Sperm parameter abnormalities, low seminal fructose and reactive oxygen species overproduction do not discriminate patients with unilateral or bilateral post-infectious inflammatory prostato-vesiculo-epididymitis

Chronic prostatitis/chronic pelvic pain syndrome induces metabolomic changes in expressed prostatic secretions and plasma

Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) is a complex disease that is often accompanied by mental health disorders. However, the potential mechanisms underlying the heterogeneous clinical presentation of CP/CPPS remain uncertain. This study analyzed widely targeted metabolomic data of expressed prostatic secretions (EPS) and plasma to reveal the underlying pathological mechanisms of CP/CPPS. A total of 24 CP/CPPS patients from The Second Nanning People's Hospital (Nanning, China), and 35 asymptomatic control individuals from First Affiliated Hospital of Guangxi Medical University (Nanning, China) were enrolled. The indicators related to CP/CPPS and psychiatric symptoms were recorded. Differential analysis, coexpression network analysis, and correlation analysis were performed to identify metabolites that were specifically altered in patients and associated with various phenotypes of CP/CPPS. The crucial links between EPS and plasma were further investigated. The metabolomic data of EPS from CP/CPPS patients were significantly different from those from control individuals. Pathway analysis revealed dysregulation of amino acid metabolism, lipid metabolism, and the citrate cycle in EPS. The tryptophan metabolic pathway was found to be the most significantly altered pathway associated with distinct CP/CPPS phenotypes. Moreover, the dysregulation of tryptophan and tyrosine metabolism and elevation of oxidative stress-related metabolites in plasma were found to effectively elucidate the development of depression in CP/CPPS. Overall, metabolomic alterations in the EPS and plasma of patients were primarily associated with oxidative damage, energy metabolism abnormalities, neurological impairment, and immune dysregulation. These alterations may be associated with chronic pain, voiding symptoms, reduced fertility, and depression in CP/CPPS. This study provides a local-global perspective for understanding the pathological mechanisms of CP/CPPS and offers potential diagnostic and therapeutic targets.

[Infections and male infertility]

BACKGROUND

The role of urogenital infections in male infertility has long been the subject of debate.

METHODS

A bibliographic search limited to English-language literature on human subjects published before 5/2023 resulted in the selection of 189 articles.

RESULTS

Male infertility is often of multifactorial aetiology, and to optimise the prognosis it is important to manage all the factors that can be corrected, including infectious causes, which represent one of the most frequent aetiologies. The infectious agents involved in urogenital infections are most often bacterial or viral, and more rarely parasitic. They can infect the seminal tract, male accessory glands and/or testicles, and usually result in inflammation and increased oxidative stress. These infections reduce male fertility, in particular by altering spermogram parameters and increasing sperm DNA fragmentation. For these reasons, the search for a urogenital infection should be systematic, involving a careful history and clinical examination, ultrasound and systematic bacteriological tests guided by clinical findings. Aetiological treatment may be proposed depending on the picture and the germ involved.

CONCLUSION

This review should help the urologist to establish an accurate diagnosis of the form and extent of the infection, and enable him to define an appropriate therapeutic strategy, tailored to the patient, in order to obtain the best chances of improving male fertility.

Levofloxacin Versus Ciprofloxacin in the Treatment of Urinary Tract Infections: Evidence-Based Analysis

Urinary tract infections (UTIs) are one of the most common bacterial infections acquired both in community and hospital. Fluoroquinolones, represented by levofloxacin and ciprofloxacin, are widely used for treatment of UTIs. However, it remains controversial for the comparison between the 2 drugs, which propelled us to conduct the first evidence-based research on this topic. To establish their relative efficacy and safety, we searched Pubmed, embase, and Web of Science for randomized controlled trials (RCTs) for UTIs. A total of 5 RCTs were finally included, involving 2,352 patients and a systematic review and meta-analysis were performed to compare the end-of-therapy and posttherapy clinical success rate, microbial eradication rate and adverse event rate. Jadad score and Review Manager 5.3.0 version were applied respectively to evaluate the study quality and heterogeneity. There was no significant difference between levofloxacin and ciprofloxacin group in end-of-therapy or posttherapy clinical success rate and microbial eradication rate (p > 0.05). As for adverse event rate, the 2 drugs were comparable and both safe for clinical use. Based on one included trial and pharmacological research, we raised hypothesis that levofloxacin was superior to ciprofloxacin for treatment of E. coli-induced chronic bacterial prostatitis (CBP) and it required a further study to prove it.

