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

BPA Exacerbates Zinc Deficiency-Induced Testicular Tissue Inflammation in Male Mice Through the TNF-α/NF-κB/Caspase8 Signaling Pathway

Bisphenol A (BPA) is an endocrine-disrupting chemical that is toxic to reproduction. Zinc (Zn) plays an important role in male reproductive health. Zn deficiency (ZD) can co-exist with BPA. In order to investigate the specific mechanism of reproductive damage caused by BPA exposure in ZD male mice, a mouse model of ZD, BPA exposure, and their combined exposure was established in this study. Forty 4-week-old SPF male ICR mice with an average body weight of 31.7 ± 4.2 g were divided into four groups including normal Zn diet group 30 mg/(kg•d), BPA exposure group 150 mg/(kg•d), zinc deficiency diet group 7.5 mg/(kg•d), and BPA + ZD combined exposure group (BPA 150 mg/(kg•d) + ZD 7.5 mg/(kg•d)). The mice were kept for 8 weeks. The results showed that the testicular tissue structure was disturbed, and semen quality, serum Zn, testicular tissue Zn, and testicular tissue free Zn ions were decreased in the BPA-exposed and ZD groups. The expression of zinc transporters (ZIP7, ZIP8, ZIP13, and ZIP14) in testicular tissue was changed. The expressions of pro-inflammatory cytokines including TNF-α and IL-1β as well as inflammatory pathway-related proteins (IKB-α, p-IKB-α, NF-κB, p-NF-κB, Caspase8, and Caspase3) were increased, while the expressions of anti-inflammatory cytokines (TGF-β and IL-10) were decreased. The changes in the above indexes in the BPA + ZD group were more obvious. Both BPA exposure and ZD can induce testicular tissue inflammation through the TNF-α/NF-κB/Caspase8 signaling pathway, and BPA further aggravates zinc deficiency-induced testicular tissue inflammation and apoptosis damage.

Short peptide perturbs spermatogenesis via immune microenvironment dysregulation and mitochondrial imbalance

A short peptide derived from the occludin protein regulates tight junctions (TJ) of the blood-testis barrier and impairs germ cell development. However, the mechanism behind how this peptide regulates TJ and induces cell apoptosis remains unclear. In the present study, an animal model with induced TJ disruption via the short peptide was used to evaluate its impact on spermatogenesis. Here, we demonstrate that the short peptide promoted the infiltration of immune cells into the testicular interstitial tissue, accompanied by upregulation expression of the pro-inflammatory factors interleukin-6 and tumor necrosis factor-α. Moreover, mitochondrial fragmentation and mitophagy were upregulated in Sertoli cells and Leydig cells. Consistently, terminal deoxynucleotidyl transferase dUTP nick end labeling staining revealed extensive apoptosis in the testes during spermatogenesis. Notably, the severity of these disruptions began to attenuate after 27 days, although full functional recovery was not observed. Our findings reveal a novel mechanism wherein peptide-induced immune dysregulation and mitochondrial dysfunction synergistically impair spermatogenesis, potentially via microenvironmental perturbation of the TJ. Overall, these findings could hold valuable insights for the development of non-hormonal male contraceptives.

Pharmacological Effects and Immune Mechanisms of Oriental Medicines in Restoring Male Infertility

Male infertility can be the result of many factors, including pathologies in the motility and formation of sperm and obstructions in the genitourinary system. Oriental medicine, using multiple components to address various targets and enhance therapeutic effectiveness, has been used to treat male infertility for thousands of years. Given the complex pathological mechanisms of aspermatogenesis, this multi-target approach in oriental medicine is believed to positively impact the prevention of male infertility. Efforts have been made to evaluate the pharmacological properties of many herbs. However, the testicular immune responses and mechanisms of these oriental medicines remain unclear from a modern scientific perspective. Some studies reviewed here have reported on the recovery of spermatogenesis in infertility, the available research that evaluates the efficacy of oriental medicines in the treatment of aspermatogenesis and briefly summarizes the available rodent and human data on facilitating immunological differences in male infertility. These findings augment the current understanding of the immune mechanisms of oriental medicine as a treatment solution for male infertility.

Heat stress enhances the expression of METTL3 to mediate N6-methyladenosine modification of SOS2 and NLRP3 inflammasome activation in boar Sertoli cells

Heat stress negatively affects pig production by disrupting the immune homeostasis of Sertoli cells (SCs), which compromises sperm quality, culminating in male infertility. Herein, we aimed to study the mechanism by which the NLRP3 inflammasome is activated by heat stress through N6-methyladenosine (m6A) modification regulation in SCs. Initially, it was found that heat stress (44°C, 30 min) markedly activated ERK1/2 signaling, which subsequently promoted NLRP3 inflammasome activation and inflammatory cytokine release from SCs. Then, using an m6A dot-blot assay, m6A sequencing, and methylated RNA immunoprecipitation, we found that heat stress augmented the level of m6A modification in SCs, and METTL3 augmented the m6A modification of mRNA encoding SOS Ras/Rho guanine nucleotide exchange factor 2 (SOS2), a key activator of the ERK pathway. Furthermore, YTHDF1 recognized and bound to the m6A-modified SOS2 mRNA to enhance its translation efficiency, ultimately triggering ERK1/2 signaling activation. In vivo experiments demonstrated that heat stress-induced decline in semen quality in mice was associated with elevated levels of m6A modifications in the testis and NLRP3 inflammasome activation. However, the damage caused by heat stress could be attenuated by intraperitoneal injection of S-Adenosylhomocysteine (SAH), a specific methyltransferase inhibitor. Our results emphasize the critical roles of m6A in regulating NLRP3 inflammasome activation under heat stress, identifying a novel therapeutic avenue to address heat stress.

Genetic insights into the immunological basis of male infertility: a translational perspective

OBJECTIVE

To elaborate the causal relationships between specific immunocyte phenotypes and male infertility.

DESIGN

Mendelian randomization using genome-wide association study data.

SUBJECTS

Large cohorts of European ancestry.

EXPOSURE

731 immunocyte phenotypes or male infertility.

MAIN OUTCOMES MEASURES

Genetic variants were used as instrumental variables to infer causality, minimizing confounding and bias. The causal associations were assessed using the inverse variance-weighted (IVW) method for primary analysis, and the findings were validated using MR-Egger, Weighted Median, Simple Mode, and Weighted Mode approaches. Additional sensitivity analyses were performed to validate the robustness of the findings.

RESULTS

Our analysis identified significant causal associations between specific immunocyte phenotypes and male infertility. Phenotypes such as naive-mature B cell %lymphocyte (odds ratio [OR] = 1.257) and IgD- CD38dim %B cell (OR = 1.100) were positively associated with increased infertility risk, whereas phenotypes like CD39+ CD8br %T cell (OR = 0.856) and B cells activator of the TNF-α family receptor (BAFF-R) on transitional (OR = 0.833) were negatively associated, suggesting a protective effect. Additionally, reverse MR analysis revealed that male infertility might causally affect certain immunocyte phenotypes, including CD14- CD16+ monocyte %monocyte (OR = 1.049).

CONCLUSION

This study provides robust evidence for the causal role of specific immunocyte phenotypes in male infertility and highlights the bidirectional relationship between immune function and reproductive health. These findings provide new insights into the immunological factors contributing to male infertility and suggest potential biomarkers and therapeutic targets for future research and clinical interventions.

Hepatitis B Virus Disrupts the Blood-Testis Barrier via the Induction of mTOR-Dependent Autophagy in Sertoli Cells

Hepatitis B virus (HBV) is one of the most serious public health threats worldwide. HBV is not only able to pass through the blood-testis barrier (BTB); It can also cause impairment of male fertility. However, the mechanisms involved in this process remain unknown. In this study, we showed that HBV can establish persistent infection in human and mouse testes. Persistent HBV infection triggers inflammatory cell invasion, testes immune homeostasis imbalance, and the disruption of the BTB formed by inter-Sertoli cells. HBV mainly persisted in the Sertoli cells and could induce the autophagy of Sertoli cells by HBV X protein (HBx), a major regulatory protein of HBV. Data indicated that the mTOR signal pathway-mediated autophagy plays a pivotal role in HBV-induced BTB damage. Autophagy inhibitor 3-MA and mTOR activator MHY1485 could ameliorate HBV-induced autophagy and BTB damage. These findings demonstrated that the mTOR-mediated excessive autophagy of Sertoli cells induced by HBx could be one of the pathological mechanisms responsible for the fertility decline caused by HBV infection.

The Codonopsis pilosula water extract improves testicular inflammatory aging in D-galactose induced aging mice by modulating the CLEC7A/inflammasome pathway

AIM OF THE STUDY

Aging-induced testicular inflammation impairs male fertility. The purpose of this study was to investigate the effectiveness and mechanism of C. pilosula water extract (CPWE) in preventing testicular inflammation in D-galactose-induced aging mice.

