Role of oxidative stress in male infertility

Effects of short term dietary zinc deficiency and zinc supplementation on nitro-oxidative stress in testes of Wistar rats

Zinc is crucial for several cellular functions in the biological system. Zinc insufficiency is one of the most prevalent types of micronutrient malnutrition in the world. Present study was conducted to detect testicular free radical levels i.e. lipid peroxidation (LPO), hydroperoxides, hydroxyl radical (OH.), nitric oxide (NO) and peroxynitrite (ONOO-) after short term dietary zinc deficiency and zinc supplementation. Pre-pubertal rats (n = 144) were divided into two groups with 6 sub-groups viz. zinc control (ZC, 100 µg/g zinc diet), pair-fed (PF, 100 µg/g zinc diet), zinc deficient (ZD, < 1.00 µg/g), zinc control supplementation (ZCS, 100 µg/g zinc diet), pair-fed supplementation (PFS, 100 µg/g zinc diet) and zinc deficient supplementation (ZDS, 100 µg/g zinc diet). Experiments were set for 2- and 4-weeks followed by 4 weeks of dietary zinc supplementation. Zinc deficient groups (2- and 4-weeks) exhibited significant (p < 0.05) increase in testicular LPO (TBARS), hydroperoxides, OH·, NO and ONOO- levels as compared to their respective control and pair-fed groups. Zinc deficient supplementation group (2ZDS) revealed a non-significant increase in OH·, NO and ONOO- levels while a significant increase in LPO and hydroperoxides levels. 4ZDS group showed a significant increase in the free radical levels, however the increase was less as compared to 4ZD group. Dietary zinc deficiency results in induction of cellular lipoperoxidation as well as causes stimulation of nitro-oxidative stress. Zinc supplementation (although for short duration signifying zinc redistribution in the testicular tissue) indicated positive response accounting for reduced free radical generation and also implicating its requirement in optimum level for sustentation of reproductive functions.

Carvacrol attenuates varicocele-induced infertility in rats

Carvacrol is a common ingredient in the pharmaceutical, cosmetic, and perfume industries. It possesses various pharmaceutical properties including pain relief, anti-cell death, antioxidant, anti-cancer, and anti-inflammatory effects. We investigated the protective impact of carvacrol on infertility caused by varicocele in rats. The animals were assigned to nine groups randomly: control, sham-operated, carvacrol alone at 10, 20, and 40 mg/kg b.w./day, varicocele-induced control, and varicocele-induced rats treated with carvacrol. After thirty days of treatment, the serum was collected to evaluate testosterone levels, and left epididymal sperm samples were obtained to assess sperm quality. Additionally, the left testis was removed for biochemical and histopathological evaluation. The findings demonstrated that carvacrol administration (20 and 40 mg/kg) notably improved sperm quality in rats with varicocele. Furthermore, carvacrol treatment (20 and 40 mg/kg) increased antioxidant levels, reduced MDA levels, decreased AQP9 expression in testicular tissue, and improved testicular tissue structure. Hence, carvacrol (20 and 40 mg/kg) may serve as a therapeutic agent for male reproductive system disorders, particularly varicocele-related infertility, due to its antioxidant properties and protective effects on testicular function.

Polygonatum sibiricum polysaccharide attenuates cyclophosphamide-induced testicular damages and sperm defects in male mice via Nrf2 mediating antioxidant protective mechanisms

Polygonatum sibiricum polysaccharides are gaining more attention with various pharmacological activities, including anti-inflammatory and antioxidant. However, whether Polygonatum sibiricum polysaccharides could be a therapeutic modality for male infertility is not clear. Herein, a water-soluble Polygonatum sibiricum polysaccharide (PSPs-1) was isolated by a novel semi-biomimetic cellulase hydrolysis method and its effects and mechanism of action in improving cyclophosphamide-induced testicular damages in mice and H2O2-induced oxidative damage in normal mouse testis sertoli cells (TM4) were investigated. Results revealed that PSPs-1 was constituted of the residues including fructose, mannose, and glucose with an average molecular weight of 1.6048 × 105 Da. The scavenging rate of hydroxyl radical free radical in vitro reached 97.70 ± 0.93 %. Next, 200 μg/mL PSPs-1 treatment could increase the cell viability of TM4 cells by 37.9 %. Oral administration of 150 mg/kg PSPs-1 could increase the sperm count by 70.27 % and significantly improve the sperm quality in testicular-damaged mice. Furthermore, the mechanism study suggests that the protection of PSPs-1 on reproductive injury was partially mediated by the activation of Nuclear Factor Erythroid 2-Related Factor 2 (Nrf2). Treatment with PSPs-1 increased the Nrf2 protein expression, which leads to up-regulated expression of a series of Nrf2 target genes, including Glutathione Peroxidase 4 (GPX4) and NAD(P)H:quinone oxidoreductase 1 (NQO1). Subsequently, the contents of antioxidant enzymes were enhanced, but the levels of lipid peroxidation products were reduced in cells and testes. Overall, our study provides a basis for developing PSPs-1 into a valuable functional food ingredient or alternative therapeutic modality that can alleviate testicular damages.

