The Associations between Infertility and Antioxidants, Proinflammatory Cytokines, and Chemokines

Immune regulatory cytokines in seminal plasma of healthy men: A scoping review and analysis of variance

OBJECTIVE

Seminal plasma cytokines are associated with fertility and reproductive health, but progressing their clinical utility is hampered by absence of reference data on concentration ranges of relevant cytokines in healthy men. We employed a systematic approach to assemble current evidence on the concentrations of immune regulatory cytokines present in seminal plasma (SP) of normozoospermic and/or fertile men and evaluated the impact of different platform methodologies for cytokine quantification.

EVIDENCE REVIEW

A systematic literature search was performed utilising PubMed, Web of Science and Scopus. Databases were searched from inception until 30th June 2022 inclusive, using combinations of keywords pertaining to seminal fluid and cytokines, and was restricted to human participants. Original data with values reported as concentration of specific cytokines in SP of men clearly defined as fertile or normozoospermic were extracted from studies written in English.

RESULTS

A total of 3769 publications were initially identified, of which 118 fulfilled the eligibility criteria for inclusion. A total of 51 individual cytokines are detectable in SP of healthy men. The number of studies reporting on each cytokine range from 1 to >20. The reported concentrations for many cytokines linked with fertility status, including IL6, CXCL8/IL8, and TNFA, are highly variable between published studies. This is associated with the different immunoassay methodologies utilised and may be exacerbated by a lack of validation of assays to ensure suitability for SP assessment. Due to the large variation between studies, accurate reference ranges for healthy men cannot be determined from the published data.

CONCLUSIONS

The concentrations of cytokines and chemokines detected in SP is inconsistent and highly variable between studies and cohorts, limiting current capacity to define reference ranges for cytokine concentrations in fertile men. The lack of standardisation in methods used to process and store SP, and variation in platforms used to evaluate cytokine abundance, are factors contributing to the observed heterogeneity. To progress the clinical utility of SP cytokine analysis will require standardisation and validation of methodologies so that reference ranges for healthy fertile men can be defined.

SIRT1/PGC-1α is involved in arsenic-induced male reproductive damage through mitochondrial dysfunction, which is blocked by the antioxidative effect of zinc

Exposure to arsenic poses threats to male reproductive system, including impairing the testes and sperm quality. Although an association regarding arsenic exposure and male reproductive damage has been reported, the undergoing molecular mechanisms and interventions for prevention remain unclear. For the present work, male mice were exposed to 0, 2.5, 5, or 10 ppm sodium arsenite (NaAsO₂) for 8 months. The results showed that arsenic-exposed mice had reduced fertility with abnormalities in the testes, epididymides, and sperm. Exposure of mice to arsenic caused a redox imbalance, decreased SIRT1 and PGC-1α levels, and affected mitochondrial biogenesis and proteins related to mitochondrial dynamics. For immortalized spermatogenic (GC-2) cells, arsenic caused apoptosis and oxidative stress, reduced SIRT1/PGC-1α levels and ATP production, inhibited mitochondrial respiration, and changed the mitochondrial membrane potential (MMP). Mitochondrial biogenesis and dynamics were also impaired. However, by reducing mitochondrial damage in GC-2 cells, upregulation of SIRT1 or zinc (Zn) supplementation reversed the apoptosis induced by arsenic. For mice, Zn supplementation blocked arsenic-induced oxidative stress, the decreases of SIRT1 and PGC-1α levels, and the impairment of mitochondrial function, and it reversed the damage to testes, low sperm quality, and low litter size. Collectively, these results suggest that arsenic causes excessive production of ROS, inhibits the SIRT1/PGC-1α pathway, and causing mitochondrial dysfunction by mediating impairment of mitochondrial biogenesis and dynamics, which results in germ cells apoptosis and male reproductive damage, processes that are blocked by Zn via an antioxidative effect. Our study contributes to understanding of the mechanisms for arsenic-induced male reproductive damage and points to the therapeutic significance of Zn.

Lycopene alleviates lipopolysaccharide-induced testicular injury in rats by activating the PPAR signaling pathway to integrate lipid metabolism and the inflammatory response

Background

Male fertility can be hampered by systemic and testicular infections and inflammation, which can lead to impaired spermatogenesis that often cannot be reversed by antibiotic treatment. There has been some suggestion that lycopene (LYC) may be useful in the preservation of fertility, although its mechanisms are complex. This current study examined the therapeutic efficacy of LYC on testicular damage and its underlying mechanisms.

