Oxidative damage to proteins and decrease of antioxidant capacity in patients with varicocele

Understanding seminal plasma in male infertility: emerging markers and their implications

Infertility affects a significant proportion of the reproductive-aged population, with male-associated factors contributing to over half of the cases. However, current diagnostic tools have limitations, leading to an underestimation of the true prevalence of male infertility. While traditional semen parameters provide some insights, they fail to determine the true fertility potential in a substantial number of instances. Therefore, it is crucial to investigate additional molecular targets responsible for male infertility to improve understanding and identification of such cases. Seminal plasma, the main carrier of molecules derived from male reproductive glands, plays a crucial role in reproduction. Amongst its multifarious functions, it regulates processes such as sperm capacitation, sperm protection and maturation, and even interaction with the egg's zona pellucida. Seminal plasma offers a non-invasive sample for urogenital diagnostics and has shown promise in identifying biomarkers associated with male reproductive disorders. This review aims to provide an updated and comprehensive overview of seminal plasma in the diagnosis of male infertility, exploring its composition, function, methods used for analysis, and the application of emerging markers. Apart from the application, the potential challenges of seminal plasma analysis such as standardisation, marker interpretation and confounding factors have also been addressed. Moreover, we have also explored future avenues for enhancing its utility and its role in improving diagnostic strategies. Through comprehensive exploration of seminal plasma's diagnostic potential, the present analysis seeks to advance the understanding of male infertility and its effective management.

Local and Systemic Oxidative Stress Biomarkers for Male Infertility: The ORION Study

Infertility problems occur in around 10% of all couples worldwide, with male-factor infertility as the sole contributor in 20–30% of these cases. Oxidative stress (OS) is suggested to be associated with the pathophysiology of male infertility. In spermatozoa, OS can lead to damage to the cell membrane, resulting in disruption of DNA integrity and a decrease in motility. Established biomarkers for OS include free thiols and malondialdehyde (MDA), both representing different components of the reactive species interactome (RSI). This exploratory study aimed to investigate seminal plasma-free thiol and MDA levels in relation to semen parameters as defined by the World Health Organization (WHO) to determine if these markers are adequate to define local OS status. Furthermore, this study investigated if there is a relation between systemic and local OS status by comparing seminal concentrations of free thiol (R-SH, sulfhydryl groups, representing the extracellular redox status) and MDA (lipid peroxidation product) levels to those measured in serum. Free thiol and MDA measurements in both serum and semen plasma were performed in 50 males (18–55 y) of couples seeking fertility treatment. A significant positive correlation was found between seminal plasma-free thiol levels and sperm concentration and progressive motility (r = 0.383, p = 0.008 and r = 0.333, p = 0.022, respectively). In addition, a significant positive correlation was found between MDA levels in seminal plasma and sperm concentration (r = 0.314, p = 0.031). This study supports that seminal plasma-free thiols may be promising as local OS biomarkers. No associations were observed between local and systemic OS biomarker concentrations.

Varicocoele and oxidative stress: New perspectives from animal and human studies

BACKGROUND

Varicocoele (VCL), one of the main causes of male subfertility, negatively affects testicular function. Due to limited access to human testicular tissue, animal model studies have been used to evaluate molecular and, recently, epigenetic changes attributed to pathophysiology induced by VCL.

OBJECTIVES

This review aims to provide an update on the latest findings regarding the link between VCL-induced biochemical stress and molecular changes in germ cells and spermatozoa. Endocrine and antioxidant status, testicular chaperone-specific hemostasis failure, altered testicular ion balance, metabolic disorders, and altered carbon cycling during spermatogenesis are among the many features that will be presented.

DISCUSSION

Literature review coupled with our own findings suggests that ionic imbalance, hypoxia, hyperthermia, and altered blood flow could lead to severe chronic oxidative and nitrosative stress in patients with VCL leading to defective spermatogenesis and impairment of the integrity of all sperm cell components and compartments down to the epigenetic information they carry.

CONCLUSION

Since oxidative stress is an important feature of the reproductive pathology of VCL, therapeutic strategies such as the administration of appropriate antioxidants could be undertaken as a complementary non-invasive treatment line.

Thiol-disulphide homoeostasis as an oxidative stress marker in men with varicocele

Oxidative stress is the most common factor leading to infertility in men with varicocele. Reactive oxygen species and other markers of oxidative stress are measured to predict the extent of oxidative stress. Thiol groups are important antioxidants and essential molecules protecting organism against the harmful effects of reactive oxygen species. Thiol-disulphide homoeostasis is a unique, easy and new method to demonstrate oxidative stress. The aim of this study was to determine thiol-disulphide homoeostasis as an oxidative stress marker in infertile men with varicocele. The hormonal profile and parameters of thiol-disulphide homoeostasis were studied in 46 infertile men with varicocele, 70 fertile men with varicocele and 37 fertile controls. Infertile men with varicocele had significantly higher disulphide concentrations and disulphide/native thiol, disulphide/total thiol and native/total thiol ratios than those of fertile men with varicocele and fertile controls. According to these results, the blood plasma of patients with varicocele contains excessive oxidative stress, even in men with normospermia, and therefore, thiol-disulphide homoeostasis may be useful as an oxidative stress marker in men with varicocele.

