Oxidative stress and acrosomal morphology: A cause of infertility in patients with normal semen parameters

Impact of calcium and reactive oxygen species on human sperm function: Role of NOX5

NOX5 is introduced as a new therapeutic target for infertility treatment. This study aimed to compare the basal and stimulated reactive oxygen species (ROS) production and sperm function in human teratozoospermic (n = 15) and normozoospermic (n = 17) semen samples following calcium overload and NOX5 activation. Washed spermatozoa incubated for 1 h under five various conditions: control group, adding a calcium ionophore A23187, phorbol myristate acetate (PMA), A23187 + PMA, and diphenylene iodonium (DPI) + A23187 + PMA. ROS generation was measured immediately after treatment for 30 min. Motility, viability, acrosome reaction, and apoptosis were evaluated after 1-h incubation. ROS production significantly increased when A23187 or PMA was added to the sperm medium. DPI had suppressive effects on ROS generation. Progressive and total motility significantly decreased following calcium elevation and NOX5 activation, which was somewhat returned by DPI. Necrotic and live cells in teratozoospermia was, respectively, higher and lower than normozoospermia samples. Incubation with A23187 significantly increased the percentage of early and late apoptosis. Teratozoosperm are more vulnerable than normal spermatozoa, and produce more basal and stimulated ROS. It seems that calcium overload induces apoptosis in spermatozoa and loss of viability through MPT pore opening and increased intracellular ROS.

Effects of BPA, BPS, and BPF on Oxidative Stress and Antioxidant Enzyme Expression in Bovine Oocytes and Spermatozoa

Bisphenol A (BPA) and its analogs, bisphenol S (BPS) and bisphenol F (BPF), might impact fertility by altering oxidative stress pathways. Here, we hypothesize that bisphenols-induced oxidative stress is responsible for decreased gamete quality. In both female (cumulus-oocyte-complexes-COCs) and male (spermatozoa), oxidative stress was measured by CM-H2DCFDA assay and key ROS scavengers (SOD1, SOD2, GPX1, GPX4, CAT) were quantified at the mRNA and protein levels using qPCR and Western blot (COCs)/immunofluorescence (sperm). Either gamete was treated in five groups: control, vehicle, and 0.05 mg/mL of BPA, BPS, or BPF. Our results show elevated ROS in BPA-treated COCs but decreased production in BPS- and BPF-treated spermatozoa. Additionally, both mRNA and protein expression of SOD2, GPX1, and GPX4 were decreased in BPA-treated COCs (p < 0.05). In sperm, motility (p < 0.03), but not morphology, was significantly altered by bisphenols. SOD1 mRNA expression was significantly increased, while GPX4 was significantly reduced. These results support BPA's ability to alter oxidative stress in oocytes and, to a lesser extent, in sperm. However, BPS and BPF likely act through different mechanisms.

Chronic unpredictable stress disturbs the blood-testis barrier affecting sperm parameters in mice

RESEARCH QUESTION

Does chronic stress affect the key proteins and sperm parameters of the blood-testis barrier (BTB)?

DESIGN

C57Bl/6 mice were divided into two groups: a non-treated control group and a chronic unpredictable stress (CUS) applied group. The stress status of the animals was confirmed with behavioural tests. Histopathologic evaluation was conducted by haematoxylin and eosin staining and electron microscope. Malondialdehyde, corticosterone and testosterone levels were evaluated in peripheral blood. Expression levels of BTB proteins, namely zonula occludens-1 (ZO-1), claudin-11 (CLDN11) and clathrin in Sertoli cells, were assessed by Western blotting and immunofluorescence techniques. Sperm samples were collected from cauda epididymis, and sperm parameters analysed.

RESULTS

The stress model was confirmed by behavioural tests. Histopathological evaluation of the testes demonstrated a mild degeneration in seminiferous tubules. Malondialdehyde (P = 0.008) and corticosterone levels increased (P = 0.004) and testosterone levels decreased (P = 0.005) in the CUS group. Electron microscopic evaluation confirmed the damage in BTB integrity in the CUS group. Western blot analysis showed that ZO-1 and CLDN11 levels were significantly decreased, although clathrin levels were unchanged. Although sperm concentration and total motility rate were not significantly different between the groups, progressive motility (P = 0.03), normal sperm morphology (P = 0.04), chromatin integrity (toluidine blue) (P = 0.002) and the acrosomal reaction rate (P = 0.002) were significantly decreased, and acrosomal abnormality rate was dramatically increased (P = 0.04) in the CUS group.

