Impact of oxidative stress on male fertility - a review

Trace and essential elements as vital components to improve the performance of the male reproductive system: Implications in cell signaling pathways

Successful male fertilization requires the main processes such as normal spermatogenesis, sperm capacitation, hyperactivation, and acrosome reaction. The progress of these processes depends on some endogenous and exogenous factors. So, the optimal level of ions and essential and rare elements such as selenium, zinc, copper, iron, manganese, calcium, and so on in various types of cells of the reproductive system could affect conception and male fertility rates. The function of trace elements in the male reproductive system could be exerted through some cellular and molecular processes, such as the management of active oxygen species, involvement in the action of membrane channels, regulation of enzyme activity, regulation of gene expression and hormone levels, and modulation of signaling cascades. In this review, we aim to summarize the available evidence on the role of trace elements in improving male reproductive performance. Also, special attention is paid to the cellular aspects and the involved molecular signaling cascades.

Chlorocholine chloride exposure induced spermatogenic dysfunction via iron overload caused by AhR/PERK axis-dependent ferritinophagy activation

Chlorocholine chloride (CCC) is a plant growth regulator used worldwide that is detectable in cereals, fruits and animal products. The health effects of CCC exposure have raised public concern. Our previous research showed that CCC exposure decreased testosterone synthesis in pubertal rats. However, little is known about whether and how pubertal CCC exposure impacts spermatogenesis. In this study, we used BALB/c mice and spermatogonia-derived GC-1 cells to examine CCC-induced spermatogenic dysfunction. In vivo, pubertal CCC exposure led to decreased testicular weight, decreased testicular germ cells and poor sperm quality. This effect worsened after cessation of CCC exposure for the next 30 days. RNA-seq and western blot analysis revealed that CCC induced aryl hydrocarbon receptor (AhR) signaling, endoplasmic reticulum stress (ERS) and ferritinophagy. Increased iron content and lipid peroxidation levels were also observed in CCC-treated testes. In vitro, it was identified that iron overload mediated by enhanced ferritinophagy occurred in CCC-treated GC-1 cells, which might be attributed to the PERK pathway in ERS. Further, for the first time, our study elucidated the involvement of AhR in CCC-induced iron overload, which aggravated testicular oxidative damage via lipid peroxidation. Considering the adverse impact of CCC exposure on rodents, supportive evidence from GC-1 cells, and the critical importance of spermatogenesis on male development, the effects of CCC on the male reproduction warrant increased attention.

Climate warming has divergent physiological impacts on sympatric lizards

Climate warming is expected to affect the vulnerability of sympatric species differentially due to their divergent traits, but the underlying physiological mechanisms of those impacts are poorly understood. We conducted field warming experiments (present climate vs. warm climate) using open-top chambers to determine the effects of climate warming on active body temperature, oxidative damage, immune competence, growth and survival in two sympatric desert-dwelling lizards, Eremias multiocellata and Eremias argus from May 2019 to September 2020. Our climate warming treatment did not affect survival of the two species, but it did increase active body temperatures and growth rate in E. multiocellata compared to E. argus. Climate warming also induced greater oxidative damage (higher malondialdehyde content and catalase activity) in E. multiocellata, but not in E. argus. Further, climate warming increased immune competence in E. multiocellata, but decreased immune competence in E. argus, with regards to white blood cell counts, bacteria killing ability and relative expression of immunoglobulin M. Our results suggest that climate warming enhances body temperature, and thereby oxidative stress, immune competence and growth in E. multiocellata, but decreases immune competence of E. argus, perhaps as a cost of thermoregulation to maintain body temperatures under climate warming. The divergent physiological effects of climate warming on sympatric species may have profound ecological consequences if it eventually leads to changes in reproductive activities, population dynamics and community structure. Our study highlights the importance of considering interspecific differences in physiological traits when we evaluate the impact of climate warming on organisms, even for those closely-related species coexisting within the same geographical area.

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.

