the intersection of two comparison groups, namely cattle versus cattle-yak and yak versus cattle-yak, with the number of DEGs, DECs, and DEMs being 4968, 360, and 59, respectively. The DEGs in cattle-yaks, cattle, and yaks were mainly associated with spermatogenesis, male gamete generation, and sexual reproduction. Concurrently, GO and KEGG analyses indicated that DEC host genes and DEM source genes were involved in the regulation of spermatogenesis. The construction of a potential competing endogenous RNA network revealed that some differentially expressed noncoding RNAs may be involved in regulating the expression of genes related to testicular spermatogenesis, including miR-423-5p, miR-449b, miR-34b/c, and miR-15b, as well as previously unreported miR-6123 and miR-1306, along with various miRNA-circRNA interaction pairs. This study serves as a valuable reference for further investigations into the mechanisms underlying male sterility in cattle-yaks.

9-cis-retinoic acid signaling in Sertoli cells regulates their immunomodulatory function to control lymphocyte physiology and Treg differentiation

BACKGROUND

Testis is an immune privileged organ, which prevents the immune response against sperm antigens and inflammation. Testicular cells responsible for immune tolerance are mainly Sertoli cells, which form the blood-testis barrier and produce immunosuppressive factors. Sertoli cells prevent inflammation in the testis and maintain immune tolerance by inhibiting proliferation and inducing lymphocyte apoptosis. It has been shown that 9-cis-retinoic acid (9cRA) blocks ex vivo apoptosis of peripheral blood lymphocytes and promotes the differentiation of Treg cells in the gut. However, the role of retinoid signaling in regulating the immune privilege of the testes remains unknown.

OBJECTIVE

The aim of this study was to determine whether 9cRA, acting via the retinoic acid receptors (RAR) and the retinoic X receptors (RXR), controls the immunomodulatory functions of Sertoli cells by influencing the secretion of anti-inflammatory/pro-inflammatory factors, lymphocyte physiology and Treg cell differentiation.

METHODS

Experiments were performed using in vitro model of co-cultures of murine Sertoli cells and T lymphocytes. Agonists and antagonists of retinoic acid receptors were used to inhibit/stimulate retinoid signaling in Sertoli cells.

RESULTS

Our results have demonstrated that 9cRA inhibits the expression of immunosuppressive genes and enhances the expression of pro-inflammatory factors in Sertoli cells and lymphocytes, increases lymphocyte viability and decreases apoptosis rate. Moreover, we have found that 9cRA blocks lymphocyte apoptosis acting through both RAR and RXR and inhibiting FasL/Fas/Caspase 8 and Bax/Bcl-2/Caspase 9 pathways. Finally, we have shown that 9cRA signaling in Sertoli cells inhibits Treg differentiation.

CONCLUSION

Collectively, our results indicate that retinoid signaling negatively regulates immunologically privileged functions of Sertoli cells, crucial for ensuring male fertility. 9cRA inhibits lymphocyte apoptosis, which can be related to the development of autoimmunity, inflammation, and, in consequence, infertility.

Alleviating 3-MCPD-induced male reproductive toxicity: Mechanistic insights and resveratrol intervention

3-Monochloropropane-1, 2-diol (3-MCPD), a food-borne contaminant, is widely regarded as the primary cause of male infertility. At present, identifying a method to improve/reduce the male reproductive toxicity caused by 3-MCPD is important. In our study, we explored the potential application of resveratrol (RSV) in mitigating the adverse effects of 3-MCPD. Using 7-week-old Sprague-Dawley (SD) rats as animal models, we investigated the impacts and underlying mechanisms of 3-MCPD and RSV on reproductive function. The administration of 3-MCPD led to significant reductions in testicular and epididymal weights, as well as disruptions in spermatogenesis and histological abnormalities. However, co-treatment with RSV and 3-MCPD mitigated these adverse effects. In vitro study, RSV exhibited the ability to reverse the decline in Leydig and Sertoli cell populations inflicted by 3-MCPD treatment. Mechanistically, RSV reduced endoplasmic reticulum stress (PARP), inflammasome activation (NLRP3), and autophagy-mediated lysosome dysfunction (p62 and LC3BII) induced by 3-MCPD. In addition, 3-MCPD treatment increased the expression level of steroidogenesis-related proteins, steroidogenic acute regulatory (StAR) and CYP11A1, but RSV normalized StAR expression. Moreover, 3-MCPD-induced pro-inflammatory responses were counteracted by RSV treatment, with the cytokine reduction and modulation of CD206 expression, a marker of macrophage activation. These findings indicate that RSV attenuates 3-MCPD-induced reproductive toxicity, highlighting its application potential as an adjuvant agent for male reproductive health.

Ciliary neurotrophic factor stimulates stem/progenitor Leydig cell proliferation but inhibits differentiation into its lineage in rats

BACKGROUND

Ciliary neurotrophic factor is a member of the interleukin-6 family of cytokines. Ciliary neurotrophic factor drives many cells for their development. However, its effects on Leydig cell development remain unclear.

METHODS

In the current study, we used three-dimensional seminiferous tubule culture system to induce the proliferation and differentiation of tubule-associated stem Leydig cells and primary progenitor Leydig cells culture to address the effects of ciliary neurotrophic factor.

RESULTS

We found that ciliary neurotrophic factor stimulated the proliferation of stem Leydig cells but inhibited their development into the Leydig cell lineage. The ciliary neurotrophic factor-mediated effects can be reversed by signal transducer and activator 3 inhibitor S3I-201 and phosphatidylinositol 3-kinase inhibitor wortmannin, indicating that ciliary neurotrophic factor acts via signal transducer and activator 3-phosphatidylinositol 3-kinase signaling pathways to increase stem/progenitor Leydig cell proliferation. Ciliary neurotrophic factor at 1 and 10 ng/mL significantly decreased androgen production by progenitor Leydig cells. Microarray analysis of ciliary neurotrophic factor-treated progenitor Leydig cells showed that ciliary neurotrophic factor blocked steroidogenic pathways by downregulating Scarb1, Star, and Hsd3b1, possibly by downregulating the transcription factor Nr5a1 expression.

CONCLUSION

Ciliary neurotrophic factor stimulates proliferation but blocks the differentiation of stem/progenitor Leydig cells.

Persistent oligonecrozoospermia after asymptomatic SARS-CoV-2 infection. A case report and literature review

COVID-19 is known to have deleterious effects on different systems such as the respiratory, cardiovascular, central nervous, and gastrointestinal. However, conflicting data about the possible implications for male reproductive health and fertility have been reported. In addition, the long-term consequences of SARS-CoV-2 infection remain unclear. Herein, we report a case of a 42-year-old man with no known co-morbidities and normal baseline semen quality, who subsequently suffered an asymptomatic SARS-CoV-2 infection. Shortly after, the patient developed sudden oligoasthenozoospermia, even reaching azoospermia, which gradually evolved into persistent severe oligonecrozoospermia, accompanied by semen inflammation and oxidative stress. Remarkably, the latter occurred in the absence of urogenital infections, hormonal imbalances, tissue/organ obstruction/damage, medication or drug treatment, smoking, or exposure to toxins/pollutants, radiation, or high temperature. This case constitutes valuable clinical evidence that adds to the current knowledge in the field and highlights the need for further and longer follow-up studies to better understand the putative long-term consequences of SARS-CoV-2 infection on male fertility.