The association between consumption of ultra-processed foods and sperm quality parameters: a cross-sectional study

BACKGROUND

While recent studies suggest a correlation between unhealthy dietary patterns, oxidative stress, inflammation, and male infertility, the potential association between ultra-processed foods (UPFs) and male infertility remains underexplored. Therefore, the aim of the present study was to investigate the association between UPF intake and male infertility by evaluating sperm quality parameters.

METHODS

The participants (n = 260) of the current cross-sectional study were recruited from an infertility center in Isfahan Province, Iran. Four semen parameters-such as total sperm motility, sperm concentration, sperm volume, and normal sperm morphology-were evaluated. Also, the participants' food intake was assessed using a validated 168-item food frequency questionnaire. Moreover, the NOVA system was employed to calculate the UPF index. The association between UPFs and sperm parameters was analyzed using logistic regression.

RESULTS

In the crude model, no significant associations were observed between the second and last tertiles of UPFs with abnormalities in sperm concentration, total motility, and morphology (p > 0.05 for all). However, after adjusting for age, marriage duration, body mass index, physical activity, depression, anxiety, stress, energy intake, cigarette history, and mineral and vitamin supplements, a significantly higher association was identified between the second tertile of UPFs and abnormalities in sperm concentration (odds ratio (OR) = 3.962, 95% confidence interval (CI): 1.345-11.670, p = 0.013).

CONCLUSIONS

In conclusion, although the analysis did not find significant associations between UPF consumption and impaired sperm motility and morphology, it revealed significant trends linking higher UPF intake with lower sperm concentration. If future studies confirm these results, they could aid in designing interventional and preventive programs aimed at addressing infertility in men of reproductive age in the field of public health.

Understanding the Associations of Urogenital Microbiomes With Fertility and In Vitro Fertilization

Infertility, defined as the inability to establish a clinical pregnancy after a year of regular, unprotected sexual intercourse, impacts 8%-12% of couples worldwide. Many of these couples turn to in vitro fertilization (IVF) to build their families. The success rate of IVF procedures is variable, with estimates of up to 40% of embryo transfers being unsuccessful. Herein we review the existing literature on the role of the female and male urogenital microbiomes and genital inflammation on fertility and IVF outcomes. We discuss the microbiome across the female reproductive tract (FRT) and identify associations with female infertility, female genital tract inflammation, and success of IVF procedures. We also discuss the male urogenital microbiome and the associations between microbial taxa, genital inflammation, and male fertility parameters. Finally, we consider microbial transfer within couples and the impact this may have on fertility and the success of IVF procedures.

Intensity and type of physical activity and semen quality in healthy young men

OBJECTIVE

To study the relationship between intensity of physical activity (PA) and semen quality in healthy young men.

DESIGN

A prospective cohort study with repeated measures for each subject.

PATIENT(S)

Healthy high school and university students who did not regularly smoke tobacco, drink alcohol, or take drugs or medicine, with normal body mass index and abdominal circumference.

EXPOSURE

The participants underwent urologic visit, fasting blood and semen sampling, and anthropometric measurements, and filled in the International Physical Activity Questionnaire, at enrollment and after 4 and 8 months. Duration and frequency of walking, moderate-intensity, and vigorous-intensity activities in the last week were assessed, and a score was computed for total PA.

MAIN OUTCOME MEASURE(S)

Semen specimens were taken at each visit through masturbation, after 3-5 days of abstinence, and analyzed by an expert urologist. Sperm concentration, total and progressive motility, and proportion of spermatozoa with normal morphology were measured. Linear and generalized linear mixed models with the Poisson family were fitted to assess the relationships between PA variables and sperm parameters, after adjusting for season, time, and study arm. The shape of the relationship was modeled through restricted cubic spline regression.

RESULT(S)

A total of 143 male subjects, aged 18-23 years (median, 20 years), were enrolled. They had a median PA of 1,960 (95% confidence interval, 1,055-3,182) Metabolic Equivalent of Tasks in min/wk. Statistically significant differences were found for total, progressive motility, and percent of cell with normal morphology across categories of total PA; the highest medians of total (47%) and progressive motility (34%) and of the percentage of normal morphology cells (7%) were found for medium PA. Positive associations of sperm total motility and normal morphology with medium levels of PA, and negative associations with walking and vigorous-intensity activity emerged. Spline regression analysis confirmed these findings, showing an inverse U-shape relationship, with the highest value of total motility and normal morphology for medium PA, and the lowest values for lower and higher activity.

CONCLUSION(S)

These findings support the present recommendations to practice moderate PA for health improvement, including semen quality.