MATERIALS AND METHODS

The "The Plant List" database (www.theplantlist.org) provided verified plant taxonomy. D-galactose was intraperitoneally injected to induce an aging mice model, with high, medium, and low dosages of CPWE used as pharmacological interventions. The concentrations of superoxide dismutase (SOD), malondialdehyde (MDA), testosterone and in mouse serum or testicle samples after CPWE treatment were quantified using biochemical method. Hematoxylin and eosin (HE) staining was employed to assess the morphological features of testicular tissues, whereas immunohistochemical (IHC) analysis and enzyme-linked immunosorbent assay (ELISA) were conducted to evaluate the presence and levels of inflammatory cytokines interleukin-6 (IL-6) and interleukin-1β (IL-1β) within testicular samples of mice. Differentially expressed genes were identified using transcriptome sequencing; the genes and pathways regulated by CPWE, as well as immune cell infiltration, were examined using bioinformatics analysis. The expression of target gene and pathway-related protein was confirmed using real-time quantitative PCR and Western blotting.

RESULTS

Treatment with CPWE alleviated the pathological alterations in the testicular tissues of aged mice, increased the concentrations of SOD and testosterone in the serum, and decreased the levels of MDA, IL-6 and IL-1β in the testes. The expression of C-C motif chemokine ligand 21a (Ccl21a) and C-C motif chemokine ligand 27b (Ccl27b) genes was downregulated after treatment with CPWE. The protein levels associated with the C-type lectin domain family 7, member A (CLEC7A)/inflammasome signaling pathway, including IL-1β, Caspase 8 (CASP8), and nuclear factor-kappa B (NF-κB), were found to be downregulated after treatment with CPWE. T cells, B cells, and macrophages showed a strong association with aging and the modulatory effects of CPWE.

CONCLUSIONS

The results indicate that CPWE regulates the CLEC7A/inflammasome pathway, thereby inhibiting inflammasomes activation and reducing the expressions of proinflammatory cytokines such as IL-6 and IL-1β, as well as chemokines such as Ccl21a and Ccl27b, providing substantial protection against age-related testicular inflammatory injury.

Impact of aging on spermatogenic function and reproductive outcomes in repro57 heterozygous male mice: A model for age-related infertility

PURPOSE

This study aims to investigate the histological changes, sperm parameters, and their impact on embryo development rates and offspring numbers in advanced-age male repro57 heterozygous mice, corresponding to approximately 40 years of age in humans.

METHODS

Sperm parameters were assessed in both young and advanced-age repro57 heterozygous mice, as well as in young and advanced-age wild-type mice. Additionally, testis weight and histological analysis of seminiferous tubules were conducted to identify degenerative changes. Male mice from each group were mated with young wild-type females to compare offspring numbers, and in vitro fertilization (IVF) was used to evaluate fertilization and blastocyst formation rates.

RESULTS

No significant differences in sperm concentration and motility were observed between young and aged wild-type mice or between young wild-type and young repro57 heterozygous mice. However, advanced-age repro57 heterozygous mice exhibited significantly lower sperm parameters and testis weight compared to advanced-age wild-type mice. Histological analysis revealed increased Sertoli cell vacuolation in the seminiferous tubules of advanced-age repro57 heterozygous mice. Additionally, these advanced-age mice exhibited significantly lower blastocyst formation rates and produced fewer offspring compared to advanced-age wild-type mice.

CONCLUSION

Advanced reproductive aging in repro57 heterozygous male mice is associated with marked senescence-like degenerative changes, leading to a decline in offspring numbers, attributed to increased Sertoli cell vacuolation and diminished sperm quality.

Correlation of 17-OH Progesterone Changes With Semen Parameters and Pregnancy Outcomes in Hypogonadal and Eugonadal Patients After Varicocelectomy

OBJECTIVE

To evaluate the impact of varicocele repair on serum 17-OH progesterone (17-OHP) levels and investigate its relationship with semen parameters and pregnancy outcomes in hypogonadal and eugonadal patients. Additionally, to address the unclear association between varicocele and serum 17-OHP levels in male infertility.

METHODS

This prospective study included 135 men who underwent microscopic subinguinal varicocelectomy. Pre-operative and post-operative (3-6 months) hormone levels, including follicle-stimulating hormone, luteinizing hormone, total testosterone (TT), and 17-OHP, and semen parameters, such as total motile sperm count (TMS) and sperm morphology, were analyzed. Patients were categorized as hypogonadal (TT <300 ng/dL) or eugonadal (TT ≥300 ng/dL). Pregnancy outcomes were recorded over a 12-month follow-up period.

RESULTS

Significant increases in TT and 17-OHP levels were observed only in hypogonadal men, while TMS and sperm morphology improved in both groups. In hypogonadal men, changes in serum 17-OHP levels (Δ-17-OHP) positively correlated with TMS improvement (r = 0.388, P = .009). Furthermore, in hypogonadal patients, although not statistically significant, Δ-17-OHP were higher in men whose partners achieved pregnancy compared to those whose partners did not.

CONCLUSION

Varicocele repair improves semen parameters in both hypogonadal and eugonadal men. In hypogonadal men, increases in Δ-17-OHP are linked to TMS improvements, highlighting its potential as a clinical biomarker. Further studies are warranted to validate 17-OHP as a predictor of pregnancy outcomes.

Causal inference of inflammatory proteins in infertility: a Mendelian randomization study

Background

Infertility affects 8-12% of couples globally, manifesting as a complex reproductive disorder with varied causes, negatively impacting emotional, physical, and social well-being. Inflammation is implicated in many diseases, including male and female infertility.

Methods

This study employed Mendelian randomization (MR) with two-sample, bidirectional, and mediation approaches to explore the relationship between circulating inflammatory proteins and infertility. Causal analysis was conducted using inverse variance-weighted (IVW) and MR-Egger regression, supplemented by enrichment analysis, protein-protein interaction (PPI) network exploration, and drug signature analysis.

Results

Our findings identified a significant positive correlation between C-X-C motif chemokine 6 (CXCL6) and male infertility, positioning CXCL6 as a potential therapeutic target or biomarker. No causal links were detected between circulating inflammatory proteins and female infertility post-FDR adjustment. Minor mediation effects were observed for metabolites such as androstenediol monosulfate, arachidonoylcholine, and serum phosphate to glycerol ratio. Cytokine-related pathways emerged as significant in both male and female infertility. Gene-drug interaction analysis highlighted the need for further investigation of pioglitazone in treating female infertility.

Conclusion

This study establishes a potentially causal relationship between CXCL6 and male infertility, suggesting its potential as a drug target or molecular biomarker. The integrative approach combining causal inference with molecular pathway and drug interaction analysis opens new avenues for understanding and treating infertility.

Decoding the Puzzle of Male Infertility: The Role of Infection, Inflammation, and Autoimmunity

Background/Objectives: Male infertility is a complex, multifactorial condition influenced by infectious, inflammatory, and autoimmune components. Immunological factors, though implicated in reproduction, remain poorly understood. This study aims to deepen the understanding of infections, inflammation, and autoimmune factors in male infertility, with a focus on immune-related disorders affecting the testes and epididymis-immunologically privileged but vulnerable sites. These factors can impair sperm quality through oxidative stress (ROS) and antisperm antibodies (ASA), further compromising fertility. Methods: A narrative review was conducted by analyzing scientific literature from the past 10 years conducted on PubMed using keywords such as "male infertility", "autoimmunity", and "inflammatory disease". Studies focusing on testicular and epididymal disorders, immunological impacts, and therapeutic approaches were included. Results: Our research highlights that conditions like epididymitis, vasectomy, testicular trauma, and previous surgeries can trigger inflammatory responses, leading to ASA formation and oxidative stress. ASA, particularly sperm-immobilizing antibodies, inhibits sperm motility and migration in the female reproductive tract. Infections caused by sexually transmitted bacteria or urinary pathogens frequently induce epididymo-orchitis, a primary contributor to male infertility. While standardized methodologies for ASA testing remain elusive, assisted reproductive treatments such as intracytoplasmic sperm injection (ICSI), in vitro fertilization (IVF), and intrauterine insemination (IUI) show promise in overcoming immune-mediated infertility. Conclusions: This review underscores the critical role of infection, inflammation, and autoimmune responses in male infertility. It highlights the necessity of improving diagnostic methods, understanding immune-pathological mechanisms, and addressing medicolegal issues associated with male infertility. This knowledge could pave the way for innovative therapies, ultimately enhancing fertility outcomes, and mitigating the societal and legal repercussions of infertility.

A new approach for hemodynamics of varicoceles: blood flow patterns based on contrast-enhanced ultrasound

BACKGROUND

Hemodynamic alterations in the spermatic vein are implicated in infertility among patients with varicocele (VC). Contrast-enhanced ultrasound (CEUS), a powerful tool for hemodynamic analysis, remains unexplored for VC. This study aimed to demonstrate the feasibility of using CEUS to evaluate spermatic vein hemodynamics in patients with VC and establish a clear correlation between specific hemodynamic patterns and impaired semen parameters. This study included 165 patients with left-sided VC and 50 healthy volunteers. All participants underwent CEUS of the spermatic veins, along with maximum venous diameter and testicular volume measurements and serum sex hormone levels and routine semen analyses. The sperm DNA fragmentation index was measured in 146 patients with VC and 37 healthy controls.