A Narrative Review Discussing Vasectomy-Related Impact upon the Status of Oxidative Stress and Inflammation Biomarkers and Semen Microbiota

Background: Male contraceptive approaches besides tubal sterilization involve vasectomy and represent the method of choice among midlife men in developing countries thanks to many advantages. However, the subsidiary consequences of this intervention are insufficiently explored since the involved mechanisms may offer insight into a much more complex picture. Methods: Thus, in this manuscript, we aimed to reunite all available data by searching three separate academic database(s) (PubMed, Web of Knowledge, and Scopus) published in the past two decades by covering the interval 2000–2023 and using a predefined set of keywords and strings involving “oxidative stress” (OS), “inflammation”, and “semen microbiota” in combination with “humans”, “rats”, and “mice”. Results: By following all evidence that fits in the pre-, post-, and vasectomy reversal (VR) stages, we identified a total of n = 210 studies from which only n = 21 were finally included following two procedures of eligibility evaluation. Conclusions: The topic surrounding this intricate landscape has created debate since the current evidence is contradictory, limited, or does not exist. Starting from this consideration, we argue that further research is mandatory to decipher how a vasectomy might disturb homeostasis.

Unraveling the effect of the inflammatory microenvironment in spermatogenesis progression

Experimental autoimmune orchitis (EAO) is a chronic inflammatory disorder that causes progressive spermatogenic impairment. EAO is characterized by high intratesticular levels of nitric oxide (NO) and tumor necrosis factor alpha (TNFα) causing germ cell apoptosis and Sertoli cell dysfunction. However, the impact of this inflammatory milieu on the spermatogenic wave is unknown. Therefore, we studied the effect of inflammation on spermatogonia and preleptotene spermatocyte cell cycle progression in an EAO context and through the intratesticular DETA-NO and TNFα injection in the normal rat testes. In EAO, premeiotic germ cell proliferation is limited as a consequence of the undifferentiated spermatogonia (CD9⁺) cell cycle arrest in G2/M and the reduced number of differentiated spermatogonia (c-kit⁺) and preleptotene spermatocytes that enter in the meiotic S-phase. Although inflammation disrupts spermatogenesis in EAO, it is maintained in some seminiferous tubules at XIV and VII-VIII stages of the epithelial cell cycle, thereby guaranteeing sperm production. We found that DETA-NO (2 mM) injected in normal testes arrests spermatogonia and preleptotene spermatocyte cell cycle; this effect reduces the number of proliferative spermatogonia and the number of preleptotene spermatocytes in meiosis S-phase (36 h after). The temporal inhibition of spermatogonia clonal amplification delayed progression of the spermatogenic wave (5 days after) finally altering spermatogenesis. TNFα (0.5 and 1 µg) exposure did not affect premeiotic germ cell cycle or spermatogenic wave. Our results show that in EAO the inflammatory microenvironment altered spermatogenesis kinetics through premeiotic germ cell cycle arrest and that NO is a sufficient factor contributing to this phenomenon.

Protective effects of Theracurmin treatment during experimental infection of the Colombian strain of Trypanosoma cruzi at the testicular site

Introduction

Chagas' disease is a tropical neglected illness caused by Trypanosoma cruzi and remains one of the most significant causes of morbidity and mortality in South and Central Americas. The disease is caused by a moderate to intense and persistent inflammatory response characterized by local upregulated expression and production of inflammatory mediators that favors the activation and recruitment of distinct cells of the immune system into different tissues to eliminate the parasites. Theracurmin is a curcumin's derived formulation of nanoparticles. Its anti-inflammatory properties make this bioactive compound a mitigating factor in pathological cases after an overwhelming inflammatory response.

Methods

Our research focused on the testicular investigation in 28 mice infected by 103 trypomastigote forms of Colombian strain of T. cruzi and preventively treated with Theracurmin. The mice were treated with 30 mg/Kg of Theracurmin during the period of 30 days. At the 30th day post infection animals were euthanized, and its testicles were collected to morphological and immunological assays.

Results

The animals infected and treated with Theracurmin presented a reduction in the testicular levels of IL-15 and IL-6. The volume density (%) of the tunica propria was also higher in all infected animals, but Theracurmin decreased this parameter in the treated animals. In the intertubular area, the percentage of some intertubular components was decreased in the infected animals such as the percentage and volume of Leydig cells, connective tissue, and macrophages.

Discussion

Furthermore, our data pointed to the daily use of Theracurmin in the diet as a protective element of the testicular function.

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.

Mechanisms underlying impaired spermatogenic function in orchitis induced by busulfan

Busulfan is an alkylating agent commonly used in cancer chemotherapy. It is also an ideal agent for preparing transplant recipients of spermatogonial stem cells because of its high efficiency in destroying endogenous germ cells in the testis. However, its toxicity mechanism remains unclear, affecting its clinical use and applications. Based on reports of busulfan causing orchitis and a previous study by our team, this article summarizes the relationship between busulfan and orchitis, cytokines, the blood-testis barrier, and the cytoskeleton, unravels the regulatory pathways and mechanism behind busulfan-induced orchitis, and reveals the molecular mechanism underlying impaired spermatogenic function in orchitis, providing new ideas for the clinical application of busulfan while reducing its testicular toxicity.

The Role of Mononuclear Phagocytes in the Testes and Epididymis

The mononuclear phagocytic system (MPS) is the primary innate immune cell group in male reproductive tissues, maintaining the balance of pro-inflammatory and immune tolerance. This article aims to outline the role of mononuclear macrophages in the immune balance of the testes and epididymis, and to understand the inner immune regulation mechanism. A review of pertinent publications was performed using the PubMed and Google Scholar databases on all articles published prior to January 2021. Search terms were based on the following keywords: 'MPS', 'mononuclear phagocytes', 'testes', 'epididymis', 'macrophage', 'Mφ', 'dendritic cell', 'DC', 'TLR', 'immune', 'inflammation', and 'polarization'. Additionally, reference lists of primary and review articles were reviewed for other publications of relevance. This review concluded that MPS exhibits a precise balance in the male reproductive system. In the testes, MPS cells are mainly suppressed subtypes (M2 and cDC2) under physiological conditions, which maintain the local immune tolerance. Under pathological conditions, MPS cells will transform into M1 and cDC1, producing various cytokines, and will activate T cell specific immunity as defense to foreign pathogens or self-antigens. In the epididymis, MPS cells vary in the different segments, which express immune tolerance in the caput and pro-inflammatory condition in the cauda. Collectively, MPS is the control point for maintaining the immune tolerance of the testes and epididymis as well as for eliminating pathogens.