Azilsartan as a preventive agent against cyclophosphamide-induced testicular injury in male rats

Cyclophosphamide (CP) is a popular cancer treatment; however, despite its efficacy, it is known to cause harm to the testicles. To mitigate the reproductive damage caused by CP in male rats, we examined the protective effect of azilsartan (AZ) on CP-induced testicular damage. Thirty Sprague-Dawley male rats were equally divided into three groups: normal control group: received 0.5% CMC suspension for 13 days; induction group: received a single dose of 200 mg/kg of CP on day 6 by intraperitoneal (IP) injection, azilsartan group: received azilsartan (4 mg/kg) orally for 5 days followed by a single dose of 200 mg/kg of (CP) on day 6 by IP injection, then azilsartan administered again for 7 days. Animals were sacrificed on day 14, and sperm characteristics, testosterone levels, and testicular histopathology were evaluated. Induction with CP caused a significant reduction in median value compared to normal control in sperm count (12.0 vs. 22.0 × 106/mm3), sperm motility (30 vs. 90%), abnormal sperm (30.32 vs. 14.43%), dead sperm count (32.43 vs. 10.49 × 106/mm3), DNA fragmentation (21.57 vs. 5.49%); meanwhile, azilsartan prevent these effects on median sperm count (17.0 × 106/mm3), sperm motility (70.0%), abnormal sperm (23.19%), dead sperm count (26.17 × 106/mm3), DNA fragmentation (13.81%), and improved plasmatic testosterone levels compared to the CP group and prevented histopathological alterations of the testes. Azilsartan's mitigation of CP's effects suggests it can prevent male rats' reproductive damage caused by CP. One possible explanation for AZ's protective effects is that it inhibits lipid peroxidation and has antioxidant properties.

Platelet Mitochondrial Function and Endogenous Coenzyme Q10 Levels Could Be Used as Markers of Mitochondrial Health in Infertile Men: A Pilot Study

Fertility disorders are a worldwide problem affecting 8-12% of the population, with the male factor substantially contributing to about 40-50% of all infertility cases. Mitochondria, crucial organelles for cellular viability, play a pivotal role in the processes of spermatogenesis and significantly affect sperm quality and their fertilizing ability. Mitochondrial oxidative phosphorylation (OXPHOS) dysfunction, reduced energy supply for sperm, reduced endogenous coenzyme Q10 (CoQ10) levels, and oxidative stress are among the main factors that contribute to male infertility. There is great interest in the role of mitochondrial dysfunction in male infertility, and the diagnosis and assessment of mitochondrial health in infertile men present challenges. Platelets are a source of viable mitochondria that can be obtained non-invasively. Changes in platelet mitochondrial respiration were documented in various diseases, confirming platelet mitochondrial bioenergetics as a marker of systemic mitochondrial health. The aim of our study was to determine whether (a) platelet mitochondrial bioenergetics and CoQ10 levels could be used as metabolic markers of mitochondrial health in infertile men and whether (b) the parameters of mitochondrial respiration in platelets correlate with sperm parameters. The high-resolution respirometry method was used for platelet bioenergetics, and the high-performance liquid chromatography (HPLC) method was used for CoQ10 level measurement. The static oxidation-reduction potential (sORP) of the ejaculate was evaluated by MiOXSYS®System. We found a deficit in mitochondrial complex I-linked OXPHOS and electron transfer capacity and CoQ10 and α-tocopherol levels in infertile men. The proportion of sperm, heads, and midpiece abnormalities correlated negatively with the complex I-linked parameters of platelet mitochondrial bioenergetics. We suppose that dysfunctional mitochondria contribute to increased oxidative stress, and these imbalances can be considered a cause of Male Oxidative Stress Infertility (MOSI). Our results suggest that platelet mitochondrial function and the endogenous levels of CoQ10 in platelets could be used as metabolic markers for monitoring mitochondrial health and targeted therapy in infertile men. sORP could be a useful clinical biomarker of MOSI.

Exploring the impact of lipid stress on sperm cytoskeleton: insights and prospects

The decline in male fertility correlates with the global rise in obesity and dyslipidaemia, representing significant public health challenges. High-fat diets induce metabolic alterations, including hypercholesterolaemia, hepatic steatosis and atherosclerosis, with detrimental effects on testicular function. Testicular tissue, critically dependent on lipids for steroidogenesis, is particularly vulnerable to these metabolic disruptions. Excessive lipid accumulation within the testes, including cholesterol, triglycerides and specific fatty acids, disrupts essential sperm production processes such as membrane formation, maturation, energy metabolism and cell signalling. This leads to apoptosis, impaired spermatogenesis, and abnormal sperm morphology and function, ultimately compromising male fertility. During spermiogenesis, round spermatids undergo extensive reorganization, including the formation of the acrosome, manchette and specialized filamentous structures, which are essential for defining the final sperm cell shape. In this Perspective, we examine the impact of high-fat diets on the cytoskeleton of spermatogenic cells and its consequences to identify the mechanisms underlying male infertility associated with dyslipidaemia. Understanding these processes may facilitate the development of therapeutic strategies, such as dietary interventions or natural product supplementation, that aim to address infertility in men with obesity and hypercholesterolaemia. The investigation of cytoskeleton response to lipid stress extends beyond male reproduction, offering insights with broader implications.