Methods

Lipopolysaccharide (LPS; 5 mg/kg) was injected intraperitoneally to induce inflammation of the testes in mature male rats. The rats in the experimental group were administered 5 mg/kg LYC intragastrically for 4 weeks. The testes were harvested from the euthanized rats for lipidomics, RNA sequencing, and related experimental tests.

Results

Laboratory data suggested that LPS-induced systemic inflammation induced cytokine excess and oxidative stress in the testes. Administration of oral LYC inhibited the excess cytokine production and oxidative stress, mitigating damage to the testes. Lipidomic studies identified significant changes to 258 lipids and 5 metabolism pathways. Coupled with RNA sequencing analysis, 1,116 genes were found to be significantly regulated and many lipid metabolism-related signaling pathways were identified. The expression of retinoid X receptor alpha (RXR) in the peroxisome proliferator-activated receptor (PPAR) signaling pathway was significantly upregulated after LYC treatment, which activated the RXR/PPAR easy dimer. The expression of downstream genes such as fatty acid binding protein 3 (FABP3) and carnitine palmitoyltransferase 1A (CPT1A) was increased. These genes are involved in the control of fatty acid metabolism, fatty acid degradation, fatty acid chain elongation, and lipid metabolism, which partially explains the changes in the content and composition of lipids.

Conclusions

LYC regulates the lipid metabolism of testes and lipid metabolism-related signaling pathways, such as the PPAR signaling pathway. Furthermore, LYC ameliorated the LPS-induced dysregulation of lipid metabolism in the testes, as well as the LPS-induced inflammatory response. This study offers a new perspective for the investigation of the mechanisms in inflammatory testicular damage and potential therapeutic targets.

Cervical immune activation during the luteal phase may compromise subsequent trans-cervical ram sperm transport

Worldwide, cervical artificial insemination using frozen–thawed semen yields low pregnancy rates. The only exception to this is in Norway, where vaginal insemination with frozen–thawed semen yields pregnancy rates in excess of 60% and which has been attributed to the specific ewe breed used. Our previous work demonstrated differences in cervical gene expression at the follicular phase of the estrous cycle in ewe breeds with known differences in pregnancy rates. In this study, we characterized the cervical transcriptome of the same ewe breeds [Suffolk, Belclare, Fur, and Norwegian White Sheep (NWS)] during the luteal phase, as an optimal environment at the luteal phase could better prepare the cervix for sperm migration through the cervix at the subsequent follicular phase. High-quality RNA extracted from postmortem cervical tissue was analyzed by RNA sequencing. After stringent filtering, 1051, 1924, and 611 differentially expressed genes (DEGs) were detected in the low-fertility Suffolk breed compared with Belclare, Fur, and NWS, respectively. Gene ontology analysis identified increased humoral adaptive immune response pathways in Suffolk. Increased expression of multiple immune genes supports the presence of an active immune response in the cervix of Suffolk ewes, which differentiates them significantly from the other three ewe breeds. Inflammatory pathways were upregulated in the Suffolk, resulting in higher expression of the potent pro-inflammatory cytokines. Therefore, higher levels of pro-inflammatory cytokines indicate unresolved inflammation in the cervix of the low-fertility Suffolk breed that could contribute to reduced cervical sperm transport in the next follicular phase.

The Activated AMPK/mTORC2 Signaling Pathway Associated with Oxidative Stress in Seminal Plasma Contributes to Idiopathic Asthenozoospermia