Perspectives in Pediatric Pathology, Chapter 20. Adolescent Varicocele

Varicocele is characterized by elongation, dilatation, and tortuosity of the veins draining the testis and its covers, causing circulatory reflux along the inner spermatic vein [ 1 ]. Varicocele results in progressive testicular lesions and, if untreated, can lead to testicular atrophy [ 2 ]. Varicocele is considered the most frequently identified cause of male infertility [ 3 ]. The mechanisms involved in varicocele formation are not well known and probably are multiple, differing from one patient to another.

Lipid and protein oxidation levels in spermatozoa and seminal plasma of Asian Elephants (Elephas maximus) and their relationship with semen parameters

Peroxidation damage to spermatozoa and seminal plasma has an important role in sperm quality. Thus, the objective of this study was to determine the levels of lipid and protein oxidation in spermatozoa and seminal plasma of Asian elephants (Elephas maximus) with varying percentage of progressive motility. Lipid and protein oxidation was measured by the thiobarbituric acid-reactive species (TBARS) assay and the 2, 4-dinitrophenylhydrazine (DNPH) carbonyl groups assay, respectively. Fresh semen samples were collected from Asian elephants and classified according to the percentage of motile spermatozoa into good (>60%) and poor (≤20%) motility. Results revealed that seminal plasma malondialdehyde (MDA) and seminal plasma protein carbonyls (PCs) were significantly higher in poor motility than in good motility (p < .05). The MDA and PC levels in seminal plasma were negatively correlated with the percentages of progressive motility (p < .05). In addition, the negative correlation between sperm concentration and seminal plasma MDA level was investigated (p < .05). The sperm viability was also negatively correlated with sperm PC level (p < .05). This study indicated that lipid and protein oxidation has deleterious effect on semen quality of Asian elephants.

The varicocele: diagnostic dilemmas, therapeutic challenges and future perspectives

A varicocele is defined as the abnormal dilation of the internal testicular vein and pampiniform venus plexus within the spermatic cord. If a semen analysis is not obtained from the adolescent male, in the absence of other symptoms, the main clinical indication used by many urologists to recommend repair is testicular atrophy. The varicocele may result in testicular damage in some males causing testicular atrophy with impaired sperm production and decreased Leydig cell function, while in other males the varicocele may seemingly cause no ill effects. In adult men, varicoceles are frequently present and surgically correctable, yet the measurable benefits of surgical repair are slight according to a Cochrane review. While occurring more commonly in infertile men than fertile men, only 20% of men with a documented varicocele will suffer from fertility problems. Most varicoceles found in adolescents are detected during a routine medical examination, and it is difficult to predict which adolescent presenting with a varicocele will ultimately show diminished testicular function in adolescence or adulthood. As in adults, the mainstay of treatment for varicocele in adolescents is surgical correction. However, unlike an adult varicocelectomy (the microsurgical approach is the most common), treatment for an adolescent varicocele is more often laparoscopic. Nevertheless, the goals of treatment are the same in the adolescent and adult patients. Controversy remains as to which patients to treat, when to initiate the treatment, and what type of treatment is the best. This review will present the current understanding of the etiology, diagnosis and treatment of the adolescent varicocele.

Correlation of inhibin and several antioxidants in children with acute lymphoblastic leukemia

BACKGROUND

Acute lymphoblastic leukemia (ALL) is most common in childhood. Inhibin (a non-steroidal glycoprotein hormone of gonadal origin) can be used as marker of fertility. The current study was conducted to evaluate inhibin levels in ALL patients and to estimate its correlation with some antioxidants in these in comparison with control subjects.

MATERIALS AND METHODS

This study was conducted on sixty patients with ALL and thirty children as controls. Fasting blood samples were taken from each subject and analyzed for haemoglobin, serum protein, vitamin E and C, in addition to glutathione and inhibin.

RESULTS

The results of the study showed highly significant decreases (p<0.001) in haemoglobin, glutathione and inhibin levels with significant decreases (p<0.05) in serum protein and vitamin E levels for patients group in comparison with controls while there was no significant differences in vitamin C. Moreover, there were significant correlations between inhibin levels and serum protein, glutathione and both vitamins (E and C) in the ALL patient group (r= 0.81, 0.80, 0.77 and 0.69, respectively).

CONCLUSIONS

The present results indicated infertility in patients with ALL demonstrated by low inhibin level as a consequence of abnormality in anti-oxidative metabolism due to the cancer process. So, it can be suggested the need for routine measurement of inhibin for leukemic patients to estimate the action of hormones of gonadal origin.

Is thioredoxin reductase involved in the defense against DNA fragmentation in varicocele?

We aimed to investigate the role of thioredoxin reductase (TR) and inducible heat shock protein 70 (iHsp70) and their relationship with sperm quality in varicocele (VAR) patients. Semen samples were obtained from 16 subfertile men diagnosed as VAR and 10 fertile men who applied to the Andrology Laboratory of Istanbul Medical Faculty of Istanbul University. The sperm TR and iHsp 70 expression levels were determined using Western blot analysis. The TR activity of the sperm was assayed spectrophometrically. The sperm quality was evaluated both by conventional sperm analysis and by a terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) technique that assayed DNA-fragmented spermatozoa in semen samples. The percentage of TUNEL-positive spermatozoa in the VAR group (16.3%± 5.6%) was higher than that in the fertile group (5.5%± 1.9%). Significant inverse correlations were detected between the percentage of TUNEL-positive cells and both the concentration (r=-0.609; P=0.001) and motility (r=-0.550; P=0.004) of spermatozoa. Both the TR expression and activity were increased significantly in the VAR group (U=22.0; P=0.001 and U=33.5; P=0.012, respectively) as analyzed using the Mann-Whitney U Wilcoxon rank sum W test. Furthermore, significant positive correlations were found between TR expression and activity (r=0.406; P=0.040) and between TR expression and the percentage of TUNEL-positive cells (r=0.665; P=0.001). Sperm iHsp70 expression did not differ between the VAR and fertile groups. In conclusion, increased sperm TR expression might be a defense mechanism against apoptosis in the spermatozoa of men with VAR.