Ultrasound evaluation of patients with male accessory gland inflammation: a pictorial review

Male accessory gland infection/inflammation (MAGI) is a major cause of male infertility. The importance of ultrasound evaluation in these patients is highly controversial, although evidence of its relevance has increased in recent years. Ultrasound criteria are an important element for confirming the clinical diagnosis. Furthermore, they help to localize the anatomical site or sites of the inflammatory process and in assessing its extension which, in turn, have different consequences on the seminological and symptomatic aspects. This article summarizes the clinical interpretations related to ultrasound aspects in patients with MAGI and the possible effects on the seminological, microbiological, endocrinologic, urological, sexological, and internist aspects.

The Relationship between Seminal Fluid Hyperviscosity and Oxidative Stress: A Systematic Review

INTRODUCTION

Seminal fluid viscosity is a key parameter to achieve fertilization. Viscosity is more frequently increased in patients with infertility. However, the mechanism by which hyperviscosity causes infertility is still poorly understood. As an increased blood viscosity is associated with diseases caused by oxidative stress, it can be supposed that there is a relationship between seminal fluid viscosity and oxidative stress in male infertility. Therefore, this systematic review aims to investigate the relationship between hyperviscous seminal fluid and oxidative stress.

MATERIALS AND METHODS

We performed a systematic search on the following databases Pubmed, MEDLINE, Cochrane, and Scopus from the earliest available date to 10 January 2021, using Medical Subjects Headings (MeSH) indexes and keywords searches. The study included all the articles that evaluated the relationship between increased seminal fluid viscosity and oxidative stress. Article reviews even though dealing with seminal fluid hyperviscosity were excluded.

RESULTS

5 articles were included in this systematic review. The results demonstrated an important impairment of antioxidant systems and increased oxidative stress in patients with high seminal fluid viscosity.

CONCLUSIONS

These findings suggest that a careful assessment of oxidative stress in patients with hyperviscosity may be very useful in clinical practice. Infertile patients with seminal fluid hyperviscosity could benefit from the treatment with antioxidants to protect sperm cells from oxidative damage and to improve their functional properties.

Evaluation of the NOX5 protein expression and oxidative stress in sperm from asthenozoospermic men compared to normozoospermic men

PURPOSE

NADPH oxidase 5 (NOX5), the main isoform of NOX in spermatozoa, has been recognized as the main active generators of reactive oxygen species (ROS), including superoxide anion (O ₂ ^-. ) and hydrogen peroxide (H₂O₂). ROS have been shown to play important roles in many physiological and pathological conditions in spermatozoa. The present study aims to investigate the alterations of NOX5 protein expression and oxidative stress (OS) status in asthenozoospermic men compared to normozoospermic men.

METHODS

Semen samples were collected from 25 asthenozoospermic men and 28 normozoospermic men. In this study, NOX5 protein expression was evaluated by Western blotting. An OS status was evaluated by measuring of ROS (O ₂ ^-. and H₂O₂), DNA damage and plasma membrane integrity in spermatozoa.

RESULTS

The protein expression of NOX5 (p < 0.0001) was remarkably higher in asthenozoospermic men in comparison to normozoospermic men. In addition, the percentages of intracellular O ₂ ^-. (p < 0.0001), H₂O₂ (p < 0.0001) in viable spermatozoa, apoptotic sperm cells with altered plasma membrane (p < 0.001) and DNA damage (p = 0.001) were significantly increased in asthenozoospermic men compared to normozoospermic men.

CONCLUSIONS

The present study provides evidence that the overexpression of NOX5 protein may induce excessive ROS production and oxidative stress damages to DNA and plasma membrane integrity in asthenozoospermic men.