RESULTS

The analyses revealed four distinct blood flow patterns of the spermatic vein: steady flow, intermittent stasis, intermittent reflux, and filling defect. In healthy spermatic veins, the predominant blood flow patterns included steady flow and intermittent stasis. Spermatic veins with VC exhibited a significant increase in the intermittent reflux and filling defect patterns, with the proportion rising as the clinical grade increased. The four patterns were further grouped into the "steady flow & intermittent stasis" and "intermittent reflux & filling defect" patterns for logistic regression analyses; the intermittent reflux & filling defect pattern was revealed as an independent risk factor for impaired sperm concentration, total sperm counts, progressive motility, morphology, and DNA fragmentation index.

CONCLUSIONS

This study validated the feasibility of CEUS for assessing the hemodynamics of the spermatic vein and established the intermittent reflux & filling defect pattern as an independent predictor of impaired semen parameters.

Comparative Impact of Microsurgical Varicocelectomy Versus Observation on Infertility in Infertile Men With Subclinical Varicocele

PURPOSE

The efficacy of varicocelectomy in treating infertility among men with ultrasonography-detected subclinical varicocele continues to be a topic of clinical uncertainty. This multicentric, prospective, non-randomized study aimed to evaluate the effect of microsurgical ligation of the internal spermatic vein in men with left subclinical varicocele and no other infertility causes.

PATIENTS AND METHODS

The study included 34 infertile men diagnosed with subclinical left varicocele by color Doppler ultrasonography. After a shared decision-making process, the participants self-selected either microsurgical ligation (n = 18) or conservative management (n = 16). Baseline age, duration of infertility, reproductive hormone levels, and semen parameters were comparable across groups. The primary outcomes included changes in sperm concentration, progressive motility, and morphology over a nine-month follow-up period.

RESULTS

After nine months, there were no statistically significant differences between the surgery and observation groups in sperm concentration or progressive motility. After adjusting for baseline values, sperm concentration increased by 3 × 106/mL (95% CI: -6.1 to 12.1), and progressive motility improved by 7.1% (95% CI: -1.3 to 15.5%) post-surgery, although these increases were not significant. However, the surgical group demonstrated a significant 5.6% improvement in sperm morphology (95% CI: 0.1 to 11.2%, p = 0.045) compared to observation.

CONCLUSION

Although this study's small sample size limits its broader generalizability, its findings provide limited evidence that microsurgical ligation may modestly improve sperm morphology in men with subclinical varicocele. Further research with larger, randomized cohorts is warranted to confirm these results and assess potential fertility outcomes.

Anti-sperm Antibody Positivity in Men with Varicocele: A Systematic Review and Meta-Analysis

PURPOSE

Despite the significant role of varicocele in the pathogenesis of male infertility, its association with anti-sperm antibodies (ASA) remains controversial. This systematic review and meta-analysis (SRMA) aims to investigate the frequency of ASA positivity in men with varicocele.

MATERIALS AND METHODS

This SRMA is conducted in accordance with the Meta-analysis of Observational Studies in Epidemiology guidelines. We investigated the frequency of ASA positivity in ejaculates or serum of men with varicocele as compared to men without varicocele (controls). A literature search was performed using the Scopus and PubMed databases following the Population Exposure Comparison Outcome, Study Design model. Data extracted from eligible studies were meta-analyzed and expressed as odds ratios (ORs) and confidence intervals (CIs).

RESULTS

Out of 151 abstracts identified during the initial screening, 6 articles met the inclusion criteria and were included in the meta-analysis. Using mixed antiglobulin reaction (MAR) assay, 61 out of the 153 (39.8%) patients with varicocele tested positive for ASA in their ejaculates as compared to 22 out of the 129 control subjects (17%, OR=4.34 [95% CI: 1.09-17.28]; p=0.04). Using direct or indirect immunobead test, 30 out of 60 cases diagnosed with varicocele (50%) had shown ASA positivity in their ejaculates as compared to 16 out of 104 controls (15.4%, OR=3.57 [95% CI: 0.81-15.68]; p=0.09). Using enzyme-linked immunosorbent assay (ELISA), out of 89 varicocele patients, 33 (37.1%) tested positive for serum ASA as compared to 9 out of 57 participants in the control group (15.8%, OR=7.87 [95% CI: 2.39-25.89]; p<0.01).

CONCLUSIONS

This SRMA indicates that ASA positivity is significantly higher among men with varicocele when tested by direct method (MAR) or indirect method (ELISA). This data suggests an immunological pathology in infertile men with varicocele and may have implications for the management of these patients.

Extracellular Vesicles in the Aging Male Reproductive System: Progresses and Perspectives

Extracellular vesicles (EVs) serve as crucial mediators of intercellular communication in spermatogenesis, steroidogenesis, and age-related pathophysiological processes within the male reproductive system. These EVs exhibit promising prospects for disease diagnosis and therapeutic administration. This review explores the impact of advanced paternal age on male fertility and testosterone decline, shedding light on the underlying mechanisms. It highlights the decline in semen quality, DNA damage, and alterations in sperm miRNA profiles associated with aging. The interplay between oxidative stress and antioxidants crucially regulates male reproductive aging. Currently, most studies focus on Sertoli cell-derived EVs, while understanding of Leydig cell-derived vesicles remains limited. Multi-omics integration will enhance the understanding of male reproductive aging and guide personalized interventions, revealing potential biomarkers and targets in the future.

IL20RA Is the Key Factor Contributing to the Stronger Antioxidant Capacity of Rongchang Pig Sertoli Cells

Variations in disease resistance among pig breeds have been extensively documented, with Sertoli cells (SCs) playing a pivotal role in spermatogenesis. Infections can induce oxidative stress, which can lead to damage to these cells. This study aimed to compare the levels of oxidative stress in SCs from Rongchang and Landrace pig breeds following LPS challenge. SCs were isolated, cultured, and stimulated with LPS to assess cell viability and markers of oxidative stress. Cell viability was evaluated along with oxidative stress markers such as reactive oxygen species (ROS), mitochondrial superoxide, malondialdehyde, and antioxidant enzymes. Mitochondrial function was assessed using JC-1 and Calcein AM probes. Transcriptomic analysis identified differentially expressed genes (DEGs), while ingenuity pathway analysis (IPA) explored enriched pathways. IL20RA, identified through transcriptomics, was validated using the siRNA knockdown technique. The results showed that Rongchang SCs exhibited lower levels of oxidative stress compared to Landrace SCs along with higher activity of antioxidant enzymes. IL20RA emerged as a key regulator since its knockdown affected mitochondrial superoxide production and catalase secretion. The findings suggest that Rongchang SCs possess superior antioxidant capacity, possibly due to the IL20RA-mediated protection of mitochondria, thereby providing insights into breed-specific resistance against oxidative stress and highlighting the role of IL20RA in maintaining stem cell function.

The role of inflammasome dysregulation in obstructive and non-obstructive azoospermia: a comparative molecular analysis of blood, tissue, and seminal plasma

Background

To address knowledge gaps, this study aimed to investigate the involvement of inflammasomes in the etiology of azoospermia. This study focused on the gene expression of key inflammasome components, including NLR family pyrin domain containing 3 (NLRP-3), CASPASE-1, Interleukin-1β (IL-1β), Interleukin-18 (IL-18), NLR family CARD domain-containing protein 4/ice protease-activating factor (NLRC-4/IPAF), and Absent in melanoma 2 (AIM-2).

Methods

We analyzed gene expression in blood and testicular tissue from patients with obstructive azoospermia (OA) and non-obstructive azoospermia (NOA). Additionally, we compared IL-1β and IL-18 expression levels in seminal plasma samples using the Enzyme-Linked Immunosorbent Assay (ELISA) method. For comparison, blood samples from normospermic (NS) individuals were also genetically evaluated.

Results

Our results indicated significantly higher gene expression of inflammasome components in NOA patients than those in OA patients either in blood or in testicular tissue. Both azoospermic groups exhibited higher mRNA levels of inflammasome genes comparing with those from blood samples of NS men. Seminal plasma samples showed significantly increased levels of IL-1β and IL-18 in NOA patients compared to men with OA. The ROC curve analysis indicated strong and significant predictive power of IL-18, AIM-2 and NLRC-4/IPAF gene expression profiles between NOA vs. NS patients and NOA vs. OA.

Conclusions

Our findings highlight the role of hidden chronic inflammation in azoospermia, particularly within the NOA group. This study provides a foundation for further detailed research, which could aid in the development of diagnostic panels to differentiate between various azoospermic groups.