Insight into oxidative stress in varicocele-associated male infertility: part 2

Varicocele, the leading cause of male infertility, can impair spermatogenesis through several pathophysiological mechanisms. Of these, current evidence suggests that oxidative stress is the central element contributing to infertility in men with varicocele, to which the testis responds by way of heat stress, ischaemia or production of vasodilators, such as nitric oxide. Surgical varicocele repair (varicocelectomy) is beneficial not only for alleviating oxidative stress-associated infertility, but also for preventing and protecting against the progressive character of varicocele and its consequent upregulations of systemic oxidative stress. However, antioxidant therapy in infertile men with surgically treated and those with untreated varicocele is poorly studied, and well-designed trials are needed.

Seasonal changes in antioxidant defence systems in seminal plasma and fluids of the boar reproductive tract

This study aimed to analyze seasonal variations in the antioxidant defence systems of the seminal plasma and fluids of the cauda epididymis and vesicular glands of the boar. The analyzed antioxidants included superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and total L-glutathione (GSH+GSSG). Seasonal changes in total protein content and total antioxidant status (TAS) of the seminal plasma and reproductive fluids were also analyzed. Compared with the spring-summer period, total protein content in the seminal plasma was significantly higher during the autumn-winter period. Among the antioxidants analyzed, only SOD activity showed marked seasonal variations, being significantly higher during the spring-summer period. Likewise, the fluid of the cauda epididymis exhibited greater SOD and CAT activity during the spring-summer period, whereas TAS levels were markedly higher during the autumn-winter period. Neither GPx activity nor total GSH+GSSG content in the cauda epididymal fluid was significantly affected by the seasonal periods. The vesicular gland fluid exhibited an approximately 4-fold greater level of SOD activity during the autumn-winter period, as compared with the spring-summer period. By contrast, greater CAT and GPx activity, and a higher level of total GSH+GSSG were observed in the vesicular gland fluid during the spring-summer period. In conclusion, the findings of this study indicate that seasonal variations could have varying effects on the antioxidant defence systems in the seminal plasma and fluids of the boar reproductive tract.

Role of oxidative stress in pathogenesis of varicocele and infertility

This review summarizes the published literature about the role of oxidative stress in the pathophysiology of varicocele and the beneficial effects of varicocele repair on oxidative stress. Literature survey was performed using the Medline, EMBASE, BIOSIS, and Cochrane databases between 1993 and 2008 that were relevant to oxidative stress and varicocele. Varicocele treatment can reduce reactive oxygen species levels and improve sperm parameters and pregnancy rates, although it is still controversial with Assisted Reproductive Techniques outcomes. We conclude that spermatozoal dysfunction in varicocele patients could be multifactorial, and oxidative stress-induced injury appears to be one of the main causes.

Does varicocele grade determine extent of alteration to spermatogenesis in adolescents?

OBJECTIVE

To determine whether grade of varicocele determines extent of alterations to semen quality in adolescents.

DESIGN

Prospective study.

SETTING

Patients recruited from a local public school.

PATIENT(S)

Adolescents (14 to 18 y of age) attending a local public school.

INTERVENTION(S)

Scrotal palpation in a temperature-controlled room, testicular volume assessment with a Prader orchidometer, and semen analysis according to World Health Organization guidelines, with morphology by Kruger's strict criteria.

MAIN OUTCOME MEASURE(S)

Presence, and grade, or absence of varicocele; testicular volume (assessed with a Prader orchidometer); semen analysis results; and prevalence of testicular asymmetry.

RESULT(S)

Among the adolescents, 27.8% (95% confidence interval [CI]: 23.2, 32.4) presented varicocele grades II and III, and 7.8% (95% CI: 5.0, 10.6) presented with a grade III varicocele. There was a high prevalence of testicular asymmetry in adolescents with left grade II (41.7%) and III varicocele (51.9%), whereas adolescents without varicocele showed very low testicular asymmetry (11.0%). Testicular asymetry was significantly less prevalent in adolescents without varicocele. Sperm progressive motility and concentration were lower in the two varicocele groups but were not different according to grade. However, the total number of progressively motile sperm in the ejaculate was lower in the varicocele grade II and III groups, and patients with varicocele grade III presented lower values than those with grade II.

CONCLUSION(S)

Grades II and III varicocele cause a decrease in testicular volume and in semen quality that is independent of grade, but when assessing the total number of progressively motile sperm in the ejaculate, grade III varicoceles place these adolescents very close to the World Health Organization cutoff rate, and thus, current guidelines for treating the adolescent varicocele may need to be revised.

Subclinical varicocele in the pediatric age group

PURPOSE

This study was designed to assess the natural history of subclinical varicocele in the pediatric age group.

