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

Unexplained male infertility: diagnosis and management

Unexplained male infertility is a diagnosis reserved for men in whom routine semen analyses results are within normal values and physical as well as endocrine abnormalities were ruled out. In addition to erectile problems and coital factors, immunologic causes and sperm dysfunction may contribute to such condition. New etiologies of unexplained male infertility include low level leukocytospermia and mitochondrial DNA polymerase gene polymorphism. Contemporary andrology may reveal cellular and sub-cellular sperm dysfunctions which may explain subfertility in such cases, thus aiding the clinician to direct the further work-up, diagnosis and counseling of the infertile male. The objective of this article is to highlight the concept of unexplained male infertility and focuses on the diagnosis and treatment of this condition in the era of modern andrology and assisted reproductive techniques. Extensive literature review was performed using the search engines: Pubmed, Science-direct, Ovid and Scopus.

Assessment of the level of trace element zinc in seminal plasma of males and evaluation of its role in male infertility

Background:

Male infertility is a serious problem all over the world. Nutritional deficiency of trace element Zinc (Zn) may play a role in male infertility as Zn plays an important role not only in normal testicular development, but also in spermatogenesis and sperm motility. Deficiency of Zn is associated with hypogonadism and insufficient development of secondary sex characteristics.

Objective:

The present study was designed to analyze the level of seminal Zn among different groups of infertile patients and to correlate it with sperm concentration, active, sluggish and immotile fractions of seminal parameters, with an objective to establish the role of Zn in male infertility.

Setting and Design:

The present study was carried out in five- years period from 2004 to 2009. It was a descriptive analytical study with non probability sampling.

Materials and Methods:

Semen examination of the patients was carried out according to the standardized method of the World Health Organization. Semen Zn was estimated by color 5 Br. PAPS method.

Statistical Analysis:

All statistical analyses were performed by using SPSS (Version 14.0 for windows) software, by applying student's t-test.

Results:

The result showed that seminal Zn was 702.92±10.60, 598.48±12.95, 617.54±9.55, 542.29±22.75, 710.36±7.87, 712.06±7.96, 789.36±21.33, and 762.06±8.99 mg/dl in azoospermic, oligozoospermic, asthenozoospermic, oligoasthenozoospermic, teratozoospermic, normozoospermic, polyzoospermic, and proven fathers group, respectively.

Conclusions:

Decreased concentration of seminal Zn do affect the sperm count, while increased level of seminal plasma Zn causes decreased sperm motility; so, it is suggested that administration of Zn should be very carefully monitored in such patients having low sperm count but normal sperm motility, as adequate seminal Zn is required for normal sperm function.

Proteomic analysis of human spermatozoa proteins with oxidative stress

BACKGROUND

Oxidative stress plays a key role in the etiology of male infertility. Significant alterations in the sperm proteome are associated with poor semen quality. The aim of the present study was to examine if elevated levels of reactive oxygen species cause an alteration in the proteomic profile of spermatozoa.

METHODS

This prospective study consisted of 52 subjects: 32 infertile men and 20 normal donors. Seminal ejaculates were classified as ROS+ or ROS- and evaluated for their proteomic profile. Samples were pooled and subjected to LC-MS/MS analysis through in-solution digestion of proteins for peptide characterization. The expression profile of proteins present in human spermatozoa was examined using proteomic and bioinformatic analysis to elucidate the regulatory pathways of oxidative stress.

RESULTS

Of the 74 proteins identified, 10 proteins with a 2-fold difference were overexpressed and 5 were underexpressed in the ROS+ group; energy metabolism and regulation, carbohydrate metabolic processes such as gluconeogenesis and glycolysis, protein modifications and oxidative stress regulation were some of the metabolic processes affected in ROS+ group.

CONCLUSIONS

We have identified proteins involved in a variety of functions associated with response and management of oxidative stress. In the present study we focused on proteins that showed a high degree of differential expression and thus, have a greater impact on the fertilizing potential of the spermatozoa. While proteomic analyses identified the potential biomarkers, further studies through Western Blot are necessary to validate the biomarker status of the proteins in pathological conditions.

Association of state and trait anxiety to semen quality of in vitro fertilization patients: a controlled study

OBJECTIVE

To investigate the relationship between semen quality and state/trait anxiety in patients enrolled in an in vitro fertilization (IVF) program and in control subjects.

DESIGN

Cross-sectional study.

SETTING

Centre for Reproductive Medicine and Biology, European Hospital, Rome.

PATIENT(S)

Ninety-four first-attempt IVF patients and 85 age-matched, random subjects recruited in the period July 2006 through March 2008.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Behavioral features of stress, including state and trait anxiety, self-perceived impact of physical disturbance on everyday activities, ethanol consumption, cigarette smoking, and semen parameters such as semen volume, sperm concentration, total count, motility, morphology, and DNA fragmentation.

RESULT(S)

Increased levels of both state and trait anxiety were associated with lower semen volume, sperm concentration and count, reduced sperm motility, and increased sperm DNA fragmentation of IVF patients, thus influencing seminal parameters at the macroscopic and cellular/subcellular levels. Similar results were obtained in the controls.

CONCLUSION(S)

Our data confirm previous observations with state anxiety and show that trait anxiety also is negatively associated with male fertility.

