Clinical relevance of oxidative stress in male factor infertility: an update

Oxidative stress impairs function and increases redox protein modifications in human spermatozoa

Oxidative stress, generated by excessive reactive oxygen species (ROS) or decreased antioxidant defenses (and possibly both), is associated with male infertility. Oxidative stress results in redox-dependent protein modifications, such as tyrosine nitration and S-glutathionylation. Normozoospermic sperm samples from healthy individuals were included in this study. Samples were incubated with increasing concentrations (0-5 mM) of exogenous hydrogen peroxide, tert-butyl hydroperoxide, or diethylamine NONOate (DA-NONOate, a nitric oxide (NO∙) donor) added to the medium. Spermatozoa treated with or without ROS were incubated under capacitating conditions and then levels of tyrosine phosphorylation and percentage of acrosome reaction (AR) induced by lysophosphatidylcholine were determined. Modified sperm proteins from cytosolic, triton-soluble, and triton-insoluble fractions were analyzed by SDS-PAGE immunoblotting and immunocytochemistry with anti-glutathione and anti-nitrotyrosine antibodies. Levels of S-glutathionylation increased dose dependently after exposure to hydroperoxides (P<0.05) and were localized mainly to the cytosolic and triton-soluble fractions of the spermatozoa. Levels of tyrosine-nitrated proteins increased dose dependently after exposure to DA-NONOate (P<0.05) and were mainly localized to the triton-insoluble fraction. ROS-treated spermatozoa showed impaired motility without affecting viability (hypo-osmotic swelling test). These treated spermatozoa had tyrosine phosphorylation and AR levels similar to that of non-capacitated spermatozoa following incubation under capacitating conditions, suggesting an impairment of sperm capacitation by oxidative stress. In conclusion, oxidative stress promotes a dose-dependent increase in tyrosine nitration and S-glutathionylation and alters motility and the ability of spermatozoa to undergo capacitation.Free Spanish abstractA Spanish translation of this abstract is freely available at http://www.reproduction-online.org/content/149/1/113/suppl/DC1.

Effect of dietary ellagic acid supplementation on semen quality parameters in chickens

Ellagic acid (EA), a polyphenoloic constituent in fruits and nuts, has been shown to have antioxidant and antiapoptotic properties. The aim of this study was to investigate the effect of dietary EA supplementation on semen quality parameters in chickens. Forty roosters (Dahlem Red breed), 28 weeks of age, were randomly assigned to four groups and fed diets containing EA at 0, 25, 50, or 75 mg/kg for 8 weeks. Semen was evaluated for volume, appearance, individual motility, sperm concentration, 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) dye reduction test, and live, dead and abnormal sperm counts. The seminal plasma was separated and evaluated for protein, alkaline phosphatase, and lipid peroxidation. At the end of the experiment, blood from individual birds was collected, and serum was separated and evaluated for superoxide dismutase activity, lipid peroxidation, and ferric-reducing ability of plasma. Supplementation with EA had no effect (P > 0.05) on gross semen parameters. Seminal plasma protein and lipid peroxidation were different (P < 0.01) between the treatment groups. The group fed EA at 75 mg/kg had high (P < 0.01) seminal plasma lipid peroxidation and lower (P < 0.05) serum superoxide dismutase activity. In conclusion, dietary supplementation of EA in chickens had no effect on the gross semen qualities and increased lipid peroxidation in seminal plasma.

Consistent age-dependent declines in human semen quality: a systematic review and meta-analysis

Reduced fertility typically occurs among women in their late 30s, but increasing evidence indicates that advanced paternal age is associated with changes in reproduction as well. Numerous studies have investigated age-based declines in semen traits, but the impact of paternal age on semen parameter values remains inconclusive. Using data from 90 studies (93,839 subjects), we conducted a systematic review and meta-analysis to quantify the effect of male age on seven ejaculate traits (semen volume, sperm concentration, total sperm count, morphology, total motility, progressive motility and DNA fragmentation). Age-associated declines in semen volume, percentage motility, progressive motility, normal morphology and unfragmented cells were statistically significant and results generally seemed to be robust against confounding factors. Unexpectedly, sperm concentration did not decline with increasing male age, even though we found that sperm concentration declined over time. Our findings indicate that male age needs more recognition as a potential contributor to the negative pregnancy outcomes and reduced offspring health associated with delayed first reproduction. We suggest that greater focus on collection of DNA fragmentation and progressive motility in a clinical setting may lead to better patient outcomes during fertility treatments of aging couples.

Assessment of changes in sperm cell membrane integrity occurring during the storage of semen from genetically different males using two diagnostic methods

Wysokińska, A. and Kondracki, S. 2014. Assessment of changes in sperm cell membrane integrity occurring during the storage of semen from genetically different males using two diagnostic methods. Can. J. Anim. Sci. 94: 601–606. The present study was carried out to assess changes in sperm cell membrane integrity occurring during the storage of semen collected from genetically different domestic male pigs. The study was aimed at assessing differences in the course of changes in the integrity of cell membranes in spermatozoa produced by males with different degrees of genetic diversity (pure-bred males, two-breed hybrids and multi-breed crosses) and testing the usefulness of two methods of sperm cell membrane integrity evaluation, based on material collected from genetically different males. The experiments were conducted on 56 ejaculates collected from 28 domestic male pigs. The examination of sperm cell membrane integrity was performed three times for each ejaculate, i.e., after 1 h, after 24 h and after 48 h from collection. The preparations for analysing cell membrane integrity were made using two methods: the SYBR 14/PI method and the eosin–nigrosin method. It was found that both SYBR 14/PI and eosin–nigrosin staining methods make it possible to successfully assess the integrity of the plasma membrane of domestic pig sperm cells under in vitro conditions. Hybrid pig spermatozoa, especially those from multi-breed crosses, better retain the integrity of their plasmalemmas than the spermatozoa of pure-bred boars. The ejaculates of Hypor cross-breed boars assessed after 1, 24 and 48 h of storage contain more spermatozoa with intact cell membranes than the ejaculates of pure-bred Duroc and Pietrain boars. The ejaculates of Hypor boars also show fewer decaying spermatozoa than those produced by pure-bred boars.