Protective Role of Melatonin Against Abamectin-Induced Biochemical, Immunohistochemical, and Ultrastructural Alterations in the Testicular Tissues of Rats

Abamectin is one of the most widely used pesticides due to its strong insecticidal and anthelmintic activities. Melatonin is a neurohormone with potent antioxidant, anti-apoptotic, and anti-inflammatory effects. This study aimed to investigate the potential ameliorative effects of melatonin against abamectin-induced testicular toxicity in rats. Twenty-four rats were divided into four groups: control group (1 mL/kg/day corn oil), melatonin-treated group (10 mg/kg/day), abamectin-treated group (0.5 mg/kg/day), and melatonin plus abamectin-treated group. Test substances were administered via oral gavage once daily for 28 days. While MDA and 8-OHdG levels increased in the testicular tissue of rats treated with abamectin, SOD, CAT, GPx, and GST enzyme activities decreased significantly. While interleukin-17 levels, TNF-α, and caspase3 expression increased in the testicular tissue, acetylcholinesterase activity decreased. At the same time, serum gonadotropins (luteinizing and follicle-stimulating hormones) and testosterone levels decreased. Light microscope examinations of testicular tissues revealed severe histopathological changes, such as atrophic hyalinized seminiferous tubules, basement membrane irregularity, degeneration, spermatogenic cell loss, and necrosis. Electron microscopy examinations revealed large vacuoles in Sertoli and spermatogenic cells, swelling and vacuolization in mitochondria, lysosomal structures, and increased pyknotic nuclei. In contrast, melatonin supplementation significantly ameliorated abamectin-induced testicular toxicity in rats through antioxidant, antiapoptotic, and anti-inflammatory mechanisms.

Assessing the efficacy of a novel sperm-washing medium enriched with serotonin, L-carnitine, and coenzyme Q10: an observational cohort study

ABSTRACT

This observational cohort study investigated the potential of a novel sperm-washing medium (SWM) enriched with serotonin (5-HT), L-carnitine (L-C), and coenzyme Q10 (CoQ10) to enhance sperm motility and reduce DNA damage. It compared this innovative medium (5-HT/L-C/CoQ10 SWM) with two widely used commercial media (SWM 1 and SWM 2). Ninety-eight volunteers from an infertility clinic provided semen samples, which were divided into three aliquots for analysis in different SWMs: group 1, SWM was composed of hydroxyethyl piperazineethanesulfonic acid (HEPES), sodium bicarbonate, human serum albumin (HSA), taurine, and gentamicin sulfate (SWM 1); group 2, SWM was composed of HEPES, sodium bicarbonate, and HSA (SWM 2); and group 3, SWM was composed of HEPES-buffered human tubal fluid supplemented with 5-HT, L-C, and CoQ10 (5-HT/L-C/CoQ10 SWM). Sperm motility was categorized as progressive, nonprogressive, or immotile. Apoptosis, reactive oxygen species (ROS) production, and DNA fragmentation were also assessed. There were no significant differences in total or progressive sperm motility among the groups. Spermatozoa in group 3 exhibited reduced apoptosis, necrosis, and ROS levels and increased viability. No significant differences were observed in the DNA fragmentation index among groups. The 5-HT/L-C/CoQ10 SWM reduced sperm oxidative stress and apoptosis compared with those of the two commercially available SWMs, suggesting that 5-HT/L-C/CoQ10 SWM could be useful for enhancing in vitro fertilization success rates.

The Human 8-oxoG DNA Glycosylase 1 (OGG1) Ser326Cys Polymorphism in Infertile Men

BACKGROUND/OBJECTIVES

8-hydroxy-2'-deoxyguanosine (8-OHdG) is a form of oxidative DNA damage caused by oxidative stress (OS), which is considered a major factor in male infertility. The cellular defense system against 8-OHdG involves base excision repair (BER) with the enzyme 8-Oxoguanine DNA glycosylase 1 (OGG1). However, studies on the single-nucleotide polymorphism (SNP) OGG1 Ser326Cys have demonstrated that the Cys326Cys genotype could be the cause of an increment in oxidative DNA damage. In this study, the OGG1 Ser326Cys polymorphism and its effect on DNA oxidation were evaluated in 118 infertile men.

METHODS

Polymorphic screening was performed using TaqMan allelic discrimination assays, and oxidative DNA damage was evaluated through the quantification of 8-OHdG and total antioxidant capacity (TAC); in addition, electrical bioimpedance spectroscopy (EBiS) measurements were used as a reference for different electrical properties associated with 8-OHdG concentrations.

RESULTS

The detected Cys (G) allele frequency (0.4) was higher compared to the allele frequency reported in the "Allele Frequency Aggregator" (ALFA) and "Haplotype Map" (HapMap) projects for American populations (0.21-0.29), suggesting that the Cys (G) allele carrier could be a factor associated with American infertile populations. The values of 8-OHdG were twofold higher in carriers of the Cys326Cys (GG) genotype than the other genotypes and, in concordance, the TAC levels were threefold lower in Cys326Cys (GG) genotype carriers compared to the other genotypes. Moreover, the EBiS magnitude exhibited potential for the detection of different oxidative damage in DNA samples between genotypes.

CONCLUSIONS

The Cys326Cys (GG) genotype is associated with oxidative DNA damage that could contribute to male infertility.