Chronic alcohol-induced dysbiosis of the gut microbiota and gut metabolites impairs sperm quality in mice

Studies have indicated that the ethanol exposure impairs the gut microbiota, At the same time, high levels of alcohol exposure damage sperm in mice. However, whether the gut microbiota is involved in mediating the effects of alcohol on sperm quality remains unclear. This study aimed to assess the effect of chronic alcohol consumption on intestinal microbiota in mice and analyze the potential pathophysiological effect of altered intestinal microbiota on sperm quality. We established a mouse model of chronic alcohol consumption by allowing male C57 mice to freely ingest 10% ethanol for 10 weeks, and collected the fecal microbiota of the male mice in the chronic drinking group (alcohol) and the control group (control) and transplanted the specimens into the transplant groups (the alcohol-fecal microbiota transplantation [FMT] group and the control-FMT group). Sperm quality was significantly decreased in the alcohol-FMT group compared with the control-FMT group. Gut microbiota analysis revealed that the abundance of 11 operational taxonomic units (OTUs) was altered in the alcohol-FMT group. Nontargeted metabolomics identified 105 differentially altered metabolites, which were mainly annotated to amino acids, lipids, glycerophosphoethanolamine, organic oxygenic compounds, organic acids and their derivatives, steroids, and flavonoids. In particular, the oxidative phosphorylation pathway, which is the key to spermatogenesis, was significantly enriched in the alcohol-FMT group. Moreover, compared with the control-FMT group, the alcohol-FMT group presented significantly higher serum endotoxin and inflammatory cytokine levels, with more pronounced T cell and macrophage infiltration in the intestinal lamina propria and elevated levels of testicular inflammatory cytokines. In addition, RNA sequencing showed significant differences in the expression of testis-related genes between the alcohol-FMT group and the control-FMT group. In particular, the expression of genes involved in gamete meiosis, testicular mitochondrial function, and the cell division cycle was significantly reduced in alcohol-FMT mice. In conclusion, these findings indicated that intestinal dysbiosis induced by chronic alcohol consumption may be an important factor contributing to impaired sperm quality. Chronic alcohol consumption induces intestinal dysbiosis, which then leads to metabolic disorders, elevated serum endotoxin and inflammatory cytokine levels, testicular inflammation, abnormal expression of related genes, and ultimately, impaired sperm quality. These findings are potentially useful for the treatment of male infertility.

The potential impact of COVID-19 on male reproductive health

The SARS-CoV-2 virus continues to overwhelm health care systems impairing human to human social and economic interactions. Invasion or damage to the male reproductive system is one of the documented outcomes of viral infection. Existing studies have reported that SARS-CoV-2 may contribute to this loss in relation to inflammatory responses and the formation of cytokine storms in COVID-19 patients. Although direct infection of the testes and entry of SARS-CoV-2 into semen as well as subsequent consequences on the male reproductive system need to be studied more systematically, warnings from two organising ASRM and SART for prospective parents when infected with SARS-CoV-2 should be considered. In the context of an increasingly complex pandemic, this review provides preliminary examples of the potential impact of COVID-19 on male reproductive health and guidance for prospective parents currently infected with or recovering from SARS-CoV-2.

Mechanism of Inflammatory Associated Impairment of Sperm Function, Spermatogenesis and Steroidogenesis

Infection and inflammation are relevant entities of male reproductive disorders that can lead to sub-/infertility. Associated damage of the testis of affected men and in rodent models include leukocytic infiltration, edema formation, fibrosis, germ cell loss and reduced androgen levels. Negative effects on spermatogenesis are thought to be elicited by oxidative stress sustained mostly by increased levels of ROS and pro-inflammatory cytokines. Under normal conditions these cytokines have physiological functions. However, increased levels as seen in inflammation and infection, but also in obesity and cancer are harmful for germ cells and impair steroidogenesis. As a summary, there is mounting evidence that the activation of inflammatory pathways is a rather common feature in various forms of male testicular disorders that extends beyond established infectious/inflammatory cues. This mini review will focus on relevant entities and the mechanisms of how a dysbalance of local testicular factors contributes to disturbances of spermatogenesis and steroidogenesis.

LPS-Induced Systemic Inflammation Caused mPOA-FSH/LH Disturbance and Impaired Testicular Function

Male reproductive function is key to the continuation of species and is under sophisticated regulation, challenged by various stressors including inflammation. In the lipopolysaccharide (LPS) intraperitoneal injection-induced acute systemic inflammation, male fecundity was compromised with decreased testosterone level, damaged spermatogenesis, and downregulations of testicular gene expression levels involved in steroidogenesis regulation and blood-testis barrier. It is also noteworthy that the testis is more sensitive to acute stress caused by LPS-induced systemic inflammation. LPS treatment resulted in lower testicular gene expression levels of steroidogenic acute regulatory protein, cholesterol side-chain cleavage enzyme, and cytochrome P450 family 11 subfamily B member 1 after LPS treatment, while no such decrease was found in the adrenal gland. In parallel to the significant decreases in testicular intercellular adhesion molecule 1, tight junction protein 1, and gap junction alpha-1 protein gene expression with LPS treatment, no decrease was found in the epididymis. In the brain, LPS treatment caused higher medial preoptic area (mPOA) activation in the hypothalamus, which is accompanied by elevated blood follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels, suggesting a disturbed hypothalamic-pituitary-gonad axis function. Besides mPOA, brain c-fos mapping and quantitative analysis demonstrated a broad activation of brain nuclei by LPS, including the anterior cingulate cortex, lateral septum, paraventricular nucleus of the hypothalamus, basolateral amygdala, ventral tegmental area, lateral habenular nucleus, locus coeruleus, Barrington's nucleus, and the nucleus of the solitary tract, accompanied by abnormal animal behavior. Our data showed that LPS-induced inflammation caused not only local testicular damage but also a systemic disturbance at the brain-testis axis level.

Male reproductive system inflammation after healing from coronavirus disease 2019

BACKGROUND

There is evidence that, after severe acute respiratory syndrome coronavirus 2 infection, male reproductive function and semen quality may be damaged OBJECTIVES: To evaluate a panel of inflammatory mediators in semen in patients recovered from coronavirus disease 2019.

MATERIAL AND METHODS

Sexually active men with previous severe acute respiratory syndrome coronavirus 2 infection and proven recovery from coronavirus disease 2019 were enrolled in a prospective cohort study. Clinical, uro-andrological data and semen specimens were prospectively collected. For previously hospitalized coronavirus disease 2019 patients, data on serum inflammatory markers were retrospectively collected.

RESULTS

A total of 43 men were enrolled in the study. Of these, 32 men were normozoospermic, three were oligozoospermic, and eight were crypto-azoospermic. Serum inflammatory markers (procalcitonin and C-reactive protein) were analyzed in previously hospitalized patients both at admission and at peak of infection. Levels at admission were statistically significantly higher in patients resulting in crypto-azoospermic with respect to those resulting in normozoospermic (p = 0.05; p = 0.03 and p = 0.02, respectively) after healing. Seminal cytokine levels were similar among all groups. Interleukin-1β and tumor necrosis factor-α levels were significantly negatively related to sperm total number and concentration, whereas interleukin-4 was correlated with sperm motility.

DISCUSSION AND CONCLUSION

Negative correlations between interleukin-1β and tumor necrosis factor-α and sperm number and the overall high levels of semen cytokines indicate a potential detrimental role of severe acute respiratory syndrome coronavirus 2 driven inflammation on spermatogenesis. Overall, our results indicate that male patients recovering from coronavirus disease 2019 deserve accurate follow-up for their fertility status.