MATERIALS AND METHODS

We conducted a school screening for varicocele in 2,107 children 10 to 16 years old, performing clinical examination and venous Doppler study. A total of 354 boys (16.8%) without clinically detectable varicocele had venous testicular reflux during a Valsalva maneuver. Of these children 36 (a 10% sample) were selected randomly and followed annually for 4 years, with assessment of testicular volume (ultrasound values), degree of varicocele according to the Dubin and Amelar classification, and Doppler findings according to the Hirsh testicular Doppler classification. The control group consisted of 20 children selected randomly from the same population, who did not have a varicocele and had a normal Doppler study. Fisher's exact test was used with a significance value at p <0.05.

RESULTS

Mean age of the 36 children at the first assessment was 12.8 years (SD 1.7). Two boys (5.5%) had spontaneous resolution of testicular venous reflux within 2 years, and in 24 (67%) the subclinical varicocele did not change. The remaining 10 children (28%) had a clinically detectable varicocele, which was grade I in 1 patient, grade II in 7 and grade III in 2. Of these patients 1 had associated left testicular hypoplasia greater than 20%. During the 4-year period there were no clinically detectable varicoceles in the control group (p = 0.01).

CONCLUSIONS

The proportion of children with subclinical varicocele progressing to a clinically detectable form of the condition was 28% (95% CI 14 to 45) during a 4-year period. We suggest that children with subclinical varicocele require long-term followup.

Attenuation of oxidative stress after varicocelectomy in subfertile patients with varicocele

PURPOSE

We examined changes due to oxidative damage to spermatozoa and alterations in antioxidant capacity in subfertile patients with varicocele before and after varicocelectomy in a prospective study.

MATERIALS AND METHODS

A total of 30 young subfertile male patients with varicocele were recruited in this study. Varicocele was diagnosed by physical examination and Doppler ultrasound. Semen analysis was performed in the 30 patients before and 6 months after varicocelectomy using a computer assisted semen analyzer. The parameters for evaluating oxidative stress changes were 4977 bp deletion of mitochondrial DNA in sperm, as detected by polymerase chain reaction, the 8-OHdG (8-hydroxy-2'-deoxyguanosine) content in spermatozoa DNA, as measured by a high performance liquid chromatography electrochemical method, and seminal plasma protein thiols and ascorbic acid, as measured by spectrophotometric methods.

RESULTS

Semen quality, including motility, morphology and sperm density, was improved in 22 patients (73.3%) after varicocelectomy. The incidence of 4977 bp deletion of mitochondrial DNA in sperm was 40% (12 of 30 patients) and 13.3% (4 of 30) before and after surgery, respectively. Mean +/- SD 8-OHdG content in sperm DNA, and seminal plasma protein thiols and ascorbic acid were 10.27 +/- 2.24/10(5) 2'-deoxyguanosine, 0.77 +/- 0.75 nmole/ml and 1.87 +/- 0.40 mg/dl before operation, and 5.95 +/- 1.46/10(5) 2'-deoxyguanosine, 3.00 +/- 1.17 nmole/ml and 3.12 +/- 0.94 mg/dl after surgery, respectively. The incidence of 4977 bp deletion of mitochondrial DNA in sperm and the level of 8-OHdG in sperm DNA were decreased, and seminal plasma protein thiols and ascorbic acid were increased significantly in all 30 patients after varicocelectomy. Also, in the 8 patients in whom semen quality did not improve after surgery a significant decrease in 8-OHdG in sperm DNA, and a significant increase in seminal plasma protein thiols and ascorbic acid were observed.

CONCLUSIONS

Subfertile patients with varicocele had a significant decrease in oxidative damage in sperm DNA and an increase in antioxidant capacity in seminal plasma after varicocelectomy, indicating that surgery is effective treatment in such patients.

Oxidative stress biomarkers and hormonal profile in human patients undergoing varicocelectomy

The aetiology of varicocele is multifactorial although hormonal imbalance and oxidative stress play a key role in the progression of illness. No conclusive evidence has been presented previously, describing the changes in these two factors and the evolution of patients after varicocelectomy. Semen characteristics and hormonal profile were analysed in 36 infertile men with unilateral left varicocele and 33 age-paired controls (proved to be fertile men), after careful inclusion/exclusion selection criteria. Liposoluble and hydrosoluble antioxidants, oligoelements and enzyme activities of the antioxidant defence system were also determined in plasma and erythrocyte from antecubital and spermatic veins, and in spermatozoa. Data were compared between groups at different times before and after varicocelectomy. Decreased levels of liposoluble and hydrosoluble antioxidants and increased activities of the antioxidant defence system enzymes were observed in patients compared with controls. Varicocelectomy normalized this condition at different post-surgical times. Levels of Zn and Se in seminal plasma, protein carbonyls and fragmented DNA remained elevated up to 1 month after surgery. Luteinizing and follicle stimulating hormone concentrations exhibited a biphasic behaviour while testosterone was diminished in patients but normalized soon after varicocelectomy. The results clearly demonstrate the link between the antioxidant defence system, hormonal status and semen characteristics along the post-varicocelectomy period. We suggest that oxidative biomarkers may be appropriate in controlling the evolution of post-varicocelectomy patients, and antioxidant supplementation may improve the clinical condition of infertile men with varicocele.

