Oxidative stress and male infertility

Oxidative Stress and Endoplasmic Reticulum Stress Are Involved in the Protective Effect of Alpha Lipoic Acid Against Heat Damage in Chicken Testes

Simple Summary

In male animals, heat stress causes injury to the testes, resulting in an increase in the number of deformed sperm, a reduction in testosterone production, and consequently, reduced reproductive performance. As an important antioxidant, alpha lipoic acid (ALA) has been reported to have a protective effect against testicular injury caused by various pathological factors. However, few studies have focused on the role of ALA in heat-induced testicular lesions. In this study, the effects of ALA on histopathological parameters, the activity of key antioxidant enzymes involved in oxidative stress, biomarkers of endoplasmic reticulum stress signaling in the testicular tissue, and testosterone levels in serum were evaluated in heat-stressed chickens. The results showed that ALA significantly alleviated heat stress-induced adverse effects by affecting the activities of antioxidant enzymes, the expression of endoplasmic reticulum stress-related apoptotic modulators, and the protein levels of steroidogenic genes in the testes of chickens exposed to heat stress. These results suggest that in chickens, ALA may be beneficial for ameliorating decreased reproductive performance caused by heat stress and this study provides the basis for the design of novel therapies for heat-induced testicular damage.

Abstract

Heat stress (HS) causes testicular injury, resulting in decreased fertility. Alpha-lipoic acid (ALA) is a well-known antioxidant. The aim of this study was to investigate the protective effects of ALA on HS-induced testicular damage in chickens. Histological changes; biomarkers of oxidative stress, including glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA); markers of endoplasmic reticulum (ER) stress, including glucose-regulated protein 78 (GRP78) and CCAAT/enhancer binding protein homologous protein (CHOP); apoptosis-related modulators, including Bax, Bcl-2, and caspase 3, in testicular tissue and serum testosterone levels were evaluated in chickens under heat stress. Heat stress induces spermatogenic cell abnormalities in chicken testes. Compared to the HS group, the histomorphological abnormalities in testicular tissue were visibly ameliorated, with significant increases in the enzyme activities of GPx, SOD, and CAT, increased serum testosterone concentration, and decreased MDA levels in the ALA + HS group. Consistent with these results, compared with the HS group, the protein levels of GRP78, CHOP, caspase 3, and Bax were significantly decreased, whereas Bcl-2, StAR, and 3β-HSD protein levels were increased in the ALA + HS group. Collectively, these findings suggest that ALA significantly ameliorates the heat-induced histomorphological abnormalities in the testes and decreased testosterone production by potentiating the activities of anti-oxidative enzymes (GPx, SOD, and CAT), inhibiting ER stress-related apoptotic pathways (Bax, Bcl-2, and caspase 3), and increasing steroidogenic gene (StAR and 3β-HSD) expression in chickens.

Riskometric assessment of factors affecting population health in situational analysis features of cytochemical indicators of activity circulating and tissue leukocytes and oxidative stress as a factor of chronic inflammation

The study of the mechanism of oxidative stress and regulation of oxygen-dependent processes is important, as the establishment of a complex interaction between oxidative stress, oxidative protein damage and the body's antioxidant system makes it possible to clarify metabolic pathways of disease pathogenesis. In our study, we concluded that in patients with chronic non-specificinflammatory diseases of the genitals of men and women, the phagocytic activity of polymorphonuclear leukocytes is reduced mainly by the oxygen-dependent mechanism, and tissue - by the oxygen-independent. As an exception in patients with chlamydial infection, the phagocytic activity of tissue polymorphonuclear leukocytes was also reduced by an oxygen-dependent mechanism.

Clinical Role of Silymarin in Oxidative Stress and Infertility: A Short Review for Pharmacy Practitioners

Silymarin (SMN) as an ancient plant has various therapeutic usage in many diseases. Almost all of its properties attributed to antioxidant and anti-inflammatory properties. Currently, infertility problems impose a heavy burden on many developing countries. As a result, effective infertility treatment is indicated. The role of oxidative stress in both male and female infertility has been revealed. Many studies have shown protective and antioxidative properties of SMN against adverse effects of chemotherapy medications and environmental toxins in sperms and oocytes. The antioxidative and clinical role of SMN in infertility has been reviewed. The use of antioxidants such as SMN can help to improve fertility rate by scavenging free radicals and inhibiting nuclear factor kappa B transcription factor. Animal studies in both male and female have indicated a beneficial effect of SMN on fertility recovery. Further clinical studies are needed considering the phytoestrogenic property of SMN, to determine the right dose and duration of treatment.

Quantitative proteomics decodes clusterin as a critical regulator of paternal factors responsible for impaired compensatory metabolic reprogramming in recurrent pregnancy loss

Recurrent pregnancy loss (RPL) is a perplexing problem experienced with two or more consecutive miscarriages wherein the cause remains unexplained in >50% of cases. However, despite several evidences of involvement of paternal factors on early embryogenesis and placental development, its contribution towards RPL has been largely unexplored. There is augmented lipid peroxidation, protein carbonylation, thionylation and enhanced histone retention in spermatozoa of RPL patients. Differentially expressed proteins in the spermatozoa of RPL patients may contribute towards aberrant embryo development and pregnancy loss. The present study comprised of male partners of RPL patients (n = 16) with the absence of any female factor abnormality and age-matched fertile healthy donors (n = 20). Pooled sperm samples from each group were subjected to high-throughput liquid chromatography-tandem mass spectrophotometry (LC-MS/MS) and subsequent bioinformatic analysis that identifies key proteins to be differentially expressed (DEPs). A total of 23 DEPs were identified with ≥2.0 fold change were considered to be significant. A key finding of the study was clusterin (CLUS), a predominant oxidative stress protein that takes part in an array of pre- and post-fertilisation molecular processes, found to be underexpressed as it was confirmed by Western blot analysis. This pilot study supports contributions of paternal oxidative predominance in RPL and encourages further investigation.

ZnO Nanoparticles Induced Male Reproductive Toxicity Based on the Effects on the Endoplasmic Reticulum Stress Signaling Pathway

Purpose

The aim of this study was to evaluate the adverse effects of ZnO NPs on male reproductive system and explore the possible mechanism.