CONCLUSIONS

In mice, CUS disrupted BTB integrity and impaired sperm parameters. A decrease in ZO-1 and CLDN11 expression levels may be proposed as the causative factor.

Decreased expression of AKAP4 and TyrPho proteins in testis, epididymis, and spermatozoa with low sexual performance of mice induced by modified CUMS

The molecular mechanism of chronic stress especially reduced motility, a major cause of male infertility, has not been proved. It is known that A-kinase anchor protein 4 (AKAP4) and tyrosine-phosphorylated (TyrPho) proteins are involved in progressive motility. This study aimed to investigate the effect of chronic unpredictable mild stress (CUMS) on sexual behaviours, sperm quality, and expressions of AKAP4 and TyrPho proteins in testis, epididymis, and spermatozoa. Sixteen male mice were divided into control and CUMS groups (n = 8/group). Animals were induced by a stressor from twelve stressors for 36 days. Sexual behaviours, corticosterone and testosterone, sperm parameters, and histopathology were observed. The expressions of AKAP4 and TyrPho proteins in testis, epididymis, and spermatozoa were examined. Results showed that CUMS significantly increased corticosterone while serum testosterone level was decreased. Sexual behaviours and sperm parameter quality were significantly decreased. CUMS mice showed vacuolisation and pyknotic cells in seminiferous epithelium and less sperm mass was observed within epididymal lumen. CUMS decreased expressions of AKAP4 and TyrPho proteins in testis, epididymis, and spermatozoa. In conclusion, the decreased expression of AKAP4 and TyrPho proteins may be a mechanism associated with low semen qualities particularly decrease of sperm motility in CUMS.

Increased Sperm DNA Fragmentation in Infertile Men with Varicocele: Relationship with Apoptosis, Seminal Oxidative Stress, and Spermatic Parameters

This study intends to determine the extent of nuclear sperm injury in patients with varicocele and to investigate its relationship with apoptosis and oxidative stress (OS). Ejaculated sperm samples from 51 patients diagnosed with varicocele and 29 fertile men were examined. According to the guidelines, the patient's sperm samples were classified into varicocele with normal semen parameters (n = 11) and varicocele with abnormal semen parameters (n = 40). Sperm DNA fragmentation was assessed using terminal deoxynucleotidyl transferase dUTP nick end labeling assay. The proportion of both viable and dead spermatozoa with externalized phosphatidylserine (PS) was detected by the bivariate annexin V/6-CFDA staining method. Seminal malondialdehyde (MDA) amounts and antioxidant enzymes activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were measured spectrophotometrically. Sperm DNA fragmentation, viable spermatozoa with externalized PS, and MDA levels were significantly higher in studied subgroups of patients with varicocele, either with normal or with abnormal semen parameters than controls. The seminal antioxidant enzymes activities were significantly reduced in both subgroups of patients with varicocele compared to the controls. The percentage of spermatozoa with fragmented DNA was positively correlated to the MDA level as well as the proportion of viable spermatozoa with externalized PS. However, the decreased seminal antioxidant status was negatively correlated with the increased proportion of sperm DNA fragmentation and apoptotic spermatozoa. Impaired seminal antioxidant profile and increased seminal level of lipid peroxidation may be involved in the pathophysiological mechanisms of cell death-mediated DNA breaks in patients with varicocele.

Sperm Antioxidant Biomarkers and Their Correlation with Clinical Condition and Lifestyle with Regard to Male Reproductive Potential

Measurement of sperm oxidative-antioxidant indicators is widely used in the assessment and detection of biochemical causes of male infertility The main purpose of this study was to identify biomarkers that assist in diagnostics and monitoring of male reproductive potential. We performed the assessment of oxidative-antioxidant malondialdehyde (MDA), glutathione (GSH), and total redox antioxidant potential (TRAP) indicators in seminal plasma, seminogram, clinical condition, and lifestyle of people with reproductive problems. The combined assessment of GSH and TRAP as potential biomarkers of male infertility in semen plasma was characterized by the highest total sensitivity and specificity. Furthermore, we provide evidence that male reproductive potential is significantly correlated with basic sperm parameters, sperm cell membrane integrity, their morphology, lifestyle, eating habits, occupation, and mental health. Our results provide evidence on the importance of oxidative stress and defense against free radicals in diagnosing and monitoring men with infertility that are consistent with previously conducted research. We provide an alternative approach on the possibility of interpreting the combination of the biomarkers that can bring benefits to a multi-threaded approach to the diagnosis and treatment of male infertility.