Asthenozoospermia is a common form of abnormal sperm quality in idiopathic male infertility. While most sperm-mediated causes have been investigated in detail, the significance of seminal plasma has been neglected. Herein, we aimed to investigate the possible pathogenic factors leading to decreased sperm motility based on seminal plasma. Semen was collected from normo- (NOR, n = 70), idiopathic oligo- (OLI, n = 57), and idiopathic asthenozoospermic (AST, n = 53) patients. Using attenuated total reflection-Fourier transform infrared coupled with chemometrics, distinct differences in the biochemical compositions of nucleic acids, protein structure (amides I, II, and III), lipids, and carbohydrates in seminal plasma of AST were observed when compared to NOR and OLI. Compared with NOR and OLI, the levels of peptide aggregation, protein phosphorylation, unsaturated fatty acid, and lipid to protein ratio were significantly increased in AST; however, the level of lipid saturation was significantly decreased in seminal plasma of AST. Compared with NOR, the levels of ROS, MDA, 8-iso-prostaglandin F2α (8-isoPGF2α), and the ratio of phospho-AMPKα/AMPKα1 were significantly increased in AST; however, the levels of SOD, glutathione S-transferase (GSTs), protein carbonyl derivative (PC), and the ratio of phospho-Rictor/Rictor were significantly decreased in seminal plasma of AST. Changes of the AMPK/mTORC2 signaling in the seminal microenvironment possibly induce abnormal glucose and lipid metabolism, which impairs energy production. Oxidative stress potentially damages seminal plasma lipids and proteins, which in turn leads to impaired sperm structure and function. These findings provide evidence that the changes in seminal plasma compositions, oxidative stress, and activation of the AMPK/mTORC2 signaling contribute to the development of asthenozoospermia.

Impact of Vitamin C on Gene Expression Profile of Inflammatory and Anti-Inflammatory Cytokines in the Male Partners of Couples with Recurrent Pregnancy Loss

Immune system disorders and increased inflammation in the male reproductive system can lead to fetal risk in the early stages of development and implantation. Antioxidants such as vitamin C can play a protective role against sperm inflammatory reactions. This study aimed to evaluate the effect of vitamin C on the expression of inflammatory and anti-inflammatory cytokine genes in the male partners of couples with recurrent pregnancy loss. In this randomized clinical trial, twenty male partners of couples with RPL were examined for sperm parameters and expression profile of some inflammatory and anti-inflammatory cytokine genes before and after treatment with vitamin C. There was a statistically significant higher rate of normal morphology and sperm concentration in each patient before and after treatment with vitamin C (p ≤ 0.05). The mRNA levels of interleukin 6 and tumor necrosis factor-alpha were significantly decreased in the sperm of patients after treatment with vitamin C compared to before treatment. In contrast, the gene expression levels of interleukin 4 and transforming growth factor-beta showed a significant increase in the sperm of patients after treatment with vitamin C. Oral daily administration of vitamin C may be effective in the fertility potential of male partners of couples with RPL not only through the improvement of the sperm parameters but also by modulating the expression profile of inflammatory and anti-inflammatory genes. Further studies on protein levels are needed to clarify the role of TNF-⍺ and IFN-γ as a prognostic value in evaluating the recurrent abortion risk in infertile male partners. This trial is registered with IRCT20180312039059N1.

Cissus quadrangularis L: A comprehensive multidisciplinary review

ETHNOPHARMACOLOGICAL RELEVANCE

Cissus quadrangularis L. is a perennial herb of the Vitaceae family and is utilized comprehensively as a medicinal herb in most tropical regions by various names. This herb is documented to possess a wide-ranging ethnomedicinal uses in malaria, fever, epilepsy, gout, piles, skin diseases, colic, etc. AIM OF THE REVIEW: A organized summary of the botany, traditional uses, phytochemistry, pharmacology, toxicology, available marketed formulations and filed patents were presented to explore the future therapeutic potential and scientific potential of this herb.

MATERIALS AND METHODS

For a review of the literature, various databases were searched, including PubMed, EMBASE, and Scopus etc. From, total 408 records of this herb, we have screened 155 articles consist of desired information and available as full text. Present manuscript is structured from comprehensive information on this herb from screened 155 records. Plant taxonomy was confirmed to the database "The Plant List".

RESULTS

Phytochemical assessment as a whole indicated the presence of flavonoids, triterpenoids, alkaloids, saponins, iridoids, stilbenes, vitamins, steroids, and glycosides. A toxicity study revealed that its LD₅₀ value is above 3000 mg/kg in animals indicating its safety. A variety of pharmacological studies of aerial parts of this herb by different extracts have demonstrated analgesic, anti-inflammatory, anticonvulsant, antimicrobial, anticancer, anti-osteoporotic activity and other bone-related disorders to justify its name as Hadjod. Still, the herb has been utilized in clinical practice and several patents were filed in India and US for its antiosteoporotic property.

CONCLUSION

The studies on Cissus quadrangularis Linn. are extensive, but gaps still remain. The molecular mechanism, structure-activity relationship, potential synergistic and antagonistic effects of these components needs to be further elucidated. These findings suggest the need for further research on this herb for the management of several other chronic ailments.