The Role of Melatonin to Ameliorate Oxidative Stress in Sperm Cells

It is widely accepted that oxidative stress (OS) coming from a wide variety of causes has detrimental effects on male fertility. Antioxidants could have a significant role in the treatment of male infertility, and the current systematic review on the role of melatonin to ameliorate OS clearly shows that improvement of semen parameters follows melatonin supplementation. Although melatonin has considerable promise, further studies are needed to clarify its ability to preserve or restore semen quality under stress conditions in varied species. The present review examines the actions of melatonin via receptor subtypes and its function in the context of OS across male vertebrates.

Sperm interaction with bacteria induces the spontaneous acrosome reaction

Bacterial contamination in the semen deteriorates spermatozoa function. One mechanism through which this may occur is by inducing a premature form of the acrosome reaction (spontaneous acrosome reaction (sAR)) which has been shown to abrogate fertilization. To understand the mechanism by which bacteria affect sperm functions, we determined the effects of bacteria on sperm sAR and on other parameters involved in sperm capacitation. Sperm cells undergo biochemical changes in the female reproductive tract collectively called capacitation. Only capacitated sperm can undergo the physiological acrosomal exocytosis process near or on the oocyte, which allows the spermatozoon to penetrate and fertilize the egg. Bovine sperm incubated with the bacteria Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) or Pseudomonas aeruginosa (P. aeruginosa), revealed a sperm-bacteria interaction, however only E. coli and P. aeruginosa caused an increase in sperm sAR. This effect was seen only when the bacteria were present with the sperm during the full incubation under capacitation conditions but not when the bacteria were added to capacitated sperm. These results indicate that bacteria affect sperm during capacitation and not at the AR step. In addition, Ca²⁺ influx, protein kinase A, and protein tyrosine phosphorylation activities, three essential processes that promote capacitation, were inhibited by the bacteria. Moreover, increasing intracellular cAMP, which also occur during sperm capacitation, caused significant reverse of sAR induced by the bacteria.

Will warmer summers increase the impact of UV filters on marine bivalves?

Marine organisms are constantly exposed to multiple stressors including pollutants released into the environment, such as personal care products (PCPs), and climate change-derived factors, namely warming, which are aggravated by anthropogenic drivers and pose increasing pressure on coastal ecosystems. Avobenzone (AVO) is one of the most used ultraviolet (UV) filters in PCPs which have been increasingly used and, thereby, identified in aquatic environments. However, data regarding the influence of warming on the impacts caused by AVO in bivalves is lacking. Mussels are considered good bioindicators thus being often employed in ecotoxicology studies. Hence, the present study aimed to evaluate the toxic effects of an environmentally relevant concentration of AVO (0.5 μg/L) and warming (21 °C), acting alone or in combination, on sperm and adults of the Mediterranean mussel species Mytilus galloprovincialis, through in vitro and in vivo tests, respectively. AVO and warming effects were evaluated by assessing oxidative status, viability, genotoxicity, motility, and kinetics in sperm, together with the quantification of energy content, metabolic capacity, biological defence mechanisms, cellular damage, and neurotoxicity in adults. AVO induced genotoxicity and increased respiration rate in sperm while enhancing the biotransformation enzymes' activity in adults. Exposure to warming led to an increase in respiration rate, ROS overproduction, cellular damage, and viability decrease in sperm whereas metabolic capacity increased in adults. AVO combined with warming caused oxidative stress, cellular damage, genotoxicity, and decreased motility in sperm, while only antioxidant enzymes' activity was enhanced in adults. Overall, the present study demonstrated that when acting in combination the effects of both stressors were more prominent. Furthermore, considering the multiple-stressor scenario tested, major toxic effects occurred in male gametes in comparison to adults.