Chronic Administration of Tadalafil Improves the Symptoms of Patients with Amicrobic MAGI: An Open Study

Aim of this study was to evaluate the effects of pharmacological treatment with Tadalafil 5 mg daily on symptoms and quality of sperm parameters in selected patients with amicrobic MAGI (male accessory gland inflammation). 120 patients with amicrobic MAGI (mean age 27.0 ± 6.0 years) with mild-moderate ED (erectile dysfunction) according to IIEF-5 (International Index of Erectile Function 5 Items) scores underwent pharmacological treatment with Tadalafil 5 mg daily for six months. Before and after treatment these patients were evaluated through IIEF-5, semen analysis (according to WHO Criteria, 2010), SI-MAGI (Structured Interview about Male Accessory Gland Inflammation), and ultrasound evaluation. Patients with PVE (prostate-vesciculo-epididymitis) showed a significant increase in the percentage of spermatozoa with total (16.0 ± 8.0 versus 30.0 ± 6.0%) and progressive motility (8.00 ± 10.0 versus 25.0 ± 6.00%). It was a significant reduction of the number of patients with complicated ultrasound forms (30.0 versus 52.0) and a significant increase of the number of patients with uncomplicated ultrasound form (90.0 versus 68.0). Finally, there was a significant reduction in the percentage of patients with alterations of sexual function different from DE, such as premature ejaculation (4.00 versus 8.00%), painful ejaculation (4.00 versus 10.0%), delayed ejaculation (12.50 versus 8.00%), and decreased libido (10.0 versus 25.0%).

Male accessory gland infection: relevance of serum total testosterone levels

Aim of the present study was to evaluate the different ultrasound characterization of fertile symptomatic patients with MAGI (male accessory gland infection) according to different serum concentrations of total T (TT). We analyzed the ultrasound and hormonal data of 200 patients aged between 24.0 and 67.0 years. Patients were divided into six groups according to the sextile distribution of TT. Patients with serum concentrations of TT < 3.6 ng mL(-1) had a higher mean duration of symptoms compared to the other examined groups. Patients with serum concentrations of TT > 6.6 ng mL(-1) showed a frequency of ultrasound criteria suggestive for bilateral form of prostatitis and prostate-vesiculo-epididymitis and significantly lower compared to the other examined groups. At multivariate logistic regression analysis adjusted for age and BMI, TT was an independent predictive factor of prostatovesiculitis (OR = 0.818 [95% CI: 0.675-0.992]; P < 0.01) and prostate-vesiculo-epididymitis (OR = 0.714 [95% CI: 0.578-0.880]; P < 0.01), which represent the main forms of complicated MAGI. The results of this study suggest that male hypogonadism could be associated with a different ultrasound characterization of these patients.

Microbiological investigation in male infertility: a practical overview

The roles of inflammation and/or infection of the male accessory sex glands are very important for the potential effects that these conditions may have on male fertility. The clinical andrologist should be aware of the pathophysiological role of the main determinants of sperm damage when these conditions occur, in particular, seminal leukocytes, oxidative stress and cytokines. In addition, it is important to have a good knowledge of the methodologies to be used in clinical practice. This article summarizes the methods used to look for and to identify the micro-organisms responsible for male urogenital tract infections. These include sperm culture, urine culture, urethral swabbing, the Meares–Stamey test and balanopreputial swabbing. Finally, we discuss the role of human papilloma virus infection in male infertility.

Persistence of ultrasound alterations after antibiotic treatment with levofloxacin in patients with male accessory gland infection

No studies have evaluated the ultrasound features of the male sex accessory glands in infertile patients with bacterial male accessory gland infection (MAGI) according to the microbiological outcomes of bacterial cultures (absent, partial or complete) following antibiotic therapy administration. Therefore, the aim of this study was to evaluate the ultrasound characteristics of the prostate, seminal vesicles, and epididymal tracts after treatment with levofloxacin (a common quinolone antibiotic), in patients with infections caused by Escherichia coli (a Gram-negative bacterium) according to the Naber's classification, which includes the following categories: eradication, eradication with superinfection, persistence and persistence with superinfection. The study was conducted in 100 patients aged 25±8 years (range: 20-40 years) with bacterial MAGI and bacterial cultures positive only for E. coli (colony forming units ≥10(6) per ml). Retrospective analysis was conducted only on patients treated with oral levofloxacin (500 mg) administered once daily for 28 days who were recruited over the last 5 years. Following antibiotic treatment, patients with microbiological persistence or persistence with superinfection had a significantly higher percentage of ultrasound abnormalities suggestive of prostato-vesiculitis (PV) (30.2% and 36.0%, respectively) or prostato-vesiculo-epididymitis (PVE) (60.2% and 70.0%, respectively) compared with patients with microbiological eradication (PV=10.2% and PVE=8.2%, respectively) or eradication with superinfection (PV=18.8% and PVE=21.2%, respectively). In conclusion, patients with microbiological persistence or persistence plus superinfection showed the highest prevalence of complicated forms of MAGI (PV and PVE), compared with patients with microbiological eradication or eradication with superinfection.