Pro-inflammatory cytokines and microRNAs in male infertility

Background

Male infertility is a problem that affects 10–15% of men of reproductive age. In particular, gametogenesis is a complex process in which inflammation may play a central role through the secretion of cytokines and the expression of microRNAs. We assessed the potential role of proinflammatory cytokines (TNF-α, IL-6 and IL-1α) and microRNAs (miR-146a-5p, miR-34a-5p and miR-23a-3p) in the seminal plasma of infertile men compared to controls, evaluating their correlation with seminal and biochemical parameters.

Methods and results

Expression of cytokines and microRNAs was analyzed by ELISA and q-PCR. Our data shows that IL-1α was significantly increased in the azoospermic group compared to controls, TNF-α mRNA was more expressed in the oligozoospermic group than controls. There were no significant differences in miRNAs expression among the three groups. The correlations between sperm parameters and inflammatory markers were evaluated, however no significance was highlighted.

Conclusions

The determination of each inflammatory marker separately in the seminal plasma of subfertile men, despite some significant differences, does not have a diagnostic value in male infertility even if an assay of selective pro-inflammatory cytokines and microRNAs in the semen may improve the diagnosis of male infertility.

Quercetin mediated attenuation of cadmium-induced oxidative toxicity and apoptosis of spermatogenic cells in caprine testes in vitro

Cadmium (Cd), an environmental toxic heavy metal, has been reported to cause testicular toxicity, which contributes to the recent decline in male fertility worldwide. Quercetin (Qcn), a major dietary antioxidant, has been shown to have protective effects under various pathological conditions. However, whether Qcn provides protection against Cd-stimulated testicular toxicity remains obscured. The present study was therefore aimed at investigating the ameliorative effect of Qcn supplementation on Cd-induced toxicity in the goat testis in vitro in a dose-(10, 50, and 100 μM) and time-dependent (4 and 8 h) manner. Different cytotoxicity, genotoxicity, and biochemical analyses have been carried out using appropriate methods. Cytotoxicity in testicular cells induced by Cd treatment was apparently mitigated by Qcn treatment, evidenced by decreased apoptotic attributes or frequency in Qcn plus Cd-treated groups compared to the only Cd-treated groups. Qcn treatment provides substantial protection to the Cd-triggered aggression in oxidative (increased MDA levels) and total antioxidant capacity (reduced FRAP activity) in testicular tissue, indicating the anti-oxidative function of Qcn against Cd exposure. Moreover, Cd-induced decline in antioxidant status (CAT, SOD, and GST activity) was markedly restored by Qcn supplementation in testicular tissue. In conclusion, this study shows that Qcn treatment significantly attenuated the Cd-evoked testicular damage, suggesting its beneficial potential in preventing or at least in managing the gonadotoxicity in males induced by steadily increasing Cd contamination in the environment.

Relationship Between Semen IL-6, IL-33 and Malondialdehyde Generation in Human Seminal Plasma and Spermatozoa

Cytokines are physiological seminal components and their abnormal levels, reported in different pathological conditions, negatively influence the sperm function. We analysed the relationship between interleukin (IL)-6 and IL-33 levels and lipid peroxidation (LPO), measured both in semen and sperm lysate, in 44 human semen samples. The semen analysis was performed following the WHO guidelines. Seminal IL-6 and IL-33 concentrations were assessed by ELISA and LPO was evaluated measuring malondialdehyde (MDA) both in seminal plasma and viable spermatozoa. Two small groups of patients with varicocele and infection were extrapolated from the cases analysed and the variables compared with those of a group of control. IL-33 levels were undetectable in all samples and IL-6 levels were positively correlated with both seminal and sperm MDA concentrations (p < 0.01) and negatively with sperm parameters (p < 0.01). Seminal and sperm MDA levels were both negatively correlated with sperm parameters (p < 0.01). IL-6 and semen MDA showed an exponential positive relationship, whereas MDA values measured in viable spermatozoa were low until IL-6 amount reached a concentration of >30 pg/mL, rising consistently. By comparing the variables in the groups, we confirmed that a high IL-6 concentration in the varicocele and infection groups was concomitant with an increase of seminal MDA levels, but also with MDA measured in viable spermatozoa, which represents the novelty of this study. We identified the IL-6 threshold, beyond which sperm MDA concentration rises concomitantly with the increase of IL-6 concentration. Other studies are needed, considering the increasing number of patients with different pathologies affecting male infertility.