Diagnostic value of advanced semen analysis in evaluation of male infertility

Conventional semen analysis is the standard of care to initially evaluate the fertility status of a male patient. However, it has some limitations and among these are failure to correctly identify the aetiology underlying fertility problems, intra- and inter-observer variability and incomplete information about sperm function. Considering these drawbacks, advanced semen tests have been developed to assess male infertility, including sperm function tests, oxidative stress (OS) and sperm DNA fragmentation (SDF) tests. This review illustrates the commonly utilised sperm function techniques, along with the assays used to assess SDF and OS and their diagnostic value.

Evaluation of seminal oxidation-reduction potential in male infertility

The role of oxidative stress in male infertility has been broadly recognised, and the search for a new marker to determine the redox environment in semen has gained considerable interest. Oxidation-reduction potential (ORP) or redox potential, is a measure of the electron transfer from antioxidants to oxidants and provides information on the redox balance. In this review, the benefits of ORP as a new oxidative stress marker, the protocol for its evaluation and the importance of its measurement in the context of male infertility are discussed. In association with the standard semen analysis, seminal ORP has been analysed to evaluate semen quality and male fertility status. However, further studies are required to establish its use in assisted reproductive techniques (ART) practice.

Comparison of Serum Inhibin B and Follicle-Stimulating Hormone (FSH) Level between Normal and Infertile Men in Yaoundé

Objective

Hormones play a vital role in initiating and maintaining male reproductive function. The present study explores the influence and predictive ability of two reproductive hormones on semen quality among men who were partners in an infertile couple.

Design

During our cross sectional study, men were recruited from private and public hospital and laboratories for clinical evaluation of fertility status.

Methods

Fresh semen samples were assessed for quality (concentration, motility and morphology) according to the 2010 World Health Organization manual and the serum levels of hormones, including follicle-stimulating hormone (FSH), Inhibin B was measured (ELISA).

Results

We found a significant difference in the two groups regarding sperm concentration (p < 0.0001), total sperm count (p < 0.0001), total sperm count (p < 0.0001), total sperm count (p < 0.0001), total sperm count (p < 0.0001), total sperm count (

Conclusion

Consistent with other studies, our results show strong association between semen quality and FSH and Inhibin B.

Oxidative stress and sperm function: A systematic review on evaluation and management

Objective: To review and present the most distinct concepts on the association of reactive oxygen species (ROS) with male reproduction.

Methods: The Preferred Reporting Items for Systematic Reviews and Meta Analyses (PRISMA) guidelines were used to search PubMed, Medline, EMBASE, and the Cochrane electronic databases for studies investigating the role of oxidative stress (OS) on sperm function.

Results: The literature search yielded 1857 studies, of which 1791 articles were excluded because of irrelevance of data, non-English language, non-human nature or because they were case reports or commentaries. All included studies were reviews (46), meta-analyses (one), original research studies (18) and guideline articles (one). The studies were published between 1984 and 2018. Under normal physiological conditions, ROS are vital for sperm maturation, hyperactivation, capacitation, acrosome reaction, as well as fertilisation. However, a number of endogenous and exogenous causes may induce supra-physiological levels of ROS resulting in lipid peroxidation, sperm DNA fragmentation and apoptosis, and consequently infertility. Several laboratory testing methods can be used in infertile men to diagnose OS. Treatment usually involves antioxidant supplementation and, when possible, elimination of the causative factor.

Conclusion: OS is an important cause of male factor infertility. Its assessment provides essential information that can guide treatment strategies aimed at improving the male’s reproductive potential.