The effect of bovine serum albumin and fetal calf serum on sperm quality, DNA fragmentation and lipid peroxidation of the liquid stored rabbit semen

The aim of the present study was to determine the effects of the bovine serum albumin (BSA) and fetal calf serum (FCS) on sperm quality, DNA fragmentation and lipid peroxidation of liquid stored rabbit semen stored up to 72 h at 5 °C. Ejaculates were collected from five New Zealand male rabbits by artificial vagina and pooled at 37 °C following evaluation. Each pooled ejaculate was split into three equal experimental groups and diluted to a final concentration of approximately 40 × 10(6)sperm/ml (single step dilution), in an Eppendorf tube, with the Tris based extender containing BSA (5mg/ml), FCS (10%) or no additive (control) at 37 °C, cooled to 5 °C and stored for up to 72 h. The extender supplemented with BSA and FCS did not improve the percentages of motility and acrosomal abnormality during 48 h compared to the control. The additives BSA and FCS had a significant effect in the maintaining of plasma membrane integrity between 48 and 72 h storage period, compared to the control (P<0.01). The supplementation of BSA and FCS had a protective effect on motility (P<0.05), plasma membrane integrity (P<0.01) and acrosomal integrity (P<0.01) at 72 h compared to the control. The supplementations with BSA and FCS led to a reduction in DNA damage of rabbit sperm at 48 and 72 h during storage period, compared to the control (P<0.001). Although supplementation of BSA and FCS caused significant (P<0.01) decreases in malondialdehyde (MDA) level at 48 h and 72 h, they significantly (P<0.01) increased the glutathione peroxidase (GPx) antioxidant activity up to 72 h when compared to the control group. In conclusion, BSA and FCS supplementation to liquid stored rabbit semen provide a protection for spermatozoa against cool storage-induced DNA damage and plasma membrane integrity by their antioxidative properties.

Baseline blood trihalomethanes, semen parameters and serum total testosterone: a cross-sectional study in China

Toxicological studies showed that trihalomethanes (THMs), the most abundant classes of disinfection by-products (DBPs) in drinking water, impaired male reproductive health, but epidemiological evidence is limited and inconsistent. This study aimed to examine the associations of baseline blood THMs with semen parameters and serum total testosterone in a Chinese population. We recruited 401 men seeking semen examination from the Reproductive Center of Tongji Hospital in Wuhan, China between April 2011 and May 2012. Baseline blood concentrations of THMs, including chloroform (TCM), bromodichloromethane (BDCM), dibromochloromethane (DBCM), and bromoform (TBM) were measured using SPME-GC/ECD method. Semen quality and serum total testosterone were analyzed. Multivariable linear regressions were used to assess the associations of baseline blood THM concentrations with semen parameters and serum total testosterone levels. We found that baseline blood THM concentrations were not associated with decrements in sperm motility, sperm straight-line and curvilinear velocity. However, moderate levels of BDCM (β=-0.13 million; 95% CI: -0.22, -0.03) and DBCM (β=-4.74%; 95% CI: -8.07, -1.42) were associated with decreased sperm count and declined sperm linearity compared with low levels, respectively. Suggestive dose-response relationships were also observed between elevated blood TCM or ∑ THMs (sum of TCM, BDCM, DBCM and TBM) concentration and decreased sperm concentration (both p for trend=0.07), and between elevated blood DBCM concentration and decreased serum total testosterone (p for trend=0.07). Our results indicate that elevated THM exposure may lead to decreased sperm concentration and serum total testosterone. However, the effects of THM exposure on male reproductive health still warrant further studies in humans.

Mucuna pruriens and its major constituent L-DOPA recover spermatogenic loss by combating ROS, loss of mitochondrial membrane potential and apoptosis

BACKGROUND

The Ayurvedic medicinal system claims Mucuna pruriens (MP) to possess pro-male fertility, aphrodisiac and adaptogenic properties. Some scientific evidence also supports its pro-male fertility properties; however, the mechanism of its action is not yet clear. The present study aimed at demonstrating spermatogenic restorative efficacy of MP and its major constituent L-DOPA (LD), and finding the possible mechanism of action thereof in a rat model.

METHODOLOGY/FINDINGS

Ethinyl estradiol (EE) was administered at a rate of 3 mg/kg body weight (BW)/day for a period of 14 days to generate a rat model with compromised spermatogenesis. MP and LD were administered in two separate groups of these animals starting 15(th) day for a period of 56 days, and the results were compared with an auto-recovery (AR) group. Sperm count and motility, testis histo-architecture, level of reactive oxygen species (ROS), mitochondrial membrane potential (MMP), apoptosis, peripheral hormone levels and testicular germ cell populations were analysed, in all experimental groups. We observed efficient and quick recovery of spermatogenesis in MP and LD groups in comparison to the auto-recovery group. The treatment regulated ROS level, apoptosis, and mitochondrial membrane potential (MMP), recovered the hypothalamic-pituitary-gonadal axis and the number of testicular germ cells, ultimately leading to increased sperm count and motility.