Lack of trusted diagnostic tools for undetermined male infertility

Semen analysis is the cornerstone of evaluating male infertility, but it is imperfect and insufficient to diagnose male infertility. As a result, about 20% of infertile males have undetermined infertility, a term encompassing male infertility with an unknown underlying cause. Undetermined male infertility includes two categories: (i) idiopathic male infertility-infertile males with abnormal semen analyses with an unknown cause for that abnormality and (ii) unexplained male infertility-males with "normal" semen analyses who are unable to impregnate due to unknown causes. The treatment of males with undetermined infertility is limited due to a lack of understanding the frequency of general sperm defects (e.g., number, motility, shape, viability). Furthermore, there is a lack of trusted, quantitative, and predictive diagnostic tests that look inside the sperm to quantify defects such as DNA damage, RNA abnormalities, centriole dysfunction, or reactive oxygen species to discover the underlying cause. To better treat undetermined male infertility, further research is needed on the frequency of sperm defects and reliable diagnostic tools that assess intracellular sperm components must be developed. The purpose of this review is to uniquely create a paradigm of thought regarding categories of male infertility based on intracellular and extracellular features of semen and sperm, explore the prevalence of the various categories of male factor infertility, call attention to the lack of standardization and universal application of advanced sperm testing techniques beyond semen analysis, and clarify the limitations of standard semen analysis. We also call attention to the variability in definitions and consider the benefits towards undetermined male infertility if these gaps in research are filled.

In vivo exposure to codeine induces reproductive toxicity: role of HER2 and p53/Bcl-2 signaling pathway

Several studies have implicated codeine use in the aetiopathogenesis of male infertility. The purpose of this study was to investigate the role of HER2, Ki67, oestrogen and p53/Bcl-2 signaling pathways and the possible outcome of codeine cessation on codeine-induced reproductive toxicity. Thirty adult male Wistar rats of comparable ages and weights were randomly allocated into 5 groups. The control animals received distilled water per os (p.o), while animals in the low-dose (LDC) and high dose (HDC) codeine-treated groups received 2 and 5 mg/kg/day of codeine respectively p.o for 6 weeks. The animals in the low-dose codeine recovery (LDC-R) and high-dose codeine recovery (HDC-R) groups received treatment as LDC and HDC respectively followed by another drug-free six weeks, recovery period. Cessation of codeine exposure led to a partial reversal of codeine-induced poor sperm quality, reduced litter size and weight, increased oxidative testicular injury, testicular apoptosis, and testicular DNA damage caused by codeine administration. Codeine-induced gonado-spermotoxicity was associated with a reduction of circulatory testosterone, suppression of testicular HER2, Ki67, and Bcl-2 expression, down-regulation of oestrogen signaling, and upregulation of testicular caspase 3 activities and p53 signaling pathway. Conclusion: Upregulation of oestrogen signaling associated with enhanced testicular HER2 and Ki67 expression during the recovery period is seemingly beneficial in protecting against codeine-related testicular injury and infertility.

Oxidative Stress is Associated with Reduced Sperm Motility in Normal Semen

Infertility is among the most serious medical problems worldwide. Male factors contribute to 40%-50% of all infertility cases, and approximately 7% of men worldwide are affected by infertility. Spermatozoa are extremely vulnerable to oxidative insult. Oxidative stress results in axonemal damage and increased midpiece sperm morphological defects, which lead to reduced sperm motility. The aim of the study is to evaluate the association between sperm motility and the levels of selected antioxidants, cytokines, and markers of oxidative damage in the seminal plasma.The study group included 107 healthy males, who were split into two subgroups based on the percentage of motile spermatozoa after 1 hr: low motility (LM, n = 51) and high motility (HM, n = 56).The glucose-6-phosphate dehydrogenase (G6PD) activity was 52% lower in the LM group compared to that in the HM group. The level of malondialdehyde (MDA) was 12% higher in the LM group compared to that in the HM group. Similarly, the median values of interleukin (IL)-1β, IL-10, IL-12, and tumor necrosis factor alpha (TNF-α) were higher in the LM group than those in the HM group. Results of the present study revealed that the percentage of motile spermatozoa after 1 hr correlated positively with the levels of IL-1β, IL-10, IL-12, and TNFα.The lower motility of spermatozoa in healthy men is associated with a decreased activity of G6PD and increased levels of cytokines, which may be related to increased oxidative stress in seminal plasma that manifests as an increased level of MDA.

