Alterations in mitochondria membrane potential and oxidative stress in infertile men: a prospective observational study

Unveiling the anticancer potential of Anamirta cocculus (L.) Wight& Arn.: Evidences from cytotoxicity studies, apoptosis analysis, and molecular docking

Anamirta cocculus, a woody climber, is extensively utilised in traditional Asian medicine. This study investigates the cytotoxic effects of A. cocculus leaf extracts on various cancer cell lines as well as on a normal cell line. The ethyl acetate extract exhibited potent anticancer activity, with the highest cytotoxicity observed against ovarian cancer cell line (PA1) (IC50 = 8.30 ± 0.38 µg/mL) and colorectal adenocarcinoma cell line (HT29) (IC50 = 17.97 ± 0.63 µg/mL). Notably, the extract displayed low toxicity (18.72 ± 0.73%) on the normal human keratinocyte cell line (HaCaT) at a concentration of 100 µg/mL, indicating selective cytotoxicity towards cancer cells. The acetone extract also demonstrated significant cytotoxicity against various cancer cell lines, including A498, MG63, PA1, and UM-SCC-83B. The ethyl acetate extract of A. cocculus demonstrated potent inhibition of colony formation in HT29 and PA1 cancer cell lines while inducing apoptosis, as evidenced by membrane blebbing, chromatin condensation, and DNA fragmentation. The number of late apoptotic cells increased with an increase in concentrations of ACLE. Molecular docking studies of compounds identified through GC-MS analysis revealed strong interactions with key apoptotic proteins, including caspase-8, p53, caspase-3, and caspase-9. Compounds such as vitamin E, epoxylathyrol, squalene, and phytol showed high binding affinity to these proteins, suggesting their role in apoptosis induction. The possibility of induction of apoptotic proteins through indirect interaction by binding to other proteins or receptors cannot be ruled out. The cytotoxic effects may result from individual, combined, or synergistic actions of these compounds. Among these, epoxylathyrol emerged as a particularly promising anticancer drug candidate based on ADME analysis and binding affinity assessments, warranting further investigation.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-024-04096-2.

Reliable Detection of Excessive Sperm Ros Production in Subfertile Patients: How Many Men with Oxidative Stress?

Sperm oxidative stress has been extensively associated to male infertility. However, tests to detect this parameter have not been yet introduced in clinical practice and no definitive data are present on the extent of oxidative stress in male infertility. In this study, we used a novel and reliable flow cytometric method to reveal sperm ROS production in subfertile patients (n = 131) and in healthy donors (n = 31). Oxidative stress was higher in subfertile patients (14.22 [10.21-22.08]%) than in healthy donors (9.75 [8.00-14.90]% (p < 0.01)), but no correlation was found with age, semen quality or sDF. We also failed to detect an increase in sperm ROS production with semen viscosity or leukocytospermia, but a sharp impact of semen bacteria was evident (with bacteria: 31.61 [14.08-46.78]% vs. without bacteria: 14.20 [10.12-22.00]%, p < 0.01). Finally, after establishing a threshold as the 95th percentile in healthy donors, we found that 29% of subfertile patients exceeded this threshold. The percentage decreased to 25.56% when we excluded subjects with bacteriospermia and increased to 60.87% when only these patients were considered. In conclusion, 29% of subfertile patients showed an excessive sperm ROS production. Surprisingly, this parameter appears to be independent from routine semen analysis and even sDF determination, promising to provide additional information on male infertility.

Effects of reactive oxygen species and mitochondrial dysfunction on reproductive aging

Mitochondria, the versatile organelles crucial for cellular and organismal viability, play a pivotal role in meeting the energy requirements of cells through the respiratory chain located in the inner mitochondrial membrane, concomitant with the generation of reactive oxygen species (ROS). A wealth of evidence derived from contemporary investigations on reproductive longevity strongly indicates that the aberrant elevation of ROS level constitutes a fundamental factor in hastening the aging process of reproductive systems which are responsible for transmission of DNA to future generations. Constant changes in redox status, with a pro-oxidant shift mainly through the mitochondrial generation of ROS, are linked to the modulation of physiological and pathological pathways in gametes and reproductive tissues. Furthermore, the quantity and quality of mitochondria essential to capacitation and fertilization are increasingly associated with reproductive aging. The article aims to provide current understanding of the contributions of ROS derived from mitochondrial respiration to the process of reproductive aging. Moreover, understanding the impact of mitochondrial dysfunction on both female and male fertility is conducive to finding therapeutic strategies to slow, prevent or reverse the process of gamete aging, and thereby increase reproductive longevity.

Expression dynamics indicate the involvement of SPG7 in the reproduction and spermiogenesis of Phascolosoma esculenta

Spastic paraplegia 7 (SPG7) is an m-AAA protease subunit involved in mitochondrial morphology and physiology. However, its function in animal reproduction is yet to be evaluated. In this study, its molecular features, subcellular localization, and expression dynamics were investigated to analyze its potential function in the reproduction of male Phascolosoma esculenta, an economically important marine species in China. The full-length cDNA of P. esculenta spg7 (Pe-spg7) measures 3053 bp and encodes an 853-amino acid protein (Pe-SPG7). Pe-SPG7 includes two transmembrane domains, an AAA domain and a proteolytic domain. Amino acid sequence alignment revealed that SPG7 was conserved during evolution. The mRNA and protein expression of spg7 indicated its involvement in reproduction. Its expression was the highest in coelomic fluid, where spermatids develop, and it was significantly higher in the breeding stage than in the nonbreeding stage. SPG7 was mainly found in the mitochondria of spermatids in the coelomic fluid, indicating that it functions in this organelle in spermatids. Immunofluorescence experiments showed that SPG7 was expressed and colocalized in the mitochondria during spermiogenesis, suggesting its involvement in P. esculenta spermiogenesis. Therefore, SPG7 may participate in spermiogenesis by functioning in the mitochondria and regulate the reproduction of male P. esculenta. This study provided insights into the function of SPG7 in animal reproduction and P. esculenta gametogenesis.

Effect of selenium nanoparticles on the quality and fertility of short-term preserved boar semen

This study was carried out to investigate the effect of different concentrations of selenium nanoparticles (Se-NPs) in the Beltsville Thawing Solution (BTS) extender on the semen quality and fertility of Hampshire crossbred pigs. For the study, semen was collected from four boars (10 ejaculates/boar) by the gloved hand method. Each ejaculate was extended @ 1:2 with the BTS extender and split into four aliquots. The control (C) samples were without the supplementation of Se-NPs, whereas the other three were supplemented with 0.5 (T1), 1 (T2), and 2 μg ml-1 of Se-NPs (T3) and stored at 15°C in a BOD incubator. Extended semen was evaluated at 0 (immediately after dilution), 24, 48, 72, and 96 h of storage for sperm motility, live sperm, plasma membrane integrity, acrosome integrity, DNA integrity, and mitochondrial membrane potential (MMP). The mean percentage of sperm motility, live sperm, and sperm with intact plasma membrane and acrosome, and MMPs were significantly (p < 0.01) higher in all treated groups in comparison to control at 24, 48, 72, and 96 h of storage. Sperm with intact DNA in all treated groups increased significantly at 48 (p < 0.05), and 72 and 96 (p < 0.01) h of storage in comparison to the control group. The concentration of 1 μg ml-1 of Se-NPs was found to be the best among other concentrations. In each group, 10 sows were artificially inseminated with the liquid semen preserved for 72 h at 15°C. Supplementation of 1 μg ml-1 of Se-NPs yielded the highest conception rate in comparison to other groups. In conclusion, supplementation of 1 μg ml-1 of Se-NPs in the BTS extender resulted in the best semen quality and conception rate during the short-time liquid preservation of boar semen.

Morin hydrate ameliorates heat-induced testicular impairment in a mouse model

BACKGROUND

Heat stress is known to adversely affect testicular activity and manifest the pathogenesis of spermatogenesis. Morin hydrate is a plant-derived compound, which contains a wide range of biological activities. Thus, it is hypothesized that morin hydrate might have an ameliorative effect on heat-induced testicular impairment. There has not been any research on the impact of morin hydrate on heat-induced testicular damage.

METHODS

The experimental mice were divided into four groups, groups1 as the normal control group (CN), and the second which underwent heat stress (HS) by immersing the lower body for 15 min in a thermostatically controlled water bath kept at 43 °C (HS), and third and fourth heat-stressed followed by two different dosages of morin hydrate 10 mg/kg (HSM10) and 100 mg/kg (HSM100) for 14 days.