Methods

In this study, the effect of oral administration of 50, 150 and 450 mg/kg zinc oxide nanoparticles (ZnO NPs) in adult male mice was studied over a 14-day period.

Results

The results showed that the number of sperms in the epididymis and the concentration of testosterone in serum were decreased with an increased dose of ZnO NPs. Testicular histopathological lesions like detachment, atrophy and vacuolization of germ cells were observed. The results showed that increased dosage of ZnO NPs correspondingly up-regulated the IRE1α, XBP1s, BIP, and CHOP (P<0.05) which are genes related to ER stress. These observations indicated that ZnO NPs had adverse effects on the male reproductive system in a dose-dependent manner possibly through ER stress. The expression of caspase-3 was significantly increased in all the treated groups (P<0.001), which reflected the possible activation of apoptosis. Additionally, there was significant down-regulation of the gene StAR (P<0.05), a key player in testosterone synthesis. When an ER-stress inhibitor salubrinal was administered to the 450 mg/kg ZnO NPs treatment group, the damages to the seminiferous tube and vacuolization of Sertoli and Leydig cells were not observed. Furthermore, the testosterone levels in the serum were similar to the control group after the subsequent salubrinal treatment.

Conclusion

It may be inferred that the ZnO NP's reproductive toxicity in male mice occurred via apoptosis and ER-stress signaling pathway.

Carnosine treatment during human semen processing by discontinuous density gradient

The aim of this article was to evaluate the effects of different concentrations of carnosine added during human semen processing. Semen samples from 34 patients were submitted to processing by discontinuous density gradient centrifugation without (control) or with different concentrations of carnosine supplementation as follows: (a) 20 mM of carnosine supplementation on the layers of Percoll; and (b) 50 mM carnosine supplementation. Sperm samples were then washed with human tubal fluid medium and evaluated according to sperm kinetics and functional assessment. For statistical analysis, data were evaluated by a general linear model or a Friedman test, whenever appropriate. The 50 mM carnosine supplementation led to improved sperm mitochondrial activity when compared to untreated samples. Motility variables, such as percentage of motile and progressively motile spermatozoa, average path velocity, straight line velocity, curvilinear velocity and linearity, showed an improvement after semen processing irrespective of carnosine supplementation. Both concentrations of carnosine increased the beat-cross frequency (BCF) when compared to samples before processing. We conclude that carnosine supplementation in semen samples benefits sperm mitochondrial activity and BCF.

DNA methylation patterns vary in boar sperm cells with different levels of DNA fragmentation

BACKGROUND

Sperm DNA integrity is considered essential for successful transmission of the paternal genome, fertilization and normal embryo development. DNA fragmentation index (DFI, %) has become a key parameter in the swine artificial insemination industry to assess sperm DNA integrity. Recently, in some elite Norwegian Landrace boars (boars with excellent field fertility records), a higher level of sperm DFI has been observed. In order to obtain a better understanding of this, and to study the complexity of sperm DNA integrity, liquid preserved semen samples from elite boars with contrasting DFI levels were examined for protamine deficiency, thiol profile and disulphide bonds. Additionally, the DNA methylation profiles of the samples were determined by reduced representation bisulphite sequencing (RRBS).

RESULTS

In this study, different traits related to sperm DNA integrity were investigated (n = 18 ejaculates). Upon liquid storage, the levels of total thiols and disulphide bonds decreased significantly, while the DFI and protamine deficiency level increased significantly. The RRBS results revealed similar global patterns of low methylation from semen samples with different levels of DFI (low, medium and high). Differential methylation analyses indicated that the number of differentially methylated cytosines (DMCs) increased in the low-high compared to the low-medium and the medium-high DFI groups. Annotating the DMCs with gene and CpG features revealed clear differences between DFI groups. In addition, the number of annotated transcription starting sites (TSS) and associated pathways in the low-high comparison was greater than the other two groups. Pathway analysis showed that genes (based on the closest TSS to DMCs) corresponding to low-high DFI comparison were associated with important processes such as membrane function, metabolic cascade and antioxidant defence system.

CONCLUSION

To our knowledge, this is the first study evaluating DNA methylation in boar sperm cells with different levels of DFI. The present study shows that sperm cells with varying levels of DNA fragmentation exhibit similar global methylation, but different site-specific DNA methylation signatures. Moreover, with increasing DNA fragmentation in spermatozoa, there is an increase in the number of potentially affected downstream genes and their respective regulatory pathways.

The capability of L-carnitine-mediated antioxidant on cock during aging: evidence for the improved semen quality and enhanced testicular expressions of GnRH1, GnRHR, and melatonin receptors MT 1/2

Precise natural anti-oxidative compounds have facilitated the research of infertile gametes and the development of novel bio-therapeutics, especially the molecules that are based on the reduction of oxidative stress, such as L-carnitine (LC). In addition to, the defect in the functioning of sperm mitochondrial and the decreasing seminal antioxidant ability due to aging, its essential role in permitting the mitochondrial import and oxidation of long chain fatty acids is worthy. Therefore, current study was designed to investigate the effects of dietary LC on semen quality, seminal antioxidant activity, and their implications for the fertility in aged cocks for 12 wk. Supplementation of the feed with two different doses of LC (50 and 150 mg/kg body weight/day) for 12 wk showed significantly increased in the reproductive activity of cock, in comparison to the control group. Seminal analysis showed that supplementation of LC significantly increased (P < 0.05) the sperm motility, concentration, livability, semen quality factor, seminal malondialdehyde concentration, catalase, and glutathione peroxidase activities. In addition, addition of LC significantly increased (P < 0.05) the plasma concentration of testosterone and prostaglandin E2 but posed no significant effect on the concentration of follicle-stimulating hormone. Furthermore, the findings of artificial insemination showed significant increased (P < 0.05) in the percentage of fertility in LC groups, while the percentage hatchability and mortality remained unchanged. Immunohistochemistry analysis revealed that LC significantly increased (P < 0.05) the testicular immunopositivity of MT1 and MT2. Moreover, the administration of LC to the aged cocks enhanced (P < 0.05) GnRH1 and GnRHR mRNA levels when compared with untreated cocks. The results of the present study suggest that LC treatment of aged cocks increases the seminal antioxidant enzymes and sexual hormones levels, which may improve the semen quality by increasing the expression of GnRH1 and melatonin receptors (MT1 and MT2) activities. Collectively, LC could be a suitable feed supplementation to increase reproductive activities through enhancing semen quality in aging cocks.