"Emerging role of Novel Seminal Plasma Bio-markers in Male Infertility: A Review"

Male infertility has emerged as an important cause of infertility worldwide. There are many factors affecting male fertility and research is going on to know impact of various factors on sperm functions. Semen analysis is gold standard diagnostic test for male infertility, but it is crude method for estimation of male infertility as seminal composition gets affected by environmental factors, infections, other pathologies, hence, results of semen analysis either becomes normal/ambiguous, leading to failure of diagnosis and delayed treatment. Hence, with need of newer, better tests for assessing male factor infertility, seminal plasma is being tested for biomarkers. Seminal plasma is considered gold mine for male fertility as it contains molecules from male reproductive glands which play important role in sperm function. Study of seminal plasma molecules can give an idea about sperm concentration, motility, morphology and cause of infertility and can serve as biomarkers for male infertility. Present review briefs on some of these novel seminal plasma biomarkers which may play significant role in male fertility and can be used in future for better identification, assessment of infertile males.

METHODOLOGY

Literature from 1985 to 2019 was searched from various databases including PUBMED, SCOPUS, Google Scholar on seminal plasma biomarkers using keywords: "seminal plasma protein biomarkers", "novel seminal plasma markers and male infertility", "hormones in seminal plasma and male infertility", "oxidative stress and male infertility", "Reactive Oxygen Species and sperm DNA", "immunoinfertility".

INCLUSION CRITERIA

All full length original or review articles or abstracts on seminal plasma markers and male infertility published in English language in various peer-reviewed journals were considered.

EXCLUSION CRITERIA

Articles published in languages other than English were excluded from the study.

RESULTS

Seminal plasma is a big reservoir of molecules derived from the various male reproductive glands which can be used as potential biomarkers of male fertility.

CONCLUSION

Hence, seminal plasma biomarkers can be used in future for better assessment of male factor infertility, its causes and may play an important role in management of male factor infertility.

The role of infections and leukocytes in male infertility

Declining birth rates are one of the problems facing society today. Male counterparts are responsible for about half of the infertility cases, and genitourinary tract infections may play a contributing role in approximately 15% of male infertility cases. Leukocytospermia is an established indicator of infection in the male urogenital tract, although other microorganisms such as bacteria and virus may also be contributors to the etiology of male infertility. The pathophysiology of these infectious agents may be initiated by a local inflammatory reaction resulting in an increase in reactive oxygen species (ROS). This results in testicular injury, thereby affecting sperm morphology, sperm motility, sperm viability and elevation of the seminal leukocyte as a result of the genital tract infection. The infectious and inflammatory changes can result in male infertility. It is proposed that high concentrations of seminal leukocyte and infectious agents may affect sperm function resulting in clumping of motile spermatozoa, decreasing acrosomal functionality and also causing alterations in sperm morphology. However, the literature has poorly clarified the role of infection in male infertility, provoking further debate and research on this topic.

Oxidative stress markers in seminal plasma of idiopathic infertile men may be associated with glutathione S-transferase M1 and T1 null genotypes

This study aimed to investigate the association between glutathione S-transferase (GST) M1 and T1 null genotypes and thiobarbituric acid reactive substances (TBARS), total antioxidant capacity (TAC) and nitric oxide (NO) levels in male infertility. For this purpose, semen samples were collected from fertile and infertile subjects, and then they were genotyped for GSTT1 and GSTM1 genes using multiplex-PCR. The TBARS, TAC and NO levels in seminal plasma were then measured via the ferric-reducing ability of plasma (FRAP). A significant association was observed between GSTT1 null genotype and oligozoospermia, asthenozoospermia and teratozoospermia. But, the GSTM1 null genotype was merely associated with teratozoospermia. Moreover, the GSTT1-/GSTM1+ combined genotype was associated with all subgroups of male infertility. Besides, an association was observed between GSTT1-/GSTM1- genotype and asthenozoospermia and teratozoospermia. Further analysis showed that the GSTT1 null genotype was associated with increased NO in asthenozoospermia. Also, the GSTT1 null genotype was associated with increased TBARS in oligozoospermia and asthenozoospermia. As well, GSTM1 null genotype was associated with decreased TAC and increased NO in asthenozoospermia respectively. As a preliminary conclusion, the GSTM1 and GSTT1 null genotypes could be considered as genetic risk factors for male infertility, interfering with some oxidative stress markers in infertile men.