Resveratrol: potential application in safeguarding testicular health

Factors such as increasing mental pressure and poor living habits in modern society have led to an increase in the incidence of male reproductive diseases, including poor semen quality, testicular malignancy, and congenital developmental defects. The decline of male fertility deserves our attention. Resveratrol (3,4', 5-trihydroxy-trans-Stilbene, 3,4',5-trihydroxy), a polyphenol widely found in plant foods, is expected to enhance testicular function and promote breakthroughs in the treatment of diseases related to the male reproductive system. A large number of studies have shown that in male animals, resveratrol can enhance testicular function and spermatogenesis by activating SIRT1 expression and resist the damage of the testicular system by adverse factors. This article reviews the basic protective pathways of resveratrol against testicular and sperm damage, which involve oxidative stress, cell apoptosis, inflammatory damage, and mitochondrial function. The healthcare framework of predictive, preventive, and personalized medicine (PPPM/3PM) is by far the most beneficial for healthcare and is suitable for the management of chronic diseases. This review also summarizes the health benefits of resveratrol on male reproduction in the context of PPPM/3PM by comprehensively collecting and reviewing the available evidence, thus leading to a working hypothesis that resveratrol can personalize prevention and protection of male reproductive function. It provides a new perspective and direction for future research on the health effects of resveratrol in improving male reproductive function.

Collagen-based materials in male genitourinary diseases and tissue regeneration

Male genitourinary dysfunction causes serious physical or mental distress, such as infertility and psychological harm, which leads to impaired quality of life. Current conventional treatments involving drug therapy, surgical repair, and tissue grafting have a limited effect on recovering the function and fertility of the genitourinary organs. To address these limitations, various biomaterials have been explored, with collagen-based materials increasingly gaining attention for reconstructing the male genitourinary system due to their superior biocompatibility, biodegradability, low antigenicity, biomimetic 3D matrix characteristics, hemostatic efficacy, and tissue regeneration capabilities. This review covers the recent biomedical applications of collagen-based materials including treatment of erectile dysfunction, premature ejaculation, penile girth enlargement, prostate cancer, Peyronie's disease, chronic kidney disease, etc. Although there are relatively few clinical trials, the promising results of the existing studies on animal models reveal a bright future for collagen-based materials in the treatment of male genitourinary diseases.

Graphic Abstract

The impact of N-acetylcysteine on hypoxia-induced testicular apoptosis in male rats: TUNEL and IHC findings

The present study aimed to evaluate the impact of N-acetylcysteine (NAC) on testicular hypoxia caused by varicocele, focusing specifically on the regulation of genes related to apoptosis and oxidative stress in the testes of mature Wistar rats. Thirty-two rats were divided into four groups: Control (Sham), hypoxia, testicular hypoxia treated with NAC (Hypoxia + NAC), and healthy animals treated with NAC. After the 8-week treatment period, testicular histopathology and the levels of oxidative stress markers-superoxide dismutase (SOD), glutathione peroxidase (GPx), and malondialdehyde (MDA)-in serum were examined. The expression of Bax and Bcl-2 mRNA was analyzed using immunocytochemistry and RT-qPCR assays, while the apoptosis rate was determined using the TUNEL method. Histopathological evaluations showed that parameters such as Johnsen's score, epithelium width, and seminiferous tubule diameter indicated significant improvement in the Hypoxia + NAC group compared to the Hypoxia group. NAC administration resulted in elevated serum levels of GPx and SOD, accompanied by a reduction in MDA levels (p < 0.003). Furthermore, the study revealed that NAC decreased Bax expression and enhanced Bcl-2 gene and protein expression compared to the varicocele group (p < 0.05). Additionally, NAC administration significantly decreased the rate of apoptosis in germ cells (p < 0.05). These findings suggest that NAC administration can mitigate testicular damage induced by hypoxia from varicocele in rats, primarily due to its antioxidant properties.

The Equilibrium of Bacterial Microecosystem: Probiotics, Pathogenic Bacteria, and Natural Antimicrobial Substances in Semen

Semen is a complex fluid that contains spermatozoa and also functions as a dynamic bacterial microecosystem, comprising probiotics, pathogenic bacteria, and natural antimicrobial substances. Probiotic bacteria, such as Lactobacillus and Bifidobacterium, along with pathogenic bacteria like Pseudomonas aeruginosa and Escherichia coli, play significant roles in semen preservation and reproductive health. Studies have explored the impact of pathogenic bacteria on sperm quality, providing insights into the bacterial populations in mammalian semen and their influence on sperm function. These reviews highlight the delicate balance between beneficial and harmful bacteria, alongside the role of natural antimicrobial substances that help maintain this equilibrium. Moreover, we discuss the presence and roles of antimicrobial substances in semen, such as lysozyme, secretory leukocyte peptidase inhibitors, lactoferrin, and antimicrobial peptides, as well as emerging antibacterial substances like amyloid proteins. Understanding the interactions among probiotics, pathogens, and antimicrobial agents is crucial for elucidating semen preservation and fertility mechanisms. Additionally, the potential for adding probiotic bacteria with recombinant antibacterial properties presents a promising avenue for the development of new semen extenders. This review offers updated insights to understand the equilibrium of the bacterial microecosystem in semen and points toward innovative approaches for improving semen preservation.

Cardiac-derived CTRP9 mediates the protection of empagliflozin against diabetes-induced male subfertility in mice

Previous studies have shown beneficial effects of empagliflozin (Empa), a selective inhibitor of the sodium-glucose cotransporter 2 (SGLT2), on diabetes and cardiovascular outcomes in patients with diabetes. However, whether Empa could ameliorate diabetes mellitus (DM)-induced male spermatogenesis dysfunction remains unclear. Our study aimed to investigate the effect of Empa in the development of DM-induced male spermatogenesis dysfunction and to reveal the molecular mechanisms. DM mice were orally treated with Empa to investigate the effects of Empa on DM-induced male mice spermatogenesis dysfunction. We employed a cardiac-specific C1q/tumor necrosis factor-related protein 9 (CTRP9)-deficient mouse model and a cardiac-specific CTRP9 overexpression mouse model to investigate its role in the protection of Empa against diabetes-induced male subfertility. We found that Empa treatment could improve DM-induced male mice subfertility. Interestingly, we discovered that cardiac-derived CTRP9 was decreased in DM mice and this decrease was prevented by Empa treatment. A CTRP9 blocking antibody or cardiac-specific depletion of CTRP9 abolished the protection of Empa on DM-induced male subfertility. Cardiac-specific CTRP9 overexpression ameliorated DM-induced male subfertility. Mechanistically, we identified that cardiac-derived CTRP9 increased steroidogenesis in mice with diabetes in a PKA-dependent manner. We also provided direct evidence that activation of AMP activated protein kinase α (AMPKα)/nuclear factor (erythroid-derived 2)-like 2 (Nrf2) signalling pathway by CTRP9 was responsible for the attenuation of ferroptosis in Leydig cells. In conclusions, we supposed that Empa was a potential therapeutic agent against DM-induced male mice spermatogenesis dysfunction.

Activating Transcription Factor 6 Mediates Inflammation in Experimental Varicocele-Induced Epididymal Epithelial Cells

Introduction

Varicocele is a dilatation of the internal spermatic vein and it is generally recognized as one cause of male infertility. This study aimed to analyze the roles of activating transcription factor 6 (ATF-6) in experimental varicocele-induced epididymal epithelial cells.

Methods

Experimental left varicocele was established in rats through partial left renal vein ligation. At 8 weeks after surgery, the left epididymal damage was observed using H&E and TUNEL staining. The expressions of neutral α-glucosidase (NAG), ATF-6, tumor necrosis factor (TNF)-α, and phospho-nuclear factor (p-NF)-κB p65 (S536) in the left epididymis were measured by immunohistochemistry. ATF-6 silence in rat epididymal epithelial cells was established by ATF-6 siRNA transfection. The cells were treated with hypoxia for 24 h, and cell viability was measured by CCK-8, levels of NAG, TNF-α, and interleukin (IL)-8 in cells were measured by ELISA, levels of p-NF-κB p65 (S536)/NF-κB p65 protein in cells were measured by Western blotting.

Results

The results showed that the experimental left varicocele induced hypertrophy and apoptosis of epididymal epithelial cells (p<0.05), and decreased the expressions of NAG in the epididymal epithelial cells compared with the sham-operated control rats (p<0.01). Meanwhile, the expressions of ATF-6, TNF-α, and p-NF-κB p65 (S536) were increased in the epididymal epithelial cells after the experimental left varicocele compared with the sham-operated control rats (p<0.05). In the hypoxia-treated cells, ATF-6 silence increased the cell viability and decreased the levels of TNF-α, IL-8, and p-NF-κB p65 (S536) compared with the control cells (p<0.05).

Discussion

The ATF-6 pathway was activated in a rat's left varicocele-induced epididymal damage. Inhibition of the ATF-6 pathway might be a possible novel therapeutic approach for left varicocele-induced epididymal damage.

Ferroptosis Is Crucial for Cisplatin Induced Sertoli Cell Injury via N6-Methyladenosine Dependent Manner

PURPOSE

This study aimed to investigate the effect of the N6-methyladenosine (m6A) dependent ferroptosis on cisplatininduced Sertoli cell injury.