Relationship Between Smoking Habit and Sperm Parameters Among Patients Attending an Infertility Clinic

Background

This study aimed to estimate stress markers, oxidative stress (OS), reproductive hormones and sperm parameters in male smokers and non-smokers and observe the impact of oxidative stress markers and smoking on sperm count, motility and morphology in a selected population of Karachi, Pakistan.

Methods

This cross-sectional study was conducted from July 2017 to July 2018 at Aga Khan University (AKU), in Karachi, Pakistan. The subjects were recruited from the Sindh Institute of Reproductive Medicine (SIRM), Karachi based on defined inclusion criteria. The subjects were categorized into fertile and infertile based on cut off values of sperm parameters as recommended by the WHO i.e., sperm count/ejaculate of 39 × 10⁶/ml, sperm motility 40% and normal morphology 4%. Two hundred eleven fertile and 165 infertile male subjects were included in the study. Serum cortisol, adrenaline, superoxide dismutase (SOD), and glutathione peroxidase (GPX) were analyzed by ELISA kits. Data was analyzed on SPSS-22. A p-value of <0.05 was considered statistically significant.

Results

Age, Body Mass Index (BMI), and body fat were similar among smokers and non-smokers. Age was significantly lower, while mean BMI and body fat were significantly higher among infertile smokers vs. fertile smokers (p-value < 0.05). The testosterone levels were significantly reduced among smokers as compared to non- smokers (p-value < 0.05). The median cortisol levels were increased as well as GPX, and steroid hormone-binding globulin (SHBG) were significantly reduced among smokers as compared to non-smokers. Additionally, the same findings with a significant difference have also been observed among infertile smokers as compared to fertile smokers (p-value < 0.05). This study has shown that the semen parameters (total count, motility, and morphology) are decreased in infertile smokers as compared to infertile non-smokers. Furthermore, the multivariate analysis showed that smoking causes a significant decrease in sperm count and morphology but it did not have any significant effect on motility.

Conclusion

Smoking has a significant effect on fertility, specifically sperm count and normal morphology of sperm. This might be due to OS produced by smoking, which has devastating effects on semen parameters, thus reducing male fertility. Infertility specialist should counsel their patients about the ill effects of smoking on their fertility status and should advise maintaining a healthy lifestyle, including normal weight and avoiding smoking, to prevent future health problems. Hence smokers should quit smoking for their next generation.

Meditation & yoga: Impact on oxidative DNA damage & dysregulated sperm transcripts in male partners of couples with recurrent pregnancy loss

Background & objectives

Recurrent pregnancy loss (RPL) is one of the devastating complications of pregnancy and current focus lies in addressing the management of paternal factors. Dysregulation in selective transcripts delivered to oocyte at fertilization can result in pregnancy losses and adversely affect embryogenesis. The objective of this study was to assess the effect of yoga-based lifestyle intervention (YBLI) on seminal oxidative stress (OS), DNA damage and spermatozoal transcript levels.

Methods

The present study was a part of a prospective ongoing exploratory study and 30 male partners of couples with RPL were included from August 2016 to June 2017. Semen samples were obtained at baseline and at the end of YBLI (21 days). Gene expression analysis was performed by quantitative polymerase chain reaction on spermatozoal FOXG1, SOX3, OGG1, PARP1, RPS6, RBM9, RPS17 and RPL29. The levels of seminal OS and sperm DNA damage was assessed by measuring levels of reactive oxygen species (ROS) by chemiluminescence and DNA fragmentation index (DFI) by sperm chromatin structure assay.

Results

SOX3, OGG1 and PARP1 were observed to be upregulated, while FOXG1, RPS6, RBM9, RPS17 and RPL29 showed downregulation. A significant reduction in ROS levels, an increase in sperm motility, sperm count (done twice) and a decrease in DFI was seen after YBLI.

Interpretation & conclusions

Adopting YBLI may help in a significant decline in oxidative DNA damage and normalization of sperm transcript levels. This may not only improve pregnancy outcomes but also improve the health trajectory of the offspring.

Epicatechin Provides Antioxidant Protection to Bovine Spermatozoa Subjected to Induced Oxidative Stress

Epicatechin (EPI) is a natural flavonoid with antibacterial, anti-inflammatory and anti-cancer properties. Furthermore, the molecule exhibits powerful reactive oxygen species (ROS) scavenging and metal-chelating properties. In this study, we assessed the efficiency of EPI to reverse ROS-mediated alterations to the motility, viability, DNA integrity and oxidative profile of bovine spermatozoa. For the first experiment, spermatozoa were washed out of fresh semen and exposed to 12.5 μmol/L EPI, 25 μmol/L EPI, 50 μmol/L EPI and 100 μmol/L EPI in the presence of ferrous ascorbate (FeAA) during a 6 h in vitro culture. For the second experiment, the ejaculates were split into aliquots and cryopreserved with a commercial semen extender supplemented with 12.5 μmol/L EPI, 25 μmol/L EPI, 50 μmol/L EPI, 100 μmol/L EPI or containing no supplement. Sperm motility was assessed using the computer-aided sperm analysis and the cell viability was studied with the metabolic activity test. ROS production was quantified using luminometry, and DNA fragmentation was evaluated using the chromatin dispersion test. Cell lysates were prepared at the end of the culture in order to assess the concentration of protein carbonyls and malondialdehyde. Exposure to FeAA led to a significantly reduced sperm motility (p < 0.001), mitochondrial activity (p < 0.001), but increased the generation of ROS (p < 0.001), as well as oxidative damage to proteins (p < 0.001), DNA (p < 0.001) and lipids (p < 0.001). EPI supplementation, particularly at a concentration range of 50–100 μmol/L, resulted in higher preservation of the spermatozoa vitality (p < 0.001). Furthermore, 50–100 μmol/L EPI were significantly effective in the prevention of oxidative damage to sperm proteins (p < 0.001), lipids (p < 0.001) and DNA (p < 0.01 in relation to 50 μmol/L EPI; p < 0.001 with respect to 100 μmol/L EPI). In the case of the cryopreserved spermatozoa, the administration of 50–100 μmol/L EPI resulted in higher sperm motility (p < 0.001) and mitochondrial activity (p < 0.001). ROS production, the number of protein carbonyls, lipid peroxidation as well as oxidative DNA damage were found to be significantly decreased particularly in samples cryopreserved in the presence of 100 μmol/L EPI (p < 0.001). Our results suggest that EPI could behave as an effective antioxidant which may prevent oxidative insults to spermatozoa, and thus, preserve their vitality and functionality. Nevertheless, its potential to achieve higher fertilization rates in reproductive technologies needs to be validated.