A narrative review of mitochondrial dysfunction and male infertility

Background and Objective

Recent investigations have highlighted mitochondrial dysfunction as a major component in reduced sperm function and male infertility. The creation of energy, control of reactive oxygen species (ROS), apoptosis, and sperm motility are all critically dependent on mitochondria. The health of the male reproductive system may be significantly impacted by any alteration of mitochondrial structure, function, or integrity. This review intends to open the door to better diagnostic methods, novel therapy strategies, and improved reproductive outcomes for infertile couples by clarifying the crucial function of mitochondria.

Methods

We searched PubMed, Google Scholar, and others for articles related to male infertility and mitochondrial dysfunction from 2014 to 2023. The articles related to the theme were preliminarily screened by abstract, and then the selected literature was read and summarized. In this essay, we examine the research on male infertility and mitochondrial malfunction. We investigate the intricate connection between sperm quality, deoxyribonucleic acid damage, oxidative stress (OS), and mitochondrial bioenergetics. We discuss about how spermatogenesis and sperm function are affected by mitochondrial mutations, deletions, and single nucleotide polymorphisms. We also explore the impact of age-related changes, lifestyle choices, and environmental factors on mitochondrial function and male fertility. This review also clarifies the mechanisms by which mitochondrial dysfunction impacts the viability, morphology, and capacitation of sperm, among other aspects of male reproductive health. Furthermore, we go over the recently developed field of mitochondrial treatments and possible therapeutic approaches that target mitochondrial malfunction to enhance male fertility.

Key Content and Findings

Mitochondria are important for sperm: The control of sperm motility, capacitation, and general quality is largely dependent on mitochondria. Deterioration of sperm motility and male infertility may result from disruption of the structure, function, or integrity of the mitochondria. Future studies should focus on figuring out the processes underlying mitochondrial dysfunction as fertility and reproductive health are significantly impacted by it.

Conclusions

We discuss the evaluation of infertile men mitochondrial function defects and difficulties, and make recommendations for further study in this area. This article provides a thorough resource for clinicians, researchers, and reproductive biologists to understand the underlying mechanisms of male infertility and explore potential therapeutic interventions.

Irisin in Reproduction: Its Roles and Therapeutic Potential in Male and Female Fertility Disorders

The current study focused on identifying the potential of irisin in mammalian reproduction. The established role of irisin, a proteolytic product of FNDC5, in adipose tissue browning, energy metabolism, and thermogenesis suggests its role in reproductive health, often disturbed by metabolic imbalances. Various studies on mice demonstrated irisin's role in improving spermatogenesis, sperm count, and testosterone levels by influencing the hypothalamus-pituitary-gonadal axis. Moreover, in females, there is a fluctuation in levels of irisin during critical reproductive stages, including menstrual cycles, puberty, and pregnancy. Conditions like pregnancy complications, precocious puberty, and polycystic ovary syndrome (PCOS) are found to have an association with abnormal irisin levels. The potential role of irisin in endometrial receptivity and preventing endometritis is also discussed in this review. Overall, the influence of irisin on female and male reproduction is evident from various studies. However, further research is needed to elucidate irisin mechanism in reproduction and its potential as a therapeutic or diagnostic tool for reproductive dysfunctions and infertility.

The Role of Selected Elements in Oxidative Stress Protection: Key to Healthy Fertility and Reproduction

Oxidative stress and its relationship to fertility and reproduction is a topic of interest in medicine, especially in the context of the effects of trace elements and micronutrients. Oxidative stress occurs when there is an excess of free radicals in the body, which can lead to cell and tissue damage. Free radicals are reactive oxygen species (ROS) that can be formed as a result of normal metabolic processes, as well as under the influence of external factors such as environmental pollution, UV radiation, and diet. Oxidative stress has a significant impact on fertility. In men, it can lead to DNA damage in sperm, which can result in reduced semen quality, reduced sperm motility and increased numbers of defective sperm, and free radical damage to sperm cell membranes causing a reduction in the number of available sperm. In women, oxidative stress can affect the quality of female reproductive cells, which can lead to problems with their maturation and with embryo implantation in the uterus and can also affect ovarian function and disrupt hormonal regulation of the menstrual cycle. A proper balance of trace elements and micronutrients is key to protecting against oxidative stress and maintaining reproductive health. Supplementation with appropriate elements such as zinc, selenium, copper, manganese, chromium, and iron can help reduce oxidative stress and improve fertility. This work discusses the effects of selected elements on oxidative stress parameters specifically in terms of fertility and reproduction.