Evaluation of mesenchymal stem cells in treatment of infertility in male rats

INTRODUCTION

The present study aimed to elucidate the therapeutic effects of mesenchymal stem cells (MSCs) derived from the bone marrow of rats (BM) against toxic effects of lead (Pb) on the male gonads of experimental rats.

METHODS

The experimental animals were exposed to lead in the form of lead nitrate (LN) one quarter of the LD50. The efficacy of MSCs to reduce gonado-totoxicity induced by lead nitrate at 21, 30 and 60 days, was evaluated experimentally in male rats.

RESULTS

The results showed that testosterone levels and semen quality ameliorated following treatment with MSCs. Also, superoxide dismutase, glutathione peroxidase and catalase levels were increased 21, 30 and 60 days post treatment of MSCs. Moreover, a decrease in genomic DNA alteration and percentage of fragmented DNA was recorded after MSCs treatment. Lead nitrate caused degeneration, necrosis, interstitial edema, and reduction in spermatogenic activity in some seminiferous tubules. The LN-induced changes in histopathologic findings of testis were partially reversed by treatment with MSCs. Histological examination of testis showed deformities in morphology of testis in test animals with gross damage within the seminiferous tubules in Lead nitrate group. The LN-induced changes in histopathologic findings of testis were partially reversed by treatment of MSCs.

CONCLUSIONS

It was concluded that lead is a gonadotoxic with a tendency of suppressing semen characteristics and testosterone levels of animals, the presence of MSCs was found to alleviate the toxic effects of lead. We conclude that MSCs derived from the bone marrow of rats can be an effective therapy of LN induced gonado toxicity, thus can contribute to the treatment of infertility.

Infertile men older than 40 years are at higher risk of sperm DNA damage

BACKGROUND

The effect of paternal age on semen quality is controversial. In this retrospective study, the aim was to investigate the effects of advancing age on sperm parameters including reactive oxygen species (ROS), total antioxidant capacity (TAC) and sperm DNA damage in infertile men. We also examined whether paternal age >40 y is associated with higher risk of sperm DNA damage.

METHODS

A total of 472 infertile men presenting for infertility were divided into 4 age groups: group A: patients ≤ 30 y; group B: patients 31- 40 y, group C: ≤ 40 y and group D: patients >40 y. The following tests were performed - semen analysis according to WHO 2010 criteria, seminal ROS by chemiluminescence, TAC by colorimetric assay and sperm DNA damage by TUNEL assay - and the results were compared amongst the 4 age groups.

RESULTS

There was no statistical difference in conventional semen parameters, TAC and ROS with advancing paternal age as well as between different age groups. However, a significant negative association was noted between sperm DNA damage and advancing paternal age. Men >40 y showed higher levels of sperm DNA damage (24.4 ± 18.5%) compared to younger men (<30 y; 16.7 ± 11.2%; p <0.05).

CONCLUSIONS

Infertile men over the age of 40 y have a greater percentage of sperm DNA fragmentation compared to infertile men aged 40 y and below. Advanced paternal age (>40 y) may increase the risk of sperm DNA damage in infertile men.

Role of Membrane Lipid Fatty Acids in Sperm Cryopreservation

Lipid is an important constituent of cell membrane. Membrane lipid composition of spermatozoa has been correlated to different function. Many researchers have related membrane lipid with survival success after cryopreservation or cold shock. Sperm maturation and acrosome reactions are natural phenomenon, but cryopreservation or cold shock is not. Therefore, sperm cells are not programmed for such change and undergo stress. So the change in membrane lipid composition due to cold shock or cryopreservation may be looked upon as response of spermatozoa to a certain stressed condition. A significant body of research worked on the relationship between membrane lipid and fatty acid composition and ability of cell to tolerate adverse change in temperature. However, as the approach of different research groups was different, it is very difficult to compare the changes. Studies have been done with different species, ejaculated/seminal or epididymal sperm. Lipid analyses have been done with whole cell membrane isolated by different methods. Fatty acids estimated were from whole cell, plasma membrane, head membrane, or phospholipids. The cryopreservation condition, media composition, and diluents/cryoprotectants were also different. At this onset a comprehensive review is needed to cover changes of sperm membrane lipid composition of different species under different cryopreservation conditions.

Exogenous melatonin supplementation prevents oxidative stress-evoked DNA damage in human spermatozoa

Reactive oxygen species (ROS) are essential for sperm physiological functions such as capacitation, hyperactivation, and acrosome reaction, on the one hand, and for stimulating the apoptotic processes involved in the regulation of spermatogenesis, on the other hand. However, the imbalance between production and removal of ROS leads to oxidative stress, which is referred to as one of the main factors involved in male infertility. The pineal hormone melatonin, given its low toxicity and well-known antioxidant capacity, could be an excellent candidate to improve sperm quality. For this reason, the objective of the present work was to analyze whether long-term supplementation with melatonin to infertile men affects human sperm quality and the quality of the embryos retrieved from their couples. Our findings showed that the daily supplementation of 6 mg melatonin, as early as after 45 days of treatment, produced an increase in melatonin endogenous levels, indirectly measured as urinary 6-sulfatoxymelatonin (aMT6-s), an enhancement of both urinary and seminal total antioxidant capacity, and a consequent reduction in oxidative damage caused in sperm DNA. Moreover, couples whose men were given melatonin showed a statistically significant increase in the percentage of grade A (embryo with blastomeres of equal size; no cytoplasmic fragmentation), B (embryo with blastomeres of equal size; minor cytoplasmic fragmentation), and C (embryo with blastomeres of distinctly unequal size; significant cytoplasmic fragmentation) embryos at the expense of grade D (embryo with blastomeres of equal or unequal size; severe or complete fragmentation.) embryos which were clearly reduced. In summary, melatonin supplementation improves human sperm quality, which is essential to achieve successful natural and/or assisted reproduction outcome.