Male Oxidative Stress Infertility (MOSI): Proposed Terminology and Clinical Practice Guidelines for Management of Idiopathic Male Infertility

Despite advances in the field of male reproductive health, idiopathic male infertility, in which a man has altered semen characteristics without an identifiable cause and there is no female factor infertility, remains a challenging condition to diagnose and manage. Increasing evidence suggests that oxidative stress (OS) plays an independent role in the etiology of male infertility, with 30% to 80% of infertile men having elevated seminal reactive oxygen species levels. OS can negatively affect fertility via a number of pathways, including interference with capacitation and possible damage to sperm membrane and DNA, which may impair the sperm's potential to fertilize an egg and develop into a healthy embryo. Adequate evaluation of male reproductive potential should therefore include an assessment of sperm OS. We propose the term Male Oxidative Stress Infertility, or MOSI, as a novel descriptor for infertile men with abnormal semen characteristics and OS, including many patients who were previously classified as having idiopathic male infertility. Oxidation-reduction potential (ORP) can be a useful clinical biomarker for the classification of MOSI, as it takes into account the levels of both oxidants and reductants (antioxidants). Current treatment protocols for OS, including the use of antioxidants, are not evidence-based and have the potential for complications and increased healthcare-related expenditures. Utilizing an easy, reproducible, and cost-effective test to measure ORP may provide a more targeted, reliable approach for administering antioxidant therapy while minimizing the risk of antioxidant overdose. With the increasing awareness and understanding of MOSI as a distinct male infertility diagnosis, future research endeavors can facilitate the development of evidence-based treatments that target its underlying cause.

The roles of reactive oxygen species and antioxidants in cryopreservation

Cryopreservation has facilitated advancement of biological research by allowing the storage of cells over prolonged periods of time. While cryopreservation at extremely low temperatures would render cells metabolically inactive, cells suffer insults during the freezing and thawing process. Among such insults, the generation of supra-physiological levels of reactive oxygen species (ROS) could impair cellular functions and survival. Antioxidants are potential additives that were reported to partially or completely reverse freeze-thaw stress-associated impairments. This review aims to discuss the potential sources of cryopreservation-induced ROS and the effectiveness of antioxidant administration when used individually or in combination.

Caffeine improves sperm quality, modulates steroidogenic enzyme activities, restore testosterone levels and prevent oxidative damage in testicular and epididymal tissues of scopolamine-induced rat model of amnesia

Objectives

This study was designed to assess the role of caffeine on fertility parameters in testicular and epididymal tissues of scopolamine-induced model of amnesia in rats.

Methods

Adult male rats were treated with scopolamine with or without caffeine. The modulatory effects of caffeine or scopolamine on fertility parameters were assessed in rats' testicular and epididymal homogenates.

Key findings

Scopolamine-induced sperm abnormalities, reduced steroidogenic enzyme 3β-Hydroxysteroid dehydrogenase (3β-HSD) and 17β-Hydroxysteroid dehydrogenase (17β-HSD) activities and serum testosterone levels in rats' testicular tissues. Treatment with caffeine increased 3β-HSD and 17β-HSD as well as testosterone levels. Caffeine also reversed sperm viability, sperm motility and sperm count in testicular tissues of scopolamine-treated rats. Furthermore, scopolamine-induced oxidative damage in rats' epididymal and testicular tissues via reduction of thiol and non-protein thiol content as well as increase in reactive oxygen species (ROS) and malondialdehyde (MDA) levels. Caffeine attenuated oxidative stress in testicular and epididymal tissues of rats treated with scopolamine via increase in non-protein and protein thiol levels with concomitant reduction in ROS and MDA levels.

Conclusion

This study revealed that caffeine (5 and 25 mg/kg) improved sperm quality, increased steroidogenic enzyme activities and attenuated oxidative damage in testis and epididymis of rats treated with scopolamine.

Aqueous and ethanol extracts of Dracaena arborea (Wild) Link (Dracaenaceae) alleviate reproductive complications of diabetes mellitus in rats

Reproductive dysfunction is one of the most prevalent diabetes complications. Draceana arborea is known to enhance sexual function in diabetic rats, but the underlying mechanisms have not been thoroughly elucidated. This study examined the effects of D. arborea on some reproductive complications of diabetes in rats. Aqueous and ethanol (500 and 100 mg/kg respectively) extracts of D. arborea, Sildenafil citrate (1.44 mg/kg), trimethylamine-N-oxide (TMAO, 20 mg/kg) and distilled water (10 ml/kg) were orally administered for 28 days to streptozotocin-induced diabetic rats. Glycaemia, body and reproductive organ masses, fertility parameters, total proteins, antioxidant enzymes activities, serum and testicular testosterone and the histology of the testes and epididymis were determined. Results revealed significant decreases in body and absolute and relative masses of testes, epididymis, seminal vesicles, prostate and vas deferens, fertility parameters, epididymal and testicular total proteins, serum and testicular testosterone levels as well as antioxidant enzymes activities. Interestingly, while having minor anti-hyperglycaemic effects, these abnormalities associated with testicular and epididymal alterations were alleviated by D. arborea especially the aqueous extract (500 mg/kg). These outcomes provided evidence of the androgenic properties of D. arborea in diabetic rats, which could be useful for a better management of sexual dysfunctions in diabetic patients.