Seasonal variations in antioxidant enzyme activity in ram seminal plasma

Seminal oxidative stress status is emerging as a significant prognostic tool in assisted reproductive technology. A dynamic interplay between pro- and anti-antioxidant substances in the ejaculate is essential. In this study, we determined seasonal changes in the activity of the antioxidant enzyme defense system comprising superoxide dismutase (SOD), glutathione reductase (GR), glutathione peroxidase (GPx) and catalase (CAT) in seminal plasma (SP) of mature Rasa Aragonesa rams. This breed corresponds to a local Spanish genotype with a short seasonal anoestrus between May and July. In addition, the activity of these enzymes was measured in protein fractions isolated from ram SP by exclusion chromatography. Total protein content in ram SP was higher during the breeding season (October-February) with a significantly higher value in first ejaculates. Antioxidant enzyme activities were higher during the non-breeding season (March-September). Comparing first and second ejaculates, SOD and CAT activities were higher in the first of all months. However, GR and GPx activities changed throughout the year. Thus, GR activity was higher in July and August in first ejaculates, this difference being significant in July (4.53 versus 2.37 nmol substrate/minmg protein, P<0.05). Conversely, GPx activity was significantly higher in September and November in second ejaculates (21.1 versus 6.81 and 10.91 versus 5.33, respectively, P<0.05). After SP fractionation by exclusion chromatography, GR activity was located in fractions 1 and 2 being irrelevant in the following peaks, and CAT activity was not detected all along the chromatographic profile. GPx and SOD activities were spread out along all fractions with a main peak in fractions 6 and 7. Given that these two fractions showed the greatest capacity to recover and prevent cold-shock membrane injury [Barrios B, Pérez-Pé R, Gallego M, Tato A, Osada J, Muino-Blanco T, Cebrián-Pérez JA. Seminal plasma proteins revert the cold-shock damage on ram sperm membrane. Biol Reprod 2000;63:1531-7, Barrios B, Fernández-Juan M, Muino-Blanco T, Cebrián-Pérez J. Immunocytochemical localization and biochemical characterization of two seminal plasma proteins that protect ram spermatozoa against cold shock. J Androl 2005;26:539-49], we could suggest that the protective effect might be, at least partially, due to the antioxidant enzyme activity.

Oxidative stress : relationship with exercise and training

Free radicals are reactive compounds that are naturally produced in the human body. They can exert positive effects (e.g. on the immune system) or negative effects (e.g. lipids, proteins or DNA oxidation). To limit these harmful effects, an organism requires complex protection - the antioxidant system. This system consists of antioxidant enzymes (catalase, glutathione peroxidase, superoxide dismutase) and non-enzymatic antioxidants (e.g. vitamin E [tocopherol], vitamin A [retinol], vitamin C [ascorbic acid], glutathione and uric acid). An imbalance between free radical production and antioxidant defence leads to an oxidative stress state, which may be involved in aging processes and even in some pathology (e.g. cancer and Parkinson's disease). Physical exercise also increases oxidative stress and causes disruptions of the homeostasis. Training can have positive or negative effects on oxidative stress depending on training load, training specificity and the basal level of training. Moreover, oxidative stress seems to be involved in muscular fatigue and may lead to overtraining.

Oxidized proteins and their contribution to redox homeostasis

Proteins are major target for radicals and other oxidants when these are formed in both intra- and extracellular environments in vivo. Formation of lesions on proteins may be highly sensitive protein-based biomarkers for oxidative damage in mammalian systems. Oxidized proteins are often functionally inactive and their unfolding is associated with enhanced susceptibility to proteinases. ROS scavenging activities of intact proteins are weaker than those of misfolded proteins or equivalent concentrations of their constituent amino acids. Protein oxidation and enhanced proteolytic degradation, therefore, have been suggested to cause a net increase in ROS scavenging capacity. However, certain oxidized proteins are poorly handled by cells, and together with possible alterations in the rate of production of oxidized proteins, may contribute to the observed accumulation and damaging actions of oxidized proteins during ageing and in pathologies such as diabetes, arteriosclerosis and neurodegenerative diseases. Protein oxidation may play a controlling role in cellular remodelling and cell growth. There is some evidence that antioxidant supplementation may protect against protein oxidation, but additional controlled studies of antioxidant intake to evaluate the significance of dietary/pharmacological antioxidants in preventing physiological/pathological oxidative changes are needed.

Epididymal stereocilia in semen of infertile men: evidence of chronic epididymitis?

As free stereocilia in semen samples from infertile men could be related to a subclinical chronic infection of the seminal tract, we carried out a retrospective analysis of 14 files of infertile men with stereocilia in semen (group 1) and in two control groups: 30 infertile men from the same study population (group 2) and 40 fertile sperm donors (group 3). Clinical, bacteriological, sonographic and microscopic findings associated with these semen samples were compared. Epididymal cysts were found in two of 14 men in group 1 and in four of 28 in group 2. Positive semen cultures for Chlamydia trachomatis, Mycoplasma hominis or Ureaplasma urealyticum (chi(2) = 8.20; P = 0.002; OR: 7.22) and varicocele (chi(2) = 8.96; P = 0.002; OR: 2.25) were associated to the presence of free stereocilia in semen. These data suggest that a silent chronic infection of the epididymis by C. trachomatis, M. hominis, U. urealyticum and/or inflammation produced by varicocele might be the cause of stereocilia loss in the semen.