RESULTS

Morin hydrate treatment at 10 mg/kg improved, circulating testosterone levels (increases 3βHSD), and oxidative stress along with improvement in the testis and caput and corpus epididymis histoarchitecture, however, both doses of morin hydrate improved sperm parameters. Morin hydrate treatment significantly increases germ cell proliferation, (GCNA, BrdU staining), expression of Bcl2 and decreases expression of active caspase 3. Heat stress also decreased the expression of AR, ER- α, and ER-β, and Morin hydrate treatment increased the expression of these markers in the 10 mg/kg treatment group.

CONCLUSION

Morin hydrate ameliorates heat-induced testicular impairment modulating testosterone synthesis, germ cell proliferation, and oxidative stress. These effects could be manifested by regulating androgen and estrogen receptors. However, the two doses showed differential effects of some parameters, which requires further investigations.

Roles of Y-27632 on sheep sperm metabolism

To investigate the effect of Y-27632 on low-temperature metabolism of sheep sperm, different concentrations of Y-27632 were added to sheep semen at 4 °C in this experiment to detect indicators such as sperm motility, plasma membrane, acrosome, antioxidant performance, mitochondrial membrane potential (MMP), and metabolomics. The results showed that the addition of 20 µM Y-27632 significantly increased sperm motility, plasma membrane integrity rate, acrosome integrity rate, antioxidant capacity, MMP level, significantly increased sperm adenosine triphosphate (ATP) and total cholesterol content, and significantly reduced sperm Ca2+ content. In metabolomics analysis, compared with the control group, the 20 µM Y-27632 group screened 20 differential metabolites, mainly involved in five metabolic pathways, with the most significant difference in Histidine metabolism (P = 0.001). The results confirmed that Y-27632 significantly improved the quality of sheep sperm preservation under low-temperature conditions.

Assessment of the In Vivo Reprotoxicity of Isotretinoin in Sprague-Dawley Male Rat

BACKGROUND

Isotretinoin (ISO) belongs to a family of drugs called retinoids. It is the most effective drug prescribed by dermatologists for the treatment of the inflammatory disease, acne vulgaris. A significant barrier to the use of ISO has worries regarding its adverse effect profile. Despite the well-recognized reproductive toxicity and teratogenicity in females, there is no warning related to the use by male patients in the medication prospectus. Current data on the effects on human male fertility is contradictory and inconclusive.

OBJECTIVES

This study was undertaken to investigate the potential effects of ISO oral doses in the Sprague-Dawley male rat germ cells using the sperm morphology assay. Also, the serum levels of the follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone were measured.

METHODS

The rat groups were given varying ISO doses via gastric gavage for seven consecutive days. The epididymis sperm specimens were microscopically examined for the following reproductive toxicity parameters: sperm concentration, examined viability, motility, and morphology. The serum FSH, LH, and testosterone levels were measured by using the corresponding enzyme-linked immunosorbent assay (ELISA) kit. The data were analyzed statistically by one-way analysis of variance (ANOVA) followed by the Tukey test at P ≤ 0.05 significance level.

RESULTS

The results indicated that the drug did not significantly increase the sex hormone levels but notably affected both the sperm quantity and quality.

CONCLUSION

These observations suggest that ISO was reprotoxic, and future therapies should be further reassessed.

Arresting calcium-regulated sperm metabolic dynamics enables prolonged fertility in poultry liquid semen storage

The preservation of liquid semen is pivotal for both industrial livestock production and genetic management/conservation of species with sperm that are not highly cryo-tolerant. Nevertheless, with regard to poultry semen, even brief in vitro storage periods can lead to a notable decline in fertility, despite the in vivo capacity to maintain fertility for several weeks when within the hen's sperm storage tubules. For fertility in sperm, intracellular calcium ions ([Ca2+]i) play a key role in signaling towards modifying energy metabolism. While reducing [Ca2+]i has been found to enhance the preservation of sperm fertility in some mammals, the connection between semen fertility and calcium availability in avian sperm has received limited attention. In this study, we demonstrate that the use of extracellular and intracellular calcium chelators in liquid semen extenders, specifically EGTA and EGTA-AM, has distinct effects on prolonging the fertility of chicken sperm. These results were validated through in vivo fertility tests. Mechanistically, the effects observed were linked to coordination of mitochondrial metabolism and ATP catabolism. Despite both calcium chelators inducing hypoxia, they differentially regulated mitochondrial respiration and ATP accumulation. This regulation was closely linked to a bimodal control of dynein ATPase activity; a direct initial activation with reduction in [Ca2+]i, and subsequent suppression by cytoplasmic acidification caused by lactic acid. These findings not only contribute to advancing poultry liquid semen preservation techniques, but also elucidates biologically relevant mechanisms that may underlie storage within the female reproductive tract in birds.

Cell-type-specific determination of reactive oxygen species by flow cytometry

BACKGROUND

Seminal leukocyte-generated reactive oxygen species may have a significant impact on sperm intracellular reactive oxygen species levels, therefore contributing to oxidative damage and consequent functional impairment of spermatozoa. This relationship may be utilized for male urogenital inflammation-driven oxidative stress diagnostics.

OBJECTIVE

To obtain seminal cell-specific, reactive oxygen species-related fluorescence intensity cut-off values to differentiate leukocytospermic samples displaying reactive oxygen species overproduction (oxidative burst) from normozoospermic seminal samples.

MATERIAL AND METHODS

Ejaculates gained by masturbation were obtained from patients in the framework of andrology consultations. The results published in this paper were generated from samples for which the attending physician requested spermatograms and seminal reactive oxygen species laboratory tests. Routine seminal analyses were performed according to World Health Organization guidelines. Samples were divided into normozoospermic "non-inflamed," and leukocytospermic groups. The semen was stained by 2',7'-dichlorodihydrofluorescein diacetate and the reactive oxygen species-related fluorescence signal and the percentage of reactive oxygen species-positive spermatozoa within the living population were quantified by flow cytometry.

RESULTS

Reactive oxygen species-related mean fluorescence intensity was higher in both spermatozoa and leukocytes from leukocytospermic samples than in those from normozoospermic samples. Mean fluorescence intensity in spermatozoa was positively and linearly correlated with mean fluorescence intensity measured in leukocytes in both groups.

DISCUSSION

The capacity of spermatozoa to generate reactive oxygen species is at least three log lower than that of granulocytes. The question is whether the reactive oxygen species-producing machinery of spermatozoa is capable of causing autologous oxidative stress or whether leukocytes are the predominant source of seminal oxidative stress. Based on our observations, the reactive oxygen species production of leukocytes may have a significant impact on the overall reactive oxygen species levels measured in spermatozoa.

CONCLUSION

Reactive oxygen species-overproducing leukocytospermic and normozoospermic seminal samples can reliably be differentiated based on reactive oxygen species mean fluorescence intensity measurement.

In Vitro and In Vivo Studies on the Efficacy of Zinc-Oxide and Selenium Nanoparticle in Cryopreserved Goat (Capra hircus) Spermatozoa

Different nanoparticles (NPs) are currently being investigated for their potential role as cryoprotectant during semen cryopreservation in several mammalian species. It may be possible to improve semen quality following cryopreservation by supplementation of NPs in the freezing extenders. The present study was carried out in semen collected from four (4) Assam Hill Goat bucks (10 ejaculates per buck) to investigate the effect of supplementing zinc oxide (ZnO) and selenium (Se) NPs in Tris-citric acid-fructose yolk (TCFY) extender on in vitro sperm quality and in vivo fertility rate after freeze-thawing. The size morphology and zeta potential of ZnO and Se NPs were evaluated prior to its incorporation in the freezing extender. Qualified semen samples (> 70% progressive motility) were divided into five (5) aliquots and then diluted in TCFY extender containing ZnO and Se NP supplementation at different concentrations (T0, control; T1, 0.1 mg/mL ZnO NPs; T2, 0.5 mg/mL ZnO NPs; T3, 0.5 µg/mL Se NPs; and T4, 1 µg/mL Se NPs). Diluted semen was packed in 0.25 mL straws and then stored in liquid nitrogen. After thawing, post-thaw in vitro sperm attributes were evaluated. Finally, the effect of NPs on in vivo fertility rate was checked in heat-synched does (n = 70) by artificial insemination (AI) using straws that showed superior results during the in vitro study. Results showed that ZnO and Se NPs were poly-crystalline in nature with particle size below 100 nm (nm). The evaluated post-thaw sperm in vitro attributes were significantly (p < 0.001) higher in T1 in comparison to T0. The antioxidant enzyme activities were significantly (p < 0.001) higher in T1. Lipid peroxidation (LPO) profile was significantly (p < 0.001) lower in T1. Sperm motility and mitochondrial membrane potential (MMP) had a highly significant (r = 0.580, p < 0.05) association in T1. No significant (p > 0.05) differences in pregnancy rates were recorded after AI in the different treatments. In conclusion, extender supplemented with 0.1 mg/mL ZnO NPs improved post-thaw semen quality of goat spermatozoa consequently by increasing activities of endogenous antioxidant enzymes thereby lowering LPO levels. However, improved in vitro outcomes might not correspond to improved field fertility outcomes.

