Search Results (27)

Oxidative stress (OS) and sperm DNA fragmentation (SDF) are complementary contributors to male infertility. OS characterizes a compromised seminal redox status, whereas SDF quantifies downstream genomic damage. Human sperm are highly susceptible to redox damage due to lipid-rich membranes and disrupted post-meiotic DNA-repair capacity. Excess reactive oxygen species (ROS) can cause lipid peroxidation, oxidative base lesions, and DNA strand breaks that impair fertilization, embryo development, and pregnancy outcomes. This review explains how OS promotes genomic instability and summarizes the main laboratory assays that assess redox status and SDF in semen. These include direct ROS chemiluminescence assay, oxidation–reduction potential, total antioxidant capacity/ferric reducing antioxidant power, and lipid peroxidation biomarkers, alongside SDF platforms (Sperm Chromatin Structure Assay, terminal deoxynucleotidyl transferase dUTP nick-end labeling, alkaline/neutral Comet, and sperm chromatin dispersion). Additionally, guideline-aligned indications are highlighted to clarify the conditions for testing OS and SDF. OS testing is most relevant in men with leukocytospermia or suspected genital tract infection or inflammation, including dysbiosis; in cases of major modifiable exposures such as smoking or heat; and for early monitoring after treatment. SDF testing is particularly informative in couples with recurrent pregnancy loss and in unexplained infertility with normal semen parameters. Combined OS and SDF testing is recommended in clinical varicocele, repeated in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) failure, poor embryo development, and follow-up after targeted therapy. Management centers on treating infection and inflammation, improving lifestyle and environmental factors, considering varicocelectomy when indicated, using targeted antioxidant therapy in men with documented OS, and selectively applying sperm selection technologies or testicular sperm for ICSI when SDF remains high. Priorities include assay standardization, etiologic attribution of DNA damage, and trials testing OS/SDF-guided pathways with live birth as the primary endpoint. When used selectively and in the appropriate context, OS and SDF testing can help refine diagnosis, improve counseling, and help personalize care of infertile couples. Full article

Male infertility is increasingly recognized as a complex, multifactorial disorder that extends beyond abnormalities in conventional semen parameters. A growing body of evidence highlights oxidative stress, sperm DNA fragmentation (SDF), and epigenetic alterations as tightly interconnected mechanisms contributing to sperm dysfunction and impaired fertility. Reactive oxygen species, though vital for sperm maturation and signaling, can inflict extensive genomic and chromatin damage when their levels exceed the antioxidant capacity of the testis and seminal plasma. These redox-driven lesions not only compromise fertilization potential but may also influence embryonic development and offspring health. Clinical studies and meta-analyses consistently report that elevated SDF and redox imbalance are associated with reduced pregnancy and live birth rates, particularly in assisted reproductive technologies (ARTs). The use of testicular sperm in men with high ejaculated SDF appears to improve ART outcomes, although long-term safety data remain limited. Advances in redox and genomic diagnostics, including assays for oxidation–reduction potential, SDF, and sperm epigenetic profiling, have opened new avenues for precision-based andrology, enabling targeted antioxidant, metabolic, and surgical interventions. Nonetheless, methodological variability, lack of assay standardization, and insufficient longitudinal follow-up constrain the full clinical translation of these findings. This review synthesizes evidence linking OS, SDF, and epigenetic alterations, highlighting their mechanistic crosstalk and translational relevance in the personalized management of male infertility. Full article