Beneficial effects of Cichorium intybus L. extract on oxidative status and reproductive parameters in male Wistar rats: An experimental study

Background

During recent years, increasing concern has been raised about the declining sperm count and human male infertility. Cichorium intybus L. (C. intybus) has traditionally been used in Iranian folk medicine as hepato protective and blood purifier and for its presumed fertility-enhancing properties.

Objective

A dose-response study was performed to determine the effect of C. intybus ethanolic leave extract on the reproductive parameters in adult Wistar male rats.

Materials and Methods

In this experimental study, 40 healthy adult male Wistar rats (8 wk old, 200-210 gr body weight) were randomly divided (n = 10/each) as control and groups treated with 50, 100, and 200 mg/kg/day of C. intybus extract via gavage for 70 days. Serum hormonal assay, epididymal sperm evaluation, and analysis of morphometrical parameters, antioxidant enzymes, and lipid peroxidation levels of testis were done in each experimental group.

Results

Weights of testis and epididymis increase significantly in male rats treated with 200 mg/kg C. intybus extract. Sperm density and percent of morphologically normal sperm were significantly increased in a dose-related manner with C. intybus treatment.Serum testosterone was higher at 100 and 200 mg/kg C. intybus extract-treated groups. C. intybus significantly reduced malondialdehyde levels and also increased superoxide dismutase and glutathione peroxidase activity in testicular tissue of rats.

Conclusion

It is concluded that C. intybus leave extract improves reproductive parameters in male rats which might be a consequence of both its antioxidant and androgenic properties.

Antioxidant and anti-apoptotic effects of royal jelly against nicotine-induced testicular injury in mice

This study describes the effects of royal jelly (RJ) on testicular injury induced by nicotine (NIC) in mice. Thirty-six male BALB/c mice were randomly divided into six groups (n = 6). Group 1 received normal saline, group 2 received 100 mg/kgBW/day RJ, groups 3 and 4 received NIC at doses of 0.50 and 1.00 mg/kgBW/day, respectively, and groups 5 and 6 received NIC at doses of 0.50 and 1.00 mg/kg BW/day, respectively, plus RJ. Following 35 days, the serum level of testosterone, histopathological changes, germ cell apoptosis, proliferating cell nuclear antigen (PCNA), malondialdehyde (MDA) content, and antioxidant indexes including total antioxidant capacity (TAC) and catalase (CAT) activity were determined. In addition, the mitochondria-dependent apoptosis was investigated by assessing the Bcl-2, p53, and Caspase-3 mRNA levels expression by reverse transcription-PCR (RT-PCR). Compared to NIC receiving groups, the concomitant administration of RJ could protect the testosterone reduction and histological damages. After RJ treatment, the level of tissue MDA content decreased, while tissue TAC and CAT levels were remarkably increased compared to NIC-exposed groups. Remarkable higher TUNEL-positive germ cells and low PCNA index were observed in NIC receiving groups. Besides, the expression level of Bcl-2 was significantly higher and the p53 and Caspase-3 levels were significantly lower in the RJ co-administration groups than NIC-only receiving groups. Our results confirmed that RJ effectively protects the testis against NIC evoked damages by antioxidant and anti-apoptotic effects involving the up regulation of the antioxidant status, mitochondria-dependent apoptosis pathway prevention, and the proliferating activity improvement.

A three-generation study on the association of tobacco smoking with asthma

Background

Mothers’ smoking during pregnancy increases asthma risk in their offspring. There is some evidence that grandmothers’ smoking may have a similar effect, and biological plausibility that fathers’ smoking during adolescence may influence offspring’s health through transmittable epigenetic changes in sperm precursor cells. We evaluated the three-generation associations of tobacco smoking with asthma.

Methods

Between 2010 and 2013, at the European Community Respiratory Health Survey III clinical interview, 2233 mothers and 1964 fathers from 26 centres reported whether their offspring (aged ≤51 years) had ever had asthma and whether it had coexisted with nasal allergies or not. Mothers and fathers also provided information on their parents’ (grandparents) and their own asthma, education and smoking history. Multilevel mediation models within a multicentre three-generation framework were fitted separately within the maternal (4666 offspring) and paternal (4192 offspring) lines.

Results

Fathers’ smoking before they were 15 [relative risk ratio (RRR) = 1.43, 95% confidence interval (CI): 1.01–2.01] and mothers’ smoking during pregnancy (RRR = 1.27, 95% CI: 1.01–1.59) were associated with asthma without nasal allergies in their offspring. Grandmothers’ smoking during pregnancy was associated with asthma in their daughters [odds ratio (OR) = 1.55, 95% CI: 1.17–2.06] and with asthma with nasal allergies in their grandchildren within the maternal line (RRR = 1.25, 95% CI: 1.02–1.55).

Conclusions

Fathers’ smoking during early adolescence and grandmothers’ and mothers’ smoking during pregnancy may independently increase asthma risk in offspring. Thus, risk factors for asthma should be sought in both parents and before conception.

Funding

European Union (Horizon 2020, GA-633212).

Green tea improves rat sperm quality and reduced cadmium chloride damage effect in spermatogenesis cycle

Introduction: Testicular tissue is part of the reproductive system that some mineral compounds such as cadmium chloride (CdCl₂) destroy. Green tea (Camellia sinensis) extract can reduce the tissue damage caused by toxins due to its antioxidant properties. The aim of this study was to evaluate the effect of green tea extract on sperm quality in cadmium chloride toxicity.

Materials and Methods: In the present study, male Wistar rats were allotted randomly into four groups, namely control group (C), CdCl₂ (1.5mg/kg), GT 1.5% (w/v) and in combinationCdCl₂+GT groups. CdCl₂ was injected intraperitoneally (1.5 mg /kg) whereas the green tea extract was administrated orally. At 13, 25 and 49 days after treatment, the rats were euthanized and the reproductive organs (testes, epididymis) were excised and used for sperm analysis and histo-morphometric examinations.

Results: The mean of the diameter of seminiferous tubes, the number of spermatogonia, Sertoli, Leydig cells and thickness of the germinal layer in the testis were significantly increased (P<0.05) in all groups compared to the CdCl₂ group (P<0.05). Sperm motility, sperm count and testosterone were significantly decreased in the CdCl₂ group compared to all groups of treatment (p<0.05). The mean of MDA was significantly increased in the CdCl₂ group compared to other groups (p<0.05).