The Role of the Mediterranean Diet in Assisted Reproduction: A Literature Review

The Mediterranean Diet, characterized by high consumption of plant-based foods, olive oil, moderate intake of fish and poultry, and low consumption of red meat and processed foods, has been suggested to improve assisted reproductive technology (ART) outcomes. This narrative review aimed to summarize and synthesize the evidence from observational studies on the associations between preconception adherence to the Mediterranean Diet and ART outcomes. PubMed/MEDLINE, Embase, ScienceDirect, Google Scholar, and Web of Science databases were searched to identify relevant studies. Seven observational studies (n = 2321 women undergoing ART) were included. Adherence to the Mediterranean Diet was assessed using food frequency questionnaires with 6-195 items. Three studies found that higher Mediterranean Diet scores were associated with improved clinical pregnancy rates (OR 1.4, 95% CI 1.0-1.9; RR 1.98, 95% CI 1.05-3.78) or live birth rates (RR 2.64, 95% CI 1.37-5.07). Two studies showed a positive effect on embryo yield (p = 0.028) and ovarian response. However, two studies reported no significant associations with ultimate ART success, and four studies found no effects on oocyte and embryo number or quality. The heterogeneity in study designs, Mediterranean Diet assessment methods, and ART protocols limited the strength of conclusions. Evidence for the effects of greater adherence to the Mediterranean Diet on ART outcomes is limited but promising. Future research should focus on conducting randomized controlled trials with standardized Mediterranean Diet assessment methods to establish causal relationships between Mediterranean Diet adherence and ART outcomes, and to elucidate potential mechanisms of action.

Genes linked to obesity-related infertility: bridging the knowledge gap

Genetic factors play a pivotal role in the complex relationship between obesity and infertility. This article delves into the genetics of obesity-related infertility, focusing on the essential genes and mechanisms in both sexes. We explored infertility factors in obese females, focusing on polycystic ovary syndrome (PCOS) and the influence of genes like insulin receptor (INSR), androgen receptor (AR), and follicle-stimulating hormone receptor (FSHR). Epigenetic changes are believed to contribute to PCOS-related infertility. The impact of adipokines and inflammation on obesity-related infertility has been discussed, with genes such as fat mass and obesity (FTO) and melanocortin-4-receptor (MC4R) playing significant roles. Genetic factors affecting sperm quality and function, including nuclear receptor subfamily 3 group C member 1 (NR3C1) and methylenetetrahydrofolate reductase (MTHFR), have been investigated in obesity-related infertility in males. Hormonal dysregulation influenced by genetic markers, such as leptin receptor (LEPR), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6), was also examined. Genetic factors play a vital role in obesity-related infertility in both sexes. Genes involved in metabolism, hormonal regulation, and inflammation contribute to the complex association between obesity and infertility. Epigenetic changes further complicate the relationship. Understanding these genetic mechanisms is essential to address obesity-related infertility and develop personalized interventions.

Maternal supplementation of alpha-lipoic acid ameliorates prenatal cytarabine-induced mutilation in reproductive development and function in F1 male adult rats

AIMS

Cytarabine (CYT), a prevalent anticancer drug for blood cancers, detrimentally affects male reproductive development and function. Alpha-lipoic acid (ALA), a universal antioxidant, offers defense against chemical-induced reproductive dysfunction. Our study sought to explore ALA's protective role against prenatal CYT-induced reproductive impairment in F1 male adult rats.

MAIN METHODS

Pregnant rats were divided into 5 groups and administered normal saline, ALA 200 mg/kg, CYT 12.5 mg/kg, CYT 25 mg/kg, and CYT 25 mg/kg + ALA 200 mg/ kg from gestational day 8 to 21. On postnatal day 73, F1 male rats were sacrificed, and general, oxidative, steroidogenic, spermatogenic, histological, and morphometrical parameters were evaluated.

KEY FINDINGS

Prenatal CYT caused dose-dependent reductions in body weight, testis, and accessory gland weights; elevated oxidative stress; delayed puberty onset; sperm anomalies (decreased count, motility, viability, seminal fructose; increased morphological anomalies); impeded steroidogenesis (lower testosterone, follicle-stimulating hormone, luteinizing hormone, 3β-Hydroxysteroid dehydrogenase(HSD), 17β-HSD, and elevated cholesterol); and testicular histopathological and morphometric disturbances. Maternal supplementation of ALA was found to alleviate all the CYT-induced reproductive disruptions.

SIGNIFICANCE

The present work accentuates the beneficial actions of ALA against CYT-induced impairment in reproductive development and functions by combating disruptions in oxidative balance, steroidogenesis, spermatogenesis, and testicular histological aberrations. However, future experimental and clinical studies are warranted to explore the molecular mechanisms involved in the ALA's protection against prenatal CYT-induced testicular injury.

Advancements in Genetic Biomarkers and Exogenous Antioxidant Supplementation for Safeguarding Mammalian Cells against Heat-Induced Oxidative Stress and Apoptosis