CONCLUSION/SIGNIFICANCE

M. pruriens efficiently recovers the spermatogenic loss induced due to EE administration. The recovery is mediated by reduction in ROS level, restoration of MMP, regulation of apoptosis and eventual increase in the number of germ cells and regulation of apoptosis. The present study simplified the complexity of mechanism involved and provided meaningful insights into MP/LD mediated correction of spermatogenic impairment caused by estrogens exposure. This is the first study demonstrating that L-DOPA largely accounts for pro-spermatogenic properties of M. pruriens. The manuscript bears CDRI communication number 8374.

Two-dimensional differential in-gel electrophoresis-based proteomics of male gametes in relation to oxidative stress

OBJECTIVE

To identify the relative abundance of proteins in pooled reactive oxygen species (ROS)-positive (ROS+) and ROS-negative (ROS-) semen samples with the use of two-dimensional differential in-gel electrophoresis (2D-DIGE).

DESIGN

Spermatozoa suspensions from ROS+ and ROS- groups by 2D-DIGE analysis.

SETTING

Tertiary hospital.

PATIENT(S)

20 donors and 32 infertile men.

INTERVENTION(S)

Seminal ejaculates evaluated for semen and proteomic analysis.

MAIN OUTCOME MEASURE(S)

Semen samples from 20 donors and 32 infertile men were pooled, divided into ROS+ and ROS- groups based on the cutoff value of <20 relative light units/s/10(6) sperm and frozen. From each pooled group, spermatozoa were labeled with Cy3/Cy5 fluorescent dye. Duplicate 2D-DIGE gels were run. Image analysis was performed with the use of Decider software. Protein spots exhibiting ≥1.5-fold difference in intensity were excised from the preparatory gel and identified by liquid chromatography-mass spectrometry. Data were analyzed with the use of Sequest and Blast programs.

RESULT(S)

A total of 1,343 protein spots in gel 1 (ROS-) and 1,265 spots in gel 2 (ROS+) were detected. The majority of protein spots had similar expression, with 31 spots were differentially expressed. Six spots were significantly decreased and 25 increased in the ROS- sample compared with the ROS+ sample.

CONCLUSION(S)

Significantly different expression of protective proteins against oxidative stress was found in ROS-compared with ROS+ samples. These differences may explain the role of oxidation species in the pathology of male infertility.

The role of varicocele treatment in the management of non-obstructive azoospermia

The literature on male reproductive medicine is continually expanding, especially regarding the diagnosis and treatment of infertility due to non-obstructive azoospermia. The advent of in vitro fertilization with intracytoplasmic sperm injection has dramatically improved the treatment of male infertility due to nonobstructive azoospermia. Assisted reproduction using testicular spermatozoa has become a treatment of hope for men previously thought to be incapable of fathering a child due to testicular failure. In addition, numerous studies on non-obstructive azoospermia have reported that varicocelectomy not only can induce spermatogenesis but can also increase the sperm retrieval rate; however, the value of varicocelectomy in patients with non-obstructive azoospermia still remains controversial. The purpose of this review is to present an overview of the current status of varicocele repair in men with non-obstructive azoospermia.

Relationship of leptin administration with production of reactive oxygen species, sperm DNA fragmentation, sperm parameters and hormone profile in the adult rat

PURPOSE

Leptin, an adipose tissue-derived hormone, plays an important role in energy homeostasis and metabolism, and in the neuroendocrine and reproductive systems. The function of leptin in male reproduction is unclear; however, it is known to affect sex hormones, sperm motility and its parameters. Leptin induces mitochondrial superoxide production in aortic endothelia and may increase oxidative stress and abnormal sperm production in leptin-treated rats. This study aims to evaluate whether exogenous leptin affects sperm parameters, hormone profiles, and the production of reactive oxygen species (ROS) in adult rats.

METHODS

A total of 65 Sprague-Dawley rats were divided into three treated groups and a control group. Treated rats received daily intraperitoneal injections of 5, 10 and 30 μg/kg of leptin administered for a duration of 7, 15, and 42 days. Control rats were given 0.1 mL of 0.9 % normal saline for the same period. One day after final drug administration, we evaluated serum specimens for follicle-stimulating hormone (FSH), leutinizing hormone (LH), free testosterone (FT), and total testosterone (TT) levels. Samples from the rat epididymis were also evaluated for sperm parameters and motility characteristics by a Computer-Aided Semen Analysis (CASA) system. Samples were treated with 2',7'-dichlorofluorescein-diacetate (DCFH-DA) and analyzed using flow cytometry and TUNEL to determine the impact of leptin administration on sperm DNA fragmentation.

RESULTS

According to CASA, significant differences in all sperm parameters in leptin-treated rats and their age-matched controls were detected, except for TM, ALH and BCF. Serum FSH and LH levels were significantly higher in rats that received 10 and 30 μg/kg of leptin compared to those treated with 5 μg/kg of leptin in the same group and control rats (P < 0.05). ROS and sperm DNA fragmentation was significantly higher in rats injected with 10 and 30 μg/kg of leptin for 7 and 15 days compared with rats treated with 5 μg/kg of leptin and the control group (P < 0.05) for the same time period. However, at day 42 of treatment, ROS and sperm DNA fragmentation levels significantly decreased in all groups (P < 0.05).

CONCLUSION

According to these results, leptin can possibly affect male infertility by ROS induction or hormone profile modulation.