Sodium nitroprusside suppresses male fertility in vitro

Sodium nitroprusside is a nitric oxide donor involved in the regulation of the motility, hyperactivation, capacitation, and acrosome reaction (AR) of spermatozoa. However, the molecular mechanism underlying this regulation has not yet been elucidated. Therefore, this study was designed to evaluate the molecular basis for the effects of sodium nitroprusside on different processes in spermatozoa and its consequences on subsequent oocyte fertilization and embryo development. In this in vitro study, mouse spermatozoa were incubated with various concentrations of sodium nitroprusside (1, 10, and 100 μM) for 90 min. Our results showed that sodium nitroprusside inhibited sperm motility and motion kinematics in a dose-dependent manner by significantly enhancing intracellular iron and reactive oxygen species (ROS), and decreasing Ca(2+), and adenosine triphosphate levels in spermatozoa. Moreover, short-term exposure of spermatozoa to sodium nitroprusside increased the tyrosine phosphorylation of sperm proteins involved in PKA-dependent regulation of intracellular calcium levels, which induced a robust AR. Finally, sodium nitroprusside significantly decreased the rates of fertilization and blastocyst formation during embryo development. Based on these results, we propose that sodium nitroprusside increases ROS production and precocious AR may alter overall sperm physiology, leading to poor fertilization and compromised embryonic development.

Alternative and antioxidant therapies used by a sample of infertile males in Jordan: a cross-sectional survey

Background

Complementary and alternative medicine (CAM) is frequently used in the Middle East, especially to treat chronic diseases such as infertility. We aimed to examine the prevalence, characteristics, and determinants of CAM use, particularly herbs and antioxidant therapies, among infertile males presenting for infertility evaluation in Jordan.

Methods

Demographic information, use of alternative and antioxidant therapies for infertility treatment, and patients’ belief in efficacy and safety of the therapies used were collected using a face-to-face questionnaire. Data were collected from 428 infertile male patients presenting at infertility clinics in Amman, the capital city of Jordan. The study was conducted between April 2013 and September 2013.

Results

Of the 428 men who completed the questionnaire, 184 (43%) used at least one of the alternative and antioxidant therapies specified in the questionnaire. Nutritional regime; vitamins, such as vitamins C and E; and medicinal herbs, such as ginger, saw palmetto, and ginseng were the most commonly used therapies reported. A correlation between the use of alternative and antioxidant therapies versus infertility duration was found. Additionally, the majority of males using CAM did not inform their health care providers about their usage.

Conclusions

The high prevalence of CAM use among infertile male patients underscores the urge to assimilate CAM into the education and training of health professionals, as well as to improve infertile patients’ knowledge of the safe use of CAM modalities.

Oral antioxidants supplementation for women with unexplained infertility undergoing ICSI/IVF: randomized controlled trial

OBJECTIVE

Good oocyte quality and maturity are important prerequisites for high fertilization and implantation rates in IVF/ICSI treatment cycles. Reactive oxygen species (ROS) are produced within ovarian follicles, especially during the ovulation process, and increased ROS activity may be a cause of impaired oocyte maturation and higher rate of failure of IVF/ICSI cycles.

STUDY DESIGN

RCT evaluating the effect of antioxidant supplementation on ICSI/IVF outcomes. Two hundred and eighteen women with unexplained subfertility undergoing IVF/ICSI were randomized into two groups. The study group (n = 112) received daily oral antioxidants in the form of multivitamins and minerals (amino acid chelated) while the control group (n = 106) did not. Main outcomes were number of mature metaphase II (MII) oocytes and clinical pregnancy rate.

RESULTS

There were no significant changes between the groups as regards age, BMI, basal FSH, number of mature (MII) oocytes (12.7 ± 9.4 vs. 13.2 ± 8.6, P = 0.7) and clinical pregnancy rate per woman randomized (38% vs. 34%; [OR = 1.2; 95% CI, 0.70-2.11].

CONCLUSION

Oral antioxidants in the form of a combination of multivitamins and minerals (amino acid chelated) did not improve oocyte quality and pregnancy rates in women with unexplained infertility undergoing IVF/ICSI treatment.

New insights into male (in)fertility: the importance of NO

Infertility is a global problem that is on the rise, especially during the last decade. Currently, infertility affects approximately 10-15% of the population worldwide. The frequency and origin of different forms of infertility varies. It has been shown that reactive oxygen and nitrogen species (ROS and RNS) are involved in the aetiology of infertility, especially male infertility. Various strategies have been designed to remove or decrease the production of ROS and RNS in spermatozoa, in particular during in vitro fertilization. However, in recent years it has been shown that spermatozoa naturally produce a variety of ROS/RNS, including superoxide anion radical (O2 (⋅-)), hydrogen peroxide and NO. These reactive species, in particular NO, are essential in regulating sperm capacitation and the acrosome reaction, two processes that need to be acquired by sperm in order to achieve fertilization potential. In addition, it has recently been shown that mitochondrial function is positively correlated with human sperm fertilization potential and quality and that NO and NO precursors increase sperm motility by increasing energy production in mitochondria. We will review the new link between sperm NO-driven redox regulation and infertility herein. A special emphasis will be placed on the potential implementation of new redox-active substances that modulate the content of NO in spermatozoa to increase fertility and promote conception.

Urinary metabolome identifies signatures of oligozoospermic infertile men

OBJECTIVE

To identify the differential urinary metabolic pattern of oligozoospermic infertile men and to determine the potential biomarkers indicative of infertility.