Heat stress represents a pervasive global concern with far-reaching implications for the reproductive efficiency of both animal and human populations. An extensive body of published research on heat stress effects utilizes controlled experimental environments to expose cells and tissues to heat stress and its disruptive influence on the physiological aspects of reproductive phenotypic traits, encompassing parameters such as sperm quality, sperm motility, viability, and overall competence. Beyond these immediate effects, heat stress has been linked to embryo losses, compromised oocyte development, and even infertility across diverse species. One of the primary mechanisms underlying these adverse reproductive outcomes is the elevation of reactive oxygen species (ROS) levels precipitating oxidative stress and apoptosis within mammalian reproductive cells. Oxidative stress and apoptosis are recognized as pivotal biological factors through which heat stress exerts its disruptive impact on both male and female reproductive cells. In a concerted effort to mitigate the detrimental consequences of heat stress, supplementation with antioxidants, both in natural and synthetic forms, has been explored as a potential intervention strategy. Furthermore, reproductive cells possess inherent self-protective mechanisms that come into play during episodes of heat stress, aiding in their survival. This comprehensive review delves into the multifaceted effects of heat stress on reproductive phenotypic traits and elucidates the intricate molecular mechanisms underpinning oxidative stress and apoptosis in reproductive cells, which compromise their normal function. Additionally, we provide a succinct overview of potential antioxidant interventions and highlight the genetic biomarkers within reproductive cells that possess self-protective capabilities, collectively offering promising avenues for ameliorating the negative impact of heat stress by restraining apoptosis and oxidative stress.

Decrease in Sperm Parameters in the 21st Century: Obesity, Lifestyle, or Environmental Factors? An Updated Narrative Review

Semen quality represents a compelling factor for fertility, and delineating the normal values has proven difficult. In the last four decades, several authors have reported a noticeable decline in sperm parameters. Also, studies investigating 'time to pregnancy' have shown that fecundity begins to be reduced when sperm numbers decrease below 30 million, even though according to the 6th edition of the WHO manual, the normal value is currently 16 million/mL or 39 million per ejaculate. There exists sufficient data to suggest a decline in sperm counts over time, even though the clear reason for this adverse trend is not well established, but some associations have been hypothesised, such as maternal smoking during pregnancy. Additional potential factors have yet to be fully illustrated but involve poor diet, increased obesity, and exposure to environmental toxins. Moreover, the change in environmental conditions and more common exposure to endocrine-disrupting chemicals (EDCs), such as pesticides and herbicides, as well as bisphenol A, phthalates, polychlorinated biphenyls, and heavy metals, starting from prenatal life and continuing into adulthood, may exhibit probable features explaining the reduction in sperm parameters. Therefore, the main goal of this narrative review is to furnish an overview of the possible effects of exposure to EDCs on testicular function and spermatogenesis and, also, to summarise the evidence regarding a decrease in sperm quality and examine its potential consequences.

Redox Homeostasis and Nrf2-Regulated Mechanisms Are Relevant to Male Infertility

Infertility represents a significant global health challenge, affecting more than 12% of couples worldwide, and most cases of infertility are caused by male factors. Several pathological pathways are implicated in male infertility. The main mechanisms involved are driven by the loss of reduction-oxidation (redox) homeostasis and the resulting oxidative damage as well as the chronic inflammatory process. Increased or severe oxidative stress leads to sperm plasma membrane and DNA oxidative damage, dysregulated RNA processing, and telomere destruction. The signaling pathways of these molecular events are also regulated by Nuclear factor-E2-related factor 2 (Nrf2). The causes of male infertility, the role of oxidative stress in male infertility and the Keap1-Nrf2 antioxidant pathway are reviewed. This review highlights the regulatory role of Nrf2 in the balance between oxidants and antioxidants as relevant mechanisms to male fertility. Nrf2 is involved in the regulation of spermatogenesis and sperm quality. Establishing a link between Nrf2 signaling pathways and the regulation of male fertility provides the basis for molecular modulation of inflammatory processes, reactive oxygen species generation, and the antioxidant molecular network, including the Nrf2-regulated antioxidant response, to improve male reproductive outcomes.

Optimum Doses and Forms of Selenium Maintaining Reproductive Health via Regulating Homeostasis of Gut Microbiota and Testicular Redox, Inflammation, Cell Proliferation, and Apoptosis in Roosters

BACKGROUND

There is a U-shaped relationship between dietary selenium (Se) ingestion and optimal sperm quality.

OBJECTIVES

This study aimed to investigate the optimal dietary dose and forms of Se for sperm quality of breeder roosters and the relevant mechanisms.

METHODS

In experiment 1, 18-wk-old Jingbai laying breeder roosters were fed a Se-deficient base diet (BD, 0.06 mg Se/kg), or the BD + 0.1, 0.2, 0.3, 0.4, 0.5, or 1.0 mg Se/kg for 9 wk. In experiment 2, the roosters were fed the BD or the BD + sodium selenite (SeNa), seleno-yeast (SeY), or Se-nanoparticles (SeNPs) at 0.2 mg Se/kg for 9 wk.

RESULTS

In experiment 1, added dietary 0.2 and 0.3 mg Se/kg led to higher sperm motility and lower sperm mortality than the other groups at weeks 5, 7, and/or 9. Furthermore, added dietary 0.2-0.4 mg Se/kg produced better testicular histology and/or lower testicular 8-hydroxy-deoxyguanosine than the other groups. Moreover, integrated testicular transcriptomic and cecal microbiomic analysis revealed that inflammation, cell proliferation, and apoptosis-related genes and bacteria were dysregulated by Se deficiency or excess. In experiment 2, compared with SeNa, SeNPs slightly increased sperm motility throughout the experiment, whereas SeNPs slightly reduced sperm mortality compared with SeY at week 9. Both SeY and SeNPs decreased malondialdehyde in the serum than those of SeNa, and SeNPs led to higher glutathione peroxidase (GPX) and thioredoxin reductase activities and GPX1 and B-cell lymphoma 2 protein concentrations in the testis compared with SeY and SeNa.