MATERIALS AND METHODS

A cisplatin exposure mouse model was established by intraperitoneal injection of cisplatin in our study. TM4 cell lines was used for in vitro study. Ferroptosis was detected according to metabolomic analysis and a series of assays, including malondialdehyde, glutathione, and glutathione disulfide concentration detection, 2',7'-dichlorodihydrofluorescein diacetate and BODIPY 581/591 C11 probe detection, and transmission electron microscope imaging. Key ferroptosis-related genes were identified via transcriptomic analysis, western blot and immunohistochemistry. The m6A modification was demonstrated via m6A RNA immunoprecipitation and luciferase reporter assays. Immune cell infiltration was detected by mass cytometry, and verified by flow cytometry and immunofluorescence.

RESULTS

Ferroptosis, but not other types of programmed cell death, is a significant phenomenon in cisplatin-induced testis damage and Sertoli cell loss. Ferroptosis induced by cisplatin in Sertoli cell/TM4 cell is GPX4 independent but is regulated by SLC7A11 and ALOX12. Both SLC7A11 and ALOX12 are regulated via m6A dependent manner by METTL3. Furthermore, overexpressed ALOX12-12HETE pathway may result in macrophage polarization and inflammatory response in cisplatin exposure testis.

CONCLUSIONS

Cisplatin-induced Sertoli cell injury via ferroptosis and promoted ferroptosis in an m6A dependent manner. m6A modification of both SLC7A11 and ALOX12 mRNA could result in ferroptosis in our in vitro model. Further, overexpressed ALOX12 can cause more production of 12-HETE, which may be responsible for testis inflammation caused by cisplatin.

Body Mass Index Combined With Inflammatory Factors Can Better Predict Varicocele

Most patients with VC have no symptoms, so they are often discovered due to male infertility. Early identification of them is a matter of concern for clinicians. A retrospective analysis of clinical data from patients between January 1, 2021, and February 1, 2024, was conducted. Patients were divided into VC and non-VC groups. Propensity score matching (PSM) was performed at a ratio of 1:1, and two cohorts with homogeneous baseline status were selected. Multivariate binary logistic regression and receiver operating characteristic (ROC) curve were used to analyze independent risk factors and protective factors and to evaluate their diagnostic value individually and in combination. A p-value <0.05 was considered statistically significant. A total of 256 patients with similar clinical characteristics were further analyzed after PSM in a 1:1 ratio of the 423 patients included in the study. The two groups had statistically significant differences in systemic immune-inflammation index (SII), neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), and body mass index (BMI) (p<0.05). Multivariate binary logistic regression analysis showed that SII and NLR were independent risk factors for VC, while high BMI could reduce the prevalence of VC. The PLR differences were not significant. The ROC analysis showed that BMI, SII, and NLR could predict VC, with areas under the curve of 68.3% (cut-off value 22.32), 83.4% (cut-off value 357.57), and 83.2% (cut-off value 1.8), respectively. The combination of BMI and inflammatory factors was more accurate for predicting VC than BMI alone (87.5% vs. 68.3%, p=0.0001), SII (87.5% vs. 83.4%, p=0.0106), and NLR (87.5% vs 83.2%, p=0.0058). Both SII and NLR are independent risk factors for VC while BMI is an independent protective factor. The BMI, SII, and NLR values have the potential to predict VC. The BMI combined with these inflammatory factors can improve the accuracy of prediction.

Uncovering the link between inflammatory rheumatic diseases and male reproductive health: a perspective on male infertility and sexual dysfunction

Inflammatory rheumatic diseases (IRDs) refer to a range of persistent disorders that have a major influence on several physiological systems. Although there is much evidence connecting IRDs to sexual dysfunction and fertility problems, research specifically focusing on male infertility in relation to these diseases is sparse. This review addresses the complicated connection between IRDs and male infertility, emphasising the physiological, psychological, and pharmacological aspects that influence reproductive health outcomes in men with rheumatic conditions. We explore the effects of IRDs and their treatments on many facets of male reproductive well-being, encompassing sexual functionality, semen characteristics, and hormonal balance. Additionally, we present a comprehensive analysis of the present knowledge on the impact of several categories of anti-rheumatic drugs on male reproductive function. Although there is an increasing awareness of the need of addressing reproductive concerns in individuals IRDs, there is a noticeable lack of research especially dedicated to male infertility. Moving forward, more comprehensive research is needed to determine the prevalence, risk factors, and mechanisms driving reproductive difficulties in males with IRDs. We can better assist the reproductive health requirements of male IRD patients by expanding our understanding of male infertility in the setting of rheumatic disorders and implementing holistic methods to care.

Chlorogenic acid can improve spermatogenic dysfunction in rats with varicocele by regulating mitochondrial homeostasis and inhibiting the activation of NLRP3 inflammasomes by oxidative mitochondrial DNA and cGAS/STING pathway

In recent years, Varicocele (VC) has been recognized as a common cause of male infertility that can be treated by surgery or drugs. How to reduce the damage of VC to testicular spermatogenic function has attracted extensive attention in recent years. Among them, overexpressed ROS and high levels of inflammation may play a key role in VC-induced testicular damage. As the key mediated innate immune pathways, cGAS-STING shaft under pathological conditions, such as in cell and tissue damage stress can be cytoplasmic DNA activation, induce the activation of NLRP3 inflammatory corpuscle, triggering downstream of the inflammatory cascade reaction. Chlorogenic acid (CGA), as a natural compound from a wide range of sources, has strong anti-inflammatory and antioxidant activities, and is a potential effective drug for the treatment of varicocele infertility. The aim of this study is to investigate the role of CGA in the spermatogenic dysfunction of the rat testis induced by VC and the potential mechanisms. The results of this study have shown that CGA gavage treatment ameliorated the pathological damage of seminiferous tubules, increased the number of sperm in the lumen, and increased the expression levels of Occludin and ZO-1, which indicated the therapeutic effect of CGA on spermatogenic dysfunction in the testis of VC rats. Meanwhile, the damage of mitochondrial structure was alleviated and the expression levels of ROS, NLRP3 and pro-inflammatory cytokines (IL-1β, IL-6, IL-18) were significantly reduced in the testicular tissues of model rats after CGA treatment. In addition, we demonstrated for the first time the high expression status of cGAS and STING in testicular tissues of VC model rats, and this was ameliorated to varying degrees after CGA treatment. In conclusion, this study suggests that CGA can improve the spermatogenic function of the testis by reducing mitochondrial damage and inhibiting the activation of the cGAS-STING axis, inhibiting the activation of the NLRP3 inflammasome, and improving the inflammatory damage of the testis, highlighting the potential of CGA as a therapeutic agent for varicocele infertility.

Whole transcriptome sequencing revealed the gene regulatory network of hypoxic response in yak Sertoli cells

Yaks live in the Qinghai-Tibet Plateau for a long time where oxygen is scarce, but can ensure the smooth development of testis and spermatogenesis. The key lies in the functional regulation of the Sertoli cells under hypoxia. In this study, we sequenced yak Sertoli cells cultured in normal oxygen concentration (Normoxia) and treated with low oxygen concentration (Hypoxia) by whole transcriptomics, and screened out 194 differentially expressed mRNAs (DEmRNAs), 934 differentially expressed LncRNAs (DELncRNAs) and 129 differentially expressed miRNAs (DEmiRNAs). GO and KEGG analysis showed that these differential genes were mainly concentrated in PI3K-AKT, MAPK, RAS, and other signaling pathways, and were associated with glucose metabolism, tight junction, steroid hormone synthesis, cell fusion, and immunity of yak Sertoli cells. We constructed the gene interaction network of yak Sertoli cells in hypoxia and screened out the relationship pairs related to glucose metabolism and tight junction. The results suggested that the changes in energy metabolism, tight junction, and immune regulation of yak Sertoli cells under hypoxia might provide favorable conditions for spermatogenesis. This study provides data for further study on the role of non-coding RNA in testis development and spermatogenesis of yak.

Shugan Tongluo Qiangjing recipe protects against varicocele of EVC rats through modulating sperm DNA damage, telomere expression and oxidative stress

Varicocele (VC) refers to expansion and tortuosity of spreading venous plexus in spermatic cord due to poor blood flow. This study aimed to investigate effects of Shugan Tongluo Qiangjing recipe (SGTL) on sperm DNA damage and oxidative stress in experimental VC (EVC) rats. EVC model was established by partial ligation of left renal vein. Spermatic vein diameter, testicular weight, sperm DNA fragmentation index (DFI) were evaluated. Telomere reverse transcriptase (TERT) expression, telomere gene transcription, and testicular tissue morphology were determined·H2O2, catalase, SOD, T-AOC were measured with colorimetry. SGTL significantly decreased spermatic vein diameter (P=0.000) and increased testicular weight (P=0.013) of rats compared those of EVC rats. SGTL maintained testicular tissue morphology in EVC rats. SGTL markedly reduced sperm DFI value in sperm of rats compared to EVC rats (P=0.000). SGTL significantly enhanced TERT expression and telomere gene transcription (P=0.028) in testis of rats compared to EVC rats. SGTL reduced H2O2 levels (P=0.001) and promoted CAT activity (P=0.016), SOD activity (P=0.049), and T-AOC activity (P=0.047) of rats, compared to EVC rats. In conclusion, SGTL could reduce pathogenic process of EVC by reducing sperm DNA damage and regulating telomere length in EVC rats, which may be related to oxidative stress regulation.