Curcumin and Mesenchymal Stem Cells Ameliorate Ankle, Testis, and Ovary Deleterious Histological Changes in Arthritic Rats via Suppression of Oxidative Stress and Inflammation

Rheumatoid arthritis (RA) is a chronic inflammatory condition, an autoimmune disease that affects the joints, and a multifactorial disease that results from interactions between environmental, genetic, and personal and lifestyle factors. This study was designed to assess the effects of curcumin, bone marrow-derived mesenchymal stem cells (BM-MSCs), and their coadministration on complete Freund's adjuvant- (CFA-) induced arthritis in male and female albino rats. Parameters including swelling of the joint, blood indices of pro-/antioxidant status, cytokines and histopathological examination of joints, and testis and ovary were investigated. RA was induced by a single dose of subcutaneous injection of 0.1 mL CFA into a footpad of the right hind leg of rats. Arthritic rats were treated with curcumin (100 mg/kg b.wt./day) by oral gavage for 21 days and/or treated with three weekly intravenous injections of BM-MSCs (1 × 10⁶ cells/rat/week) in phosphate-buffered saline (PBS). The treatment with curcumin and BM-MSCs singly or together significantly (P < 0.05) improved the bioindicators of oxidative stress and nonenzymatic and enzymatic antioxidants in sera of female rats more than in those of males. Curcumin and BM-MSCs significantly (P < 0.05) improved the elevated TNF-α level and the lowered IL-10 level in the arthritic rats. Furthermore, joint, testis, and ovary histological changes were remarkably amended as a result of treatment with curcumin and BM-MSCs. Thus, it can be concluded that both curcumin and BM-MSCs could have antiarthritic efficacies as well as protective effects to the testes and ovaries which may be mediated via their anti-inflammatory and immunomodulatory potentials as well as oxidative stress modulatory effects.

Impaired semen parameters in patients with confirmed SARS-CoV-2 infection: A prospective cohort study

In this prospective study, we investigated the impact of SARS‐CoV‐2 infection on semen parameters in a cohort of men who had recently recovered from COVID‐19. A total of 24 men who had recently recovered from mild COVID‐19 were included in the study. Their semen parameters were normal before COVID‐19 according to the World Health Organization 2010 reference values. Semen samples were collected from these participants in the recovery phases of COVID‐19. To determine the effect of SARS‐CoV‐2 infection on semen parameters, the patients' pre‐COVID‐19 and post‐COVID‐19 semen analyses were compared. The mean age of the participants was 34.7 ± 6.4 years. The median interval between the positive nasopharyngeal swab test and obtaining semen samples was 111.5 (158) days. There was no significant difference in semen parameters before and after COVID‐19 in terms of semen volume (p = .56), sperm concentration (p = .06), and progressive motility (p = .14). Total motility (p = .01) and total motile sperm count (p = .02) decreased significantly after SARS‐CoV‐2 infection compared to the pre‐infection values. This study demonstrated that sperm motility and total motile sperm count were the semen parameters which showed a significant reduction in cases with a history of mild COVID‐19.

Pathogenesis of Brucella epididymoorchitis-game of Brucella death

Brucellosis is a worldwide zoonotic disease caused by Brucella spp. Human infection often results from direct contact with tissues from infected animals or by consumption of undercooked meat and unpasteurised dairy products, causing serious economic losses and public health problems. The male genitourinary system is a common involved system in patients with brucellosis. Among them, unilateral orchitis and epididymitis are the most common. Although the clinical and imaging aspect of orchi-epididymitis caused by brucellosis have been widely described, the cellular and molecular mechanisms involved in the damage and the immune response in testis and epididymis have not been fully elucidated. In this review, we first summarised the clinical characteristics of Brucella epididymo-orchitis and the composition of testicular and epididymal immune system. Secondly, with regard to the mechanism of Brucella epididymoorchitis, we mainly discussed the process of Brucella invading testis and epididymis in temporal and spatial order, including i) Brucella evades innate immune recognition of testicular PRRs；ii) Brucella overcomes the immune storm triggered by the invasion of testis through bacterial lipoproteins and virulence factors, and changes the secretion mode of cytokines; iii) Brucella breaks through the blood-testis barrier with the help of macrophages, and inflammatory cytokines promote the oxidative stress of Sertoli cells, damaging the integrity of BTB; iv) Brucella inhibits apoptosis of testicular phagocytes. Finally, we revealed the structure and sequence of testis invaded by Brucella at the tissue level. This review will enable us to better understand the pathogenesis of orchi-epididymitis caused by brucellosis and shed light on the development of new treatment strategies for the treatment of brucellosis and the prevention of transition to chronic form. Facing the testicle with immunity privilege, Brucella is like Bruce Lee in the movie Game of Death, winning is survival while losing is death.HIGHLIGHTSWe summarized the clinical features and pathological changes of Brucellaepididymoorchitis.Our research reveals the pathogenesis of Brucella epididymoorchitis, which mainly includes the subversion of testicular immune privilege by Brucella and a series of destructive reactions derived from it.As a basic framework and valuable resource, this study can promote the exploration of the pathogenesis of Brucella and provide reference for determining new therapeutic targets for brucellosis in the future.

MERTK-Mediated LC3-Associated Phagocytosis (LAP) of Apoptotic Substrates in Blood-Separated Tissues: Retina, Testis, Ovarian Follicles

Timely and efficient elimination of apoptotic substrates, continuously produced during one’s lifespan, is a vital need for all tissues of the body. This task is achieved by cells endowed with phagocytic activity. In blood-separated tissues such as the retina, the testis and the ovaries, the resident cells of epithelial origin as retinal pigmented epithelial cells (RPE), testis Sertoli cells and ovarian granulosa cells (GC) provide phagocytic cleaning of apoptotic cells and cell membranes. Disruption of this process leads to functional ablation as blindness in the retina and compromised fertility in males and females. To ensure the efficient elimination of apoptotic substrates, RPE, Sertoli cells and GC combine various mechanisms allowing maintenance of tissue homeostasis and avoiding acute inflammation, tissue disorganization and functional ablation. In tight cooperation with other phagocytosis receptors, MERTK—a member of the TAM family of receptor tyrosine kinases (RTK)—plays a pivotal role in apoptotic substrate cleaning from the retina, the testis and the ovaries through unconventional autophagy-assisted phagocytosis process LAP (LC3-associated phagocytosis). In this review, we focus on the interplay between TAM RTKs, autophagy-related proteins, LAP, and Toll-like receptors (TLR), as well as the regulatory mechanisms allowing these components to sustain tissue homeostasis and prevent functional ablation of the retina, the testis and the ovaries.

Interleukin-6 deficiency modulates testicular function by increasing the expression of suppressor of cytokine signaling 3 (SOCS3) in mice

Several cytokines have been reported to participate in spermatogenesis, including interleukin-6 (IL6). However, not many studies have been conducted on the loss of Il6 on the male reproductive tract. Nonetheless, there is considerable knowledge regarding the pathological and physiological role of IL6 on spermatogenesis. In this way, this study evaluated the impact of Il6 deficiency on mice testicles in the absence of infection or inflammation. We showed that Il6 deficiency increases daily sperm production, the number of spermatids, and the testicular testosterone and dihydrotestosterone levels. Besides that, mice with a deleted Il6 (IL6KO) showed increased testicular SOCS3 levels, with no changes in pJAK/JAK and pSTAT3/STAT3 ratios. It is worth noting that the aforementioned pathway is not the only pathway to up-regulate SOCS3, nor is it the only SOCS3 target, thus proposing that the increase of SOCS3 in the testis occurs independently of the JAK-STAT signaling in IL6KO mice. Therefore, we suggest that the lack of Il6 drives androgenic production by increasing SOCS3 in the testis, thus leading to an increase in spermatogenesis.