CONCLUSIONS

The optimal dietary Se dose for reproductive health of breeder roosters is 0.25-0.35 mg Se/kg, and SeNPs displayed better effects on reproductive health than SeNa and SeY in laying breeder roosters. The optimal doses and forms of Se maintain reproductive health of roosters associated with regulation intestinal microbiota homeostasis and/or testicular redox balance, inflammation, cell proliferation, and apoptosis.

Male Reproductive Toxicity of Antifouling Chemicals: Insights into Oxidative Stress-Induced Infertility and Molecular Mechanisms of Zinc Pyrithione (ZPT)

Zinc pyrithione (ZPT), a widely utilized industrial chemical, is recognized for its versatile properties, including antimicrobial, antibacterial, antifungal, and antifouling activities. Despite its widespread use, recent research has shed light on its toxicity, particularly towards the male reproductive system. While investigations into ZPT's impact on male reproduction have been conducted, most of the attention has been directed towards marine organisms. Notably, ZPT has been identified as a catalyst for oxidative stress, contributing to various indicators of male infertility, such as a reduced sperm count, impaired sperm motility, diminished testosterone levels, apoptosis, and degenerative changes in the testicular tissue. Furthermore, discussions surrounding ZPT's effects on DNA and cellular structures have emerged. Despite the abundance of information regarding reproductive toxicity, the molecular mechanisms underlying ZPT's detrimental effects on the male reproductive system remain poorly understood. This review focuses specifically on ZPT, delving into its reported toxicity on male reproduction, while also addressing the broader context by discussing other antifouling chemicals, and emphasizing the need for further exploration into its molecular mechanisms.

Human Papillomavirus and Male Infertility: What Do We Know?

In recent years, increasing attention has been paid to understanding the causes of infertility, which is being recognized as a growing health problem affecting large numbers of couples worldwide. Male infertility is a contributing factor in approximately 30-40% of cases, and one of its etiological causes is sexually transmitted infections (STIs). Among sexually transmitted pathogens, human papillomavirus (HPV) can contribute in various ways to the failure of spontaneous and assisted reproduction, acting in the different phases of conception, especially in the early ones. In particular, HPV infection can affect sperm DNA integrity, sperm motility, count, viability, and morphology and can induce the production of anti-sperm antibodies (ASAs). In this narrative review, we aimed to provide an overview of existing research on the potential adverse effects of HPV infection on male reproductive health. Furthermore, we analyzed how limiting the spread of the infection, particularly with gender-neutral vaccination, could be a possible therapeutic tool to counteract male and female fertility problems.

Spermatogenesis recovery treatment in less than four months from zero to almost 16 million sperms per milliliter after several cycles of steroids in 44-year-old healthy man

The most common external factors that men can have influence on, and improve its own spermatogenesis, are related to lifestyle, habits, stress level, sport activities, nutrition quality, and medications. Steroids became one of the key issues in young men during reproductive stage of life. More and more teenagers who are not even developed yet naturally start using supplements very early to build up body and strengths of muscles in the shortest possible time. In this report is presented the case of 44-year-old (November 2022), healthy, and sporty man, who is 1-2 times per year on steroid cycles since he turned 40th. He had intention to become a father; however after 6 months of the last steroid cycle, sperm count was zero. This case will show what was needed and successfully done within less than 4 months after last steroids administration and the moment when sperm count reached almost 16 million sperms per milliliter. However, it has to be clear that this is unique case and additional tests would be needed on bigger population to confirm fast post steroid sperm count recovery in healthy subjects, using approach from this manuscript.

Captivating Colors, Crucial Roles: Astaxanthin's Antioxidant Impact on Fish Oxidative Stress and Reproductive Performance

Fish, constantly exposed to environmental stressors due to their aquatic habitat and high metabolic rates, are susceptible to oxidative stress. This review examines the interplay between oxidative stress and fish reproduction, emphasizing the potent antioxidant properties of astaxanthin. Our primary objective is to highlight astaxanthin's role in mitigating oxidative stress during critical reproductive stages, leading to improved gamete quality, ovary development, and hormone levels. We also explore its practical applications in aquaculture, including enhanced pigmentation and overall fish health. We conducted a comprehensive literature review, analyzing studies on astaxanthin's antioxidant properties and its impact on fish reproduction. Astaxanthin, a carotenoid pigment, effectively combats reactive oxygen species, inhibiting lipid peroxidation and maintaining membrane integrity. It significantly enhances reproductive success in fish and improves overall fish health in aquaculture settings. This review reveals astaxanthin's multifaceted benefits in fish health and reproduction, offering economic advantages in aquaculture. Future research should delve into species-specific responses, optimal dosages, and the long-term effects of astaxanthin supplementation to inform sustainable aquaculture strategies.