Lipids, lipid-modified drug target genes, and the risk of male infertility: a Mendelian randomization study

Background

Previous observational studies have reported a possible association between circulating lipids and lipid-lowering drugs and male infertility (MIF), as well as the mediating role of circulating vitamin D. Then, due to issues such as bias, reverse causality, and residual confounding, inferring causal relationships from these studies may be challenging. Therefore, this study aims to explore the effects of circulating lipids and lipid-lowering drugs on MIF through Mendelian randomization (MR) analysis and evaluate the mediating role of vitamin D.

Method

Genetic variations related to lipid traits and the lipid-lowering effect of lipid modification targets are extracted from the Global Alliance for Lipid Genetics Genome-Wide Association Study. The summary statistics for MIF are from the FinnGen 9th edition. Using quantitative expression feature loci data from relevant organizations to obtain genetic variations related to gene expression level, further to explore the relationship between these target gene expression levels and MIF risk. Two-step MR analysis is used to explore the mediating role of vitamin D. Multiple sensitivity analysis methods (co-localization analysis, Egger intercept test, Cochrane's Q test, pleiotropy residuals and outliers (MR-PRESSO), and the leave-one-out method) are used to demonstrate the reliability of our results.

Result

In our study, we observed that lipid modification of four lipid-lowering drug targets was associated with MIF risk, the LDLR activator (equivalent to a 1-SD decrease in LDL-C) (OR=1.94, 95% CI 1.14-3.28, FDR=0.040), LPL activator (equivalent to a 1-SD decrease in TG) (OR=1.86, 95% CI 1.25-2.76, FDR=0.022), and CETP inhibitor (equivalent to a 1-SD increase in HDL-C) (OR=1.28, 95% CI 1.07-1.53, FDR=0.035) were associated with a higher risk of MIF. The HMGCR inhibitor (equivalent to a 1-SD decrease in LDL-C) was associated with a lower risk of MIF (OR=0.38, 95% CI 0.17-0.83, FDR=0.39). Lipid-modifying effects of three targets were partially mediated by serum vitamin D levels. Mediation was 0.035 (LDLR activator), 0.012 (LPL activator), and 0.030 (CETP inhibitor), with mediation ratios of 5.34% (LDLR activator), 1.94% (LPL activator), and 12.2% (CETP inhibitor), respectively. In addition, there was no evidence that lipid properties and lipid modification effects of six other lipid-lowering drug targets were associated with MIF risk. Multiple sensitivity analysis methods revealed insignificant evidence of bias arising from pleiotropy or genetic confounding.

Conclusion

This study did not support lipid traits (LDL-C, HDL-C, TG, Apo-A1, and Apo-B) as pathogenic risk factors for MIF. It emphasized that LPL, LDLR, CETP, and HMGCR were promising drug targets for improving male fertility.

The Effects of Varicocelectomy on Sperm DNA Fragmentation and Conventional Semen Parameters in Men with Severe Oligoasthenoteratozoospermia: A Prospective Study

BACKGROUND

The dilation and torsion of testicular veins in the plexus pampiniformis causes Varicocele, which is a surgically repairable cause of male infertility. This study assessed the impact of varicocelectomy on semen characteristics, total motile sperm count (TMSC) and sperm DNA integrity in patients with severe oligoasthenoteratozoospermia (OAT).

MATERIALS AND METHODS

In this prospective study, semen samples of 360 men with severe OAT who underwent varicocelectomy according to World Health Organization (WHO) criteria 2021 were studied (pre-operatively and at 6, 12, and 18 months post-operatively).

RESULTS

The average age of our patients was 38.5 years. The mean spermatozoa concentration was found to be 1.60 ± 0.83 million/ml pre-operatively, while the mean post-operative concentration was 5.17 ± 1.23 million/ml at 6 months, 8.32 ± 0.98 million/ml at 12 months, and 13.51 ± 1.48 million/ml at 18 months (P<0.0001). The mean percentage of A+B motile spermatozoa was 2.92 ± 1.17% pre-operatively, 6.10 ± 1.51% at six months, 9.58 ± 1.49% at 12 months and 13.92 ± 1.88% at 18 months postoperatively (P<0.0001). The mean Modified David's morphology score was 3.80 ± 1.43% pre-operatively, 5.95 ± 1.23% at 6 months, 7.94 ± 1.18% at 12 months, and 10.82 ± 1.91% at 18 months post-operatively (P<0.0001). The mean of total motile sperm count (TMSC) was statistically improved after varicocelectomy (P<0.001). The mean of DNA fragmentation index (DFI) of the spermatozoa was 31.40 ± 0.52% pre-operatively, and post-operatively at 28.20 ± 0.32% at 6 months, 25.90 ± 0.31% at 12 months and 20.50 ± 0.40% at 18 months (P<0.001).

CONCLUSION

Varicocelectomy was associated with significant improvement of sperm parameters and DNA fragmentation resulting in significant improvement of spermatogenesis quality. We believe that universalization in the routinely used sperm dispersion chromatin (SDC) test could be beneficial in the treatment of infertility.

Adverse effects and potential mechanisms of polystyrene microplastics (PS-MPs) on the blood-testis barrier

Microplastics (MPs) are defined as plastic particles or fragments with a diameter of less than 5 mm. These particles have been identified as causing male reproductive toxicity, although the precise mechanism behind this association is yet to be fully understood. Recent research has found that exposure to polystyrene microplastics (PS-MPs) can disrupt spermatogenesis by impacting the integrity of the blood-testis barrier (BTB), a formidable barrier within mammalian blood tissues. The BTB safeguards germ cells from harmful substances and infiltration by immune cells. However, the disruption of the BTB leads to the entry of environmental pollutants and immune cells into the seminiferous tubules, resulting in adverse reproductive effects. Additionally, PS-MPs induce reproductive damage by generating oxidative stress, inflammation, autophagy, and alterations in the composition of intestinal flora. Despite these findings, the precise mechanism by which PS-MPs disrupt the BTB remains inconclusive, necessitating further investigation into the underlying processes. This review aims to enhance our understanding of the pernicious effects of PS-MP exposure on the BTB and explore potential mechanisms to offer novel perspectives on BTB damage caused by PS-MPs.

Role of nuclear factor erythroid 2-related factor 2 (Nrf2) in female and male fertility

Oxidative stress refers to a condition where there is an imbalance between the production of reactive oxygen species and their removal by antioxidants. While the function of reactive oxygen species as specific second messengers under physiological conditions is necessary, their overproduction can lead to numerous instances of cell and tissue damage. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a master regulator of many cytoprotective genes that respond to redox stresses. Nrf2 is regularly degraded by kelch-like ECH-associated protein 1 through the ubiquitin-proteasome pathway. The kelch-like ECH-associated protein 1 and Nrf2 complex have attracted attention in both basic and clinical infertility research fields. Oxidative stress is implicated in the pathogenesis of female infertility, including primary ovarian insufficiency, polycystic ovarian syndrome, and endometriosis, as well as male infertility, namely varicocele, cryptorchidism, spermatic cord torsion, and orchitis. Most scientists believe that Nrf2 is a potential therapeutic method in female and male infertility disorders due to its antioxidant effect. Here, the potential roles of oxidative stress and Nrf2 in female and male infertility disorders are reviewed. Moreover, the key role of Nrf2 in the inhibition or induction of these diseases is discussed.

Cyto- and Histopographic Assessment of CPA3-Positive Testicular Mast Cells in Obstructive and Non-Obstructive Azoospermia

Infertility is an important personal and society disease, of which the male factor represents half of all causes. One of the aspects less studied in male infertility is the immunological testicular microenvironment. Mast cells (MCs), having high potential for regulating spermatogenesis due to fine-tuning the state of the integrative buffer metabolic environment, are one of the most crucial cellular subpopulations of the testicular interstitium. One important component of the MC secretome is proteases that can act as proinflammatory agents and in extracellular matrix (ECM) remodeling. In the testis, MCs are an important cell component of the testicular interstitial tissue (TIT). However, there are still no studies addressing the analysis of a specific MC protease-carboxypeptidase A3 (CPA3)-in cases with altered spermatogenesis. The cytological and histotopographic features of testicular CPA3+ MCs were examined in a study involving 34 men with azoospermia. As revealed, in cases with non-obstructive azoospermia, a higher content of CPA3+ MCs in the TIT and migration to the microvasculature and peritubular tissue of seminiferous tubules were observed when compared with cases with obstructive azoospermia. Additionally, a high frequency of CPA3+ MCs colocalization with fibroblasts, Leydig cells, and elastic fibers was detected in cases with NOA. Thus, CPA3 seems to be of crucial pathogenetic significance in the formation of a profibrogenic background of the tissue microenvironment, which may have direct and indirect effects on spermatogenesis.