Glutathione and free sulphydryl content of seminal plasma in healthy medical students during and after exam stress

BACKGROUND

It has been reported that there is a relationship between stress and infertility. The mechanisms of stress-related semen quality alterations have not been fully elucidated. In the present study, we investigated the effect of examination stress on seminal glutathione and free sulphydryl content and sperm quality.

METHODS

Semen samples were collected from 34 healthy volunteers who were students of medical school in the fourth semester just before (stress period) and 3 months after (non-stress period) their final examinations. Their psychological examination stress was measured by the State Trait Anxiety Inventory (STAI) questionnaire. After standard semen analysis, semen samples were centrifuged at 10 000g for 15 min. Glutathione and free sulphydryl concentration of seminal plasma were measured.

RESULTS

During the period of examination stress, the glutathione and free sulphydryl content of seminal plasma and the motility index of spermatozoa were significantly lower, whereas the percentage of morphologically abnormal spermatozoa was higher, than during the non-stress period (P < 0.001, for all). An association between seminal plasma glutathione and motility index was observed at both periods (P < 0.05 and P < 0.01, respectively).

CONCLUSIONS

This study demonstrated that glutathione and free sulphydryl levels in seminal plasma decreased in subjects undergoing examination stress. Furthermore, poor sperm quality may be due to loss of glutathione and free sulphydryl content of seminal plasma.

8-HYDROXY-2′-DEOXYGUANOSINE IN LEUKOCYTE DNA OF SPERMATIC VEIN AS A BIOMARKER OF OXIDATIVE STRESS IN PATIENTS WITH VARICOCELE

PURPOSE

We examined oxidative damage to leukocyte DNA in the spermatic vein and sperm DNA of patients with varicocele.

MATERIALS AND METHODS

A total of 32 young male patients with varicocele (group 1), 20 young male patients with subclinical varicocele (group 2) and 15 normal young males without varicocele (group 3) were recruited in this study. Varicocele and subclinical varicocele were confirmed by physical examination and Doppler ultrasonography. Blood samples were drawn from peripheral and spermatic veins of controls and patients before varicocelectomy. The 8-hydroxy-2'-deoxyguanosine (8-OHdG) in leukocyte DNA and sperm DNA were measured by high performance liquid chromatography. The 4977 bp deletion of mitochondrial DNA (mtDNA) in spermatozoa was detected by polymerase chain reaction.

RESULTS

The mean 8-OHdG level +/- SD in leukocyte DNA of spermatic veins was significantly higher than that of corresponding peripheral veins in groups 1 and 2 (12.39 +/- 2.90 vs 7.11 +/- 0.75/10 deoxyguanosine for group 1 and 10.28 +/- 2.43 vs 6.82 +/- 0.62/10 deoxyguanosine for group 2, p <0.001). The 8-OHdG level in leukocyte DNA of the spermatic vein and 8-OHdG in sperm DNA were highest in group 1 followed by those in groups 2 and 3, and correlated inversely with motility, morphology and density of spermatozoa. The incidence of 4977 bp deletion of mtDNA in sperm was 40.6%, 20% and 0% in groups 1, 2 and 3, respectively. These results indicate that oxidative stress in patients with varicocele or subclinical varicocele was greater than in healthy subjects.

CONCLUSIONS

8-OHdG in leukocyte DNA of the spermatic vein and in sperm DNA, and 4977 bp deletion of mtDNA in sperm might be useful markers for the assessment of oxidative stress in patients with varicocele and subclinical varicocele.

Increased nitric oxide is accompanied by lipid oxidation in adolescent varicocele

Summary One of the mechanisms of injury in varicocele has been proposed to be elevated nitric oxide (NO). We aimed to determine the association between the elevation of NO and lipid oxidation in varicocele compared with peripheral venous levels of these two substances as it has not been studied before. The study group consisted of 13 adolescents with left idiopathic varicocele of grades II-III. Blood specimens were obtained from dilated spermatic and peripheral veins simultaneously. Peripheral samples were also collected from 13 healthy children as controls. Nitrite/nitrate levels (NO(x)) and levels of malonedialdehyde (MDA) were determined using Griess reaction and thiobarbituric acid test, respectively. Results were compared with Kruskal-Wallis and Mann-Whitney tests. Peripheral NO(x) and MDA were the same in the study and control groups (p = 0.069 and p = 0.27, respectively). Spermatic vein NO(x) and MDA levels were elevated significantly compared with the peripheral levels in the study group (p = 0.005 and p = 0.048, respectively). Increased NO(x) levels with lipid oxidation occur locally in adolescent varicocele, implying that these events could be reversed by early treatment.