DESIGN

Observational study.

SETTING

University hospital.

PATIENT(S)

Totals of 158 fertile volunteers and 135 oligozoospermic infertile men.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Urinary metabolic profiles were acquired with the use of liquid chromatography/mass spectrometry. Potential oligozoospermic biomarkers were screened from orthogonal projections to latent structures discriminant analysis and further evaluated by receiver operating characteristic analysis. The Spearman correlations between the individual sets of biomarkers and between biomarkers and sperm parameters were investigated. The disrupted biologic pathways which the biomarkers were involved in also were analyzed.

RESULT(S)

Oligozoospermic infertile men could be differentiated from fertile control subjects based on altered urinary metabolic profiles. A total of ten potential biomarkers were screened and tentatively identified. Among those, decreased acylcarnitines, aspartic acid, and leucylproline and increased adenine and methylxanthine were strongly associated with oligozoospermic risk. Many biomarkers were associated with sperm concentration and amplitude of lateral head displacement. The combined pattern of acetylcarnitine, carnitine C3:1, and aspartic acid provided moderate diagnostic power.

CONCLUSION(S)

Urinary metabolomics identified unique metabolic pattern of oligozoospermic infertility. The potential biomarkers suggested that oligozoospermia may be tightly associated with energy consumption and antioxidant defenses in spermatogenesis.

Impact of saffron on rat sperm membrane integrity and spermatogenesis status

BACKGROUND

Male factor has been considered as a 50% of infertility causes. One of the reasons for poor semen quality is oxidative stress. Saffron and vitamin E as antioxidant agent can be involved in free radical scavenging and improvement of semen quality.

MATERIALS AND METHODS

We divided 30 adult male Wistar rats into saffron (n = 10), vitamin E (n = 10) and control (n = 10) groups randomly. Saffron (100 mg/kg/day), vitamin E (100 mg/kg/day), and distilled water (0.5 ml/day) were fed by gavage to the animals for 60 consecutive days in aforementioned groups. After cervical dislocation, both testes and left epididymis of each animal were removed and the cauda epididymal spermatozoa were aspirated for analysis of sperm parameters. Sperm membrane integrity was assessed by hypo-osmotic swelling test (HOST). In different groups, seminiferous tubule histological assessments were done after Hematoxylin -Eosin staining.

RESULTS

The mean percentage of HOST positive sperm was increased in vitamin E and saffron groups as compared to control group. As we can see there was a significant difference among control and experimental groups (P < 0.001); also a significant difference was obtained between vitamin E and saffron groups (P = 0.002). The evaluation of seminiferous tubules has shown no significant differences among groups.

CONCLUSIONS

The present data suggest that saffron had superior antioxidant properties which can improve sperm parameters and membrane integrity so it can lead to develop fertility potential.

Blood serum and seminal plasma selenium, total antioxidant capacity and coenzyme q10 levels in relation to semen parameters in men with idiopathic infertility

In this case-control study, we aimed to evaluate the serum and seminal plasma levels of Selenium (Se), total antioxidant capacity (TAC), and Coenzyme Q10 (CoQ-10) and determine their relationship with sperm concentration, motility, and morphology in men with idiopathic infertility. A total of 59 subjects were enrolled in the study. Forty four patients were diagnosed with idiopathic male infertility and had abnormal sperm parameters, and 15 subjects had normal sperm parameters with proven fertility. Serum Se, semen Se, and semen TAC levels were significantly different in the fertile and infertile groups (p<0.01, p<0.001, and p<0.001, respectively). However, serum TAC, serum, and seminal plasma CoQ-10 levels did not differ between fertile and infertile groups. When the levels of the measured parameters were compared in serum and seminal plasma, serum levels of Se were found to be correlated positively with the semen levels in all subjects included into the study (N=59) (r=0.46, p<0.01). A relationship was found between neither serum and semen levels of TAC nor between serum and semen levels of CoQ-10. Correlations among measured serum and semen parameters with sperm parameters demonstrated that both the serum and semen levels of Se were correlated positively with spermatozoa concentration, motility, and morphology. Additionally, seminal plasma levels of TAC correlated positively with all these sperm parameters. On the other hand, seminal plasma levels of CoQ-10 correlated only with sperm morphology but not with concentration or motility. No relationship was observed between serum levels of TAC or serum levels of CoQ-10 and sperm parameters. In conclusion, serum and seminal plasma Se deficiency may be a prominent determinant of abnormal sperm parameters and idiopathic male infertility. Measurement of serum Se levels may help determine nutritional status and antioxidant capacity in infertile patients, which may help distinguish those patients who will benefit from supplementation therapy.

Recent insights on the significance of transcriptomic and metabolomic analysis of male factor infertility

Infertility is a worldwide reproductive health problem which affects approximately 15% of couples, with male factor infertility dominating nearly 50% of the affected population. The nature of the phenomenon is underscored by a complex array of transcriptomic, proteomic and metabolic differences which interact in unknown ways. Many causes of male factor infertility are still defined as idiopathic, and most diagnosis tends to be more descriptive rather than specific. As such, the emergence of novel transcriptomic and metabolomic studies may hold the key to more accurately diagnose and treat male factor infertility. This paper provides the most recent evidence underlying the role of transcriptomic and metabolomic analysis in the management of male infertility. A summary of the current knowledge and new discovery of noninvasive, highly sensitive and specific biomarkers which allow the expansion of this area is outlined.