Semen alterations and flow-citometry evaluation in patients with male accessory gland infections

Male accessory gland infections (MAGI) represent a major cause of male infertility mainly through the secretory dysfunction of the prostate, seminal vesicles, and epididymis. This study was undertaken to evaluate conventional and nonconventional sperm parameters in these patients, therefore 150 patients with MAGI were selected. Each of them underwent to two sperm analyses and evaluation of DNA fragmentation mitochondrial membrane potential (MMP), phosphatidylserine (PS) externalization, chromatin compactness, by flow cytometry. Results showed that patients with MAGI had a lower sperm progressive motility (11.4 ± 5.0 vs 34.0 ± 7.0%), and percentage of normal forms (9.0 ± 3.7 vs 33.0 ± 13.0%) compared to controls, instead, these patients showed higher number of seminal white blood cells (2.2 ± 1.0 vs 0.4 ± 0.6 106/ml). Patients with MAGI showed a higher number of spermatozoa with DNA fragmentation compared to controls (8.2 ± 3.0 vs 1.0 ± 1.0%). In addition, they have also a higher percentage of spermatozoa with low MMP (28.0 ± 4.0 vs 2.0 ± 2.0%). Patients with MAGI, showed a higher percentage of spermatozoa with PS externalization (8.0 ± 4.0 vs 3.0 ± 3.0%), an early sign of apoptosis, and lower percentage of viable spermatozoa (64.5 ± 12.0 vs 88.0 ± 10.0%). An increased percentage of spermatozoa with abnormal chromatin compactness (18.0 ± 4.0 vs 5.0 ± 3.0%) was found in patients with MAGI. In conclusion, patients with MAGI show alterations of conventional and biofunctional sperm parameters compared to controls. These results suggest to consider the flow cytometry evaluation among the diagnostic tools for male infertility.

Seminal vesicles and diabetic neuropathy: ultrasound evaluation in patients with couple infertility and different levels of glycaemic control

The aim of this study was to evaluate the ultrasound characteristics of the seminal vesicles (SVs) of infertile patients with diabetes mellitus (DM) and diabetic neuropathy (DN) and to investigate possible changes in ultrasound characteristics related to glycaemic control. To accomplish this, 45 infertile patients with type 2 DM and symptomatic DN were selected. Twenty healthy fertile men and 20 patients with idiopathic oligoasthenoteratozoospermia without DM represented the control groups. DM patients were arbitrarily divided into three groups according to glycaemic control level (A=glycosylated haemoglobin <7%; B=glycosylated haemoglobin between 7% and 10%; C=glycosylated haemoglobin >10%). Patients underwent prostate-vesicular transrectal ultrasonography and sperm analysis. The following SV ultrasound parameters were recorded: (i) body antero-posterior diameter (APD); (ii) fundus APD; (iii) parietal thicknesses of the right and left SVs; and (iv) the number of polycyclic areas within both SVs. We then calculated the following parameters: (i) fundus/body (F/B) ratio; (ii) difference of the parietal thickness between the right and the left SV; and (iii) pre- and post-ejaculatory APD difference. All DM patients had a higher F/B ratio compared to controls (P<0.05). Group C had a higher F/B ratio compared to the other DM groups (P<0.05). All DM patients had a lower pre- and post-ejaculatory difference of the body SV APD compared to controls (P<0.05). Groups A and B had a similar pre- and post-ejaculatory difference of the body SV APD, whereas this difference was lower in Group C (P<0.05). In conclusion, infertile DM patients with DN showed peculiar SV ultrasound features suggestive of functional atony, and low glycaemic control was associated with greater expression of these features.

Hypertrophic-congestive and fibro-sclerotic ultrasound variants of male accessory gland infection have different sperm output

INTRODUCTION

Male accessory gland infection (MAGI) exerts a negative influence on male fertility which depends upon its extension. Indeed, we have shown that patients with MAGI involving prostate, seminal vesicles and epididymis have worse sperm parameters compared with patients with prostatitis alone or prostate-vesiculitis. Similarly, MAGI extending bilaterally is associated with a worse sperm output. The aims of this study were to evaluate the prevalence of two different additional ultrasound (US) findings (hypertrophic- congestive and a fibro-sclerotic US form) and to evaluate their semen quality.