Conclusion: Green tea has an antioxidant effect that reduces the effects of free oxygen radicals produced from toxins such as cadmium chloride. In addition, it could decrease lipid peroxidation of the cell membrane and ultimately prevent the destruction of tissues in the long run.

Time-dependent effect of ground water fluoride on motility, abnormality and antioxidant status of spermatozoa: An in vitro study

The present study was undertaken to investigate the toxic effect of ground water fluoride (F) on motility, abnormality, and antioxidant status of spermatozoa. Treatment of ground water F with epididymal sperm suspension caused complete loss of sperm motility and decrease in the activities of superoxide dismutase (SOD) and catalase (CAT) and increase in the concentration of malondialdehyde (MDA) and abnormality of spermatozoa at 15 and 30 min time intervals. Further, incubation of spermatozoa with ground water F for 5, 10, and 15 min time intervals significantly reduced the sperm motility and activities of SOD and CAT and increased the concentration of MDA and abnormality of spermatozoa. The study revealed that F-induced effect on sperm motility and antioxidant status is time dependent. Increase in oxidative stress and concomitant decrease in motility of spermatozoa in ground water F clearly indicates that F-induced oxidative stress affected the sperm motility. The present study for the first time demonstrated the toxic effect of ground water F on spermatozoa at shorter duration of exposure, which affects the capability of spermatozoa in fertilization.

Ejaculate-mediated paternal effects: evidence, mechanisms and evolutionary implications

Despite serving the primary objective of ensuring that at least one sperm cell reaches and fertilises an ovum, the male ejaculate (i.e. spermatozoa and seminal fluid) is a compositionally complex 'trait' that can respond phenotypically to subtle changes in conditions. In particular, recent research has shown that environmentally and genetically induced changes to ejaculates can have implications for offspring traits that are independent of the DNA sequence encoded into the sperm's haploid genome. In this review, we compile evidence from several disciplines and numerous taxonomic systems to reveal the extent of such ejaculate-mediated paternal effects (EMPEs). We consider a number of environmental and genetic factors that have been shown to impact offspring phenotypes via ejaculates, and where possible, we highlight the putative mechanistic pathways by which ejaculates can act as conduits for paternal effects. We also highlight how females themselves can influence EMPEs, and in some cases, how maternally derived sources of variance may confound attempts to test for EMPEs. Finally, we consider a range of putative evolutionary implications of EMPEs and suggest a number of potentially useful approaches for exploring these further. Overall, our review confirms that EMPEs are both widespread and varied in their effects, although studies reporting their evolutionary effects are still in their infancy.

Human Semen Samples with High Antioxidant Reservoir May Exhibit Lower Post-Cryopreservation Recovery of Sperm Motility

Cryopreservation-thawing of human semen was found to reduce the level of antioxidant activity surrounding the sperm, which may negatively affect post-cryopreservation (post-thaw) recovery of sperm motility. Therefore, the current manufactured cryoprotectant media have been supplemented with certain antioxidants to preserve the loss in seminal antioxidant activity. In this study, we aimed to explore the correlation between total antioxidant capacity (TAC) of human semen samples before cryopreservation and the post-thaw recovery of sperm motility. Normal semen specimens (n = 77) were recruited in this study. Sperm motility was measured for each semen sample before and after cryopreservation and the post-thaw recovery of sperm motility was calculated. Seminal TAC was measured spectrophotometrically before cryopreservation for each semen sample using the sensitive cupric ion-reducing antioxidant capacity (CUPRAC) method. The results from this study showed that the post-thaw recovery of sperm motility is negatively correlated (p = 0.0404, p = 0.0402) with the absorbance at 450 nm and the values of seminal TAC in terms of µM Trolox equivalents, as evaluated by CUPRAC, respectively. In conclusion, the total antioxidant reservoir in each ejaculated semen specimen could be a factor in determining the post-thaw recovery of sperm motility toward lower recovery for semen specimens of high antioxidant content.

Protective role of N-acetylcysteine (NAC) on human sperm exposed to etoposide

Background

Although recent progress in cancer treatment has increased patient survival and improved quality of life, reproductive side effects are still for concern. One way to decrease gonadal impairment is to use cytoprotectors. In testicular cancer, etoposide is generally used in combination with other agents, but there are no in-vitro studies of sperm exposure to etoposide and cytoprotectors, namely N-acetylcysteine (NAC).

Methods

Twenty semen samples were individually divided into five groups: control, incubation with NAC alone, incubation with etoposide alone, sequential exposure of NAC followed by etoposide (pre-treatment) and sequential exposure of etoposide followed by NAC (post-treatment). Sperm characteristics, chromatin condensation (aniline blue), DNA fragmentation (TUNEL), oxidative stress (OxyDNA labelling) and glutathione quantification were used to evaluate the capabilities of NAC as a prophylactic (pre-treatment) or ameliorator (post-treatment) agent over the effects caused in sperm during in-vitro exposure to etoposide.

Results

No deleterious effects were observed on sperm motility or sperm membrane integrity. Results revealed that prophylactic use of NAC (pre-treatment) increased rates of immature sperm chromatin as compared to ameliorator use of NAC (post-treatment), and increased rates of sperm DNA fragmentation in relation to controls. Pre and post-treatment with NAC increased oxidative levels in comparison to controls, but also increased levels of cellular antioxidant glutathione.

Conclusions

The results indicate that NAC has the ability to counteract etoposide-induced toxicity rather than preventing the etoposide cytotoxic effects over sperm DNA, suggesting that the administration of NAC to cells formerly exposed to etoposide is preferable to its prophylactic use. As the results evidenced that NAC seems to be more efficient in attenuating sperm etoposide cytotoxic effects instead of being used as a chemoprophylactic agent, this reinforces the idea that there might be a new NAC mechanism over DNA.