Immunologic Environment of the Testis

Mammalian spermatogenesis is a carefully orchestrated male germ cell differentiation process by which spermatogonia differentiate to spermatozoa in the testis. A highly organized testicular microenvironment is therefore necessary to support spermatogenesis. Regarding immunologic aspects, the testis adapts a specialized immune environment for the protection of male germ cells and testicular functions. The mammalian testis possesses two immunologic features: (1) it is an immunoprivileged organ where immunogenic germ cells do not induce deleterious immune responses under physiologic conditions; and (2) it creates its own effective innate defense system against microbial infection. Various pathologic conditions may disrupt testicular immune homeostasis, thereby resulting in a detrimental immune response and perturbing testicular functions, one of the etiologic factors of male infertility. Understanding the mechanisms underlying immunoregulation in the testis can aid in establishing strategies for the prevention and therapy of immunologic testicular dysfunction and male infertility. This chapter focuses on the mechanisms underlying immune privilege, local innate immunity, and immunologic diseases of the testis.

T Lymphocytes and Testicular Immunity: A New Insight into Immune Regulation in Testes

The immune privilege of the testes is necessary to prevent immune attacks to gamete-specific antigens and paternal major histocompatibility complex (MHC) antigens, allowing for normal spermatogenesis. However, infection and inflammation of the male genital tract can break the immune tolerance and represent a significant cause of male infertility. Different T cell subsets have been identified in mammalian testes, which may be involved in the maintenance of immune tolerance and pathogenic immune responses in testicular infection and inflammation. We reviewed the evidence in the published literature on different T subtypes (regulatory T cells, helper T cells, cytotoxic T cells, γδ T cells, and natural killer T cells) in human and animal testes that support their regulatory roles in infertility and the orchitis pathology. While many in vitro studies have indicated the regulation potential of functional T cell subsets and their possible interaction with Sertoli cells, Leydig cells, and spermatogenesis, both under physiological and pathological processes, there have been no in situ studies to date. Nevertheless, the normal distribution and function of T cell subsets are essential for the immune privilege of the testes and intact spermatogenesis, and T cell-mediated immune response drives testicular inflammation. The distinct function of different T cell subsets in testicular homeostasis and the orchitis pathology suggests a considerable potential of targeting specific T cell subsets for therapies targeting chronic orchitis and immune infertility.

Hypogonadism and cancer survivorship

PURPOSE OF REVIEW

Hypogonadism is highly prevalent among not only patients with a history of prior treatment for cancer, but also among those patients with a new oncologic diagnosis who have not yet received any cancer therapy. Hypogonadism can cause a wide array of signs and symptoms including: deceased muscle mass; increased fat mass; decreased energy, mood, and overall sense of well being; diminished bone mineral density; infertility; and impaired libido and sexual function. This purpose of this manuscript is to review the mechanisms by which cancer and oncologic treatment regimens can adversely affect the hypothalamic pituitary gonadal axis, resulting in hypogonadism. Risks and benefits associated with the treatment of testosterone deficiency are also discussed, which are important considerations for clinicians caring for affected patients.

RECENT FINDINGS

Hypogonadism has a high prevalence in the setting of cancer and is an important survivorship issue. Recent randomized controlled trials confirm testosterone's therapeutic benefits in terms of sexual function, mood body composition, and bone health, but the specific benefits in terms of quality of life are less clear.

SUMMARY

More prospective studies are needed to further delineate the risks, benefits, and overall outcomes of testosterone replacement therapy in patients with cancer and cancer survivors.

Multiple Expression Assessments of ACE2 and TMPRSS2 SARS-CoV-2 Entry Molecules in the Urinary Tract and Their Associations with Clinical Manifestations of COVID-19

Background

Since December 2019, the novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), first spread quickly in Wuhan, China, then globally. Based on previously published evidence, ACE2 and TMPRSS2 are both pivotal entry molecules that enable cellular infection by SARS-CoV-2. Also, increased expression of pro-inflammatory cytokines, or a “cytokine storm,” is associated with multiple organ dysfunction syndrome often observed in critically ill patients.

Methods

We investigated the expression pattern of ACE2 and TMPRSS2 in major organs in the human body, especially in specific disease conditions. Multiple sequence alignment of ACE2 in different species was used to explain animal susceptibility. Moreover, the cell-specific expression patterns of ACE2 and cytokine receptors in the urinary tract were assessed using single-cell RNA sequencing (scRNA-seq). Additional biological relevance was determined through Gene Set Enrichment Analysis (GSEA) using an ACE2-specific signature.

Results

Our results revealed that ACE2 and TMPRSS2 were highly expressed in genitourinary organs. ACE2 was highly and significantly expressed in the kidney among individuals with chronic kidney diseases or diabetic nephropathy. In single cells, ACE2 was primarily enriched in gametocytes in the testis and renal proximal tubules. The receptors for pro-inflammatory cytokines, especially IL6ST, were notably concentrated in endothelial cells, macrophages, spermatogonial stem cells in the testis, and renal endothelial cells, which suggested the occurrence of alternative damaging autoimmune mechanisms.

Conclusion

This study provided new insights into the pathogenic mechanisms of SARS-CoV-2 that underlie the clinical manifestations observed in the human testis and kidney. These observations might substantially facilitate the development of effective treatments for this rapidly spreading disease.

Pathomechanisms of Autoimmune Based Testicular Inflammation

Infection and inflammation of the male reproductive tract are relevant causes of infertility. Inflammatory damage occurs in the special immunosuppressive microenvironment of the testis, a hallmark termed testicular immune privilege, which allows tolerance to neo-antigens from developing germ cells appearing at puberty, long after the establishment of systemic immune tolerance. Experimental autoimmune orchitis (EAO) is a well-established rodent model of chronic testicular inflammation and organ specific autoimmunity that offers a valuable in vivo tool to investigate the pathological and molecular mechanisms leading to the breakdown of the testicular immune privilege. The disease is characterized by the infiltration of the interstitium by immune cells (mainly macrophages, dendritic cells, and T cells), formation of autoantibodies against testicular antigens, production of pro-inflammatory mediators such as NO, MCP1, TNFα, IL6, or activins and dysregulation of steroidogenesis with reduced levels of serum testosterone. EAO leads to sloughing of germ cells, atrophic seminiferous tubules and fibrotic remodeling, parameters all found similarly to changes in human biopsies from infertile patients with inflammatory infiltrates. Interestingly, testosterone supplementation during the course of EAO leads to expansion of the regulatory T cell population and inhibition of disease development. Knowledge of EAO pathogenesis aims to contribute to a better understanding of human testicular autoimmune disease as an essential prerequisite for improved diagnosis and treatment.