MATERIALS AND METHODS

One hundred infertile patients with MAGI, diagnosed according to the World Health Organization (WHO) 1993 criteria, were evaluated by scrotal and transrectal ultrasound scans. The control group consisted of 100 healthy, age-matched men.

RESULTS

The ultrasound examination confirms two separate US variants of MAGI: a hypertrophic-congestive (prevalence of 56%) and a fibro-sclerotic form (prevalence of 29%). Patients with hypertrophic-congestive MAGI showed higher sperm concentration, motility and normal forms, but also higher sperm leukocytes concentration and seminal reactive oxygen species compared to patients with fibro-sclerotic MAGI. However, all these parameters were significantly worse than those observed in the control group.

DISCUSSION

Infertile patients with hypertrophic-congestive MAGI have a better sperm quality compared with patients with fibrosclerotic MAGI; however, they showed higher oxidative stress in semen.

Elevated body mass index correlates with higher seminal plasma interleukin 8 levels and ultrasonographic abnormalities of the prostate in men attending an andrology clinic for infertility

BACKGROUND

Obesity is associated with a systemic, low-grade inflammatory state. Although the relationship between obesity and semen parameters or prostate diseases has been previously investigated, the association between body mass index (BMI), prostate inflammatory diseases and color- Doppler ultrasound (CDU) of the male genital tract (MGT) has been poorly studied.

AIM

To evaluate the association between BMI and CDU features of the MGT, signs and symptoms of prostate inflammation, semen parameters.

MATERIALS/SUBJECTS AND METHODS

We studied 222 men seeking medical care for couple infertility. According to the World Health Organization classification, subjects were divided into 3 groups: normal weight (no.=131, BMI=18.5-24.9 kg/m2), overweight (no.=71, BMI=25.0-29.9 kg/m2), obese (no.=20, BMI≥30.0 kg/m2). All patients underwent simultaneous testosterone evaluation and seminal analysis, including interleukin 8 (sIL-8), along with scrotal and transrectal CDU, before and after ejaculation. Prostatitis symptoms were evaluated by National Institutes of Health- Chronic Prostatitis Symptom Index questionnaire.

RESULTS

After adjusting for age and testosterone levels, higher BMI was significantly related to higher prostate volume and several CDU features of the prostate, including macro-calcifications, inhomogeneity, higher arterial peak systolic velocity (the latter adjusted also for blood pressure), but not with abnormalities of testis, epididymis, seminal vesicles. Furthermore, higher BMI and BMI class were significantly related to higher sIL-8, a reliable surrogate marker of prostate inflammatory diseases, even after adjustment for age. Conversely, no associations among BMI, clinical symptoms of prostatitis or semen parameters were observed.

CONCLUSIONS

Subjects with higher BMI might develop CDU and biochemical signs suggestive of prostate inflammation, although not clinically overt.

Ultrasonographic evaluation of patients with male accessory gland infection

MAGI is the inflammation of the accessory male glands that notoriously exerts a negative influence on male fertility. The diagnosis is integrated by clinical, laboratory and ultrasound evaluation. In particular, the ultrasound criteria were published in 1999. The aim of this study was to analyse the sensitivity and specificity of additional diagnostic ultrasound criteria as well as of conventional criteria in a selected category of infertile patients with MAGI. To accomplish this, 100 patients with MAGI were evaluated by scrotal and transrectal ultrasound by three different operators. The control group consisted of 100 age-matched healthy men. Statistical analysis was performed to evaluate sensitivity, specificity, positive and negative predictive values, and ROC curve analysis. The results showed that additional ultrasound criteria had a diagnostic accuracy similar to traditional criteria. The threshold value of two criteria for each diagnostic category (traditional and additional criteria) obtained high values of sensitivity and specificity. In conclusion, this study confirms the validity of the ultrasound criteria of MAGI previously published; in addition, it suggests the clinical utility of other indicators in clinical practice with good diagnostic accuracy and finally it establishes a clear threshold ultrasonographic value for the diagnosis of MAGI.