Exposure to phthalates in couples undergoing in vitro fertilization treatment and its association with oxidative stress and DNA damage

This prospective study of 599 couples seeking fertility treatment and who were recruited between 2015 and 2017 was conducted to (a) explore the associations between phthalate exposure and in vitro fertilization (IVF) outcomes; and (b) examine the implication of oxidative stress as a mediator of these. We measured eight phthalate metabolites in two spot urine samples; oxidative stress biomarkers such as malondialdehyde, 8-hydroxy-2-deoxyguanosine, hydrogen peroxide, catalase (CAT), and total antioxidant capacity in follicular fluid and seminal plasma. We also examined DNA damage in sperm and granulosa cells. Couples were exposed to a broad range of phthalate compounds and seven metabolites were detected in over 94% of the urine samples, whereas monobenzyl phthalate was found in only 24% of women and 26% of men. Our results showed high levels of seven urinary phthalate metabolites (except monobenzyl phthalate) and a notable increase in many oxidative stress markers in both follicular fluid and seminal plasma. However, their associations with exposure were rather limited. Multivariate binomial regression modeling showed higher levels of follicular CAT levels reduced the probability of fertilization rate (≤ 50%) [Adjusted relative risk (RR_adj) = 0.52, p = 0.005] and unsuccessful live birth (RR_adj = 0.592, p = 0.023). We observed a 46% decrease in the probability of clinical pregnancy in association with an elevated percentage of DNA in the tail (RR_adj = 0.536, p = 0.04). There was a 32% and 22% increase in the probability of clinical pregnancy and unsuccessful live birth associated with higher levels of mono-(2-ethylhexyl) phthalate (RR_adj = 1.32, p = 0.049) and monoethyl phthalate (RR_adj = 1.22, p = 0.032) in women, respectively. In contrast, the probability of clinical pregnancy reduced by 20% with higher levels of mono-(2-ethyl-5-carboxypentyl) phthalate (RR_adj = 0.797, p = 0.037) and 19.6% with mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP) (RR_adj = 0.804, p = 0.041) in men. Other oxidative stress biomarkers or urinary phthalate metabolites showed suggestive relationships with certain IVF outcomes. Lastly, our results demonstrated that elevated levels of CAT in follicular fluid might have a positive impact on fertilization rate ≥ 50% and successful live birth. CAT seems to play a potential role in mediating the relationship between the risk of poor fertilization rate and MEOHP and mono-isobutyl phthalate. Additional data are required to understand the clinical implications of oxidative stress and its contribution to the reproductive toxicity of phthalate exposure.

Grape seed proanthocyanidin extract alleviates high-fat diet induced testicular toxicity in rats

The present study aimed to investigate the protective effects of grape seed proanthocyanidin extract (GSPE) on high-fat diet (HFD) induced testicular damage, oxidative stress, and apoptotic germ cell death. Male rats (n = 40) were randomly divided into four groups: the control group (treated with physiological saline), HFD group, HFD + GSPE (100 mg kg⁻¹) group and HFD + GSPE (300 mg kg⁻¹) group. Compared with the HFD group the rats of the GSPE-treated group showed improved serum testosterone levels, sperm quality and histological appearance of the testis tissue. Significant elevation of antioxidant enzyme (SOD, GSH, and GSH-Px) activities and remarkable reduction in MDA were also observed by GSPE administration, indicating that GSPE can decrease testicular oxidative stress. Finally, a significant reduction in spermatogenic cell apoptosis was detected by TUNEL assay. In summary, these results indicated that GSPE can suppress testicular dysfunction and this effect may be attributed to its antioxidant and anti-apoptotic properties. The current study indicates that GSPE can be considered a promising candidate for use as a drug or a food supplement to alleviate HFD-induced testicular dysfunction.

GSPE alleviates high-fat diet induced testicular toxicity in rats by promoting anti-apoptotic activity.

Role of Oxidative Stress in Male Infertility: An Updated Review

Current evidence links oxidative stress (OS) to male infertility, reduced sperm motility, sperm DNA damage and increased risk of recurrent abortions and genetic diseases. A review of PubMed, Medline, Google Scholar, and Cochrane review databases of published articles from years 2000–2018 was performed focusing on physiological and pathological consequences of reactive oxygen species (ROS), sperm DNA damage, OS tests, and the association between OS and male infertility, pregnancy and assisted reproductive techniques outcomes. Generation of ROS is essential for reproductive function, but OS is detrimental to fertility, pregnancy, and genetic status of the newborns. Further, there is a lack of consensus on selecting OS test, type, and duration of antioxidants treatment as well as on the target patients group. Developing advanced diagnostic and therapeutic options for OS is essential to improve fertility potential and limit genetic diseases transmitted to offspring.

Docosahexaenoic acid in the treatment of male infertility

Literature review is devoted to the analysis of modern data on the use of docosahexaenoic acid in the treatment of male infertility. A brief description of modern ideas about the possible causes of male infertility (a disturbance of function of the cell membrane and genetic damage of sperm) was conducted. The data on the anti-inflammatory properties of omega-3 polyunsaturated fatty acids are described in detail. The bioavailability of docosahexaenoic acid and the choice of drugs containing it for the treatment of male infertility are discussed. Increasing the content of polyunsaturated fatty acids, in particular docosahexaenoic acid, in the sperm membrane was associated with higher ejaculate quality. Therapy with the use of these substances led to the improvement of standard indicators of semen and a decrease in the proportion of sperm with fragmented DNA.

Royal jelly protects male rats from heat stress-induced reproductive failure

Royal jelly (RJ) as an antioxidant has been shown to have attenuated oxidative stress damages in reproductive organs. The objective was carried out the effects of RJ on sperm characteristics, sperm malondialdehyde (MDA) concentration and in vitro fertilisation (IVF) outcome in heat stress (HS) exposed male rats. Forty-eight male rats were randomly divided into eight groups; group 1 received normal saline, group 2 received RJ (100 mg kg^-1  day^-1 ; PO), groups 3, 4 and 5 were heat-stressed (43, 39 and 37°C for 20 min per day respectively) and groups 6, 7 and 8 were heat-stressed along with RJ (43, 39 and 37°C for 20 min per day, respectively, plus RJ at a dose of 100 mg kg^-1  day^-1 ; PO). The HS was induced through immersion of experimental rat scrotums in a water bath. After 48 days, the HS induced remarkable diminish in sperm motility, viability and fertilising potential along with reduced blastulation rate and enhanced sperm chromatin abnormality, MDA levels and DNA damage. Nevertheless, RJ co-administration improved sperm characteristics and early embryo development as well as sperm lipid peroxidation level. Our data suggest that RJ can effectively ameliorate the experimental HS-induced infertility in rats through MDA concentration restoration and sperm characteristics and pre-implantation embryo development improvement.