Effects of Nigella sativa L. seed oil on abnormal semen quality in infertile men: a randomized, double-blind, placebo-controlled clinical trial

In recent years, wide utilization of herbal drugs has encouraged scientists to determine their impressive effects on health. Since Nigella sativa L. seed (N. sativa) has many uses including infertility in traditional medicine, the effects of Nigella sativa L. seed oil on abnormal semen quality in infertile men with abnormal semen quality are of interest. This study was conducted on Iranian infertile men with inclusion criteria of abnormal sperm morphology less than 30% or sperm counts below 20×10(6)/ml or type A and B motility less than 25% and 50% respectively. The patients in N. sativa oil group (n=34) received 2.5mlN. sativa oil and placebo group (n=34) received 2.5ml liquid paraffin two times a day orally for 2 months. At baseline and after 2 months, the sperm count, motility and morphology and semen volume, pH and round cells as primary outcomes were determined in both groups. Results showed that sperm count, motility and morphology and semen volume, pH and round cells were improved significantly in N. sativa oil treated group compared with placebo group after 2 months. It is concluded that daily intake of 5ml N. sativa oil for two months improves abnormal semen quality in infertile men without any adverse effects.

Basic diagnostics in andrology

Basic andrological diagnosis consists of taking the patient's medical history and the couple's history as well as performing a physical examination including genital ultrasound, spermiogram, and hormonal analysis. If needed, a testicular biopsy and genetic testing may also be performed. Recent studies have shown the effect of lifestyle factors on male fertility. Thus, the patient history and clinical/andrological examinations have been broadened to include information on metabolic disorders like obesity and diabetes mellitus. The biggest changes occurred with the publication of the fifth edition of the WHO laboratory manual in 2010 and the introduction of a section on semen analysis in the German Medical Association guidelines (RiliBÄK). The reference values for almost all spermiogram parameters were adapted in an evidence-based approach using worldwide prospective population studies. For central parameters such as sperm motility and morphology, the assessment criteria were changed. New independent markers such as sperm DNA fragmentation rate are now routinely used in clinical diagnosis. For German andrological laboratories, there are now mandatory quality assurance measures for semen analysis (in the German "Rili-BÄK" guidelines). These include duplicate testing of all standard semen parameters and inter-laboratory comparison at regular intervals.

Redox reactions in mammalian spermatogenesis and the potential targets of reactive oxygen species under oxidative stress

Reduction-oxidation (Redox) reactions are ubiquitous mechanisms for vital activities in all organisms, and they play pivotal roles in the regulation of spermatogenesis as well. Here we focus on 3 redox-involved processes that have drawn much recent attention: the regulation of signal transduction by reactive oxygen species (ROS) such as hydrogen peroxide, oxidative protein folding in the endoplasmic reticulum (ER), and sulfoxidation of protamines during sperm chromatin condensation. The first 2 of these processes are emerging topics in cell biology and are applicable to most living cells, which includes spermatogenic cells. The roles of ROS in signal transduction have been elucidated in the last 2 decades and have received broad attention, most notably from the viewpoint of the proper control of mitotic signals. Redox processes in the ER are important because this is the organelle where secretory and membrane proteins are synthesized and proceed toward their functional structure, so that malfunction of the ER affects not only the involved cells but also the accepting cells of the secreted proteins in multicellular organisms. Sulfoxidation is the third of these processes, and the sulfoxidation of chromatin is a unique process in sperm maturation. During recent sulfoxidase research, GPX4 has emerged as a promising enzyme that plays essential roles in the production of fertile sperm, but the involvement of other redox proteins is also becoming evident. Because the molecules involved in the redox reactions are prone to oxidation, they can be sensitive to oxidative damage, which makes them potential targets for antioxidant therapy.

Effect of oxidative stress on male reproduction

Infertility affects approximately 15% of couples trying to conceive, and a male factor contributes to roughly half of these cases. Oxidative stress (OS) has been identified as one of the many mediators of male infertility by causing sperm dysfunction. OS is a state related to increased cellular damage triggered by oxygen and oxygen-derived free radicals known as reactive oxygen species (ROS). During this process, augmented production of ROS overwhelms the body's antioxidant defenses. While small amounts of ROS are required for normal sperm functioning, disproportionate levels can negatively impact the quality of spermatozoa and impair their overall fertilizing capacity. OS has been identified as an area of great attention because ROS and their metabolites can attack DNA, lipids, and proteins; alter enzymatic systems; produce irreparable alterations; cause cell death; and ultimately, lead to a decline in the semen parameters associated with male infertility. This review highlights the mechanisms of ROS production, the physiological and pathophysiological roles of ROS in relation to the male reproductive system, and recent advances in diagnostic methods; it also explores the benefits of using antioxidants in a clinical setting.

Reproductive parameters and oxidative stress status of male rats fed with low and high salt diet

BACKGROUND:

Deficiency of minerals and micronutrients has been reported to impair the process of spermatogenesis. Historically, salt has been used by women on their husbands to increase their libido, however, the role of salt diet on sperm parameters are yet to be ascertained.

AIM:

The present study was designed to determine the effect of low and high salt diet on sperm parameters, oxidative status and reproductive hormone levels of male rats.

MATERIALS AND METHODS:

A total of 18 rats were divided into three groups: Group I: (control) received 0.3% salt diet, Group II: low salt (received 0.14% salt diet) and Group III: high salt (received 8% salt diet). All animals were treated for 6 weeks; after which epididymal sperm parameters; oxidative stress markers (malondialdehyde, glutathione, catalase and superoxide dismutase) in the testes and epididymal tissues, as well as follicle stimulating hormone (FSH), luteinizing hormone (LH) and testosterone levels were determined.

RESULTS:

The results showed decreased sperm count in the low salt diet rats while increased sperm count was observed in the high salt diet treated rats. Both low salt and high salt diet fed rats exhibited increased abnormal sperm cells and increased epididymal oxidative stress when compared with their respective control. FSH and testosterone levels were increased in the high salt fed rats while LH level was decreased when compared with the control values.

CONCLUSION:

This study suggests that both low and high salt diet play a negative role in the fertility of male rats.