Background/Objectives: Traditional semen analysis techniques frequently result in incorrect male infertility diagnoses, despite advancements in assisted reproductive technology (ART). Reduced fertilization potential, decreased embryo development, and lower pregnancy success rates are associated with elevated DNA Fragmentation Index (DFI), which has been proposed as a diagnostic indicator of sperm DNA integrity. Improving reproductive outcomes requires incorporating DFI into predictive models due to its diagnostic importance. Methods: In this study, semen samples were stratified into low and high DFI groups across two datasets: the “Reference” dataset (162 samples) containing sperm motility (A, B, and C), total sperm count, and morphology percentage, and the “ORP” dataset (37 samples) with the same features plus oxidation-reduction potential (ORP). We trained and evaluated four machine learning (ML) models—Logistic Regression, Support Vector Machines (SVM), Bernoulli Naive Bayes (BNB), and Random Forest (RF)- using three feature subsets and three preprocessing techniques (Robust Scaling, Min-Max Scaling, and Standard Scaling). Results: Feature subset selection had a significant impact on model performance, with the full feature set (X_all) yielding the best results, and the combination of Robust and MinMax scaling forming the most effective preprocessing pipeline. Conclusions: ORP proved to be a critical feature, enhancing model generalization and prediction performance. These findings suggest that data enrichment, particularly with ORP, could enable the development of ML frameworks that improve prognostic precision and patient outcomes in ART. Full article

This cross-sectional pilot study aimed to examine associations between urinary metabolites of organophosphate (OP) pesticides and semen quality in 42 healthy young men. Participants answered questionnaires, provided semen and urine samples, and had anthropometric measures taken. Urine and seminal plasma were assayed for dialkylphosphate (DAP) metabolites of OP pesticides using high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry. Semen quality parameters were analyzed according to the World Health Organization protocol, and seminal oxidative stress was assayed using MiOXSYS, a galvanic cell-based technology that yields an integrated measure of oxidants and antioxidants. Associations of OP pesticide metabolites with continuous and dichotomous sperm concentration, percent motility, and percent normal morphology, and with seminal oxidative-reduction potential (ORP) were analyzed statistically. OP pesticide exposure was associated with lower overall semen quality. Specifically, ∑DAP metabolites, driven by diethyl metabolites, was inversely associated with percent sperm motility, but this relationship was not mediated by seminal ORP. Seminal ORP was inversely associated with sperm concentration, but OP pesticide exposure was not associated with seminal ORP. Full article

Background and Objectives: Male infertility is a growing public health concern, with up to 50% of cases lacking a clearly identifiable cause. This study aimed to assess the epidemiological characteristics of male infertility in Lithuania and evaluate the clinical utility of oxidative stress assessment using the MiOXSYS system. Materials and Methods: A two-stage retrospective study was conducted between 2019 and 2023 at one of the largest fertility centers in Lithuania. The first stage involved an epidemiological analysis of 718 men who met the inclusion criteria. In the second stage, 261 men underwent oxidation-reduction potential (ORP) testing using the MiOXSYS system. Semen parameters were evaluated according to World Health Organization (WHO) 2010 guidelines. ROC curve analysis was used to assess the diagnostic value of ORP. Results: Male infertility was identified as the sole factor in 20.1% of couples, while unexplained infertility accounted for 24.4% of all cases. Among normozoospermic men, 48.5% exhibited elevated ORP levels (>1.34 mV/10⁶ sperm/mL). ROC analysis demonstrated moderate diagnostic accuracy of ORP (AUC = 0.634; sensitivity: 75.3%; specificity: 51.5%). The inclusion of ORP testing reduced the proportion of unexplained cases and supported their reclassification under the Male Oxidative Stress Infertility (MOSI) framework. Conclusions: This study provides novel epidemiological data on male infertility in Lithuania and highlights the potential of ORP testing as a supplementary diagnostic tool. Systematic evaluation of oxidative stress may help better identify cases previously labeled as unexplained and enable more personalized treatment strategies. Full article