Period of Boar Ejaculate Collection Contributes to the Yearly Intra-Male Variability of Seminal Plasma Cytokines

The concentrations of cytokines in seminal plasma (SP) fluctuate over time in healthy males, weakening their practical usefulness as diagnostic tools. This study evaluated the relevance of intra-male variability in SP cytokines and to what extent the period of the year when ejaculate is collected contributes to such variability. Thirteen cytokines (GM-CSF, IFNγ, IL-1α, IL-1β, IL-1ra, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, IL-18, and TNFα) were measured using the Luminex xMAP^® technology for 180 SP samples of ejaculate collected over a year from nine healthy and fertile boars. The SP samples were grouped into two annual periods according to decreasing or increasing daylight and ambient temperature. Intra-male variability was higher than inter-male variability for all cytokines. All SP cytokines showed concentration differences between the two periods of the year, showing the highest concentration during the increasing daylength/temperature period, irrespective of the male. Similarly, some cytokines showed differences between daylength/temperature periods when focusing on their total amount in the ejaculate. No strong relationship (explaining more than 50% of the total variance) was found between annual fluctuations in SP-cytokine levels and semen parameters. In conclusion, the period of the year during which ejaculates were collected helps explain the intra-male variability of SP-cytokine levels in breeding boars.

Heavy metal exposure, oxidative stress and semen quality: Exploring associations and mediation effects in reproductive-aged men

BACKGROUND

Heavy metal exposure induces oxidative stress, which is critical for adverse male reproductive health.

OBJECTIVE

To explore the mediating effect of oxidative stress on the relationship of heavy metal exposure with semen quality.

METHODS

Urinary levels of three oxidative stress markers, semen quality, and urinary arsenic, cadmium and lead were examined among 1020 men. Multivariate linear regression was applied to explore cross-sectional associations, and the role of oxidative stress as mediators was investigated.

RESULTS

Quartiles of metals showed significant dose-dependent relationships with increasing levels of 8-hydroxy-2deoxyguanosine (8-OHdG), 8-iso-prostaglandin F2α (8-isoPGF2α) and 4-hydroxy-2-nonenal-mercapturic acid (HNE-MA). Significant or suggestive associations were also found between urinary 8-OHdG levels and the percentage of normal sperm morphology (p_trend < 0.001), between urinary 8-isoPGF2α levels and total motility (p_trend = 0.052), progressive motility (p_trend = 0.050) respectively. The mediation analysis showed that about 14.59%, 18.06%, 15.35% or 16.49% of the association between arsenic/cadmium exposure and the decreased total motility/progressive motility was mediated by 8-isoPGF_2α, respectively. In addition, about 16.47% of the relationship between lead exposure and the decreased percentage of normal sperm morphology was mediated by 8-OHdG.

CONCLUSIONS

Our findings suggest that higher urinary arsenic, cadmium and lead levels were associated with increased oxidative stress markers, which also related with altered semen quality. 8-isoPGF_2α and 8-OHdG might be the possible mediators of the associations between urinary heavy metals and total motility, progressive motility or the proportion of normal sperm morphology.

Oxidative stress and male infertility: current knowledge of pathophysiology and role of antioxidant therapy in disease management

Infertility is a global health problem involving about 15% of couples. Approximately half of the infertility cases are related to male factors. The oxidative stress, which refers to an imbalance in levels of reactive oxygen species (ROS) and antioxidants, is one of the main causes of infertility in men. A small amount of ROS is necessary for the physiological function of sperm including the capacitation, hyperactivation and acrosomal reaction. However, high levels of ROS can cause infertility through not only by lipid peroxidation or DNA damage but inactivation of enzymes and oxidation of proteins in spermatozoa. Oxidative stress (OS) is mainly caused by factors associated with lifestyle. Besides, immature spermatozoa, inflammatory factors, genetic mutations and altering levels of sex hormones are other main source of ROS. Since OS occurs due to the lack of antioxidants and its side effects in semen, lifestyle changes and antioxidant regimens can be helpful therapeutic approaches to overcome this problem. The present study aimed to describe physiological ROS production, roles of genetic and epigenetic factors on the OS and male infertility with various mechanisms such as lipid peroxidation, DNA damage, and disorder of male hormone profile, inflammation, and varicocele. Finally, the roles of oral antioxidants and herbs were explained in coping with OS in male infertility.