Male Reproductive Toxicity of Trichloroethylene: Sperm Protein Oxidation and Decreased Fertilizing Ability1

The objective of the present study was to characterize and investigate potential mechanisms for the male reproductive toxicity of trichloroethylene (TCE). Male rats exposed to TCE in drinking water exhibited a dose-dependent decrease in the ability to fertilize oocytes from untreated females. This reduction in fertilizing ability occurred in the absence of treatment-related changes in combined testes/epididymides weight, sperm concentration, or sperm motility. In addition, flow cytometric analysis showed that there were no treatment-related differences in sperm mitochondrial membrane potential or acrosomal stability. TCE caused slight histological changes in efferent ductule epithelium, coinciding with the previously reported ductule localization of cytochrome P450 2E1. However, no alterations were noted in the testis or in any segment of the epididymis. Because there were no treatment-related changes to sperm indices and no clear pathological lesions to explain the reduced fertilization, the present study investigated TCE-mediated sperm oxidative damage. Oxidized proteins were detected by immunochemical techniques following the derivatization of sperm protein carbonyls with dinitrophenyl hydrazine. Immunochemical staining of whole, intact sperm showed the presence of halos of oxidized proteins around the head and midpiece of sperm from TCE-treated animals. The presence of oxidized sperm proteins was confirmed by Western blotting using in vitro-oxidized sperm as a positive control. Thiobarbituric acid reactive substances analyses showed a dose-dependent increase in the level of lipid peroxidation in sperm from treated animals, as well. Oxidative damage to sperm may explain the diminished fertilizing capacity of exposed animals and provide another mechanism by which TCE can adversely affect reproductive capabilities in the male.

Evaluation of nuclear DNA damage in spermatozoa from infertile men with varicocele

OBJECTIVE

To examine levels of sperm DNA damage and oxidative stress (OS) in infertile men with varicocele.

DESIGN

Prospective controlled study.

SETTING

Male infertility clinic, Glickman Urological Institute, Cleveland Clinic Foundation, Cleveland, Ohio.

PATIENT(S)

Thirty-one infertility patients and 16 fertile controls.

INTERVENTION(S)

Sperm DNA fragmentation index (DFI), levels of seminal reactive oxygen species (ROS), and total antioxidant capacity (TAC) were assessed using the sperm chromatin structure assay, chemiluminescence assay, and enhanced chemiluminescence assay, respectively. ROS-TAC score was calculated as a measure of OS.

MAIN OUTCOME MEASURE(S)

Median (interquartile range) DFI and ROS-TAC scores.

RESULT(S)

Sixteen of the 31 patients had left varicocele [grade I (n = 3), grade II (n = 10), and grade III(n = 3)], and the remaining 15 had normal genital examination. Patients with varicoceles had significantly higher percent DFI than controls (25%, range: 20%-35%; vs. 15%, range: 10%-22%). Patients with varicoceles had significantly lower ROS-TAC scores (21, range: 9.5-31) than the infertile patients with normal genital examination (34, range: 28-42) or the controls (40.3, range: 38-44).

CONCLUSION(S)

Infertile men with varicoceles showed significantly increased spermatozoal DNA damage that appears to be related to high levels of OS in semen.

Seminal antioxidant capacity in pre- and postoperative varicocele

In order to explore the impact of surgical treatment on antioxidant defense system in varicocele (VAR), we evaluated seminal total antioxidant capacity (TAC) in 25 patients affected by VAR, in 14 patients studied 10-24 months after varicocelectomy (post-VAR) and separated into normo- and oligospermic groups, and in 24 non-VAR control patients with seminal parameters matched to patients with VAR in the oligo- and normospermic groups (7 subjects with idiopathic oligospermia and 17 normal fertile subjects). TAC was measured in seminal plasma with the system H(2)O(2)-metamyoglobin as a source of radicals, which interact with a chromogen 2,2',-azinobis (3-ethylbenzothiazoline-6-sulphonate) (ABTS), generating a radical cation spectroscopically detectable. The presence of antioxidants induces a lag time in the production of ABTS cation proportional to the concentration of antioxidant compounds. When whole groups of patients were analyzed, lag values were significantly higher in VAR vs non-VAR controls (mean +/- SEM, 106.6 +/- 8.8 seconds vs 78.7 +/- 8.8 seconds) but were not modified by surgery (mean +/- SEM, 105.8 +/- 8.6 seconds). In groups separated according to seminal parameters, oligospermic VAR presented significantly higher lag values than oligospermic controls. Finally, when exploring a possible association of TAC with seminal parameters, we found a significant correlation between lag and sperm motility only in patients with VAR who were in the normospermic group (r = 0.65, P <.01). This correlation was not yet manifest post-VAR. In conclusion, surgical treatment does not seem to modify absolute values of TAC but influences its fine regulation and relationships with sperm motility.

Protein carbonylation in human diseases

Oxidative modifications of enzymes and structural proteins play a significant role in the aetiology and/or progression of several human diseases. Protein carbonyl content is the most general and well-used biomarker of severe oxidative protein damage. Human diseases associated with protein carbonylation include Alzheimer's disease, chronic lung disease, chronic renal failure, diabetes and sepsis. Rapid recent progress in the identification of carbonylated proteins should provide new diagnostic (possibly pre-symptomatic) biomarkers for oxidative damage, and yield basic information to aid the establishment an efficacious antioxidant therapy.

Protein carbonyl groups as biomarkers of oxidative stress

Oxidative stress, an imbalance toward the pro-oxidant side of the pro-oxidant/antioxidant homeostasis, occurs in several human diseases. Among these diseases are those in which high levels of protein carbonyl (CO) groups have been observed, including Alzheimer's disease (AD), rheumatoid arthritis, diabetes, sepsis, chronic renal failure, and respiratory distress syndrome. What relationships might be among high level of protein CO groups, oxidative stress, and diseases remain uncertain.The usage of protein CO groups as biomarkers of oxidative stress has some advantages in comparison with the measurement of other oxidation products because of the relative early formation and the relative stability of carbonylated proteins. Most of the assays for detection of protein CO groups involve derivatisation of the carbonyl group with 2,4-dinitrophenylhydrazine (DNPH), which leads to formation of a stable dinitrophenyl (DNP) hydrazone product. This then can be detected by various means, such as spectrophotometric assay, enzyme-linked immunosorbent assay (ELISA), and one-dimensional or two-dimensional electrophoresis followed by Western blot immunoassay. At present, the measurement of protein CO groups after their derivatisation with DNPH is the most widely utilized measure of protein oxidation.