Polystyrene microplastics (PS-MPs) released in the environment reportedly affect the reproduction of various organisms, induced oxidative stress and apoptosis, resulting in altered sperm parameters. In this in vitro study, we tested the cytotoxicity and genotoxicity of PS-MPs by exposing human semen samples to PS-MPs levels (105 and 210 μg/mL) for 30–60–90 min. Semen parameters, genome stability, sperm DNA fragmentation (SDF) and reactive oxygen species (ROS) production were analyzed before and after exposure. Moreover, we also evaluated the expression level of spermatozoa-specific expressed genes essential for the fusion with oocyte (DCST1, DCST2, IZUMO1, SPACA6, SOF1, and TMEM95). After PS-MP exposure, semen concentration and morphology did not differ, while sperm vitality and motility decreased in a time-dependent manner. In addition, sperm agglutination was observed in the groups exposed to both PS-MPs concentrations tested. A time- and concentration-dependent reduction in genomic stability, as well as increased SDF and ROS production, was also observed. Moreover, all investigated transcripts were down-regulated after PS-MP exposure. Our results confirm the oxidative stress-mediated genotoxicity and cytotoxicity of PS-MPs on human spermatozoa. The sperm agglutination observed after treatment could be due to the aggregation of PS-MPs already adhered to the sperm membranes, hindering sperm movement and fertilizing capability. Interestingly, the downregulation of genes required for sperm–oocyte fusion, resulting from data on the in vitro experimental system, suggests that PS-MP exposure may have implications for sperm functionality. While these findings highlight potential mechanisms of sperm dysfunction, further investigations using in vivo models are needed to determine their broader biological implications. Possible environmental and working exposure to pollutants should be considered during the counselling for male infertility. Full article

Introduction: Infertility affects 15% of couples, with oxidative stress recognized as a key contributor to male infertility. Night-shift work, through circadian disruption, may exacerbate oxidative imbalance and impair reproductive function. This study investigates the impact of night-shift work on oxidative stress and semen quality and evaluates the potential benefits of antioxidant supplementation in this context. Materials and Methods: We retrospectively analysed 96 white-European men aged 18–45, seeking fertility assessment at a single academic centre. Participants were classified as day or night workers based on their shift schedule, and all underwent standardised clinical, hormonal, and semen evaluations. Oxidative stress was assessed using the d-ROMs test. A subgroup of 40 patients (20 per group) treated for 3 months with antioxidant supplementation (Drolessano) to evaluate changes in oxidative stress and semen parameters was also considered. Statistical comparisons were performed using non-parametric tests and logistic regression analyses. Results: Night-shift workers exhibit significantly higher oxidative stress levels compared to day workers (median D-ROMs values of 340 vs. 280 U.CARR, p = 0.01), and a greater proportion of men exceeding the oxidative stress threshold (74.4% vs. 24.4%, p = 0.01). Logistic regression confirmed night-shift work as an independent predictor of elevated oxidative stress (OR 2.1, p = 0.001), even after adjusting for age and smoking. Following three months of antioxidant supplementation with Drolessano, both groups experienced significant reductions in oxidative stress (all p < 0.01), but night workers showed a substantially greater decrease (mean change −58.5 vs. −15.4 U.CARR, p = 0.001). Improvements in semen quality, including sperm concentration, motility, and morphology, were also more pronounced in the night group after treatment. Conclusions: At baseline, night-shift workers had significantly higher oxidative stress than day workers, likely due to circadian disruption. Both groups improved after antioxidant treatment, but night workers showed a greater reduction in D-ROMs. This pilot study might suggest a potential benefit of antioxidant therapy particularly in night workers. Full article

Because male obesity may result in reproductive failure, we aimed to examine the possible links among body mass index (BMI), the waist–hip ratio (WHR), and basic semen parameters, the oxidation–reduction potential of semen, the total antioxidant capacity of seminal plasma, the ability of sperm to bind hyaluronic acid, and sperm DNA fragmentation (SDF). This study was performed on semen (n = 543) collected from volunteers classified as follows: normal weight (BMI 18.5–24.9 kg/m²), overweight (BMI 25.0–29.9 kg/m²), obese (BMI ≥ 30.0 kg/m²), with a normal WHR (<1) or abnormal WHR (≥1). No significant differences in standard semen parameters were found between men with a normal BMI and those with overweight/obesity. However, compared with overweight men, obese men had a higher SDF index prevalence and risk for an SDF index > 20%. Compared with men with WHR < 1, those with WHR ≥ 1 had significantly lower sperm motility, morphology, and vitality and an increased SDF index, prevalence and risk for an SDF index > 20%. In conclusion, abnormal WHR had a greater negative impact on conventional semen parameters than abnormal BMI. Both BMI ≥ 30.0 and WHR ≥ 1 negatively influenced sperm chromatin integrity only. Obesity is a potential risk factor for sperm DNA damage. Full article