Potential mechanisms of SARS-CoV-2 action on male gonadal function and fertility: Current status and future prospects

The novel coronavirus was recognised in December 2019 and caught humanity off guard. The virus employs the angiotensin‐converting enzyme 2 (ACE2) receptor for entry into human cells. ACE2 is expressed on different organs, which is raising concern as to whether these organs can be infected by the virus or not. The testis appears to be an organ enriched with levels of ACE2, while the possible mechanisms of involvement of the male reproductive system by SARS‐CoV‐2 are not fully elucidated. The major focus of the present studies is on the short‐term complications of the coronavirus and gains importance on studying the long‐term effects, including the possible effects of the virus on the male reproductive system. The aim of this review was to provide new insights into different possible mechanisms of involvement of male gonads with SARS‐CoV‐2 including investigating the ACE2 axis in testis, hormonal alterations in patients with COVID‐19, possible formation of anti‐sperm antibodies (ASA) and subsequently immunological infertility as a complication of SARS‐CoV‐2 infection. Finally, we suggest measuring the sperm DNA fragmentation index (DFI) as a determiner of male fertility impairment in patients with COVID‐19 along with other options such as sex‐related hormones and semen analysis. Invasion of SARS‐CoV‐2 to the spermatogonia, Leydig cells and Sertoli cells can lead to sex hormonal alteration and impaired gonadal function. Once infected, changes in ACE2 signalling pathways followed by oxidative stress and inflammation could cause spermatogenesis failure, abnormal sperm motility, DNA fragmentation and male infertility.

Pattern recognition receptor-mediated innate immune responses in seminal vesicle epithelial cell and their impacts on cellular function†

The seminal vesicles can be infected by microorganisms, thereby resulting in vesiculitis and impairment in male fertility. Innate immune responses in seminal vesicles cells to microbial infections, which facilitate vesiculitis, have yet to be investigated. The present study aims to elucidate pattern recognition receptor-mediated innate immune responses in seminal vesicles epithelial cells. Various pattern recognition receptors, including Toll-like receptor 3, Toll-like receptor 4, cytosolic ribonucleic acid, and deoxyribonucleic acid sensors, are abundantly expressed in seminal vesicles epithelial cells. These pattern recognition receptors can recognize their respective ligands, thus activating nuclear factor kappa B and interferon regulatory factor 3. The pattern recognition receptor signaling induces expression of pro-inflammatory cytokines, such as tumor necrosis factor alpha (Tnfa) and interleukin 6 (Il6), chemokines monocyte chemoattractant protein-1 (Mcp1) and C-X-C motif chemokine 10 (Cxcl10), and type 1 interferons Ifna and Ifnb. Moreover, pattern recognition receptor-mediated innate immune responses up-regulated the expression of microsomal prostaglandin E synthase and cyclooxygenase 2, but they down-regulated semenogelin-1 expression. These results provide novel insights into the mechanism underlying vesiculitis and its impact on the functions of the seminal vesicles.

Immunolocalization of IL-6 and IL-10 in the testicular tissue of testicular dysfunction rat treated with secretome

OBJECTIVE

This study was carried out to find out the immunolocalization of Interleukin 6 (IL-6) and Interleukin 10 (IL-10) in the testicular tissue of testicular dysfunction rat treated with secretome from human umbilical stem cells.

MATERIALS AND METHODS

Rats were induced with cisplatin for testicular dysfunction condition. After that, the rats were grouped into two categories and were treated with secretome at 0.2 and 0.5 ml/kg BW once every week for 4 weeks. One week later, after the secretome treatment, the rats were sacrificed for histological evaluation using the immunohistochemical method. The preparation slides were examined using a light microscope and were analyzed descriptively and quantitatively.

RESULTS

There were no IL-6 and IL-10 immunoreactivities seen in the testicular tissue after cisplatin induction. However, the immunoreactivities of IL-6 and IL-10 were detected after secretome treatment, with both dosages of 0.2 and 0.5 ml/kg BW. These immunoreactivities were detected in the spermatogonia, spermatid/luminal tissue of seminiferous tubule, spermatogenic cells, and Leydig cells. In the cell calculation, the numbers of IL-6 immunoreactive cells were higher at the lower secretome dosage. In contrast, the numbers of IL-10 immunoreactive cells were higher at the higher secretome dosage.

CONCLUSION

IL-6 and IL-10 can be localized in the testicular tissue of testicular dysfunction rat after secretome treatment.

Oncofertility in adult and pediatric populations: options and barriers

Cancer and its treatments can affect fertility in a variety of ways, and recent advances in cancer detection and treatment have led to an increasing number of cancer survivors for whom future fertility is a primary concern. Oncofertility is the study of interactions between cancer, anti-cancer therapy, fertility, and reproductive health. Fertility preservation aims to optimize fertility potential before initiation of gonadotoxic therapies. Sperm cryopreservation from an ejaculated sample is the gold standard for adults and post-pubertal adolescents, though added maneuvers such as medical therapy, penile vibratory stimulation, and electroejaculation can be employed when appropriate. When all these approaches fail, testicular sperm extraction can be used to obtain and cryopreserve testicular sperm from the azoospermic patient. Fertility preservation in the pre-pubertal pediatric patient is still experimental, but recent scientific breakthroughs with use of spermatogonial stem cells and testicular tissue transplantation offer great promise for the future. While there may be several practical, cultural, religious, and other barriers to fertility preservation, the establishment of a dedicated fertility preservation team can help to overcome these obstacles and optimize the utilization of fertility preservation in cancer patients of all ages.

Human spermatozoa of male patients with subfertility express the interleukin-6 receptor

Male subfertility has been associated with bacterial infections and chronic inflammation. In this context, several studies investigated cytokine levels in seminal plasma, whereas interleukin-6 (IL-6) appears to be crucial. However, little is known about its receptor, the IL-6R expression on human spermatozoa. Thus, the aim of the present study was to screen spermatozoa for IL-6R expression and to identify its localisation. Semen samples of 137 patients (median age 37.69, SD ± 7.82) with subfertility were analysed. Sperm analysis including determination of IL-6 was performed following the World Health Organization criteria. Also, flow cytometry was performed for sperm IL-6R expression. IL-6R⁺ cells were used for immunofluorescence staining to identify receptor localisation. The results showed positive staining for IL-6R in the midpiece of spermatozoa. Furthermore, a significant correlation between sperm IL-6R expression, seminal plasma IL-6 and total sperm count could be demonstrated, whereas a negative correlation was observed in sperm IL-6R expression and motility. However, no statistical significance could be observed between IL-6R expression, vitality and morphology. Moreover, incubation of spermatozoa with IL-6 led to a slight but significant decrease in motility after 24 hr. These data suggest that IL-6R expression may play a role in impaired sperm function during inflammation.

Fluoride Induces Autoimmune Orchitis Involved with Enhanced IL-17A Secretion in Mice Testis

Fluoride (F) widely exists in the water and food. Recent studies reported that F induced testicular toxicity via inflammation reaction. This study was aimed to explore the mechanism of F-induced inflammation in testis. 100 healthy male mice (BALB/cJ strain) were randomly divided into five groups including: control, experimental autoimmune orchitis (EAO), and three F groups (25, 50, and 100 mg/L sodium fluoride (NaF)). After 150 d, the results showed a significant increase in testicular cytokines levels including of IL-17A, IL-6, IFN-γ, and TNF-α in NaF and EAO groups compared with control group. Interestingly, the presence of specific antisperm autoantibodies in antitesticular autoantibodies and the notable recruitment of immunocyte (T cells and dendritic cells) were also observed in NaF and EAO groups. In addition, findings showed that in NaF and EAO groups macrophages and T cells both significantly secreted IL-17A, and the protein and mRNA levels of cytokines (IL-6 and TGF-β) were significantly increased. From these results, it can be concluded that autoimmune orchitis and IL-17A are implicated in F-induced testicular inflammation.