Experimental Study of the Effectiveness of Phenolic Antioxidants in Male Infertility Caused by Pathospermia

The effect of phenolic antioxidants (dihydroquercetin, p-tyrosol, dibornol) on the morphology, functions, and redox processes in the reproductive cells of male rats was studied on the model of experimental pathospermia. All antioxidants reduced the percentage of degenerative forms of spermatozoa. Dibornol was most effective. Dihydroquercetin and p-tyrosol did not increase the total number of spermatozoa and the percentage of their mobile forms. These indicators were improved only by dibornol. After administration of all test drugs, the antioxidant potential of spermatozoa increased and did not significantly differ from the baseline values.

Paternal factors and embryonic development: Role in recurrent pregnancy loss

The events occurring at the maternal-foetal interface define a successful pregnancy but the current paradigm has shifted towards assessing the contribution of spermatozoa for embryogenesis. Spermatozoa with defective DNA integrity may fertilise the oocyte but affect subsequent embryonic development. The present case-control study was conducted in male partners of couples experiencing recurrent pregnancy loss (RPL) to assess the gene expression of spermatozoal FOXG1, SOX3, OGG1, PARP1, RPS6, RBM9, RPS17 and RPL29. This was correlated with reactive oxygen species (ROS) levels and DNA Fragmentation Index (DFI). Semen samples were obtained from 60 cases and 30 fertile controls. Gene expression was done by qPCR analysis, and relative quantification was calculated by the 2^-ΔΔCt method. Chemiluminescence and the sperm chromatin structure assay were used to measure the ROS and DFI levels respectively. FOXG1, OGG1, RPS6 and RBM9 were seen to be upregulated, while SOX3 and PARP1 were downregulated. Relative expression of SOX3, OGG1, RPS6 and RPS17 showed a significant difference between patients and controls (p < 0.05). RPL patients were seen to have high ROS (>27.8; p = 0.001) and DFI (>30.7; p < 0.0001) with respect to controls. Sperm transcript dysregulation and oxidative DNA damage can be "carried over" after implantation, thus affecting embryogenesis and health of the future progeny.

Association between expression of TNF-α, P53 and HIF1α with asthenozoospermia

Reduced sperm motility (asthenozoospermia) accounts for a significant percentage of male infertility and numerous factors have been suggested to explain this phenomenon among which hypoxic and inflammatory markers are the least studied. Therefore, the aim of this study was to assess the main molecular markers involved in hypoxia (P53 and HIF-1α) and inflammation (TNF-α) pathways in infertile men with asthenozoospermia. Expression of these markers were assessed by qRT-PCR, and analysis of data show that mean of hypoxia markers (P53, HIF-1α) and also TNF- α were significantly higher in infertile men with asthenozoospermia compared to fertile men (p < 0.05). Unlike TNF-α, significant negative correlations were observed between expression of P53 (r = -0.568; p = 0.002) and HIF-1α (r = -0.403; p = 0.046) with sperm motility. In addition, a significant negative correlation was observed between expression of P53 with sperm concentration (r = -0.576; p < 0.001). In addition, a significant positive correlation was observed between hypoxia markers (P53, HIF-1α) and TNF-α (p < 0.01). However, no significant relation was observed between TNF-α and semen parameters. Taken together, the results of this study suggest the involvement of hypoxia pathway is more pronounced than the inflammatory pathway in asthenozoospermia.

Alterations in oxidative responses and post-translational modification caused by p,p´-DDE in Mus spretus testes reveal Cys oxidation status in proteins related to cell-redox homeostasis and male fertility

The major derivate of DDT, 1,1-dichloro-2,2-bis (p-chlorophenyl) ethylene (p,p´-DDE), is a persistent pollutant previously associated with oxidative stress. Additionally, p,p´-DDE has been linked to several metabolic alterations related to sexual function in rodents. In this study, we analysed the effects of a non-lethal p,p´-DDE dose to Mus spretus mice in testes, focusing on oxidative damage to biomolecules, defence mechanisms against oxidative stress and post-translational protein modifications. No increase in lipid or DNA oxidation was observed, although antioxidative enzymatic defences and redox status of glutathione were altered in several ways. Global protein carbonylation and phosphorylation were significantly reduced in testes from p,p´-DDE-exposed mice; however, the total redox state of Cys thiols did not exhibit a defined pattern. We analysed the reversible redox state of specific Cys residues in detail with differential isotopic labelling and a shotgun labelling-based MS/MS proteomic approach for identification and quantification of altered peptides. Our results show that Cys residues are significantly affected by p,p´-DDE in several proteins related to oxidative stress and/or male fertility, particularly those participating in fertilization, sperm capacitation and blood coagulation. These molecular changes could explain the sexual abnormalities previously described in p,p´-DDE exposed organisms.

Reactive oxygen species and male reproductive hormones

Reports of the increasing incidence of male infertility paired with decreasing semen quality have triggered studies on the effects of lifestyle and environmental factors on the male reproductive potential. There are numerous exogenous and endogenous factors that are able to induce excessive production of reactive oxygen species (ROS) beyond that of cellular antioxidant capacity, thus causing oxidative stress. In turn, oxidative stress negatively affects male reproductive functions and may induce infertility either directly or indirectly by affecting the hypothalamus-pituitary-gonadal (HPG) axis and/or disrupting its crosstalk with other hormonal axes. This review discusses the important exogenous and endogenous factors leading to the generation of ROS in different parts of the male reproductive tract. It also highlights the negative impact of oxidative stress on the regulation and cross-talk between the reproductive hormones. It further describes the mechanism of ROS-induced derangement of male reproductive hormonal profiles that could ultimately lead to male infertility. An understanding of the disruptive effects of ROS on male reproductive hormones would encourage further investigations directed towards the prevention of ROS-mediated hormonal imbalances, which in turn could help in the management of male infertility.