Fertility disorders are a worldwide problem affecting 8–12% of the population, with the male factor substantially contributing to about 40–50% of all infertility cases. Mitochondria, crucial organelles for cellular viability, play a pivotal role in the processes of spermatogenesis and significantly affect sperm quality and their fertilizing ability. Mitochondrial oxidative phosphorylation (OXPHOS) dysfunction, reduced energy supply for sperm, reduced endogenous coenzyme Q₁₀ (CoQ₁₀) levels, and oxidative stress are among the main factors that contribute to male infertility. There is great interest in the role of mitochondrial dysfunction in male infertility, and the diagnosis and assessment of mitochondrial health in infertile men present challenges. Platelets are a source of viable mitochondria that can be obtained non-invasively. Changes in platelet mitochondrial respiration were documented in various diseases, confirming platelet mitochondrial bioenergetics as a marker of systemic mitochondrial health. The aim of our study was to determine whether (a) platelet mitochondrial bioenergetics and CoQ₁₀ levels could be used as metabolic markers of mitochondrial health in infertile men and whether (b) the parameters of mitochondrial respiration in platelets correlate with sperm parameters. The high-resolution respirometry method was used for platelet bioenergetics, and the high-performance liquid chromatography (HPLC) method was used for CoQ₁₀ level measurement. The static oxidation–reduction potential (sORP) of the ejaculate was evaluated by MiOXSYS^®System. We found a deficit in mitochondrial complex I-linked OXPHOS and electron transfer capacity and CoQ₁₀ and α-tocopherol levels in infertile men. The proportion of sperm, heads, and midpiece abnormalities correlated negatively with the complex I-linked parameters of platelet mitochondrial bioenergetics. We suppose that dysfunctional mitochondria contribute to increased oxidative stress, and these imbalances can be considered a cause of Male Oxidative Stress Infertility (MOSI). Our results suggest that platelet mitochondrial function and the endogenous levels of CoQ₁₀ in platelets could be used as metabolic markers for monitoring mitochondrial health and targeted therapy in infertile men. sORP could be a useful clinical biomarker of MOSI. Full article

Background: Male factors contribute to approximately 50% of infertile couples. However, obvious causes remain unknown in many cases. This observational study aimed to investigate the associations of clinical and lifestyle parameters with sperm parameters. Methods: This study enrolled 41 men in infertile couples without obvious causes for male infertility from July 2023 to April 2024. Semen samples were evaluated for sperm number, motility, DNA fragmentation, and oxidative stress (OS) marker oxidation–reduction potential (ORP). Blood samples were analyzed for biochemical parameters, including advanced glycation end products (AGEs), and systemic OS marker diacron-reactive oxygen metabolites (d-ROMs). Skin-accumulated AGE levels were identified with an autofluorescence method. Lifestyle factors were assessed with a lifestyle questionnaire. Results: Most of the participants were under 40 years old and non-obese with normal clinical parameters. Multiple regression analyses revealed that body mass index, serum d-ROMs, and semen ORP levels were independently associated with decreased sperm number. Additionally, serum zinc and semen ORP levels were associated with sperm motility. Furthermore, serum zinc and high-density lipoprotein cholesterol levels were associated with sperm progressive motility and DNA fragmentation, respectively. The rest of the clinical and lifestyle factors, including skin-accumulated and serum AGE levels, were not correlated with any sperm parameters. Furthermore, serum d-ROM and semen ORP levels were not correlated with each other or any of the clinical and lifestyle factors. Conclusions: Our present study indicates that both systemic and local OS may be independently involved in sperm abnormality in healthy men without obvious causes for male infertility. Full article