Influence of ovarian stimulation for IVF/ICSI on the antioxidant defence system and relationship to outcome

Ovarian stimulation is used with IVF/intracytoplasmic sperm injection (ICSI) cycles to obtain multiple oocytes and improve pregnancy rates; however, it also induces perturbation in the oxidant-antioxidant balance leading to oxidation stress. The present study monitored the plasma antioxidant status in women undergoing a long agonist protocol of ovarian stimulation at three different time points: at baseline (T0), after pituitary suppression (T1) and on the day of oocyte retrieval (T2). The antioxidant composition of follicular fluid samples collected on T2 was also evaluated. Significant decreases (P < 0.05) of plasma vitamin C, vitamin E and carotenoids were found between T1 and T2 but not between T0 and T1. At T2, high plasma vitamin E was associated with high numbers of total and mature oocytes retrieved per patient, which, in turn, were favourable for achieving pregnancy. Accordingly, women who became pregnant presented higher vitamin E concentrations both in plasma and FF than those who did not. In conclusion, this study confirmed the occurrence of significant modifications of the plasma antioxidant profile during ovarian stimulation with gonadotrophins; at the same time, it was found that both systemic and follicular antioxidant status may be related to IVF/ICSI outcome.

Effects of leached components from silorane and methacrylate-based dental composites on the male mice reproductive system

BACKGROUND

This study aimed to investigate the potential toxic effects of leached components from either a methacrylate-based composite (Filtek Z250) or a silorane-based composite (Filtek P90) on the male mice reproductive system.

METHODS

Sixty adult Syrian male mice were divided into six groups. In test groups, leached components from composite specimens in artificial saliva or 75% aqueous ethanol solution were administered intragastrically daily for 28 days. The mice were then euthanized and the following reproductive parameters recorded: body weight changes; weight of paired testes; testis volume; Gonadosomatic Index (GSI); sperm motility; sperm viability; daily sperm production and epididymal sperm count.

RESULTS

There were no significant differences in body weight changes, weight of paired testes, GSI, testis volume, epididymal sperm count, and daily sperm production between groups. Sperm motility and sperm viability were significantly lower in all the test groups in comparison to the control groups. In addition, they were significantly lower in the test groups in which composite samples were immersed in aqueous ethanol solution.

CONCLUSIONS

Within the limitations of this study, the present data indicate that leached components from dental composites could affect sperm quality and therefore could potentially cause adverse effects on the male mice reproductive system.

Effects of various physical stress factors on mitochondrial function and reactive oxygen species in rat spermatozoa

The aim of the present study was to evaluate the effects of various physical interventions on the function of epididymal rat spermatozoa and determine whether there are correlations among these functional parameters. Epididymal rat spermatozoa were subjected to various mechanical (pipetting, centrifugation and Percoll gradient separation) and anisotonic conditions, and sperm motility, plasma membrane integrity (PMI), mitochondrial membrane potential (MMP) and intracellular reactive oxygen species (ROS) were evaluated. Repeated pipetting caused a loss in motility, PMI and MMP (P<0.05). Minimal centrifugation force (200 g) had no effect on motility, PMI and MMP, whereas an increase in the centrifugation force to 400 g or 600 g decreased sperm function (P<0.005). Percoll gradient separation increased total motility, PMI and MMP (P<0.05). However, the spermatozoa that were subjected to mechanical interventions showed high susceptibility to a ROS stimulant (P<0.005). Anisotonic conditions decreased motility, PMI and MMP, and hypotonic conditions in particular increased basal ROS (P<0.05). In correlation tests, there were strong positive correlations among total motility, PMI and MMP, whereas ROS showed no or negatively weak correlations with the other parameters. In conclusion, the physical interventions may act as important variables, affecting functional parameters of epididymal rat spermatozoa. Therefore, careful consideration and proper protocols for handling of rat spermatozoa and osmotic conditions are required to achieve reliable results and minimise damage.

Peroxiredoxins: hidden players in the antioxidant defence of human spermatozoa

Spermatozoon is a cell with a precious message to deliver: the paternal DNA. Its motility machinery must be working perfectly and it should be able to acquire fertilizing ability in order to accomplish this mission. Infertility touches 1 in 6 couples worldwide and in half of the cases the causes can be traced to men. A variety of conditions such as infections of the male genital tract, varicocele, drugs, environmental factors, diseases, smoking, etc., are associated with male infertility and a common feature among them is the oxidative stress in semen that occurs when reactive oxygen species (ROS) are produced at high levels and/or when the antioxidant systems are decreased in the seminal plasma and/or spermatozoa. ROS-dependent damage targets proteins, lipids, and DNA, thus compromising sperm function and survival. Elevated ROS in spermatozoa are associated with DNA damage and decreased motility. Paradoxically, ROS, at very low levels, regulate sperm activation for fertilization. Therefore, the regulation of redox signaling in the male reproductive tract is essential for fertility. Peroxiredoxins (PRDXs) play a central role in redox signaling being both antioxidant enzymes and modulators of ROS action and are essential for pathological and physiological events. Recent studies from our lab emphasize the importance of PRDXs in the protection of spermatozoa as infertile men have significant low levels of PRDXs in semen and with little enzymatic activity available for ROS scavenging. The relationships between sperm DNA damage, motility and lipid peroxidation and high levels of thiol-oxidized PRDXs suggest the enhanced susceptibility of spermatozoa to oxidative stress and further support the importance of PRDXs in human sperm physiology. This review aims to characterize PRDXs, hidden players of the sperm antioxidant system and highlight the central role of PRDXs isoforms in the protection against oxidative stress to assure a proper function and DNA integrity of human spermatozoa.