Role of reactive nitrogen species in male infertility

Reactive nitrogen species (RNS) is a subset of free oxygen radicals called reactive oxygen species (ROS). Physiological levels of ROS are necessary to maintain the reproductive functions such as cell signaling, tight junction regulation, production of hormones, capacitation, acrosomal reaction, sperm motility, and zona pellucida binding. However, an excess of RNS can adversely affect reproductive potential by causing testicular dysfunction, decreased gonadotropin secretion, and abnormal semen parameters. Because such levels of RNS have been demonstrated in males with fertility problems and routine semen analysis has not been able to accurately predict IVF outcomes, it is imperative that novel strategies be developed in order to both assess and treat oxidative stress. This article describes both physiological and pathological roles of this unique subset of ROS.

Oxidative, inflammatory and immunologic status in children with undescended testes

BACKGROUND

In order to better understand the pathogenesis of risk of future sub-/infertility in children with undescended testes (UDT), we designed this prospective study to examine the oxidative stress, inflammatory response and autoimmunity in children with UDT. We examined the concentrations of malondialdehyde (MDA), interleukin-6 (IL-6) and antisperm antibodies (ASA) in children with UDT and healthy controls.

METHODS

The UDT group consisted of 88 boys (aged 1-14 years, unilateral in 67 and bilateral in 21 cases), and 44 boys with normal descended testes served as a control group. Clinical evaluation revealed no testicular or other system abnormalities. MDA was used as lipid peroxidation index. IL-6 levels were measured using a commercial enzyme-linked immunosorbent assay kit. ASA was determined with an anti-human spermatozoa immunoglobulin G test.

RESULTS

Mean age values ± SD were 4.6 ± 3.2 in the UDT group and 4.7 ± 3.4 in the control group (P= 0.872). MDA and IL-6 results for the UDT and control groups were significantly different (P= 0.003 and P= 0.019, respectively), but those for ASA were not (P= 0.473). The mean MDA and IL-6 values were significantly higher in bilateral cases than the respective values in the unilateral cases (MDA: 4.03 ± 3.68 vs 3.49 ± 5.22, P= 0.015; IL-6: 7.70 ± 6.86 vs 3.48 ± 6.50, P= 0.001) (P= 0.015).

CONCLUSION

The results indicate that children with UDT are exposed to high levels of oxidative stress and inflammatory reaction. This could negatively affect the future fertility in these children.

Spermatozoa and seminal plasma fatty acids as predictors of cryopreservation success

There is a lack of information about the importance of fatty acid composition of the human sperm membranes and seminal plasma in the cryopreservation procedure. Our aims were to study the possible relationships between the fatty acid composition of human spermatozoa or seminal fluid before freezing, and the sperm quality, measured in terms of viability and motility, before and after freezing-thawing. A further objective of this study was to determine whether the antioxidant capacity (TAC) of the seminal plasma is related to fatty acid (FA) composition and to success of the cryopreservation process. Polyunsaturated fatty acids (PUFA), ω3 PUFAs and docosahexaenoic acid (DHA) in spermatozoa were significantly positively correlated with sperm viability and motility parameters before and after freezing. An inverse relationship was found for monounsaturated (MUFA), ratio ω6/ω3, ratio saturated saturated fatty acids/PUFA (SFA/PUFA) with the seminal parameters. Seminal plasma fatty acid composition was not related to viability. However, motility parameters before and after freezing were related to stearic acid (C18:0) and DHA. TAC in seminal plasma was directly related to PUFA, w3 and DHA. On the other hand, SFA, C22:0, C24:0 and MUFA in seminal plasma were inversely related to the antioxidant capacity. TAC was directly correlated with motion parameters after thawing, We described a significant correlation between the fatty acid composition of the human spermatozoa or seminal plasma and the sperm parameters of the samples after thawing. PUFA, W3 and specially DHA are directly correlated with sperm motility and viability after freezing/thawing, and MUFA was inversely correlated. This means that in the future the fatty acid composition could be used as a predictor of the capacity of cryopreservation. On the other hand, we could design further procedures to modify the lipid composition or/and antioxidant capacity of ejaculate to make it more resistant to the cryopreservation process.

An investigation of excess residual cytoplasm in human spermatozoa and its distinction from the cytoplasmic droplet

Recent studies have shown cytoplasmic droplets to be normal morphological occurrences in human male spermatozoa. When the cytoplasm around the sperm midpiece is present in large amounts, however, pathological effects may transpire. The cytoplasmic droplet then becomes known as excess residual cytoplasm, which can impair overall sperm function and produce higher levels of reactive oxygen species, potentially leading to male infertility. Though the distinction between cytoplasmic droplets and excess residual cytoplasm has been made, some studies fail to recognize the difference and incorrectly label the latter as a cytoplasmic droplet. This review attempts to clarify excess residual cytoplasm's effect on fertility, examine the enzymes responsible, and suggest tests and possible treatment options for those affected by this defect.