Oxidative stress (OS) affects men’s health and impairs spermatogenesis. Micronutrient antioxidants are available for male infertility as complemental support; however, their efficacy remains debatable. This study aimed to investigate whether antioxidants can help to reduce sperm OS and improve semen analysis and quality. We included 171 male partners of couples planning to undergo assisted reproductive technology (ART). Male partners, aged 29–41 years, of couples intending to conceive were self-selected to take daily antioxidants (n = 84) containing folic acid and zinc, or not to take antioxidants (n = 52) for 6 months. We analyzed the alterations in serum oxidant levels, sperm parameters, OS, and deoxyribonucleic acid fragmentation after 3 and 6 months. Additionally, implantation, clinical pregnancy, and miscarriage rates after vitrified–warmed embryo transfer were compared between those taking antioxidants and those not taking them after 6 months. In men with high static oxidation–reduction potential (sORP), we observed a significant improvement in sperm concentration and sORP. The high-quality blastocyst rate tended to increase, and implantation and clinical pregnancy rates also significantly increased after 6 months of intervention. The micronutrient antioxidants could improve sperm function by reducing OS and improving ART outcomes. Therefore, micronutrient antioxidants may be a viable treatment option for male infertility. Full article

Cryopreservation of human spermatozoa is a necessity for males suffering from infertility who cannot produce fresh semen for insemination. However, current ART cryopreservation protocols are associated with losses of sperm motility, vitality and DNA integrity, which are thought to be linked to the induction of oxidative damage and the toxic properties of commercial cryoprotectants (CPAs). Preventing or mitigating these losses would be hugely beneficial to sperm survival during ART. Therefore, in this in vitro investigation, lipid peroxidation, production of reactive oxygen species, movement characteristics, antioxidant capacity, vitality, and DNA integrity were examined in semen samples both pre- and post-cryopreservation with CPA supplementation. The findings revealed a 50% reduction in antioxidant capacity with CPA addition, which was accompanied by significant increases in generation of reactive oxygen species and formation of lipid aldehydes. These changes were, in turn, correlated with reductions in sperm viability, motility and DNA integrity. Antioxidant supplementation generated bell-shaped dose-response curves with both resveratrol and vitamin C, emphasising the vulnerability of these cells to both oxidative and reductive stress. At the optimal dose, vitamin C was able to significantly enhance vitality and reduce DNA damage recorded in cryopreserved human spermatozoa. An improvement in sperm motility did not reach statistical significance, possibly because additional pathophysiological mechanisms limit the potential effectiveness of antioxidants in rescuing this aspect of sperm function. The vulnerability of human spermatozoa to reductive stress and the complex nature of sperm cryoinjury will present major challenges in creating the next generation of cryoprotective media. Full article

(1) Background: This case–control study examined whether men from couples with unexplained recurrent pregnancy loss (RPL) or infertility exhibited higher seminal oxidative stress (OS) and sperm DNA fragmentation (SDF) compared to fertile controls. (2) Methods: The study included 30 participants from each group: unexplained RPL, unexplained infertility, and proven fertility. Data were collected at Aalborg University Hospital tertiary RPL and fertility treatment clinics (Aalborg, Denmark), excluding couples with mixed conditions for homogeneity. Semen samples were analyzed using computer-aided sperm analysis (CASA) for concentration, motility, and morphology. SDF was assessed via a CASA-based sperm chromatin dispersion test. OS was measured as static oxidation-reduction potential (sORP). (3) Results: The results showed no significant OS differences between groups. The RPL group had significantly lower SDF levels than the control group. A significant positive correlation between SDF and OS was observed in the infertility group. Overall, this study did not find significant differences in OS levels between men from couples with unexplained RPL or infertility and fertile controls, while SDF levels were lower in the RPL group compared to controls. (4) Conclusion: In conclusion, despite the existing literature suggesting that OS and SDF are negative prognostic factors, our findings suggest they may not be reliable diagnostic markers for RPL and infertility. Full article