The Effect of Mycotoxins and Their Mixtures on Bovine Spermatozoa Characteristics

There is growing concern about the effects of mycotoxins on mammalian reproduction. Although the effects of single mycotoxins have been well documented, the impact of their mixtures on spermatozoon quality is less known. Here, frozen-thawed semen (n = 6 bulls) was in-vitro-cultured (2 h) without (control) or with (i) a single mycotoxin [zearalenone (ZEN), ochratoxin A (OTA), toxin 2 (T2), and diacetoxyscirpenol (DAS)] in a dose-response manner; (ii) binary mixtures (OTA + T2, OTA + ZEN, OTA + DAS, ZEN + T2, DAS + T2 and ZEN + DAS); or (iii) ternary mixtures (OTA + DAS + T2, OTA + ZEN + T2, and ZEN + DAS + T2). Then, the spermatozoa quality was characterized according to its plasma- and acrosome-membrane integrity, mitochondrial membrane potential, and oxidation status by a flow cytometer. Exposure to single mycotoxins or binary mixtures did not affect the spermatozoa characteristics. However, exposure to the ternary mixtures, OTA + DAS + T2 and OTA + ZEN + T2, reduced (p < 0.05) the mitochondrial membrane potential relative to the control. In addition, OTA + ZEN + T2 increased (p < 0.05) the proportion of spermatozoa with reactive oxygen species relative to the control. The most suggested interaction effect between the mycotoxins was found to be an additive one. A synergistic interaction, mainly regarding the oxidation status of the spermatozoa, was also found between the mycotoxins. The current study sheds light on the potential risk of exposing spermatozoa to a mycotoxin mixture.

Assessment of Prior Infection With Hepatitis B Virus and Fecundability in Couples Planning Pregnancy

IMPORTANCE

The association of hepatitis B virus (HBV) infection with reduced fecundability among reproductive-aged couples lacks large-population, in-depth study evidence.

OBJECTIVE

To investigate the association of HBV infection with time to pregnancy in couples planning pregnancy, and to explore whether this association varied by gravidity, health statuses, or lifestyles.

DESIGN, SETTING, AND PARTICIPANTS

This is a population-based cohort study of Chinese couples participating in the National Free Preconception Check-up Projects during 2015 to 2017. They were planning pregnancy and were followed-up every 3 months until getting pregnant, as confirmed by gynecologic ultrasonography, or were followed-up for 1 year. Data were analyzed between March 1, 2022, and September 30, 2022.

MAIN OUTCOMES AND MEASURES

The main outcome was time to pregnancy, assessed using fecundability hazard ratios (HRs). The Cox proportional hazards regression models were used to estimate the association of HBV infection with fecundability.

RESULTS

Among 2 419 848 couples (mean [SD] age, 27.87 [5.20] years for women and 29.58 [5.50] years for men), 126 728 women (5.24%) and 156 572 men (6.47%) were infected with HBV. Compared with the HBV-negative group, the fecundability of both women and men in the HBV-positive group decreased by 5% (HR, 0.95; 95% CI, 0.94-0.95). Compared with couples in which both partners were HBV negative, the fecundability of those in which both partners were HBV positive declined by 6% (HR, 0.94; 95% CI, 0.93-0.96) among all couples, by 3% (HR, 0.97; 95% CI, 0.95-0.99) among nulligravidas couples, and by 7% (HR, 0.93; 95% CI, 0.91-0.95) among multigravidas couples. Both the female-male and couple models suggested that the association of HBV infection with decreased fecundability was more pronounced in couples with multigravidas. The negative association was greater in people with overweight and obesity and was inconsistent in certain subgroups; in particular, it was more pronounced in women with reproductive tract infections, normal fasting plasma glucose, and no alcohol intake and in men with normal blood pressure.

CONCLUSIONS AND RELEVANCE

In this population-based cohort study, HBV infection was associated with decreased fecundability in a general reproductive-aged population, especially in couples with multigravidas. For women and men with certain health statuses and lifestyles, a comprehensive consideration of this association is recommended to provide personalized fertility guidance.

From oxidative imbalance to compromised standard sperm parameters: Toxicological aspect of phthalate esters on spermatozoa

The exponential rise in global male infertility and subfertility-related issues raises severe concern. One of the major contributors is phthalate esters, typical endocrine disruptors affecting millions of lives. The inevitable exposure to phthalates due to their universal application as plasticizers leaves the human population vulnerable to this silent threat. This review explicitly deals with the spermiotoxic effects of different phthalate esters on in vivo and in vitro models and on surveyed human populations to find the most plausible link between global usage of phthalates and poor sperm health. As the free radicals in spermatozoa are prerequisites for their standard structure and functioning, the precise regulation and phthalate-mediated impairment of pro-oxidant:anti-oxidant balance with subsequent loss of structural and functional integrity have also been critically discussed. Furthermore, we also provided future directives, which, if addressed, will fill the still-existing lacunae in phthalate-mediated male reproductive toxicity research.

Multiple flow cytometry analysis for assessing human sperm functional characteristics

Multiparametric analysis by flow cytometry solves one of the major problems in sperm evaluation, the inability to test multiple attributes simultaneously in a single cell, which would increase the precision to predict fertility potential since several sperm parameters are tested. The association of fluorochromes and compounds conjugated to fluorochromes in multiparametric sperm analysis is well-established in microscopy techniques. However, these techniques are subjective and limit the assessment in small cell numbers, thereby harming analytic accuracy. Therefore, the current study aimed to present new possibilities for assessing the integrity and stability of the sperm plasma membrane, acrosome status, mitochondrial potential, and superoxide anion production in the mitochondrial matrix in only 2 cytometric assays using cytometers equipped with 2 and 3 lasers. For this, human semen samples collected by masturbation and selected by the swim-up technique were divided into 3 treatments: T0 (flash-frozen semen), T50 (flash-frozen semen + fresh semen, V: V), and T100 (fresh semen) for the validation of the multiparametric protocols by flow cytometry. For both protocols, sperm percentage with positive stain for all fluorophores differed significantly between treatments. The determination coefficients presented values close to 1, which validated objective, sensitive, rapid, and reproducible methodologies. Therefore, we concluded that the results reflect the status of analyzed structure, enabling a more accurate diagnosis of male infertility that has become an increasingly prevalent worldwide setback due to exposure to a variety of environmental toxicants.

The effect of pentoxifylline and calcium ionophore treatment on sperm cell biology in oligoasthenoteratozoospermia samples

The objective of this study was to assess the effects of pentoxifylline (PTX) and Ca²⁺ ionophore (CI) A12387 treatment on some biological characteristics of sperm cells in oligoasthenoteratozoospermia (OAT) patients. After processing, each sample was divided into four groups: 1, control; 2, exposed to 3.6 mM PTX; 3, exposed to 5 μm calcium ionophore (CI); and 4, exposed to both PTX and CI; 30 min at 37°C. Sperm motility was measured before and after preparation. Acrosome reaction (AR), status of sperm vacuoles, mitochondrial membrane potential (MMP) and DNA fragmentation were assessed using PSA-FITC staining, motile sperm organelle morphology examination (MSOME), JC-1 staining and sperm chromatin dispersion (CSD) test, respectively. Treatment with PTX and CI led to increased and decreased sperm motility, respectively (P < 0.05). Furthermore, vacuole status and rates of sperm DNA fragmentation were not significantly different among groups (P > 0.05). Moreover, the data showed that the rates of AR and disrupted MMP were significantly different between groups (P < 0.05). In conclusion, in vitro application of PTX not only did not have any adverse effects on sperm cell biology characteristics, but also can rectify the harmful effect of CI.

Unraveling the harmful effect of oxidative stress on male fertility: A mechanistic insight

Male infertility is a widely debated issue that affects males globally. There are several mechanisms involved. Oxidative stress is accepted to be the main contributing factor, with sperm quality and quantity affected by the overproduction of free radicals. Excess reactive oxygen species (ROS) cannot be controlled by the antioxidant system and, thus, potentially impact male fertility and hamper sperm quality parameters. Mitochondria are the driving force of sperm motility; irregularities in their function may lead to apoptosis, alterations to signaling pathway function, and, ultimately, compromised fertility. Moreover, it has been observed that the prevalence of inflammation may arrest sperm function and the production of cytokines triggered by the overproduction of ROS. Further, oxidative stress interacts with seminal plasma proteomes that influence male fertility. Enhanced ROS production disturbs the cellular constituents, particularly DNA, and sperms are unable to impregnate the ovum. Here, we review the latest information to better understand the relationship between oxidative stress and male infertility, the role of mitochondria, the cellular response, inflammation and fertility, and the interaction of seminal plasma proteomes with oxidative stress, as well as highlight the influence of oxidative stress on hormones; collectively, all of these factors are assumed to be important for the regulation of male infertility. This article may help improve our understanding of male infertility and the strategies to prevent it.