Relationship of seminal reactive nitrogen and oxygen species and total antioxidant capacity with sperm DNA fragmentation in infertile couples with normal and abnormal sperm parameters

The objective of this study was to investigate the association between the amount of superoxide anion, peroxynitrite as oxidative stress (OS) markers and total antioxidant capacity (TAC) with sperm DNA fragmentation in infertile men with abnormal semen parameters. Semen samples were obtained from 102 infertile couples and divided into groups with normal and abnormal semen parameters according to the World Health Organization (WHO). Peroxynitrite and superoxide anions were detected using spectrofluorometric assays combined with 2,7 dicholorofluorescein (DCF)-DA and 4-chloro-7-nitrobenzo-2-oxa -1, 3-diazole (NBD-CL). Colorimetric assay was used for evaluation of TAC, while DNA fragmentation was studied by using sperm chromatin dispersion test. Superoxide anion, peroxynitrite and DNA fragmentation were significantly higher in infertile couples with abnormal semen parameters as compared to infertile couples with normal semen (P < 0.01). TAC was significantly lower in infertile men with abnormal semen parameters (P < 0.01). There was also a significant positive correlation between OS markers with sperm DNA fragmentation (r = 0.59, P < 0.01 and r = 0.67, P < 0.01, respectively). We have found that imbalance between superoxide anion and peroxynitrite with antioxidant capacity in infertile men with abnormal sperm parameters is associated with higher sperm DNA fragmentation.

The hypoxic testicle: physiology and pathophysiology

Mammalian spermatogenesis is a complex biological process occurring in the seminiferous tubules in the testis. This process represents a delicate balance between cell proliferation, differentiation, and apoptosis. In most mammals, the testicles are kept in the scrotum 2 to 7°C below body core temperature, and the spermatogenic process proceeds with a blood and oxygen supply that is fairly independent of changes in other vascular beds in the body. Despite this apparently well-controlled local environment, pathologies such as varicocele or testicular torsion and environmental exposure to low oxygen (hypoxia) can result in changes in blood flow, nutrients, and oxygen supply along with an increased local temperature that may induce adverse effects on Leydig cell function and spermatogenesis. These conditions may lead to male subfertility or infertility. Our literature analyses and our own results suggest that conditions such as germ cell apoptosis and DNA damage are common features in hypoxia and varicocele and testicular torsion. Furthermore, oxidative damage seems to be present in these conditions during the initiation stages of germ cell damage and apoptosis. Other mechanisms like membrane-bound metalloproteinases and phospholipase A2 activation could also be part of the pathophysiological consequences of testicular hypoxia.

Double stranded sperm DNA breaks, measured by Comet assay, are associated with unexplained recurrent miscarriage in couples without a female factor

It is known that sperm samples from recurrent pregnancy loss (RPL) couples have an increase in their sperm DNA fragmentation (SDF), but no studies have been performed in order to identify differences between single stranded SDF (ssSDF) and double stranded SDF (dsSDF) in these patients. This could be relevant because the type of DNA damage could have different effects. Semen samples were classified attending their clinical status: 25 fertile donors and 20 RPL patients with at least two unexplained first trimester miscarriages. SDF was analysed using alkaline and neutral Comet assay, SCD test and pulsed-field gel electrophoresis (PFGE), and ROC analysis including data from 105 more infertile patients (n = 150) was performed to establish predictive threshold values. SDF for alkaline and neutral Comet, and the SCD test was analysed in these categories of individuals. Data revealed the presence of two subgroups within fertile donors. The values obtained were 21.10±9.13, 23.35±10.45 and 12.31±4.31, respectively, for fertile donors with low values for both ssSDF and dsSDF; 27.86±12.64, 80.69±12.67 and 12.43±5.22, for fertile donors with low ssSDF and high dsSDF; and 33.61±15.50, 84.64±11.28 and 19.28±6.05, for unexplained RPL patients, also showing a low ssSDF and high dsSDF profile. This latter profile was seen in 85% of unexplained RPL and 33% of fertile donors, suggesting that it may be associated to a male risk factor for undergoing RPL. ROC analysis regarding recurrent miscarriage set the cut-off value at 77.50% of dsDNA SDF. PFGE for low ssSDF and high dsSDF profile samples and positive controls treated with DNase, to induce dsDNA breaks, showed a more intense band of about 48 kb, which fits the toroid model of DNA compaction in sperm, pointing out that some nuclease activity may be affecting their sperm DNA in RPL patients. This work identifies a very specific SDF profile related to the paternal risk of having RPL.

Protein modification as oxidative stress marker in normal and pathological human seminal plasma

OBJECTIVE

Our study aims to assess the oxidative stress status of seminal plasma from normozoospermic, azoospermic, and leukocytospermic males, since abnormal sperm and leukocytes in human ejaculates are the main source of reactive oxygen species (ROS) which lead to oxidative damages. For this purpose we applied a biochemical approach to the assessment of the oxidative stress status by using two-dimensional (2D) electrophoresis to check the level of protein oxidation after specific labeling of free thiol (-SH) groups.

METHODS

Seminal plasma samples from normal and pathological males were analyzed by a luminol-based chemiluminescent assay. The same samples after specific labeling of free -SH groups with 3-N-maleimidopropionyl biocytin, were analyzed by 2D electrophoresis and computer-assisted semiquantitative determination of the amount of free -SH groups.