Role of indoleamine 2,3-dioxygenase in testicular immune-privilege

Male meiotic germ cell including the spermatozoa represent a great challenge to the immune system, as they appear long after the establishment of normal immune tolerance mechanisms. The capacity of the testes to tolerate autoantigenic germ cells as well as survival of allogeneic organ engrafted in the testicular interstitium have led to consider the testis an immunologically privileged site. Disruption of this immune privilege following trauma, tumor, or autoimmune orchitis often results in male infertility. Strong evidence indicates that indoleamine 2,3-dioxygenase (IDO) has been implicated in fetal and allograft tolerance, tumor immune resistance, and regulation of autoimmune diseases. IDO and tryptophan 2,3-dioxygenase (TDO) catalyze the same rate-limiting step of tryptophan metabolism along a common pathway, which leads to tryptophan starvation and generation of catabolites collectively known as kynurenines. However, the relevance of tryptophan metabolism in testis pathophysiology has not yet been explored. Here we assessed the in vivo role of IDO/TDO in experimental autoimmune orchitis (EAO), a model of autoimmune testicular inflammation and immunologically impaired spermatogenesis. EAO was induced in adult Wistar rats with testicular homogenate and adjuvants. Control (C) rats injected with saline and adjuvants and normal untreated rats (N) were also studied. mRNA expression of IDO decreased in whole testes and in isolated Sertoli cells during EAO. TDO and IDO localization and level of expression in the testis were analyzed by immunostaining and Western blot. TDO is expressed in granulomas from EAO rats, and similar protein levels were observed in N, C, and EAO groups. IDO was detected in mononuclear and endothelial cells and reduced IDO expression was detected in EAO group compared to N and C rats. This phenomenon was concomitant with a significant reduction of IDO activity in EAO testis measured by tryptophan and kynurenine concentrations (HPLC). Finally, in vivo inhibition of IDO with 1-methyl-tryptophan increased severity of the disease, demonstrating down regulation of IDO-based tolerance when testicular immune regulation was disrupted. We present evidence that an IDO-based mechanism is involved in testicular immune privilege.

Altered endocrine, cytokine signaling and oxidative stress: A plausible reason for differential changes in testicular cells in diet-induced and genetically-inherited - obesity in adult rats

Obesity is emerging as a potential risk factor for male infertility. It is a multifactorial disorder with primarily genetic and/or environmental factors. Our earlier studies have shown differential effects of genetically inherited-and high fat diet induced-obesity on hormones, fertility and spermatogenesis in adult male rats. In the present study, we assessed the effect of high fat diet induced - and genetically inherited - obesity on the underlying molecular mechanisms affecting spermatogenesis. The expression of hormone receptors, cytokines and markers of oxidative stress as well as cell cycle mediators were affected in both the obese groups, however, the changes were different in the two groups. This could be due to difference in fat distribution between the two types of obese groups. Altered expression of hormone receptors, cytokines, cell cycle mediators and differential effects on oxidative stress could be the plausible reason for differential changes in germ cell population in both the groups.

Interleukin 6 inhibits the differentiation of rat stem Leydig cells

Inflammation causes male hypogonadism. Several inflammatory cytokines, including interleukin 6 (IL-6), are released into the blood and may suppress Leydig cell development. The objective of the present study was to investigate whether IL-6 affected the proliferation and differentiation of rat stem Leydig cells. Leydig cell-depleted rat testis (in vivo) and seminiferous tubules (in vitro) with ethane dimethane sulfonate (EDS) were used to explore the effects of IL-6 on stem Leydig cell development. Intratesticular injection of IL-6 (10 and 100 ng/testis) from post-EDS day 14 to 28 blocked the regeneration of Leydig cells, as shown by the lower serum testosterone levels (21.6% of the control at 100 ng/testis dose), the down-regulated Leydig cell gene (Lhcgr, Star, Cyp11a1, Cyp17a1, and Hsd17b3) expressions, and the reduced Leydig cell number. Stem Leydig cells on the surface of the seminiferous tubules were induced to enter the Leydig cell lineage in vitro in the medium containing luteinizing hormone and lithium. IL-6 (1, 10, and 100 ng/ml) concentration-dependently decreased testosterone production and Lhcgr, Cyp11a1, Cyp17a1, Hsd17b3 and Insl3 mRNA levels. The IL-6 mediated effects were antagonized by Janus kinase 1 (JAK) inhibitor (filgotinib) and Signal Transducers and Activators of Transcription 3 (STAT3) inhibitor (S3I-201), indicating that a JAK-STAT3 signaling pathway is involved. In conclusion, our results demonstrated that IL-6 was an inhibitory factor of stem Leydig cell development.

Infectious, inflammatory and 'autoimmune' male factor infertility: how do rodent models inform clinical practice?

BACKGROUND

Infection and inflammation of the reproductive tract are significant causes of male factor infertility. Ascending infections caused by sexually transmitted bacteria or urinary tract pathogens represent the most frequent aetiology of epididymo-orchitis, but viral, haematogenous dissemination is also a contributory factor. Limitations in adequate diagnosis and therapy reflect an obvious need for further understanding of human epididymal and testicular immunopathologies and their contribution to infertility. A major obstacle for advancing our knowledge is the limited access to suitable tissue samples. Similarly, the key events in the inflammatory or autoimmune pathologies affecting human male fertility are poorly amenable to close examination. Moreover, the disease processes generally have occurred long before the patient attends the clinic for fertility assessment. In this regard, data obtained from experimental animal models and respective comparative analyses have shown promise to overcome these restrictions in humans.

OBJECTIVE AND RATIONALE

This narrative review will focus on male fertility disturbances caused by infection and inflammation, and the usefulness of the most frequently applied animal models to study these conditions.

SEARCH METHODS

An extensive search in Medline database was performed without restrictions until January 2018 using the following search terms: 'infection' and/or 'inflammation' and 'testis' and/or 'epididymis', 'infection' and/or 'inflammation' and 'male genital tract', 'male infertility', 'orchitis', 'epididymitis', 'experimental autoimmune' and 'orchitis' or 'epididymitis' or 'epididymo-orchitis', antisperm antibodies', 'vasectomy'. In addition to that, reference lists of primary and review articles were reviewed for additional publications independently by each author. Selected articles were verified by each two separate authors and discrepancies discussed within the team.