Nano-depletion of morbid spermatozoa up-regulate Ca2+ channel, depolarization of membrane potential and fertility in buffalo

Despite recent advances in technique of spermatozoa cryopreservation, there are still ejaculates present that fail to meet strict quality standard; mainly due to detrimental effect of imbalance of free radicals. The omnipresence of dead/defective spermatozoa in ejaculates of eutherian species is a major source of excessive free radicals. Though sperm-selection techniques, as well as addition of antioxidants addressed the problem to a certain extent, the major source of free radicals in the semen remained, causing much damage. This study attempts to remove dead/damaged spermatozoa using negative fertility-marker. The effect is unraveled by Hypo-osmotic (HOS), and fluorescein-conjugated Pisum sativum agglutinin (FITC-PSA) assay, further confirmed by Ca²⁺-regulating mechanisms and depolarization of sperm membrane potential, reduction in concentration of free radicals and finally by in vitro fertility assay. The study involved functionalization of iron oxide nanoparticles (IONPs) with silane followed by bio-conjugation with anti-ubiquitin antibodies. The nano-purification of semen using anti-ubiquitin conjugated iron oxide nanoparticles (IONPs) (antibody concentrations 0.5, 1.0 and 2.0 μg/ml) was attempted. The efficiency of nano-purification was 18.1%-43.8% in the study. The results revealed greater (P ≤ 0.05) spermatozoa population with intact plasma membrane, acrosome integrity, high mitochondrial membrane potential and pattern-F (least intracellular Ca²⁺), evidence of low lipid peroxidation and higher total antioxidant capacity in nano-purified groups. More number of spermatozoa were bound to zona pellucida of matured oocytes from nano-depleted than non-depleted group. The findings demonstrate antibody concentration of 1.0 μg/ml bio-conjugated with IONPs as most efficient in enriching the ejaculate with functional spermatozoa with the highest percentage of zona binding.

Melatonin Protects Against Titanium Oxide-Induced Neurotoxicity: Neurochemical, Neurobehavioral, and Histopathological Evidences

titania (titanium dioxide, TiO₂) is known to induce neurotoxicity and CNS dysfunctions. Numerous studies have explored the neuroprotective effects of melatonin against neurotoxicity. This study evaluates the potential of melatonin to protect against titania-induced neurotoxicity and the role of the Keap1/Nrf2/ARE signaling pathway. One group of animals were treated with Titania (0.045 and 0.075 g/rat) alone while the other with added melatonin (1 mg/kg and 3 mg/kg) and behavioral alterations were assessed using OFT (open field test). Neurochemical and histopathological changes were also studied in the hippocampus by analyzing kelch ECH associating protein 1 (Keap1), nuclear factor erythroid 2-related factor 2 (Nrf2), and antioxidant response element (ARE). It was seen that the animals with added Melatonin had improved behavioral scores in the OFT, like anxiety and motor dysfunction triggered by TiO₂. Melatonin also reduced lipid peroxidation, ROS, GSSG, IL1β, TNFα, Bax, and Keap1 levels, but boosted GSH, GPx, GR, SOD,IL10,IL4, Bcl2, Nrf2, and ARE levels and improved quadruple mitochondrial enzyme complex activity in titania-treated animals. Histopathological examination showed melatonin induced cytoprotection against vacuolization and necrosis in granular cells of DG and pyramidal cells of CA1 area of the hippocampus. In our study, pretreatment with melatonin reduced titania-induced neurotoxicity in the hippocampus through a mechanism potentially mediated by the Keap-1/Nrf2/ARE pathway.

Viral tropism for the testis and sexual transmission

The mammalian testis adopts an immune privileged environment to protect male germ cells from adverse autoimmune reaction. The testicular immune privileged status can be also hijacked by various microbial pathogens as a sanctuary to escape systemic immune surveillance. In particular, several viruses have a tropism for the testis. To overcome the immune privileged status and mount an effective local defense against invading viruses, testicular cells are well equipped with innate antiviral machinery. However, several viruses may persist an elongated duration in the testis and disrupt the local immune homeostasis, thereby impairing testicular functions and male fertility. Moreover, the viruses in the testis, as well as other organs of the male reproductive system, can shed to the semen, thus allowing sexual transmission to partners. Viral infection in the testis, which can impair male fertility and lead to sexual transmission, is a serious concern in research on known and on new emerging viruses. To provide references for our scientific peers, this article reviews research achievements and suggests future research focuses in the field.

Obesity: A Doorway to a Molecular Path Leading to Infertility

The dramatic rise in obesity has recently made it a global health issue. About 1.9 billion were overweight, and 650 million global populations were obese in 2016. Obese women suffer longer conception time, lowered fertility rates, and greater rates of miscarriage. Obesity alters hormones such as adiponectin and leptin, affecting all levels within the hypothalamic-pituitary-gonadal axis. Advanced glycation end products (AGEs) and monocyte chemotactic protein-1 (MCP-1) are inflammatory cytokines that may play an important role in the pathophysiology of ovarian dysfunction in obesity. In obese males, there are altered sperm parameters, reduced testosterone, increased estradiol, hypogonadism, and epigenetic modifications transmitted to offspring. The focus of this article is on the possible adverse effects on reproductive health resulting from obesity and sheds light on different molecular pathways linking obesity with infertility in both female and male subjects. Electronic databases such as Google Scholar, Embase, Science Direct, PubMed, and Google Search Engine were utilized to find obesity and infertility-related papers. The search strategy is detailed in the method section. Even though multiple research work has shown that obesity impacts fertility in both male and female negatively, it is significant to perform extensive research on the molecular mechanisms that link obesity to infertility. This is to find therapeutics that may be developed aiming at these mechanisms to manage and prevent the negative effects of obesity on the reproductive system.

Human seminal virome: a panel based on recent literature

Background

The seminal virome and its implications for fertility remain poorly understood. To date, there are no defined panels for the detection of viruses of clinical interest in seminal samples.

Results

In this study, we characterized the human seminal virome based on more than 1,000 studies published over the last five years.

Conclusions

The number of studies investigating viruses that occur in human semen has increased, and to date, these studies have been mostly prospective or related to specific clinical findings. Through the joint analysis of all these studies, we have listed the viruses related to the worsening of seminal parameters and propose a new panel with the main viruses already described that possibly affect male fertility and health. This panel can assist in evaluating semen quality and serve as a tool for investigation in cases of infertility.

Exploring the Role of Oxidative Stress in Sperm Motility: A Proteomic Network Approach

Significance: Infertility is a major global health problem, with nearly half of the cases being associated with male factors. Although reactive oxygen species (ROS) are crucial for sperm cell normal physiological processes, an imbalance between ROS production and antioxidants can lead to oxidative stress that can impair sperm function. Indeed, high semen ROS levels are reported in 30%-80% of infertile men. Recent Advances: Male oxidative stress infertility is an uprising classification for idiopathic infertility. Proteomic approaches, including quantitative mass spectrometry (MS)-based proteomics, are being utilized to explore the molecular mechanisms associated with oxidative stress in male infertility. Critical Issues: In this review, proteome data were collected from articles available on PubMed centered on MS-based proteomic studies, performed in seminal plasma and sperm cell samples, and enrolling men with impaired semen parameters. The bioinformatic analysis of proteome data with Cytoscape (ClueGO+CluePedia) and STRING tools allowed the identification of the biological processes more prevalent in asthenozoospermia, with focus on the ones related to oxidative stress. Future Directions: The identification of the antioxidant proteins in seminal plasma and sperm cells that can protect sperm cells from oxidative stress is crucial not only for a better understanding of the molecular mechanisms associated with male infertility but specially to guide new therapeutic possibilities. Antioxid. Redox Signal. 37, 501-520.