Preliminary report on nitric oxide-mediated oxidative damage in adolescent varicocele

BACKGROUND

The current study was designed to characterize the process of nitric oxide (NO) and peroxynitrite generation through the determination of nitrotyrosine concentration in the dilated veins of varicoceles in adolescents.

METHODS

Ten adolescents with a median age of 13 years (range 12-17) affected by a left idiopathic varicocele (grade II and III) were studied. Whole blood samples were withdrawn from a peripheral vein at time of induction of anaesthesia, and from a dilated spermatic vein before ligation. Peripheral blood samples from five adolescents undergoing minor surgical procedures were used as controls. The nitrotyrosine concentration was evaluated by a sandwich enzyme-linked immunosorbent assay (ELISA), using a monoclonal anti-nitrotyrosine antibody and Western blot analysis.

RESULTS

Plasma nitrotyrosine concentrations were significantly greater in the spermatic vein when compared with the peripheral vein (P = 0.031). Nitrotyrosine in plasma of controls did not show any significant difference in comparison with peripheral samples from varicocele patients. Western blot analysis confirmed the above data.

CONCLUSIONS

In adolescents with a varicocele, there is an increase in nitrotyrosine concentration within the spermatic vein that can cause protein nitration and cytotoxicity via its reaction with various molecular targets. This could have repercussions on both sperm and testis function. We conclude that an oxidative stress status is present and should be considered as an indication for varicocele treatment in the adolescent.

Protective effect of Fructus Lycii polysaccharides against time and hyperthermia-induced damage in cultured seminiferous epithelium

Lycium barbarum L. (Solanaceae) is a Chinese medicinal plant whose fruits (Fructus Lycii) are used by Chinese physicians for treatment of infertility. However, the active ingredients and the mechanism of action underlying Lycium's fertility-facilitating effects remain unknown. Here we report that Fructus Lycii polysaccharides (FLPS) inhibit time- and hyperthermia-induced structural damage in murine seminiferous epithelium, in vitro. Moreover, we found that FLPS delayed apoptosis in this system, both at normothermic and hyperthermic culture conditions. Oxidative stress was reported to be a major cause of structural degradation and apoptosis in hyperthermic testes, and thus the protective effect of FLPS could implicate an antioxidant mechanism of action. To test this hypothesis we assayed the effect of FLPS on ultraviolet light-induced lipid peroxidation, and cytochrome c reduction by free radicals. We found that FLPS is a potent inhibitor of both of these reactions. Together, these results demonstrate the protective effect of FLPS on time- and hyperthermia-induced testicular degeneration in vitro, indicate the potential mechanism of action for this protective effect, and provide a scientific basis for the traditional use of this plant.

Polymorphisms of glutathione S-transferase M1 and male infertility in Taiwanese patients with varicocele

BACKGROUND

To examine glutathione S-transferase M1 (GST M1) gene polymorphism and male infertility in Taiwanese patients with varicocele, 80 young male patients with varicocele (group 1), 62 young male patients with subclinical varicocele (group 2) and 60 normal young males (group 3) were recruited in this study.

METHODS

GST M1 null homozygous genotype [GST M1-] and the occurrence of a 4977 bp deletion of sperm mitochondrial DNA (mtDNA) were determined by polymerase chain reaction. The 8-hydroxy-2'-deoxyguanosine (8-OHdG) content of sperm DNA was measured by high-performance liquid chromatography.

RESULTS

The frequencies of GST M1- genotype were 43.8, 41.9 and 45% for patients in groups 1, 2 and 3 respectively. In group 1 patients with GST M1- genotype, the frequency of the presence of the 4977 bp deletion in sperm mtDNA (54.3%) was significantly higher than that of the patients without the 4977 bp deletion in sperm mtDNA (45.7%, OR: 2.63, P = 0.04). Patients of groups 1 and 2 with GST M1- genotype had significantly higher 8-OHdG content in sperm DNA and lower protein thiols and ascorbic acid in seminal plasma than those with GST M1+ genotype.

CONCLUSION

GST M1- genotype predisposes to increased oxidative damage to sperm of patients with varicocele.

Oxidative stress, spermatogenesis and fertility

Reactive oxygen species production and glutathione depletion in mammalian male germ cells are physiological events that are requisite to the functional maturation and capacitation of spermatozoa. In relation to this oxidative stress, an oxidation of the bulk of protein sulfydryl groups takes place during the final phases of male germ cell maturation. The selenoenzyme phospholipid hydroperoxide glutathione peroxidase catalyzes this reaction, and accounts for both the assembly of the mid-piece of spermatozoa and chromatin condensation. This process highlights the role of H2O2 and selenium in spermatogenesis and provides a mechanism for coupling a 'physiologically controlled' oxidative stress to a specialized phenotypic function.