Male accessory gland infection and sperm parameters (review)

Male accessory gland infection (MAGI) has been identified among those diagnostic categories which have a negative impact on the reproductive function and fertility in males (Rowe et al., World Health Organization Manual for the Standardised Investigation and Diagnosis of the Infertile Couple, Cambridge University Press, Cambridge, 1993). MAGI is a hypernym which groups the following different clinical categories: prostatitis, prostate-vesiculitis and prostate-vesiculo-epididymitis. Some of the characteristics they share are: common diseases, mainly have a chronic course, rarely cause obstruction of the seminal pathways, can have an unpredictable intracanicular spread to one or more sexual accessory glands of the reproductive tract, as well as to one or both sides. In this review, we show that all components involving the inflammatory response (from the agents which first trigger it to each component of the inflammatory response dynamic) can deteriorate conventional and/or non-conventional sperm parameters arising from one or more of the following mechanisms: altered secretory function of the epididymis, seminal vesicles, and prostate which reduce the antioxidant properties or scavenging role of the seminal plasma; deterioration of spermatogenesis; and (unilateral or bilateral) organic or functional sub-obstruction of the seminal tract.

Evaluation of Serum Testosterone, Progesterone, Seminal Antisperm Antibody, and Fructose Levels among Jordanian Males with a History of Infertility

Due to the biochemical complexity of seminal fluid, we attempt to study the possible correlation between fructose, which is secreted under the effect of androgen hormone, and autoimmunity, which might play a role in varicocele associated infertility, in reducing sperm motility. Seminal fructose, antisperm antibodies (ASAs) and blood steroids hormones (testosterone and progesterone) levels were measured in 66 infertile males with varicocele and 84 without varicocele referred for fertility treatment. Seminal analysis was performed with biochemical measurements of seminal fructose and mixed agglutination reaction (MAR) for ASA. Serum levels of progesterone and testosterone were estimated using a competitive chemoluminescent enzyme immunoassay. The mean values for serum testosterone were 380.74 ± 24.331, 365.9 ± 16.55, and 367.5 ± 21.8 ng/dl, progesterone 0.325 ± 0.243, 0.341 ± 0.022, and 0.357 ± 0.0306 ng/ml, and seminal plasma fructose 359.6 ± 26.75, 315.6 ± 13.08, and 332.08 ± 24.38 mg/dl in males with varicocele, without varicocele, and fertile males, respectively. A significant high level of testosterone was observed within varicocele group (P = .001). This result showed that testosterone may play a role as an infertility determinant in subjects with varicocele. ASA was detected in 18 (26.47%) of cases with varicocele, 20 (38.46%) without varicocele, and in 16 (32.0%) fertile men. Cases with ASAs associated with low sperm motility morphology. An inverse correlation between sperm-bound antibodies and viscosity has been shown (P = .017). ASA showed some significant inverse relations with ages, durations of infertility, and viscosity (P < .05). In addition, a significant correlation was observed between ASA positive seminal plasma and testosterone concentration among infertile cases (with or without varicocele) and fertile (P < .05). Our results suggest a relationship between testicular steroid hormone levels with autoimmunity and sperm antibodies which influence the motility of ejaculated spermatozoa among Jordanian infertile males.

Epididymis seleno-independent glutathione peroxidase 5 maintains sperm DNA integrity in mice

The mammalian epididymis provides sperm with an environment that promotes their maturation and protects them from external stresses. For example, it harbors an array of antioxidants, including non-conventional glutathione peroxidase 5 (GPX5), to protect them from oxidative stress. To explore the role of GPX5 in the epididymis, we generated mice that lack epididymal expression of the enzyme. Histological analyses of Gpx5-/- epididymides and sperm cells revealed no obvious defects. Furthermore, there were no apparent differences in the fertilization rate of sexually mature Gpx5-/- male mice compared with WT male mice. However, a higher incidence of miscarriages and developmental defects were observed when WT female mice were mated with Gpx5-deficient males over 1 year old compared with WT males of the same age. Flow cytometric analysis of spermatozoa recovered from Gpx5-null and WT male mice revealed that sperm DNA compaction was substantially lower in the cauda epididymides of Gpx5-null animals and that they suffered from DNA oxidative attacks. Real-time PCR analysis of enzymatic scavengers expressed in the mouse epididymis indicated that the cauda epididymidis epithelium of Gpx5-null male mice mounted an antioxidant response to cope with an excess of ROS. These observations suggest that GPX5 is a potent antioxidant scavenger in the luminal compartment of the mouse cauda epididymidis that protects spermatozoa from oxidative injuries that could compromise their integrity and, consequently, embryo viability.