Effect of Myo-inositol on sperm quality and biochemical factors in cryopreserved semen of patients with Asthenospermia

In this study, the influence of myoinositol (MYO) as an antioxidant on the inhibition of the negative impacts of cryopreservation on sperm quality in men with Asthenospermia was investigated. In this prospective study, each semen sample from 25 cases was separated into three groups: Fresh, Control (with freezing medium), Myoinositol (2 mg/ml). According to the World Health Organization criteria (WHO) (2010), total motility, progressive sperm motility, viability, normal morphology, and DNA integrity were assessed. In addition, the hypo-osmotic swelling (HOS) test and mitochondrial membrane potential (MMP) were used. Total antioxidant capacity (TAC), malondialdehyde (MDA), and antioxidant enzyme activity were determined by the ELISA method. In contrast to the fresh samples, lipid peroxidation, DNA integrity damage, DNA fragmentation, HOST, and MMP had significant enhancement in the control samples. Sperm quality was significantly decreased (p < 0.05). Mean percentage viability, normal morphology, total motility, progressive motility, and DNA integrity were significantly enhanced in the MYO group in comparison to the control group (p < 0.05). The MDA and TAC levels and DNA damage in the MYO group were significantly lower compared to the control group (p < 0.05). The findings confirm that sperm quality in patients with Asthenospermia is improved by the administration of 2 mg/ml of myoinositol together with the freezing medium after sperm cryopreservation.

Oxidative Stress-Induced Male Infertility: Role of Antioxidants in Cellular Defense Mechanisms

Male infertility is linked to several environmental and mutagenic factors. Most of these factors, i.e., lifestyle, radiations, and chemical contaminations, work on the fundamental principles of physics, chemistry, and biology. Principally, it may induce oxidative stress (OS) and produce free radicals within the cells. The negative effect of OS may enhance the reactive oxygen species (ROS) levels in male reproductive organs and impair basic functions in a couple's fertility. Evidence suggests that infertile men have significantly increased ROS levels and a reduced antioxidant capacity compared with fertile men. Although, basic spermatic function and fertilizing capacity depend on a delicate balance between physiological activity of ROS and antioxidants to protect from cellular oxidative injury in sperm, that is essential to achieve pregnancy. The ideal oxidation-reduction (REDOX) equilibrium requires a maintenance of a range of ROS concentrations and modulation of antioxidants. For this reason, the chapter focuses on the effects of ROS in sperm functions and the current concepts regarding the benefits of medical management in men with diminished fertility and amelioration of the effect to improve sperm function. Also, this evidence-based study suggests an increasing rate of infertility that poses a global challenge for human health, urging the need of health care professionals to offer a correct diagnosis, comprehension of the process, and an individualized management of the patients.

Sperm quality parameters and oxidative stress: Exploring correlation in fluoride-intoxicated rats

Background:

Assessment of male fertility needs evaluation of sperm quality parameters, namely sperm count, viability, motility and morphology.

Aims:

The present study aimed to analyse and correlate oxidative stress with sperm quality parameters.

Settings and Design:

The male Wistar albino rats, weighing between 100 and 150 g, were employed in the present study under the Committee for the Purpose of Control and Supervision of Experiments on Animals guidelines with ethical clearance from the Institutional Ethical Committee. These rats were categorised into four groups with six rats in each as control and test animals.

Materials and Methods:

Young male Wistar albino rats, weighing between 100 and 150 g, were divided into four groups of six rats each. The first group of rats served as control (n = 6) and was maintained under normal laboratory condition and was provided with clean drinking water, whereas rats in the second (n = 6), third (n = 6) and fourth (n = 6) groups were orally intubated with sodium fluoride of 100 ppm, 200 ppm and 300 ppm, respectively, for 40 days.

Statistical Analysis Used:

After the treatment period of 40 days, animals were sacrificed and alterations in sperm quality parameters were analysed by complete randomised design SAS 9.4 and Statistical Package for the Social Sciences (SPSS) IBM 17 and judged significant if P < 0.05.

Results:

In the experiment, a negative correlation emerged between sperm motility, viability, count versus malondialdehyde (MDA) levels, whereas the level of MDA has a positive correlation with sperm abnormalities. Sperm motility, viability and count were positively correlated with activities of superoxide dismutase and catalase, whereas decreased activities of antioxidants were related to increased sperm morphological abnormalities.

Conclusion:

These results suggest that MDA causes a decline in sperm motility, count and viability and an increase in morphological abnormalities via oxidative damage of membrane lipids.

Molecular Mechanisms Underlying the Relationship between Obesity and Male Infertility

In recent decades, the worldwide prevalence of obesity has risen dramatically and is currently estimated to be around 20%. Obesity is linked to an increased risk of comorbidities and premature mortality. Several studies have shown that obesity negatively impacts male fertility through various mechanisms. This review aims to investigate the molecular mechanisms through which obesity impairs male reproduction, including obesity-associated hypogonadism and its effects on spermatogenesis, chronic inflammation, and oxidative stress. Obesity negatively impacts both conventional and biofunctional sperm parameters, and it also induces epigenetic changes that can be transferred to offspring. Moreover, obesity-related diseases are linked to a dysregulation of adipocyte function and micro-environmental inflammatory processes. The dysregulated adipokines significantly influence insulin signaling, and they may also have a detrimental effect on testicular function. Sirtuins can also play an important role in inflammatory and metabolic responses in obese patients. Understanding the molecular mechanisms that are involved in obesity-induced male infertility could increase our ability to identify novel targets for the prevention and treatment of obesity and its related consequences.

The Impact of Endocrine-Disrupting Chemicals in Male Fertility: Focus on the Action of Obesogens

The current scenario of male infertility is not yet fully elucidated; however, there is increasing evidence that it is associated with the widespread exposure to endocrine-disrupting chemicals (EDCs), and in particular to obesogens. These compounds interfere with hormones involved in the regulation of metabolism and are associated with weight gain, being also able to change the functioning of the male reproductive axis and, consequently, the testicular physiology and metabolism that are pivotal for spermatogenesis. The disruption of these tightly regulated metabolic pathways leads to adverse reproductive outcomes. The permanent exposure to obesogens has raised serious health concerns. Evidence suggests that obesogens are one of the leading causes of the marked decline of male fertility and key players in shaping the future health outcomes not only for those who are directly exposed but also for upcoming generations. In addition to the changes that lead to inefficient functioning of the male gametes, obesogens induce alterations that are “imprinted” on the genes of the male gametes, establishing a link between generations and contributing to the transmission of defects. Unveiling the molecular mechanisms by which obesogens induce toxicity that may end-up in epigenetic modifications is imperative. This review describes and discusses the suggested molecular targets and potential mechanisms for obesogenic–disrupting chemicals and the subsequent effects on male reproductive health.

Targeted antioxidant delivery modulates mitochondrial functions, ameliorates oxidative stress and preserve sperm quality during cryopreservation

Mitochondria are vital organelles with a multifaceted role in cellular bioenergetics, biosynthesis, signaling and calcium homeostasis. During oxidative phosphorylation, sperm mitochondria generate reactive oxygen species (ROS) at physiological levels mediating signaling pathways essential for sperm fertilizing competence. Moreover, sperm subpopulation with active mitochondria is positively associated with sperm motility, chromatin and plasma membrane integrity, and normal morphology. However, the osmotic and thermal stress, and intracellular ice crystal formation generate excess ROS to cause mitochondrial dysfunction, potentiating cryoprotectant-induced calcium overload in the mitochondrial matrix. It further stimulates the opening of mitochondrial permeability transition pores (mPTP) to release pro-apoptotic factors from mitochondria and initiate apoptotic cascade, with a decrease in Mitochondrial Membrane Potential (MMP) and altered sperm functions. To improve the male reproductive potential, it is essential to address challenges in semen cryopreservation, precisely the deleterious effects of oxidative stress on sperm quality. During semen cryopreservation, the supplementation of extended semen with conventional antioxidants is extensively reported. However, the outcomes of supplementation to improve semen quality are inconclusive across different species, which is chiefly attributed to the unknown bioavailability of antioxidants at the primary site of ROS generation, i.e., mitochondria. Increasing evidence suggests that the targeted delivery of antioxidants to sperm mitochondria is superior in mitigating oxidative stress and improving semen freezability than conventional antioxidants. Therefore, the present review comprehensively describes mitochondrial-targeted antioxidants, their mechanism of action and effects of supplementation on improving semen cryopreservation efficiency in different species. Moreover, it also discusses the significance of active mitochondria in determining sperm fertilizing competence, cryopreservation-induced oxidative stress and mitochondrial dysfunction, and its implications on sperm fertility. The potential of mitochondrial-targeted antioxidants to modulate mitochondrial functions and improve semen quality has been reviewed extensively.

Highly Cited Articles in the Field of Male Infertility and Antioxidants: A Scientometric Analysis

PURPOSE

The objective of this scientometric analysis was to recognize the top 100 cited articles on 'Male infertility and Antioxidants' and analyze its publication characteristics.

MATERIALS AND METHODS

The Scopus database was used to retrieve related articles and the top 100 identified based on citation rate.