Abbreviations: bp: base-pair; CAT: catalase; LPO: lipid peroxidation; MDA: malondialdehyde; MiOXSYS: Male Infertility Oxidative System; mtDNA: mitochondrial DNA; NAD(PH): nicotinamide adenine dinucleotide (phosphate); NO: nitric oxide; 8-OHdG: 8-hydroxy-2’-deoxyguanosine; ORP: oxidation–reduction potential; OS: oxidative stress; PKA: protein kinase A; PLA2: phospholipase A2; PRISMA: Preferred Reporting Items for Systematic Reviews and Meta-Analyses; PUFA: poly-unsaturated fatty acid; ROS: reactive oxygen species; SOD: superoxide dismutase; TAC: total antioxidant capacity; TBA: thiobarbituric acid

Disruption of bovine sperm functions in the presence of aplastic midpiece defect

BACKGROUND

Bulls are of great importance in the productive chain and for this reason they should have a good semen quality. There is no doubt that sperm morphology is very important to bull fertility, although little is known about how exactly the abnormal morphologies may affect sperm functions.

OBJECTIVES

To detail the morphological description of the aplastic midpiece defect (AMD), as well as to understand its consequences for male fertility based on membrane and acrosome status, mitochondrial membrane potential and DNA integrity parameters.

MATERIALS AND METHODS

The bulls were divided into two groups: control, consisting of satisfactory potential breeders (n = 3); and AMD, consisting of unsatisfactory potential breeders with a high percentage of AMD (n = 3). Bulls were evaluated by the breeding soundness evaluation; five ejaculates were collected from each animal and analyzed by flow cytometry.

RESULTS

Spermatozoa from AMD group exhibited lower sperm motility and vigor (p < 0.05). In addition, it also exhibited lower mitochondrial membrane potential (p < 0.05), a higher percentage of spermatozoa with DNA fragmentation (p < 0.05), lower acrosome and plasma membrane integrity (p < 0.05), and higher lipid bilayer sperm membrane disorganization (p < 0.05) in comparison with control bulls.

DISCUSSION

These findings may be due to oxidative stress and a reduction of the energy production capacity in addition to an alteration in the structural composition of the sperm cell. Moreover, semen with a high percentage of AMD may also be undergoing apoptosis.

CONCLUSION

Bulls with a high percentage of AMD in their semen are not suitable for reproduction. Furthermore, it suggests there is a putative genetic basis for this sperm defect.

Is male infertility associated with increased oxidative stress in seminal plasma? A-meta analysis

Objectives

We conducted a systematic review and meta-analysis of observational case-control studies to evaluate markers of oxidative stress in seminal plasma of patients with male infertility.

Background

Current evidence links oxidative stress to male infertility, in which multiple markers of oxidative stress have been widely detected, publishing inconsistent results with regard to the role of oxidative stress markers in the evaluation of male infertility. Therefore, a systematic review and meta-analysis on this issue is necessary.

Results

From the 1024 articles initially retrieved, 65 studies were included in our meta-analysis with 11 oxidative stress markers, containing 3819 male infertility patients and 2012 controls. The concentrations of malondialdehyde (SMD = 1.86, p < 0.00001), NO (SMD = 0.89, p = 0.001), carbonyl protein (SMD = 2.09, p < 0.00001) in seminal plasma were significantly higher in infertility patients. The concentrations of GSH (SMD = -1.68, p < 0.00001), vitamin C (SMD = -1.12, p < 0.00001), and vitamin E (SMD = -1.48, p = 0.003), as well as the activities of catalase (SMD = -1.91, p < 0.0001), glutathione peroxidase (SMD = -1.96, p = 0.0002) and glutathione-S-transferase (SMD = -1.62, p = 0.009) declined remarkably, resulting in decreased total antioxidant capacity (SMD = -1.77, p < 0.00001). Besides, the activity of superoxide dismutase showed no statistical difference between infertility patients and controls (SMD = -0.51, p = 0.07).

Conclusions

Our meta-analysis suggests that oxidative stress in seminal plasma resulting from decreased antioxidant defense are associated with male infertility.

Methods

Using PubMed, EMBASE, CNKI, VIP, and Wanfang database, we searched for literature reporting the detection of oxidative stress markers in the seminal plasma of male infertility published up to June 2017. Standardized mean differences (SMDs) and 95% confidence intervals (95%CI) were calculated for the finally analysis.