Oxidative stress and male infertility: current knowledge of pathophysiology and role of antioxidant therapy in disease management

Infertility is a global health problem involving about 15% of couples. Approximately half of the infertility cases are related to male factors. The oxidative stress, which refers to an imbalance in levels of reactive oxygen species (ROS) and antioxidants, is one of the main causes of infertility in men. A small amount of ROS is necessary for the physiological function of sperm including the capacitation, hyperactivation and acrosomal reaction. However, high levels of ROS can cause infertility through not only by lipid peroxidation or DNA damage but inactivation of enzymes and oxidation of proteins in spermatozoa. Oxidative stress (OS) is mainly caused by factors associated with lifestyle. Besides, immature spermatozoa, inflammatory factors, genetic mutations and altering levels of sex hormones are other main source of ROS. Since OS occurs due to the lack of antioxidants and its side effects in semen, lifestyle changes and antioxidant regimens can be helpful therapeutic approaches to overcome this problem. The present study aimed to describe physiological ROS production, roles of genetic and epigenetic factors on the OS and male infertility with various mechanisms such as lipid peroxidation, DNA damage, and disorder of male hormone profile, inflammation, and varicocele. Finally, the roles of oral antioxidants and herbs were explained in coping with OS in male infertility.

Levels of activity of superoxide dismutase in seminal plasma do not predict fertility of pig AI-semen doses

Superoxide dismutase (SOD) is a major antioxidant enzyme in boar seminal plasma (SP). This study evaluated how SP-SOD affected sperm attributes when semen of boars of various breeds, included in commercial artificial insemination (AI)-programs, was extended and liquid-stored at 17 °C for AI; as well as their in vivo fertility (farrowing rate and litter size of 10,952 AI-sows). SP-SOD-activity was assessed in 311 ejaculates (100 boars) while sperm motility (by CASA), viability and intracellular H₂O₂ generation in viable spermatozoa (by flow cytometry) were measured at 0 and 72 h of liquid storage. SP-SOD activity was not affected by breed but differed (P < 0.001) between boars (n = 50), ranging from 1.16 ± 0.11 to 7.02 ± 0.75 IU/mL. Semen AI-doses (n = 44) hierarchically grouped (P < 0.001) with low SP-SOD activity showed lower (P < 0.05) sperm motility and intracellular H₂O₂ at 72 h of liquid storage. Fertility did not differ between AI-boars (n = 39) hierarchically grouped (P < 0.001) with high or low SP-SOD activity. In conclusion, SP-SOD activity is boar dependent and positively related with sperm functionality of liquid-stored semen AI-doses. However, this positive effect is not reflected on in vivo fertility post-AI.

Cynomorium Songaricum may protect against spermatogenic damage caused by cyclophosphamide in SD rats

Aim: The aim of the study is to investigate the effect of Cynomorium songaricum (CS) on the damage caused by cyclophosphamide (CP) in SD rats. Methods: Rats with CP-induced oligoasthenospermia were treated with different concentration of CS. Testicle weight, epididymal sperm count (ESC), sperm motility, and serum testosterone were analyzed, and expression levels of Thy1, Oct4, PLZF, C-kit, and GDNF were detected in testis tissues. Transmission electron microscopy (TEM) was performed to observe the effect of CS on the spermatogenic damage by CP. Results: Compared with the CP group, there were significant differences in testicle weight, ESC, and sperm motility (p<0.05) observed in all concentrations of CS and CP+VitE groups (p<0.05). There were no significant differences in serum testosterone among the 6 groups (p>0.05). The qPCR results revealed a significant difference in Thy1, Oct4, PLZF and GDNF expression between the CP group and CS group (p <0.05), but there was no significant difference in C-kit between the two groups (p>0.05). The damage of CP was cured by CS observed under TEM. Conclusion: CS can increase sperm counts in the epididymis and improve sperm motility and has a therapeutic effect on the spermatogenic damage caused by CP in SD rats.