RESULTS

The articles were published in 56 journals between 1995 and 2019 with a median (interquartile range) citation score of 17 (5-62). Among the top 100 articles, 69 were clinical studies, which included controlled and blinded (33.33%), prospective (27.54%), randomized-controlled trials (26.09%), uncontrolled (11.59%), and retrospective (1.45%) studies. In addition to conventional semen parameters, advanced sperm function tests such as oxidative stress (51%) and sperm DNA damage (23%) were reported. Pregnancy rate (33%) was found to be the most reported reproductive outcome. Antioxidant therapy was mostly investigated in male cohorts with sperm abnormalities such as asthenozoospermia (28%) and clinical conditions such as idiopathic male infertility (20%), varicocele/varicocelectomy (17%) and general male infertility (16%).

CONCLUSIONS

The most influential publications on antioxidants and male infertility were identified for the first time in the literature. This will serve as a reliable source of information for researchers and clinicians alike.

Inflammation and Mitochondrial Dysfunction in Autism Spectrum Disorder

Autism Spectrum Disorders (ASD) is a severe childhood psychiatric condition with an array of cognitive, language and social impairments that can significantly impact family life. ASD is classically characterized by reduced communication skills and social interactions, with limitations imposed by repetitive patterns of behavior, interests, and activities. The pathophysiology of ASD is thought to arise from complex interactions between environmental and genetic factors within the context of individual development. A growing body of research has raised the possibility of identifying the aetiological causes of the disorder. This review highlights the roles of immune-inflammatory pathways, nitro-oxidative stress and mitochondrial dysfunctions in ASD pathogenesis and symptom severity. The role of NK-cells, T helper, T regulatory and B-cells, coupled with increased inflammatory cytokines, lowered levels of immune-regulatory cytokines, and increased autoantibodies and microglial activation is elucidated. It is proposed that alterations in mitochondrial activity and nitrooxidative stress are intimately associated with activated immune-inflammatory pathways. Future research should determine as to whether the mitochondria, immune-inflammatory activity and nitrooxidative stress changes in ASD affect the development of amygdala-frontal cortex interactions. A number of treatment implications may arise, including prevention-orientated prenatal interventions, treatment of pregnant women with vitamin D, and sodium butyrate. Treatments of ASD children and adults with probiotics, sodium butyrate and butyrate-inducing diets, antipurinergic therapy with suramin, melatonin, oxytocin and taurine are also discussed.

Evaluation of Microscopic, Flow Cytometric, and Oxidative Parameters of the Frozen-Thawed Bull Sperm in a Freezing Extender Containing Myo-Inositol

Introduction: This research was conducted to assess the effect of myo-inositol (MYO) in the freezing extender on the semen quality and oxidative stress parameters of frozen-thawed bull sperm. Materials and Methods: Semen samples were obtained from four bulls (n = 24, six ejaculates per bull), twice a week, and diluted into four equal aliquots in freezing extenders containing different concentrations of MYO (0, 2, 3, and 4 mg/mL). After a freezing/thawing process, velocity parameters, plasma membrane integrity, apoptosis status, malondialdehyde level, and oxidative stress parameters were assessed. Results: Supplementation of freezing extender with 3 mg/mL MYO resulted in higher rapid motility (62.22% ± 2.63%), progressive motility (77.45% ± 2.65%), viability (78% ± 0.91%), plasma membrane integrity (86 ± 0.85), catalase (20.03 ± 0.39 U/mL) activity, and lower significance of lipid peroxidation (3.60 ± 0.15 nmol/dL) than those of the control group (p < 0.05). A significantly lower percentage of normal morphology and intact acrosomes were observed for frozen-thawed semen in the extender supplemented with 4 mg/mL MYO than those of the control group (p < 0.05). Freezing of the sperm in the extender containing 3 mg/mL of MYO leads to a higher percentage of live cells (38.3 ± 2.76). Beat-cross-frequency, amplitude of lateral head displacement, linearity, total antioxidant capacity, total peroxidase activity, early apoptotic status, and superoxide dismutase activities were not affected by MYO levels in the extenders (p > 0.05). Conclusion: The findings of this study suggest that the supplementation of the freezing extender with 3 mg/mL MYO resulted in a higher quality of frozen-thawed bull sperm.

Sperm Motility, Oxidative Status, and Mitochondrial Activity: Exploring Correlation in Different Species

Sperm quality assessment is the first step for evaluating male fertility and includes the estimation of sperm concentration, motility, and morphology. Nevertheless, other parameters can be assessed providing additional information on the male reproductive potential. This study aimed to evaluate and correlate the oxidative status, mitochondrial functionality, and motility in spermatozoa of two marine invertebrate (Ciona robusta and Mytilus galloprovincialis) and one mammalian (Bos taurus) species. By combining fluorescent staining and spectrofluorometer, sperm oxidative status was evaluated through intracellular reactive oxygen species (ROS) and plasma membrane lipid peroxidation (LPO) analysis. Mitochondrial functionality was assessed through the mitochondrial membrane potential (MMP). In the three examined species, a negative correlation emerged between sperm motility vs ROS levels and LPO. Sperm motility positively correlated with MMP in bovine, whereas these parameters were not related in ascidian or even negatively related in mussel spermatozoa. MMP was negatively related to ROS and LPO levels in ascidians, only to LPO in bovine, and positively related in mussel spermatozoa. These results suggest that energy sources for sperm motility vary between species and that ROS causes a decline in sperm motility via oxidative damage of membrane lipids. Overall, this study validates the use of fluorescent probes in combination with spectrofluorometer as a simple and powerful methodology for supplementary evaluation of sperm quality shedding light on new potential quality markers and provided relevant information on sperm energetic metabolism.

Is addition or removal of seminal plasma able to compensate for the dilution effect of buffalo semen?

The present study aimed to compensate dilution effect using additional seminal plasma (SP) in conventional (80 million (M) spermatozoa/ml) dose and low spermatozoa/dose (8M spermatozoa/ml). We also attempted to confirm whether removal of SP before the extension of ejaculates affects post-thaw sperm quality of buffalo semen. For this, semen ejaculates (N = 15) were divided into four groups: control (CON), removal of SP by centrifugation (NSP), resuspension of the centrifuged semen pellet into SP (CEN) and extra supplementation of SP (ESP). All groups were diluted into two different semen doses to 20 and 2M spermatozoa/0.25 ml using tris egg yolk extender and subsequently cryopreserved. We found that neither addition nor removal of SP affected sperm motility, kinematics, longevity, mitochondrial superoxide production and high mitochondrial membrane potential (MMP). Further, the addition or removal of SP was not able to compensate dilution effect in 2M groups resulting in a significantly (p < .05) reduction in sperm motility, kinematics, sperm longevity, membrane integrity, MMP, and an increase production of mitochondrial superoxide. In conclusion, it appears that role of SP in the sperm cryopreservation process is insignificant.

The MTT assay application to measure the viability of spermatozoa: A variety of the assay protocols

The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assay is one of the methods used to evaluate the viability of sperm. In the assay, a tetrazolium component (MTT) is converted into MTT formazan by some specific enzymes in the viable cells. The amount of formazan product in theory is directly correlated with the percentage of viable sperms. It is quantified by measuring the absorbance using a spectrophotometer. The present article compiles the MTT assays that have been used to determine sperm viability in most animal species and humans. In each assay, other factors apart from the number of viable cells that potentially influence the accuracy and precision of results are stated, such as preparations of sperm and MTT solutions, length and conditions of incubation, and a solubilizing agent as well as the formazan detection method. Also, the strengths and shortcomings of the MTT test comparison with the others are summarized at the end of this article. This information may be useful for prospective researchers deciding to implement this colorimetric method in their experiments.