RESULTS

Using a standard chemiluminescence assay, we demonstrated a high, low and normal level of ROS, respectively, in seminal plasma from leukocytospermic, azoospermic, and normozoospermic subjects. By 2D electrophoresis and streptavidin blotting of specifically labeled free -SH groups of proteins, we detected in the same samples a higher level of oxidated -SH groups comparable between azoospermic and leukocytospermic samples, whereas a significantly higher level of free -SH groups was detected in normozoospermic subjects.

DISCUSSION

Our results demonstrated that a pathological oxidative stress status in seminal plasma may be revealed by the levels of the protein free -SH groups, both in the presence or absence of cells.

Differences in blood and semen oxidative status in fertile and infertile men, and their relationship with sperm quality

Oxidative stress plays a fundamental role in the aetiology of male infertility by negatively affecting sperm quality and function. Assessment of blood and seminal plasma oxidative profiles might be a valuable tool to improve evaluation of sperm reproductive capacity and functional competence. This study examined the lipid-soluble antioxidant profile and levels of lipid peroxidation both in blood and seminal plasma samples of infertile and fertile males, in relation to semen parameters. Total antioxidant capacity (TAC) and vitamin E concentrations were significantly (P<0.05) lower in seminal plasma of infertile men compared with fertile subjects; concurrently, a significant accumulation of malondialdehyde was found in infertile patients (P=0.032 compared with controls), which was negatively correlated with sperm motility and morphology. In blood samples, infertile men presented lower concentrations of TAC, carotenoids and vitamin E than fertile subjects; TAC and carotenoids were positively correlated with sperm motility, morphology and concentration. Finally, blood TAC and vitamin E concentrations were positively correlated with the corresponding seminal values, confirming the close relationship between blood and semen antioxidants. All these results indicated the possibility of using not only seminal antioxidants but also blood antioxidants as biochemical markers to support sperm quality evaluation. Oxidative stress induced by reactive oxygen species (ROS) has been widely recognized as one of the major causes of male infertility; indeed, excessive ROS production can negatively impact sperm quality and function. The assessment of blood and seminal plasma oxidative profiles has been suggested as a valuable tool to improve the evaluation of sperm reproductive capacity and functional competence in infertile men. With this in mind, in the present study we examined the lipid soluble antioxidant profile (carotenoids and vitamins A and E) and the levels of lipid peroxidation (malondialdehyde; MDA) both in blood and seminal plasma samples of infertile and fertile males, in correlation with semen parameters namely motility, morphology and concentration. As a result, we obtained evidence that the total antioxidant capacity (TAC) and the concentrations of vitamin E of seminal plasma samples were significantly lower in infertile men than in fertile subjects; at the same time, a significant accumulation of MDA was found in infertile patients. MDA, in turn, negatively correlated with sperm motility and morphology, thus confirming that oxidative damage to lipids impairs sperm quality. In blood samples, infertile men presented lower TAC and lower concentrations of carotenoids and vitamin E than fertile subjects; interestingly, TAC and carotenoid concentrations were positively correlated with sperm motility, morphology, and concentration, confirming the close relationship between blood antioxidants and sperm quality. In conclusion, all these results suggested that the examination of blood and semen oxidative profiles might furnish useful information on sperm quality and function in infertile men.

Are old males still good males and can females tell the difference? Do hidden advantages of mating with old males off-set costs related to fertility, or are we missing something else?

Sperm function generally declines with male age. Paradoxically, females of many species still choose to mate with old males rather than young males. Females choosing old mates may suffer reduced fertilization rates and an increased incidence of birth defects in offspring, lowering fitness which may in turn lead to conflict between the sexes. This apparent paradox has generated much interest from theorists, but whether this paradox presents in nature remains equivocal. Empirical studies have found mixed support for both a decline in fertility with male age and age-based female mate preference. Here, we examine recent evidence for this paradox, identify confounding variables, highlight areas that deserve further investigation, and suggest avenues for future research.

Asymptomatic seminal infection of herpes simplex virus: impact on male infertility

In more than half of infertile men, the cause of their infertility is unknown. Several studies revealed the role of viral infections in male infertility. The aim of the present study was to determine the prevalence of herpes simplex virus-1 (HSV-1) and HSV-2 in semen from asymptomatic infertile male patients, and its association with altered semen parameters. A total of 70 semen samples were collected from infertile men who attended the Research and Clinical Center for Infertility in Yazd, Iran. Semen analysis and diagnostic real-time PCR using specific primers and probes for HSV-1 and HSV-2 DNA were performed. Comparison of semen parameters between virally infected and non-infected samples were performed with independent t-test and Mann-Whitney test. Semen analysis showed that infertile men fell into two groups, the male factor group and the unexplained group. HSV-1 and HSV-2 DNA was detected in 16 (22.9%) and 10 (14.3%) of 70 semen samples, respectively. All HSV-positive samples had abnormal semen parameters (the male factor group). Although HSV infection was not associated with sperm motility and morphological defects, it was correlated with lower sperm count in the seminal fluid. The findings suggest that asymptomatic seminal infection of HSV plays an important role in male infertility by adversely affecting sperm count.