Protective Effects of Lycium barbarum Polysaccharides on Testis Spermatogenic Injury Induced by Bisphenol A in Mice

To observe the effects of Lycium barbarum polysaccharides (LBP) on testis spermatogenic injuries induced by Bisphenol A (BPA) in mice. BPA was subcutaneously injected into mice at a dose of 20 mg/kg body weight (BW) for 7 consecutive days. LBP was administered simultaneously with BPA by gavage daily at the dose of 50, 100, and 200 mg/kg BW for 7 days. After treatment, the weight and the histopathology changes of testis and epididymis were examined; the contents of T, LH, GnRH, antioxidant enzyme, and malondialdehyde (MDA) in serum were detected; proapoptotic protein Bax and antiapoptotic protein Bcl-2 were also detected by immunohistochemical method. Results showed that the weights of testis and epididymis were all increased after supplement with different dosages of LBP compared with BPA group, and the activities of SOD and GSH-Px were significantly increased in LBP groups, while MDA contents were gradually decreased. Moreover, the levels of T, LH, and GnRH were significantly elevated in serum treated with 100 mg/kg LBP. LBP also shows significant positive effects on the expression of Bcl-2/Bax in BPA treated mice. It is concluded that LBP may be one of the potential ingredients protecting the adult male animals from BPA induced reproductive damage.

Serum Levels of Melatonin and Oxidative Stress Markers and Correlation between Them in Infertile Men

INTRODUCTION

Infertility is the problem of 15% of young couples in different societies. One of the factors that could affect fertility is oxidative stress. Therefore, the aim of the present study is to investigate the level of Melatonin, a free radical scavenger, and its correlation with oxidative biomarkers in infertile men.

METHODS

For this purpose, fertile and infertile men in 2 groups, 30 people in each group, were studied. The fertile men were selected from husbands of patients admitted to Alzahra obstetric and gynecology hospital, according to WHO standards. The infertile men were selected from patients referred to infertility ward. Blood sampling from the participants carried out at a specific time, sera collected and the levels of malondialdehyde, total antioxidant capacity and Melatonin were detected in the sera. The data were analyzed using t-test and Sperman's correlation method.

RESULTS

Melatonin level in the sera from fertile men were 522 (39.32) ng/L and in infertile men were 511.78 (34.6) ng/L. MDA level in fertile and infertile men were 2.26 (0.34) vs 2.99 (0.44) nmol/ml which was significantly different. The level of TAC in the sera from fertile men were significantly higher than in infertile men. The result obtained for correlation coefficient Spearman's test revealed a significant, strong and direct correlation between Melatonin and TAC and a significant and reverse correlation between melatonin and MDA.

CONCLUSION

It is concluded that melatonin could be involved in infertility. In other word, melatonin treatment and antioxidant-rich nutrition could help fertility by combating oxidative stress.

Double-stranded DNA breaks hidden in the neutral Comet assay suggest a role of the sperm nuclear matrix in DNA integrity maintenance

We used a mouse model in which sperm DNA damage was induced to understand the relationship of double-stranded DNA (dsDNA) breaks to sperm chromatin structure and to the Comet assay. Sperm chromatin fragmentation (SCF) produces dsDNA breaks located on the matrix attachment regions, between protamine toroids. In this model, epididymal sperm induced to undergo SCF can religate dsDNA breaks while vas deferens sperm cannot. Here, we demonstrated that the conventional neutral Comet assay underestimates the epididymal SCF breaks because the broken DNA ends remain attached to the nuclear matrix, causing the DNA to remain associated with the dispersion halo, and the Comet tails to be weak. Therefore, we term these hidden dsDNA breaks. When the Comet assay was modified to include an additional incubation with sodium dodecyl sulfate (SDS) and dithiothreitol (DTT) after the conventional lysis, thereby solubilizing the nuclear matrix, the broken DNA was released from the matrix, which resulted in a reduction of the sperm head halo and an increase in the Comet tail length, exposing the hidden dsDNA breaks. Conversely, SCF-induced vas deferens sperm had small halos and long tails with the conventional neutral Comet assay, suggesting that the broken DNA ends were not tethered to the nuclear matrix. These results suggest that the attachment to the nuclear matrix is crucial for the religation of SCF-induced DNA breaks in sperm. Our data suggest that the neutral Comet assay identifies only dsDNA breaks that are released from the nuclear matrix and that the addition of an SDS treatment can reveal these hidden dsDNA breaks.

[Varicocele and infertility: where do we stand in 2013?]

While the incidence of clinical varicocele is common in infertile men (about 40%), the reasons why varicocele may affect sperm parameters is still unclear. In addition, the improvement of fertility after treatment of varicocele is also a subject of debate. The purpose of this review is to get new insight into the physiopathology of varicocele, its impact on sperm parameters and the effectiveness of varicocele treatment on fertility. Treatment is likely to be effective in infertile men with clinical varicocele and impaired spermatogenesis. Even if it does not systematically lead to an improvement in sperm parameters, it may prevent further sperm degradation. In case of non-obstructive azoospermia, few studies reported a slight improvement in the process of spermatogenesis. The critical role of an adequate methodology in order to establish clinical guidelines needs to be stressed. Indeed, the huge intra-individual variability in sperm production makes the usual analysis of sperm parameters inadequate to measure treatment effectiveness. Regarding the assessment of conception, it requires not only well designed and properly sized studies but also a multivariate analysis for weighing predictive factors of success. Thus, an active scientific research is needed to better identify pathogenic agents and appropriately assess the impact of varicocele treatment.

What should it take to describe a substance or product as 'sperm-safe'

BACKGROUND

Male reproductive potential continues to be adversely affected by many environmental, industrial and pharmaceutical toxins. Pre-emptive testing for reproductive toxicological (side-)effects remains limited, or even non-existent. Many products that come into direct contact with spermatozoa lack adequate testing for the absence of adverse effects, and numerous products that are intended for exposure to spermatozoa have only a general assumption of safety based on the absence of evidence of actual harm. Such assumptions can have unfortunate adverse impacts on at-risk individuals (e.g. couples who are trying to conceive), illustrating a clear need for appropriate up-front testing to establish actual 'sperm safety'.