OUTCOMES

There is clear evidence that models mimicking testicular and/or epididymal inflammation and infection have been instructive in a better understanding of the mechanisms of disease initiation and progression. In this regard, rodent models of acute bacterial epididymitis best reflect the clinical situation in terms of mimicking the infection pathway, pathogens selected and the damage, such as fibrotic transformation, observed. Similarly, animal models of acute testicular and epididymal inflammation using lipopolysaccharides show impairment of reproduction, endocrine function and histological tissue architecture, also seen in men. Autoimmune responses can be studied in models of experimental autoimmune orchitis (EAO) and vasectomy. In particular, the early stages of EAO development showing inflammatory responses in the form of peritubular lymphocytic infiltrates, thickening of the lamina propria of affected tubules, production of autoantibodies against testicular antigens or secretion of pro-inflammatory mediators, replicate observations in testicular sperm extraction samples of patients with 'mixed atrophy' of spermatogenesis. Vasectomy, in the form of sperm antibodies and chronic inflammation, can also be studied in animal models, providing valuable insights into the human response.

WIDER IMPLICATIONS

This is the first comprehensive review of rodent models of both infectious and autoimmune disease of testis/epididymis, and their clinical implications, i.e. their importance in understanding male infertility related to infectious and non-infectious/autoimmune disease of the reproductive organs.

Association Between Nonalcoholic Fatty Liver Disease and Severe Male Reproductive Organ Impairment (Germinal Epithelial Loss): Study on a Mouse Model and on Human Patients

Metabolic syndrome (MS) has been associated with testicular damage. Nonalcoholic fatty liver disease (NAFLD) is a multisystemic disease that affects different organs, but its effect on the testes is unknown. A study analyzing germ cell involvement on BALB/c mice was carried out. A parallel comparative study was conducted that investigated alterations in the germinal epithelium of male humans that died from an unrelated acute event. The complete medical histories and histologic samples of the thoracic aorta, liver tissue, and testicular tissue from the deceased subjects were collected. The degree of germinal epithelial loss (DGEL) was evaluated and the clinical and histologic data were compared between individuals with and without NAFLD. The only metabolic or morphologic variable that caused a significant difference in the DGEL, in both the animal model and humans, was the presence of liver steatosis. The percentage of steatosis was also correlated with the percentage of the DGEL. In humans, steatosis (greater than 20%) increased the risk 12-fold for presenting with a severe DGEL (OR: 12.5; 95% CI [1.2, 128.9]; p = .03). There was no association with age above 50 years or MS components. Steatosis grade was also correlated with atherosclerosis grade. NAFLD was a strongly associated factor implicated in severe DGEL, as well as the testis was identified as a probable target organ for damage caused by the disease. This finding could result in the search for new approach strategies in the management of men with fertility problems. Further studies are required to confirm these results.

Platelet-rich Plasma Protects HUVECs against oX-LDL-induced Injury

Platelet-rich plasma (PRP) contains a variety of cytokines, some of which ameliorate oX-LDL (oxidized low-density lipoprotein)-induced endothelial cell (EC) injury. Therefore, we hypothesized that PRP might alleviate oX-LDL-induced injury.

METHODOLOGY

Human umbilical vein endothelial cells (HUVECs) were divided into four groups: a PPP (platelet-poor plasma) group, an oX-LDL group, an oX-LDL+PRP group and a PRP group. CCK-8 (Cell Counting Kit) assay, Annexin V-FITC/7-AAD and Hochest 33342 staining were performed to assess cell proliferation and apoptosis. Tube formation and cell migration assays were performed to evaluate HUVEC-mediated vasculogenesis and migration. Expression levels of Bcl-2, Bax, caspase-3, cleaved caspase-3, PI3K, Akt, eNOS p-Akt, p-eNOS, IL-6 and IL-1 were detected by western blotting or immunofluorescence.

PRINCIPAL FINDINGS

PRP promoted HUVEC proliferation in a non-linear pattern, protected HUVECs against oX-LDL-induced apoptosis and attenuated oX-LDL-mediated inhibition of HUVEC migration and vasculogenesis. Additionally, compared to the PPP group, PRP downregulated pro-apoptotic proteins (ratio of Bax/Bcl-2, caspase-3 and cleaved caspase-3) as well as IL-6 and IL-1. Moreover, the PI3K/Akt/eNOS pathway was activated by PRP and inactivated by oX-LDL.

CONCLUSIONS

It was demonstrated that PRP protected HUVECs against oX-LDL-induced injury and that the PI3K/Akt/eNOS pathway was activated in this process.

Protective influence of rosiglitazone against testicular ischaemia-reperfusion injury in rats

Testicular torsion is a urology urgent disease which causes testicular injury and potential sterility. In this study, we explored the protective influence of rosiglitazone on testicular ischaemia-reperfusion damage. There were 28 male Sprague Dawley rats in total, which were assigned randomly to four groups. Group A was blank control one; group B was testicular injury one; group C was rosiglitazone one; group D was rosiglitazone antagonist one. The testicles were counter-rotated after 2 hr and then underwent orchiectomy 24 hr later. We found that testicular tissue structure of rats was seriously damaged in groups B and D. However, group C had better testicular architecture. Similar findings were also shown for lipid peroxidation by evaluating the MDA activity (p < .05). Unlike group B or group D, the levels of inflammation by evaluating the MPO activity, the levels of TNF-a, IL-1 and IL-6 and the expressions of ICAM-1 were prominently lower in group C (p < .05) as well. So our researches demonstrated that rosiglitazone significantly decreased the amount of responsive oxygen radical and regulated inflammatory responses. Rosiglitazone had a protective influence against testicular ischaemia-reperfusion injury in rats and possibly depended on its anti-inflammatory and antioxidant traits.

Mouse Testicular Cell Type-Specific Antiviral Response against Mumps Virus Replication

Mumps virus (MuV) infection has high tropism to the testis and usually leads to orchitis, an etiological factor in male infertility. However, MuV replication in testicular cells and the cellular antiviral responses against MuV are not fully understood. The present study showed that MuV infected the majority of testicular cells, including Leydig cells (LC), testicular macrophages, Sertoli cells (SC), and male germ cells (GC). MuV was replicated at relatively high efficiencies in SC compared with LC and testicular macrophages. In contrast, MuV did not replicate in male GC. Notably, testicular cells exhibited different innate antiviral responses against MuV replication. We showed that interferon β (IFN-β) inhibited MuV replication in LC, macrophages, and SC, which were associated with the upregulation of major antiviral proteins. We provided primary evidence that autophagy plays a role in blocking MuV replication in male GC. Autophagy was also involved in limiting MuV replication in testicular macrophages but not in Leydig and SC. These findings indicate the involvement of the innate defense against MuV replication in testicular cells.

Cytokines in Male Fertility and Reproductive Pathologies: Immunoregulation and Beyond

Germline development in vivo is dependent on the environment formed by somatic cells and the differentiation cues they provide; hence, the impact of local factors is highly relevant to the production of sperm. Knowledge of how somatic and germline cells interact is central to achieving biomedical goals relating to restoring, preserving or restricting fertility in humans. This review discusses the growing understanding of how cytokines contribute to testicular function and maintenance of male reproductive health, and to the pathologies associated with their abnormal activity in this organ. Here we consider both cytokines that signal through JAKs and are regulated by SOCS, and those utilizing other pathways, such as the MAP kinases and SMADs. The importance of cytokines in the establishment and maintenance of the testis as an immune-privilege site are described. Current research relating to the involvement of immune cells in testis development and disease is highlighted. This includes new data relating to testicular cancer which reinforce the understanding that tumorigenic cells shape their microenvironment through cytokine actions. Clinical implications in pathologies relating to local inflammation and to immunotherapies are discussed.