Trace and essential elements as vital components to improve the performance of the male reproductive system: Implications in cell signaling pathways

Successful male fertilization requires the main processes such as normal spermatogenesis, sperm capacitation, hyperactivation, and acrosome reaction. The progress of these processes depends on some endogenous and exogenous factors. So, the optimal level of ions and essential and rare elements such as selenium, zinc, copper, iron, manganese, calcium, and so on in various types of cells of the reproductive system could affect conception and male fertility rates. The function of trace elements in the male reproductive system could be exerted through some cellular and molecular processes, such as the management of active oxygen species, involvement in the action of membrane channels, regulation of enzyme activity, regulation of gene expression and hormone levels, and modulation of signaling cascades. In this review, we aim to summarize the available evidence on the role of trace elements in improving male reproductive performance. Also, special attention is paid to the cellular aspects and the involved molecular signaling cascades.

FDG Uptake Caused by Right Varicocele

ABSTRACT

A 67-year-old man underwent 18 F-FDG PET/CT for lung cancer staging. Interestingly, the PET scan revealed strip-shaped FDG uptake in the right inguinal contoured area, which was later confirmed as a right varicocele through ultrasound imaging.

Inflammatory cytokines may mediate the causal relationship between gut microbiota and male infertility: a bidirectional, mediating, multivariate Mendelian randomization study

Introduction

Studies have shown that the gut microbiota is associated with male infertility (MI). However, their causal relationship and potential mediators need more evidence to prove. We aimed to investigate the causal relationship between the gut microbiome and MI and the potential mediating role of inflammatory cytokines from a genetic perspective through a Mendelian randomization approach.

Methods

This study used data from genome-wide association studies of gut microbes (Mibiogen, n = 18, 340), inflammatory cytokines (NFBC1966, FYPCRS, FINRISK 1997 and 2002, n=13, 365), and male infertility (Finngen, n=120, 706) to perform two-way Mendelian randomization (MR), mediated MR, and multivariate MR(MVMR) analyses. In this study, the inverse variance weighting method was used as the primary analysis method, and other methods were used as supplementary analysis methods.

Results

In the present study, two gut microbes and two inflammatory cytokines were found to have a potential causal relationship with MI. Of the two gut microorganisms causally associated with male infertility, Anaerotruncus increased the risk of male infertility (odds ratio = 1.81, 95% confidence interval = 1.18-2.77, P = 0.0062), and Bacteroides decreased the risk of male infertility (odds ratio = 0.57, 95% confidence interval = 0.33-0.96, P = 0.0363). In addition, of the two inflammatory cytokines identified, hepatocyte growth factor(HGF) reduced the risk of male infertility (odds ratio = 0.50, 95% confidence interval = 0.35-0.71, P = 0.0001), Monocyte chemotactic protein 3 (MCP-3) increased the risk of male infertility (odds ratio = 1.28, 95% confidence interval = 1.03-1.61, P = 0.0039). Mediated MR analysis showed that HGF mediated the causal effect of Bacteroides on MI (mediated percentage 38.9%). Multivariate MR analyses suggest that HGF may be one of the pathways through which Bacteroides affects MI, with other unexplored pathways.

Conclusion

The present study suggests a causal relationship between specific gut microbiota, inflammatory cytokines, and MI. In addition, HGF may mediate the relationship between Bacteroides and MI.

Transcriptome analysis reveals the genes involved in spermatogenesis in white feather broilers

Semen volume is an important economic trait of broilers and one of the important indices for continuous breeding. The objective of this study was to identify genes related to semen volume through transcriptome analysis of the testis tissue of white feather broilers. The testis samples with the highest semen volume (H group, n = 5) and lowest semen volume (L group, n = 5) were selected from 400-day-old roosters for transcriptome analysis by RNA sequencing. During the screening of differentially expressed genes (DEGs) between the H and L groups, a total of 386 DEGs were identified, among which 348 were upregulated and 38 were downregulated. Gene ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that the immune response, leukocyte differentiation, cell adhesion molecules and collagen binding played vital roles in spermatogenesis. The results showed that 4 genes related to spermatogenesis, namely, COL1A1, CD74, ARPC1B and APOA1, were significantly expressed in Group H, which was consistent with the phenotype results. Our findings may provide a basis for further research on the genetic mechanism of semen volume in white feather broilers.

Lycopene inhibits apoptosis of mouse spermatocytes in varicocele via miR-23a/b-induced downregulation of PROK2

Context The varicocele is the leading cause of male infertility and can impair sperm quality and testicular function through various mechanisms. In our previous study, we found that lycopene could attenuate hypoxia-induced testicular injury. Aims To illustrate the detailed mechanism of lycopene on spermatocytes. Methods The effect of lycopene on GC-2 cells under hypoxia were detected by flow cytometry and western blot assay. miR-seq was used to determine miRNA expression in varicocele rat model testes. The function of miR-23a/b were determined by flow cytometry and western blot assay. Key results We demonstrate that lycopene could alleviate hypoxia-induced GC-2 cell apoptosis and could elevate miR-23a/b expression of the hypoxia model in vivo and in vitro . The miR-23a and -23b mimics could reduce the hypoxia-induced GC-2 cell apoptosis. Both miR-23a and -23b could directly bind with prokineticin 2 (PROK2) mRNA and downregulate its expression. Conclusions Lycopene could attenuate hypoxia-induced spermatocyte injury through the miR-23a/b-PROK2 pathway. Implications Lycopene may be an effective treatment for varicocele to improve testicular impairment.

The Evolving Landscape of Male Varicocele Pathophysiology in the Era of Multi-Omics: A Narrative Review of the Current Literature

Male-factor infertility is implicated in over half of the millions of cases of infertility worldwide, and varicoceles are the most common correctable cause of male-factor infertility. The pathophysiologic mechanism for varicoceles is complex and next-generation technologies offer promising insights into the molecular underpinnings of this condition. In this narrative review, we highlight historical and contemporary paradigms associated with varicoceles, with an emphasis on the biological underpinnings of this disease. Specifically, we review the literature describing the underlying causes of varicoceles, discuss the molecular and cellular mechanisms causing pathological changes in some (but not all) men, and highlight key articles regarding the next-generation analyses (e.g., transcriptome, epigenome, proteome, and microbiome) being applied to better understand the condition and its treatment. These data demonstrate an ongoing evolution of the knowledge of varicoceles and the potential for improved personalized care in the future for men with this condition.

Molybdenum and cadmium cause blood-testis barrier dysfunction through ROS-mediated NLRP3 inflammasome activation in sheep

In this study, 24 healthy male sheep were divided into four groups: the control group, Mo group (45 mg Mo·kg-1·BW), Cd group (1 mg Cd·kg-1·BW), and Mo + Cd group (45 mg Mo·kg-1·BW + 1 mg Cd·kg-1·BW). The experiment was last for 50 d. The results showed that Mo and Cd co-exposure induced histopathological changes and ultrastructural damage, decreased the mRNA and protein expression levels of BTB (blood-testis barrier)-related factors (CX-43, ZO-1, OCLN) (P < 0.05) and the T-SOD and CAT activity (P < 0.05), increased the MDA content (P < 0.05) and the proinflammatory factors levels (P < 0.05) in sheep testes. Moreover, the results showed that a sharp decline in BTB-related factors and antioxidase activity, and a significant increase in reactive oxygen species (ROS) levels (P < 0.05) and the expression levels of NLRP3 inflammasome-related factors (P < 0.05) in primary Sertoli cells (SCs) under Mo and Cd co-exposure. However, treatment with a ROS scavenger or NLRP3 inflammasome inhibitors could relieve BTB damage and oxidative injury, reduce the production of ROS (P < 0.05) and decrease the level of inflammatory factors (P < 0.05). Overall, these results indicated that Mo and Cd co-exposure reduced BTB-related protein levels and promoted ROS production and inflammatory reactions by activating the ROS/NLRP3 inflammasome pathway in sheep testes, which eventually induced reproductive toxicity.

Effects of zingerone on rat induced testicular toxicity by sodium arsenite via oxidative stress, endoplasmic reticulum stress, inflammation, apoptosis, and autophagy pathways

Objectives

This study aimed to investigate the effects of zingerone (ZNG) treatment on testicular toxicity in rats induced by sodium arsenite (SA).

Materials and Methods

In the study, five groups were formed (n=7) and the experimental groups were designated as follows; Vehicle group, ZNG group, SA group, SA+ZNG 25 group, and SA+ZNG 50 group. While SA was administered orally to rats at 10 mg/kg/bw, ZNG was given to rats orally at 25 and 50 mg/kg/bw doses for 14 days.

Results

As a result of the presented study, an increase was observed in the MDA contents of the testicular tissue of the rats administered SA, while significant decreases were observed in GSH levels, SOD, CAT, and GPx activities. The mRNA transcript levels of the pro-inflammatory genes NF-κB, TNF-α, IL-1β, and IL-6 were triggered after SA administration. Additionally, SA administration caused inflammation by increasing RAGE, NLRP3, and JAK-2/STAT3 gene expression. Moreover, endoplasmic reticulum (ER) stress occurred in the testicular tissues of SA-treated rats and thus ATF-6, PERK, IRE1, and GRP78 genes were up-regulated. SA caused apoptosis by up-regulating Bax and Caspase-3 expressions and inhibiting Bcl-2 expression in testicles. SA caused histological irregularities in the testicles, resulting in decreased sperm quality.