METHODS

After compiling a list of general areas within the review's scope, relevant literature and other information was obtained from the authors' personal professional libraries and archives, and supplemented as necessary using PubMed and Google searches. Review by co-authors identified and eliminated errors of omission or bias.

RESULTS

This review provides an overview of the broad range of substances, materials and products that can affect male fertility, especially through sperm fertilizing ability, along with a discussion of practical methods and bioassays for their evaluation. It is concluded that products can only be claimed to be 'sperm-safe' after performing objective, properly designed experimental studies; extrapolation from supposed predicate products or other assumptions cannot be trusted.

CONCLUSIONS

We call for adopting the precautionary principle, especially when exposure to a product might affect not only a couple's fertility potential but also the health of resulting offspring and perhaps future generations.

Grape powder intake prevents ovariectomy-induced anxiety-like behavior, memory impairment and high blood pressure in female Wistar rats

Diminished estrogen influence at menopause is reported to be associated with cognitive decline, heightened anxiety and hypertension. While estrogen therapy is often prescribed to overcome these behavioral and physiological deficits, antioxidants which have been shown beneficial are gaining nutritional intervention and popularity. Therefore, in the present study, utilizing the antioxidant properties of grapes, we have examined effect of 3 weeks of grape powder (GP; 15 g/L dissolved in tap water) treatment on anxiety-like behavior, learning-memory impairment and high blood pressure in ovariectomized (OVX) rats. Four groups of female Wistar rats were used; sham control, sham-GP treated, OVX and OVX+GP treated. We observed a significant increase in systolic and diastolic blood pressure in OVX rats as compared to sham-controls. Furthermore, ovariectomy increased anxiety-like behavior and caused learning and memory impairment in rats as compared to sham-controls. Interestingly, providing grape powder treated water to OVX rats restored both systolic and diastolic blood pressure, decreased anxiety-like behavior and improved memory function. Moreover, OVX rats exhibited an impaired long term potentiation which was restored with grape powder treatment. Furthermore, ovariectomy increased oxidative stress in the brain, serum and urine, selectively decreasing antioxidant enzyme, glyoxalase-1 protein expression in the hippocampus but not in the cortex and amygdala of OVX rats, while grape powder treatment reversed these effects. Other antioxidant enzyme levels, including manganese superoxide dismutase (SOD) and Cu/Zn SOD remained unchanged. We suggest that grape powder by regulating oxidative stress mechanisms exerts its protective effect on blood pressure, learning-memory and anxiety-like behavior. Our study is the first to examine behavioral, biochemical, physiological and electrophysiological outcome of estrogen depletion in rats and to test protective role of grape powder, all in the same study.

Proteomic analysis of seminal fluid from men exhibiting oxidative stress

BACKGROUND

Seminal plasma serves as a natural reservoir of antioxidants. It helps to remove excessive formation of reactive oxygen species (ROS) and consequently, reduce oxidative stress. Proteomic profiling of seminal plasma proteins is important to understand the molecular mechanisms underlying oxidative stress and sperm dysfunction in infertile men.

METHODS

This prospective study consisted of 52 subjects: 32 infertile men and 20 healthy donors. Once semen and oxidative stress parameters were assessed (ROS, antioxidant concentration and DNA damage), the subjects were categorized into ROS positive (ROS+) or ROS negative (ROS-). Seminal plasma from each group was pooled and subjected to proteomics analysis. In-solution digestion and protein identification with liquid chromatography tandem mass spectrometry (LC-MS/MS), followed by bioinformatics analyses was used to identify and characterize potential biomarker proteins.

RESULTS

A total of 14 proteins were identified in this analysis with 7 of these common and unique proteins were identified in both the ROS+ and ROS- groups through MASCOT and SEQUEST analyses, respectively. Prolactin-induced protein was found to be more abundantly present in men with increased levels of ROS. Gene ontology annotations showed extracellular distribution of proteins with a major role in antioxidative activity and regulatory processes.

CONCLUSIONS

We have identified proteins that help protect against oxidative stress and are uniquely present in the seminal plasma of the ROS- men. Men exhibiting high levels of ROS in their seminal ejaculate are likely to exhibit proteins that are either downregulated or oxidatively modified, and these could potentially contribute to male infertility.

Mitochondrial hydrogen peroxide and defective cholesterol efflux prevent in vitro fertilization by cryopreserved inbred mouse sperm

Recent advances in the cryopreservation of mouse sperm have resulted in dramatically improved in vitro fertilization (IVF) rates, but the biological mechanisms underlying the techniques remain unclear. Two different classes of compounds have been widely utilized to improve the IVF rates of cryopreserved mouse sperm: antioxidants and cyclodextrins. To determine how cryopreservation reduces mouse sperm IVF and how antioxidants and cyclodextrins mitigate this effect, we examined sperm function and oxidative damage after cryopreservation, with and without treatments, in mouse strains important for biomedical research. Our investigation revealed mouse strain-specific effects on IVF by modulation of oxidative stress and cholesterol efflux of cryopreserved sperm. Antioxidants improved IVF rates of C57Bl6/J cryopreserved mouse sperm by reducing hydrogen peroxide produced by sperm mitochondria and ameliorating peroxidative damage to the sperm acrosome. Enhancing cholesterol efflux with cyclodextrin restored capacitation-dependent sperm function and IVF after cryopreservation of C57Bl/6J, C57Bl/6N, and 129X1 mouse sperm. Our results highlight two accessible pathways for continued development of IVF techniques for mouse sperm and provide novel endpoints prognostic of IVF success. These insights may improve sperm cryopreservation methods of other mouse strains and species.