Comparative evidence support better antioxidant efficacy of mitochondrial-targeted (Mitoquinone) than cytosolic (Resveratrol) antioxidant in improving in-vitro sperm functions of cryopreserved buffalo (Bubalus bubalis) semen

The present study compared the effect of mitochondria-targeted (Mitoquinone, MitoQ) and untargeted cytosolic antioxidant (Resveratrol, RESV) supplementation on lipid peroxidation (LPO) and in-vitro sperm functions of cryopreserved buffalo bull semen. To optimize additive's concentration, sperm pellet obtained from twenty-four ejaculates was supplemented with different concentrations of MitoQ (20 nM, 100 nM, 200 nM); and RESV (10 μM, 25 μM, 50 μM) against control in the extender. The post-thaw sperm motility, livability, and membrane integrity were higher (P < 0.05) in 200 nM MitoQ and 50 μM RESV than other concentrations used. In another experiment, sperm pellet from thirty-two ejaculates was supplemented with 200 nM MitoQ and 50 μM RESV in the extender. Pre-freeze and post-thaw progressive motility and livability were higher (P < 0.05) in MitoQ (200 nM) than RESV (50 μM) treatment. MitoQ supplementation improved post-thaw membrane integrity (CFDA-PI) higher (P < 0.05) than RESV, however, hypo-osmotic swelling response observed no improvement with RESV treatment. Post-thaw LPO rate was lower (P < 0.05) and Bovine cervical mucus penetration was higher (P < 0.05) in MitoQ than RESV treatment. In post-thaw semen, MitoQ showed higher (P < 0.05) proportion of acrosome intact (FITC-PNA), live non-apoptotic (P < 0.01) sperm with a higher reduction (P < 0.05) in membrane scrambling. MitoQ improved (P < 0.01) proportion of sperm with high Mitochondrial Membrane Potential and low LPO (P < 0.01) than RESV treatment. In conclusion, improvement in post-thaw in-vitro sperm functions and cryo-tolerance was more evident in MitoQ than RESV supplemented buffalo bull semen. Our study provides a better strategy to mitigate oxidative stress by enhancing mitochondrial antioxidant system with targeted antioxidants than cytosolic antioxidant supplementation.

Effects of Pulsed-Wave Photobiomodulation Therapy on Human Spermatozoa

BACKGROUND AND OBJECTIVES

Previous studies reported that photobiomodulation (PBM) positively affects the mitochondrial respiratory chain in sperm, resulting in improved motility and velocity. As laser settings are not yet fully established, the present study aimed at optimizing PBM on human sperm. In addition, possible side-effects of PBM on sperm DNA fragmentation level and acrosomal integrity have been analyzed.

STUDY DESIGN/MATERIALS AND METHODS

A pulsed laser-probe (wavelength 655 nm, output power 25 mW/cm², impulse duration 200 nanoseconds) was used. Native fresh liquefied semen samples underwent radiation with energy doses of 0 (control), 4, 6, and 10 J/cm². Sperm parameters were assessed at 0, 30, 60, 90, and 120 minutes after radiation using a computer-assisted sperm analysis system. Motility and velocity of sperm from asthenozoospermic patients (n = 42) and normozoospermic controls (n = 22) were measured. The amount of DNA strand breaks was analyzed using ligation-mediated quantitative polymerase chain reaction in patients with asthenozoospermia (n = 18) and normozoospermia (n = 13). Post-irradiance acrosomal integrity was investigated using flow cytometry based on CD46 protein expression (n = 7).

RESULTS

Exposure to laser energy-doses of 4 and 6 J/cm² improved sperm motility and velocity in asthenozoospermic patients. PBM exhibited no significant effect on DNA fragmentation level and expression of CD46 serving as a biomarker for acrosome integrity.

CONCLUSION

PBM improves sperm motility parameters by maintaining DNA and acrosome integrity and, therefore, represents a promising new tool for assisted reproductive therapy. In particular, improving sperm motility in asthenozoospermic patients by PBM in future may contribute to increasing the chance for successful intrauterine insemination. The present trial has no clinical registration number, as only in vitro studies were performed. The study was approved by the local ethics committee and performed according to the Declaration of Helsinki. Lasers Surg. Med. © 2021 The Authors. Lasers in Surgery and Medicine published by Wiley Periodicals LLC.

Cryo-banking of human spermatozoa by aseptic cryoprotectants-free vitrification in liquid air: Positive effect of elevated warming temperature

Cryoprotectant-free vitrification is a common method for spermatozoa cryopreservation by direct plunging into liquid nitrogen. However, the commercial liquid nitrogen could be potentially contaminated by microorganisms. Warming temperature plays an essential role for quality of human spermatozoa after vitrification. This study aimed to evaluate comparatively a quality spermatozoa after vitrification in liquid nitrogen and clean liquid air as well as with two warming rates: at 42 °C and 45 °C. After performing of routine swim-up of normozoospermia samples, spermatozoa from the same ejaculate were divided into two groups: vitrified in liquid nitrogen (LN) and sterile liquid air (LA). Spermatozoa of LN group were warmed at 42 °C, and spermatozoa of LA groups were divided and warmed at 42 °C (LA42) and 45 °C (LA45). Then spermatozoa motility, reactive oxygen species (ROS), mitochondrial membrane potential (MMP), reactive nitrogen species (RNS), and viability were assessed. It was no found significant differences in quality of spermatozoa from LN and LA groups in the motility, ROS, MMP, RNS rates after warming at 42 °C. A tendency to obtain better spermatozoa quality was found with using of warming by 42 °C in comparison with 45 °C. It was concluded that cryoprotectant-free vitrification by direct dropping of human spermatozoa into clean liquid air can be used as an alternative to cooling in liquid nitrogen. Warming of spermatozoa at 42 °C allows to preserve the spermatozoa physiological parameters.

Modulation of Human Sperm Mitochondrial Respiration Efficiency by Plant Polyphenols

Plant bioactives, such as polyphenols, can differentially affect (positively or negatively) sperm quality, depending on their concentration. These molecules have been proposed as natural scavengers of reactive oxygen species (ROS) for male infertility treatment. However, few data are available about their effects on the molecular mechanisms related to sperm quality and, in particular, to sperm mitochondrial function. We investigated the effects of quercetin, naringenin, genistein, apigenin, luteolin, and resveratrol at the concentration of 0.1-1000 nM on mitochondrial respiration efficiency. Upon chemical exposure, spermatozoa were swollen in a hypotonic solution and used for polarographic assays of mitochondrial respiration. All tested compounds, except for apigenin, caused a significant increase in the mitochondrial respiration efficiency at the concentration of 0.1 nM, and a significant decrease starting from concentrations of 10 nM. The analysis of oxygen consumption rate in the active and in the resting state of mitochondrial respiration suggested different mechanisms by which the tested compounds modulate mitochondrial function. Therefore, by virtue of their ability to stimulate the respiration active state, quercetin, genistein, and luteolin were found to improve mitochondrial function in asthenozoospermic samples. Our results are relevant to the debate on the promises and perils of natural antioxidants in nutraceutical supplementation.

Mitochondrial Reactive Oxygen Species (ROS) Production Alters Sperm Quality

Besides ATP production, mitochondria are key organelles in several cellular functions, such as steroid hormone biosynthesis, calcium homoeostasis, intrinsic apoptotic pathway, and the generation of reactive oxygen species (ROS). Despite the loss of the majority of the cytoplasm occurring during spermiogenesis, mammalian sperm preserves a number of mitochondria that rearrange in a tubular structure at the level of the sperm flagellum midpiece. Although sperm mitochondria are destroyed inside the zygote, the integrity and the functionality of these organelles seem to be critical for fertilization and embryo development. The aim of this review was to discuss the impact of mitochondria-produced ROS at multiple levels in sperm: the genome, proteome, lipidome, epigenome. How diet, aging and environmental pollution may affect sperm quality and offspring health—by exacerbating oxidative stress—will be also described.

Ameliorative effect of melatonin on apoptosis, DNA fragmentation, membrane integrity and lipid peroxidation of spermatozoa in the idiopathic asthenoteratospermic men: In vitro

Fertility loss, recurrent spontaneous abortion and poor outcome in assisted reproductive techniques (ART) have been associated with DNA fragmentation. This work was achieved to evaluate the protective role of melatonin versus apoptosis, DNA fragmentation, membrane integrity and lipid peroxidation of spermatozoa from men with asthenoteratozoospermia (ATS). Some researchers maintain that melatonin can serve as a remedy for apoptosis induction, and it has an impressive effect on boosting the quality and quantity of spermatozoa. For this purpose, semen samples were collected from 50 ATS men and they were divided into control and melatonin (6 mM) groups at 2, 4, 6 and 24 hr. Concentrating on the reasons for apoptosis is an arduous process, but in the present study for this evaluation mitochondrial membrane potential (MMP), DNA fragmentation by TUNEL and sperm chromatin dispersion (SCD) methods and lipid peroxidation were carried out. Also, sperm viability was performed. In the control group, MDA, TUNEL-positive and SCD were significantly increased but viability and MMP of spermatozoa were significantly decreased. Moreover, in the melatonin group, TUNEL-positive, SCD and MDA levels were significantly decreased and viability and MMP significantly increased, compared to the control group. In outcome, melatonin prescription paves the way for apoptosis down-regulating in the ATS men.