Differences in the ability of spermatozoa from individual boar ejaculates to withstand different semen-processing techniques

The present study aimed to evaluate the ability of spermatozoa from individual boar ejaculates to withstand different semen-processing techniques. Eighteen sperm-rich ejaculate samples from six boars (three per boar) were diluted in Beltsville Thawing Solution and split into three aliquots. The aliquots were (1) further diluted to 3×10(7) sperm/mL and stored as a liquid at 17°C for 72 h, (2) frozen-thawed (FT) at 1×10(9) sperm/mL using standard 0.5-mL straw protocols, or (3) sex-sorted with subsequent liquid storage (at 17°C for 6 h) or FT (2×10(7) sperm/mL using a standard 0.25-mL straw protocol). The sperm quality was evaluated based on total sperm motility (the CASA system), viability (plasma membrane integrity assessed using flow cytometry and the LIVE/DEAD Sperm Viability Kit), lipid peroxidation (assessed via indirect measurement of the generation of malondialdehyde (MDA) using the BIOXYTECH MDA-586 Assay Kit) and DNA fragmentation (sperm chromatin dispersion assessed using the Sperm-Sus-Halomax(®) test). Data were normalized to the values assessed for the fresh (for liquid-stored and FT samples) or the sorted semen samples (for liquid stored and the FT sorted spermatozoa). All of the four sperm-processing techniques affected sperm quality (P<0.01), regardless of the semen donor, with reduced percentages of motile and viable sperm and increased MDA generation and percentages of sperm with fragmented DNA. Significant (P<0.05) inter-boar (effect of boars within each semen-processing technique) and intra-boar (effect of semen-processing techniques within each boar) differences were evident for all of the sperm quality parameters assessed, indicating differences in the ability of spermatozoa from individual boars to withstand the semen-processing techniques. These results are the first evidence that ejaculate spermatozoa from individual boars can respond in a boar-dependent manner to different semen-processing techniques.

Effect of nonylphenol on male reproduction: analysis of rat epididymal biochemical markers and antioxidant defense enzymes

The mechanism by which nonylphenol (NP) interferes with male reproduction is not fully elucidated. Therefore, the present study was conducted to evaluate the effect of NP on male reproductive organ's weight, sperm characteristics, and to elucidate the nature and mechanism of action of NP on the epididymis. Adult male Wistar rats were gavaged with NP, dissolved in corn oil, at 0, 100, 200 or 300mg/kg/day for 30 consecutive days. Control rats were gavaged with vehicle (corn oil) alone. Body weight did not show any significant change while, absolute testes and epididymides weights were significantly decreased. Sperm count in cauda and caput/corpus epididymides, and sperm motility was significantly decreased. Daily sperm production was significantly decreased in a dose-related manner. Sperm transit time in cauda epididymis was significantly decreased by 300mg/kg, while in the caput/corpus epididymis it was significantly decreased by 200 and 300mg/kg of NP. Plasma LDH was significantly increased while; plasma testosterone was significantly decreased in a dose-related pattern. In the epididymal sperm, NP decreased acrosome integrity, Δψm and 5'-nucleotidase activity. Hydrogen peroxide (H(2)O(2)) production and LPO were significantly increased in a dose-related pattern. The activities of SOD, CAT and GPx were significantly decreased in the epididymal sperm. In conclusion, this study revealed that NP treatment impairs spermatogenesis and has a cytotoxic effect on epididymal sperm. It disrupts the prooxidant and antioxidant balance. This leads oxidative stress in epididymal sperms of rat. Moreover, the reduction in sperm transit time may affect sperm quality and fertility potential.

Quinestrol treatment induced testicular damage via oxidative stress in male Mongolian gerbils (Meriones unguiculatus)

The hypothesis that quinestrol exerts testicular damage via oxidative stress was investigated in male gerbils using a daily oral gavage of 3.5 mg/kg body weight for 2 weeks (the multidose-treated group) or 35 mg/kg body weight (the single-dose-treated group). The testicular histological morphology, antioxidant capacity and malondialdehyde (MDA) concentration in testicular tissue and plasma were assessed at 15, 30, and 60 days following treatment. The results showed that the activity of the antioxidant enzymes, including superoxide dismutase (SOD) and glutathione peroxide (GSH-Px), and total antioxidant capacity (T-AOC), at 15 days after treatment in testicular tissue decreased, which led to the MDA concentration increasing while at the same time germ cells were rarefied and showed an irregular distribution in seminiferous tubules of quinestrol-treated gerbils. At 30 days, the testicular weight and antioxidant capacity continued to decrease, while the MDA concentration continued to increase, and testicular histopathological changes were more pronounced. Single-dose and multidose drug treatment had a similar effect on the antioxidant enzymes and MDA, but testicular damage was relatively severe at 15 and 30 days after multidose treatment. By 60 days of treatment withdrawal, however, the above parameters recovered to control levels. The results show that quinestrol causes reversible damage to gerbil testes that might be caused by the oxidative stress and that multidose treatment has more effects on testicular damage compared with one-dose treatment.

Cell phones and male infertility: a review of recent innovations in technology and consequences

Cell phones have become a vital part of everyday life. However, the health risks associated with their usage are often overlooked. Recently, evidence from several studies supports a growing claim that cell phone usage may have a detrimental effect on sperm parameters leading to decreased male fertility. Nonetheless, other studies showed no conclusive link between male infertility and cell phone usage. The ambiguity of such results is attributed to the lack of a centralized assay for measuring inflicted damage caused by cell phones. Study design, ethics, and reproducibility are all aspects which must be standardized before any conclusions can be made.