Semen preservation involves lengthening sperm’s fertile lifespan without any detrimental effects on its biochemical, functional, and ultrastructural properties. Liquid storage at 4 °C is a ram sperm preservation method. However, this method of storage causes irreversible damage due to cold shocks, osmotic stresses, oxidative stresses, and reductions in sperm metabolism. The present study aims to investigate whether the supplementation of mitochonic acid 5 (MA-5) in a sperm extender could improve chilled ram sperm quality and elucidate its mechanism of action. Ram sperm were diluted with a tris-citrate-glucose extender containing different concentrations of MA-5 (0, 0.1, 1, 10, and 100 nM) and stored at 4 °C for up to 48 h. Sperm motility, membrane integrity, acrosome integrity, mitochondrial membrane potential, reactive oxygen species (ROS) level, ATP content, and the expression of NADPH dehydrogenase subunits 1 (MT-ND1) and NADPH dehydrogenase subunits 6 (MT-ND6) were evaluated. It was observed that compared to the control, the 10 nM MA-5 treatment significantly (p < 0.05) increased total motility (82 ± 3.5% vs. 76 ± 5.9%), progressive motility (67.6 ± 8.2% vs. 51 ± 8.3%), and other parameters (straight-line velocity (VSL), average path velocity (VAP), and curvilinear velocity (VCL)). In addition, 10 nM MA-5 supplementation also improved ram sperm membrane integrity and acrosomal integrity as well increased mitochondrial membrane potential (51.1 ± 0.7% vs. 37.7 ± 1.3%), reduced ROS levels, and elevated adenosine triphosphate (ATP) contents. Furthermore, a Western blot analysis demonstrated that the addition of MA-5 significantly (p < 0.05) increased the expression of MT-ND1 and MT-ND6 proteins in ram sperm, with the 10 nM MA-5 treatment resulting in the highest expression level. These results suggest that MA-5 improves ram sperm quality by maintaining high sperm mitochondrial function during liquid storage at 4 °C. Full article

Cryopreservation deteriorates boar sperm quality and lifespan, which restricts the use of artificial insemination with frozen-thawed boar semen in field conditions. The objective of this study was to test the effects of post-thaw storage time and temperature on boar sperm survival. Semen ejaculates from five Landrace boars (one ejaculate per boar) were collected and frozen following a 0.5 mL-straw protocol. Straws from the five boars were thawed and diluted 1:1 (v:v) in BTS. The frozen-thawed semen samples were aliquoted into three parts and respectively stored at 5 °C, 17 °C, and 37 °C for up to 6 h. At 0.5, 2, and 6 h of storage, sperm motility, viability, mitochondrial membrane potential, and intracellular reactive oxygen species (ROS) levels and apoptotic changes were measured. Antioxidant and oxidant levels were tested in boar sperm (SPZ) and their surrounding environment (SN) at each timepoint. The results showed significant effects of post-thaw storage time and temperature and an impact on boar sperm quality (total and progressive motility, VCL, viability, acrosome integrity), early and late sperm apoptotic changes, and changes in MDA levels in SPZ and SN. Compared to storage at 5 °C and 37 °C, frozen-thawed semen samples stored at 17 °C displayed better sperm quality, less apoptotic levels, and lower levels of SPZ MDA and SN MDA. Notably, post-thaw storage at 17 °C extended boar sperm lifespan up to 6 h without obvious reduction in sperm quality. In conclusion, storage of frozen-thawed boar semen at 17 °C preserves sperm quality for up to 6 h, which facilitates the use of cryopreserved boar semen for field artificial insemination. Full article