Protective effect of L-carnitine on apoptosis, DNA fragmentation, membrane integrity and Lipid peroxidation of spermatozoa in the asthenoteratospermic men

This in vitro study aimed to measure the ameliorative effect of L-carnitine against apoptosis, DNA fragmentation, membrane integrity and lipid peroxidation of spermatozoa from men with asthenoteratozoospermia (ATS). L-carnitine has an impressive effect on boosting the quality and quantity of spermatozoa and also can prevent apoptosis induction. For this purpose, semen samples were collected from 50 ATS men. Semen was divided into control and L-carnitine (0.5 mg/ml) groups at 2, 4, 6 and 24 hr. Concentrating on the reasons for apoptosis is an arduous process, but in the present research for this evaluation, mitochondrial membrane potential (MMP), DNA fragmentation by TUNEL and SCD methods, and lipid peroxidation were carried out. Also, sperm viability was performed. In the control group, MDA levels were increased significantly at 6 hr; however, sperm viability was decreased significantly at 4 and 6 hr. Moreover, in the L-carnitine group, TUNEL, SCD and MDA levels were decreased significantly and MMP and viability were increased significantly compared with the control group. In this writers' view, in vitro L-carnitine treatment can downregulate apoptosis in men with ATS.

Effect of plasma separation techniques and sperm selection on sperm recovery and viability of cooled pony stallion semen for 48h at 5°C

ABSTRACT Separation techniques of seminal plasma [centrifugation (SC) and Sperm Filter® (SF)] and sperm selection [Androcoll-E (SCA) and filtration glass wool (GW)] were used in 24 ejaculates from 6 stallions. In experiment 1, the ejaculates were allocated into control (no spin), centrifugation at 600 g x 10min, SF and GW. In experiment 2, semen was submitted to SC, SGA and filtered through GW. Following the treatments in both experiments, samples were kept chilled at 5°C to 50 x 106 sperm/ml for 48h. The variables measured on fresh and cooling semen were pH, motility, membrane viability function by 6-carboxyfluorescein diacetate and propidium iodide (CFDA / PI), viability or vitality (eosin / nigrosine) and mitochondrial activity. In experiment 1, centrifugation to remove seminal plasma resulted in greater damage to sperm than separation by sperm filter, and selection by glass wool was more efficient in separating viable cells and maintaining viability during cooling. In experiment 2 Androcoll-E and glass wool treatments resulted in higher (P <0.0001) motility, membrane function, mitochondrial activity, and viability than centrifuged semen. Both selection by Androcoll- E and glass wool improved the quality of semen pony stallions for preservation for up to 48h to 5ºC.

A Comparative Analysis of Fluoride-Contaminated Groundwater and Sodium Fluoride-Induced Reproductive Toxicity and Its Reversibility in Male Rats

The present study was undertaken to investigate the toxic effect of sodium fluoride (NaF)- and fluoride (F)-contaminated groundwater on male reproduction and it's reversibility in male rats. Adult male rats were orally treated with different concentrations of NaF- (1 mg, 5 mg, and 10 mg/kg/bw/rat) and F-contaminated groundwater for 52 days and after the confirmation of F-induced damage, the rats were allowed for recovery studies for 52 days. Exposure of NaF- and F-contaminated groundwater caused significant decline in total sperm count, sperm motility, serum concentration of testosterone, activities of testicular 3β-HSDH, counts of type A spermatogonia, preleptotene spermatocytes, midpachytene spermatocytes, elongated spermatids and round spermatids, activities of testicular and spermatozoa SOD and CAT, and increase in sperm abnormality and concentration of MDA of testis and spermatozoa compared to controls. Further, significant histological alterations characterized by shrunken seminiferous tubules and degeneration of different stages of spermatogonial cells were observed in rats treated with NaF of 10 mg/kg/bw and F-contaminated groundwater Majority of parameter studied showed severe damage in 10 mg/kg/bw of NaF-treated rats compared to that of F-contaminated groundwater. Further, dose-dependent alterations were observed with increase in concentration of NaF in most of the parameters. In recovery group rats of NaF- and F-contaminated groundwater, all the parameters were restored to control levels. The present study revealed the toxic effect of NaF and F-contaminated groundwater on male reproductive system of rats and the effects induced by NaF were dose-dependent. In addition, the study clearly revealed that F-induced toxicity on male reproduction is reversible in short-term exposure.

Mitochondrial Membrane Potential Predicts 4-Hour Sperm Motility

The evaluation of conventional and biofunctional sperm parameters is of fundamental importance for assessing male reproductive function. Among these, sperm motility is one of the most important parameters. Indeed, asthenozoospermia is a frequent cause of male infertility. Sperm motility depends on mitochondrial function and the measurement of mitochondrial membrane potential (MMP) better accounts for the function of this intracellular organelle. On the basis of these premises, the present study assessed whether the MMP predicts sperm motility at 4 h in patients with low or normal MMP. To accomplish this, 31 men were enrolled. Sperm analysis was conducted according to the WHO 2010 criteria. Particular attention was paid to the evaluation of MMP after liquefaction (T0) using JC-1 staining by flow cytometry. Sperm total and progressive motility were measured at T0 and after 4 h from seminal fluid collection (T4). Patients were divided into two groups based on their sperm mitochondrial function at T0. Group A (n = 18) was composed of men with normal mitochondrial function since they had a percentage of spermatozoa with low MMP (L-MMP) below the normal reference value of our laboratory (<36.5%). In contrast, group B (n = 13) was made up of men with impaired sperm mitochondrial function (L-MMP > 36.5%). Group A had a slight but not significant reduction in total and progressive sperm motility at T4 compared with the values recorded at T0. In contrast, patients in group B showed a significant decline in both total and progressive sperm motility at T4 compared with T0 (p < 0.05). The results of this study showed that worse mitochondrial function, assessed by staining with JC1, is associated with a significant decline in sperm motility over time. These findings may be of clinical relevance in programs of assisted reproduction techniques. Based on our knowledge, there is no other evidence in the literature that has shown this relationship in healthy men with low MMP of idiopathic etiology, but normozoospermics according to the WHO 2010 criteria.

Effects of bacteria on male fertility: Spermatogenesis and sperm function

Bacterial infection can negatively affect different parts of the male genital tract and subsequently cause impaired spermatogenesis and male fertility. However, most of the previous studies have focused on the infected organs of the male genital tract and there are not many studies that investigated the direct effect of bacteria on sperm and their mechanism of action. Interestingly, bacteria can induce different damages on sperm cells such as DNA fragmentation, cell membrane peroxidation, and acrosome impairment. Such negative effects can be mediated by bacteria-secreted toxins and metabolites or by direct attachment of bacteria on the sperm cells and subsequent activation of signaling pathways related to oxidative stress, apoptosis, and inflammation. These bacteria-induced changes can impair semen parameters and subsequently cause infertility. Given the significant destructive effect of some bacteria on sperm function and male fertility, in this study, we reviewed the impact of male urogenital bacteria on spermatogenesis and sperm functions as well as the underlying mechanisms by which the bacteria can damage sperm.

Seminal oxidation-reduction potential levels are not influenced by the presence of leucocytospermia

Oxidative stress (OS) is characterised by an excessive amount of reactive oxygen species (ROS) which negatively affect sperm functions. In this study, the influence of leucocytes on seminal oxidation-reduction potential (ORP) and sperm DNA fragmentation (SDF) was investigated in 1,068 men. Seminal leucocyte concentration did not correlate with SDF, unadjusted ORP, ORP normalised for sperm concentration (sORP), ORP normalised for total motile sperm concentration (motORP) or total motile sperm count (TMSC-ORP). Although receiver operator characteristic (ROC) curve analyses show that leucocytospermia does not predict high sORP values (>1.34 mV/10⁶ spermatozoa/ml), the motORP (AUC: 0.666) and TMSC-ORP (AUC: 0.683) predict the rate of leucocytospermia significantly (p = .0195 and p = .0085 respectively). Moreover, SDF can significantly predict leucocytospermia (AUC: 0.679; p = .011) and vice versa (AUC: 0.657, p = .0298). Our data confirm the association between OS and SDF. In conclusion, motORP and TMSC-ORP may be better predictive factors of leucocytospermia, probably because sperm motility, included in motORP and TMSC-ORP calculation, is the first seminal parameter to be affected by OS. Although all these parameters are indicative of OS, ORP values, SDF and leucocytospermia should be considered independently for the evaluation of redox seminal status, as they probe distinct seminal features.

Evaluation of seminal oxidation-reduction potential in male infertility

The role of oxidative stress in male infertility has been broadly recognised, and the search for a new marker to determine the redox environment in semen has gained considerable interest. Oxidation-reduction potential (ORP) or redox potential, is a measure of the electron transfer from antioxidants to oxidants and provides information on the redox balance. In this review, the benefits of ORP as a new oxidative stress marker, the protocol for its evaluation and the importance of its measurement in the context of male infertility are discussed. In association with the standard semen analysis, seminal ORP has been analysed to evaluate semen quality and male fertility status. However, further studies are required to establish its use in assisted reproductive techniques (ART) practice.