Novel concepts in male infertility

Extraordinary advances have been achieved in the field of male infertility in the last decades. There are new concepts in sperm physiology and several modern tools for the assessment of spermatogenesis kinetics in vivo. New tests using molecular biology and DNA damage assays allow the clinician to correctly diagnose men so far classified as having idiopathic male infertility. In the field of treatment, microsurgery has increased success rates either for reconstruction of the reproductive tract or the retrieval of spermatozoa for assisted conception. Emerging evidence suggests that life-style and environmental conditions are of utmost importance in male fertility and subfertility. This review discusses several concepts that have changed over the last years, such as the duration of the spermatogenic cycle in humans, Y-chromosome infertility, the reproductive potential of non-mosaic Klinefelter syndrome men, the impact of paternal age and sperm DNA in male infertility, the role of antioxidants in the treatment of infertile men, the predictive factors and techniques for sperm retrieval in non-obstructive azoospermia, and the microsurgical treatment of clinical varicoceles. Whenever possible, levels of evidence are provided as suggested by the Oxford Center of Evidence-based Medicine.

Mechanisms and clinical correlates of sperm DNA damage

Among the different DNA anomalies that can be present in the male gamete, DNA fragmentation is the most frequent, particularly in infertile subjects. There is now consistent evidence that a sperm containing fragmented DNA can be alive, motile, morphologically normal and able to fertilize an oocyte. There is also evidence that the oocyte is able to repair DNA damage; however, the extent of this repair depends on the type of DNA damage present in the sperm, as well as on the quality of the oocyte. Thus, it is important to understand the possible consequences of sperm DNA fragmentation (SDF) for embryo development, implantation, pregnancy outcome and the health of progeny conceived, both naturally and by assisted reproductive technology (ART). At present, data on the consequences of SDF for reproduction are scarce and, in many ways, inconsistent. The differences in study conclusions might result from the different methods used to detect SDF, the study design and the inclusion criteria. Consequently, it is difficult to decide whether SDF testing should be carried out in fertility assessment and ART. It is clear that there is an urgent need for the standardisation of the methods and for additional clinical studies on the impact of SDF on ART outcomes.

Induction of hair growth by insulin-like growth factor-1 in 1,763 MHz radiofrequency-irradiated hair follicle cells

Radiofrequency (RF) radiation does not transfer high energy to break the covalent bonds of macromolecules, but these low energy stimuli might be sufficient to induce molecular responses in a specific manner. We monitored the effect of 1,763 MHz RF radiation on cultured human dermal papilla cells (hDPCs) by evaluating changes in the expression of cytokines related to hair growth. The expression of insulin-like growth factor-1 (IGF-1) mRNA in hDPCs was significantly induced upon RF radiation at the specific absorption rate of 10 W/kg, which resulted in increased expression of B-cell chronic lymphocytic leukemia/lymphoma 2 (BCL-2) and cyclin D1 (CCND1) proteins and increased phosphorylation of MAPK1 protein. Exposure to 10 W/kg RF radiation 1 h per day for 7 days significantly enhanced hair shaft elongation in ex vivo hair organ cultures. In RF-exposed follicular matrix keratinocytes in the hair bulb, the expression of Ki-67 was increased, while the signal for terminal deoxynucleotidyl transferase dUTP nick end labeling was reduced. From these results, we suggest that 1,763 MHz RF exposure stimulates hair growth in vitro through the induction of IGF-1 in hDPCs.

Age-related instability in spermatogenic cell nuclear and mitochondrial DNA obtained from Apex1 heterozygous mice

The prevalence of spontaneous mutations increases with age in the male germline; consequently, older men have an increased risk of siring children with genetic disease due to de novo mutations. The lacI transgenic mouse can be used to study paternal age effects, and in this system, the prevalence of de novo mutations increases in the male germline at old ages. Mutagenesis is linked with DNA repair capacity, and base excision repair (BER), which can ameliorate spontaneous DNA damage, decreases in nuclear extracts of spermatogenic cells from old mice. Mice heterozygous for a null allele of the Apex1 gene, which encodes apurinic/apyrimidinic endonuclease I (APEN), an essential BER enzyme, display an accelerated increase in spontaneous germline mutagenesis early in life. Here, the consequences of lifelong reduction of APEN on genetic instability in the male germline were examined, for the first time, at middle and old ages. Mutant frequency increased earlier in spermatogenic cells from Apex1(+/-) mice (by 6 months of age). Nuclear DNA damage increased with age in the spermatogenic lineage for both wild-type and Apex1(+/-) mice. By old age, mutant frequencies were similar for wild-type and APEN-deficient mice. Mitochondrial genome repair also depends on APEN, and novel analysis of mitochondrial DNA (mtDNA) damage revealed an increase in the Apex1(+/-) spermatogenic cells by middle age. Thus, Apex1 heterozygosity results in accelerated damage to mtDNA and spontaneous mutagenesis, consistent with an essential role for APEN in maintaining nuclear and mtDNA integrity in spermatogenic cells throughout life.