Conclusion

ZNG treatment reduced SA-induced oxidative stress, ER stress, inflammation, apoptosis, and histological irregularities in the testicles while increasing sperm quality. As a result, it was observed that ZNG could alleviate the toxicity caused by SA in the testicles.

Recent advances in anti-inflammatory active components and action mechanisms of natural medicines

Inflammation is a series of reactions caused by the body's resistance to external biological stimuli. Inflammation affects the occurrence and development of many diseases. Anti-inflammatory drugs have been used widely to treat inflammatory diseases, but long-term use can cause toxic side-effects and affect human functions. As immunomodulators with long-term conditioning effects and no drug residues, natural products are being investigated increasingly for the treatment of inflammatory diseases. In this review, we focus on the inflammatory process and cellular mechanisms in the development of diseases such as inflammatory bowel disease, atherosclerosis, and coronavirus disease-2019. Also, we focus on three signaling pathways (Nuclear factor-kappa B, p38 mitogen-activated protein kinase, Janus kinase/signal transducer and activator of transcription-3) to explain the anti-inflammatory effect of natural products. In addition, we also classified common natural products based on secondary metabolites and explained the association between current bidirectional prediction progress of natural product targets and inflammatory diseases.

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.

[Varicocele and male infertility]

BACKGROUND

Varicocele is the most common correctable cause of male infertility. It was the subject of recent Association française d'urologie (AFU) Comité d'andrologie et de médecine sexuelle (CAMS) recommendations. Since then, the literature has provided additional information. This review will comprehensively reassess current indications for the treatment of varicocele, and revisit contemporary issues in the light of current advances.

METHODS

Update of the literature search carried out as part of the CAMS recommendations for the period between 2020 and 2023.

RESULTS

Microsurgical sub-inguinal varicocelectomy remains the surgical treatment of choice for infertile men with clinical varicocele and abnormal sperm parameters. It offers recurrence rates of less than 4%. It significantly improves both natural and in vitro fertilization live birth and pregnancy rates, as well as sperm count, total and progressive motility, morphology and DNA fragmentation rates. All in all, it modifies the MPA strategy in around one in two cases. Varicocele grade and bilaterality are predictive of improved sperm parameters and pregnancy rate. Treatment of subclinical varicocele is not recommended. Complications are rare, notably hydroceles (0.5%), unilateral testicular atrophy due to arterial damage (1/1000), hematomas, delayed healing and postoperative pain. Retrograde embolization is an alternative to surgery.

CONCLUSION

Whenever possible, the urologist should present and discuss treatment options for varicocele with the MPA team and the patient, taking a personalized approach.

Research progress of NLRP3 inflammasome and its inhibitors with aging diseases

In recent years, a new target closely linked to a variety of diseases has appeared in the researchers' vision, which is the NLRP3 inflammasome. With the deepening of the study of NLRP3 inflammasome, it was found that it plays an extremely important role in a variety of physiological pathological processes, and NLRP3 inflammasome was also found to be associated with some age-related diseases. It is associated with the development of insulin resistance, Alzheimer's disease, Parkinson's, cardiovascular aging, hearing and vision loss. At present, the only clinical approach to the treatment of NLRP3 inflammasome-related diseases is to use anti-IL-1β antibodies, but NLRP3-specific inhibitors may be better than the IL-1β antibodies. This article reviews the relationship between NLRP3 inflammasome and aging diseases: summarizes some of the relevant experimental results reported in recent years, and introduces the biological signals or pathways closely related to the NLRP3 inflammasome in a variety of aging diseases, and also introduces some promising small molecule inhibitors of NLRP3 inflammasome for clinical treatment, such as: ZYIL1, DFV890 and OLT1177, they have excellent pharmacological effects and good pharmacokinetics.

Inflammasomes in human reproductive diseases

Inflammasomes are multi-protein complexes localized within immune and non-immune cells that induce caspase activation, proinflammatory cytokine secretion, and ultimately pyroptosis-a type of cell death. Inflammasomes are involved in a variety of human diseases, especially acute or chronic inflammatory diseases. In this review, we focused on the strong correlation between the NLRP3 inflammasome and various reproductive diseases, including ovarian aging or premature ovarian insufficiency, PCOS, endometriosis, recurrent spontaneous abortion, preterm labor, pre-eclampsia, and male subfertility, as well as the multifaceted role of NLRP3 in the pathogenesis and treatment of these diseases. In addition, we provide an overview of the structure and amplification of inflammasomes. This comprehensive review demonstrates the vital role of NLRP3 inflammasome activation in human reproductive diseases together with the underlying mechanisms, offers new insights for mechanistic studies of reproduction, and provides promising possibilities for the development of drugs targeting the NLRP3 inflammasome for the treatment of reproductive disorders in the future.

The emerging role of exosomes in the development of testicular

The mechanisms of testicular development in mammals are complex. Testis is an organ that produces sperm and secretes androgens. It is rich in exosomes and cytokines that mediate signal transduction between tubule germ cells and distal cells, promoting testicular development and spermatogenesis. Exosomes are nanoscale extracellular vesicles that transmit information between cells. By transmitting information, exosomes play an important role in male infertility diseases such as azoospermia, varicocele, and testicular torsion. However, due to the wide range of sources of exosomes, extraction methods are numerous and complex. Therefore, there are many difficulties in studying the mechanisms of exosomal effects on normal development and male infertility. Therefore, in this review, first, we introduce the formation of exosomes and methods for culturing testis and sperm. Then, we introduce the effects of exosomes on different stages of testicular development. Finally, we summarize the prospects and shortcomings of exosomes when used in clinical applications. We lay the theoretical foundation for the mechanism of the influence of exosomes on normal development and male infertility.

Study on the cytokines related to SARS-Cov-2 in testicular cells and the interaction network between cells based on scRNA-seq data

Inflammatory cytokine storms (CS) in COVID-19 patients are associated with elevated levels of 13 specific cytokines, potentially impacting male fertility by causing testicular cell damage and disrupting the immune microenvironment. Some patients present with scrotal discomfort and orchitis. However, few studies have explored cytokine expression in testicular cells and their role in cell-to-cell communication. In this study, we integrated single-cell sequencing data sets of testicular cells, annotating 20 cell clusters using marker genes and the Human Cell Landscape database. We constructed cell pseudo-chronological trajectories, hub genes, and analyzed the cytokine interaction network between sperm cells using CellChat. Our findings identified 12 types of testicular cells, with four cytokines (IL8, CCL2, CCL3, and TNF) potentially involved in immune processes. Pseudo-chronological trajectory analysis indicated IL8 and CCL3's essential roles in testicular macrophages and endothelial cell development, affecting the immune microenvironment. We determined eight key cytokines (IL1, IL2, IL4, IL6, CCL, CSF3, TNF, and IFN-II) functions in cell interaction networks. Network analysis of exogenous cytokines directly acting on testicular cells showed IL2 potentially affecting all testicular cells, suggesting a vital role in cell communication. This research offers valuable insights into CSs effects on testicular cells and their potential impact on male fertility during COVID-19 infection.

Researching the molecular mechanisms of Taohong Siwu Decoction in the treatment of varicocele-associated male infertility using network pharmacology and molecular docking: A review

Taohong Siwu Decoction (THSWD) was widely used for the treatment of varicocele-associated male infertility. However, the pharmacological mechanism of action is not completely clear. Therefore, network pharmacology and molecular docking were performed to explore potential mechanism of THSWD in the treatment of varicocele-associated male infertility. The Traditional Chinese Medicine Systems Pharmacology (TCMSP), Swiss Target Prediction, and GeneCards were used to retrieve candidate compounds, action targets, and disease-related targets. The construction of the protein-protein interaction (PPI) network and the screening of core genes were completed by the STRING and Cytoscape 3.9.1, respectively. The DAVID was used to obtain results of gene ontology function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. The Mcule analysis platform was used to perform molecular docking. There were a total of 53 candidate compounds and 782 relevant targets in THSWD. There were 45 common targets between THSWD, varicocele, and male infertility, and 23 core genes were found in the PPI network. Biological processes involved response to hypoxia, regulation of blood pressure, cellular response to hypoxia, and regulation of the nitric oxide biosynthetic process. Furthermore, the KEGG pathway enrichment analysis showed that the common targets mainly regulated the disease of varicocele-associated male infertility through the HIF-1 signaling pathway, PI3K-Akt signaling pathway, Relaxin signaling pathway, and TNF signaling pathway. Finally, the molecular docking showed that luteolin, quercetin, and kaempferol had good intercalation with major targets. As predicted by network pharmacology, THSWD regulated varicocele-associated male infertility through multiple compounds and targets, and its mechanism was closely related to inflammatory response, reactive oxygen species damage, and function of blood vessels.