A Combination of Taurine and Caffeine in Stallion Semen Extender Positively Affects the Spermatozoa Parameters

This study was aimed to determine the impact of different taurine and caffeine combinations on the motility, viability, and oxidative markers of chilled stallion spermatozoa. Each stallion semen sample was diluted in a ratio of 1:2, with various taurine and caffeine concentrations (2.5-7.5 mg/mL taurine + 0.625-1.25 mg/mL caffeine) dissolved in a conventional extender. The control samples (CON) were prepared by diluting ejaculate only using the conventional extender. The motility was analyzed using a CASA system at different time intervals (0, 6, 12, 24, and 30 h) and the viability was evaluated using a mitochondrial toxicity test (MTT) performed at the end of the incubation at 5 °C. The liquid part of experimental samples was separated by centrifugation after 30 h of incubation and underwent the evaluation of oxidative stress via the quantification of markers ferric reducing ability of plasma (FRAP) and total oxidant status (TOS). The samples that were treated with a combination of taurine and caffeine significantly improved the motility parameters, mainly after 12, 24, and 30 h of incubation. Samples extended with combination of taurine and caffeine neither compromise viability nor alterations of redox status. The results of this study describe the combination of taurine and caffeine as an optimal supplement for improving the quality of stallion semen during chilled storage.

Elderberry Diet Restores Spermatogenesis in the Transient Scrotal Hyperthermia-Induced Mice

Over the past years, several studies have also reported the adverse effects of hyperthermia on normal testicular tissues in several species including mice, rats, and humans. These deleterious impacts include temporarily drop in relative weight of testis along with a temporary partial or complete infertility. Sambucus nigra, also known as elderberry or sweet elder, is a source of bioactive compounds that has drawn growing attention for its potential beneficial effects in preventing and treating several diseases. This experimental research divided 30 mice into the following three groups: (1) control, (2) hyperthermia, and (3) hyperthermia receiving elderberry diet for 35 days. Scrotal hyperthermia was induced by water bath with 43 °C for 30 min. Then, the mice were euthanized, and their sperm samples were collected for sperm parameters analysis. Then, we took the testis samples for histopathological experimentations, immunohistochemistry against TNF-α and caspase-3 and serum testosterone, FSH and LH levels. Our outputs indicated that elderberry diet could largely improve the sperms parameters and stereological parameters, like spermatogonia, primary spermatocyte, round spermatid, and Leydig cells together with an increasing level of the serum testosterone compared to the scrotal hyperthermia induced mice. In addition, it was found that the expression of TNF-α and caspase-3 significantly decreased in the treatment groups by elderberry diet compared to the scrotal hyperthermia-induced mice. In conclusion, it could be concluded that elderberry diet may be regarded as an alternative treatment for improving the spermatogenesis process in the scrotal hyperthermia induced mice.

Effect of combined calcium, magnesium, vitamin C and E supplementation on seminal parameters and serum oxidative stress markers in fructose-induced diabetic Wistar rats

CONTEXT

Deleterious effects of diabetes on seminal quality, serum metals and antioxidants have been confirmed.

OBJECTIVE

This study evaluated the effect of combined calcium, magnesium, vitamin C and E supplementation on seminal parameters, serum total antioxidant capacity (TAC), nitric oxide (NO), malonyldialdehyde (MDA), calcium and magnesium in fructose-induced diabetic rats.

MATERIALS AND METHODS

Thirty rats were grouped into non-diabetic controls, diabetic controls, diabetic rats given vitamin E + C, calcium + magnesium and vitamin E + C + calcium + magnesium. The analytes were evaluated using standard methods. Statistical significance was set at p < .05.

RESULTS

The diabetic controls had significantly higher MDA (p = .036) but lower (p = .0001) TAC, calcium, magnesium, sperm count, and %motility than the non-diabetic controls. The Vitamin C + E group showed the greatest improvement as they had the highest values of seminal parameters compared to other supplemented groups.

CONCLUSION

Combined Vitamin C + E supplementation may provide better ameliorative benefits than a combination of Vitamin C, E, calcium and magnesium in diabetics.

The Impact of Bacteriocenoses on Sperm Vitality, Immunological and Oxidative Characteristics of Ram Ejaculates: Does the Breed Play a Role?

Bacterial contamination of semen is an often overlooked, yet important, factor contributing to decreased sperm vitality. Understanding the impact of bacterial presence on sperm structural integrity and functional activity may assist the development of effective strategies to prevent, or manage, bacteriospermia in the breeding practice. The aim of this study was to describe the bacterial profiles of ram semen (n = 35), and we also focused on the associations between bacteriospermia, sperm structure, and function, as well as oxidative and inflammatory characteristics of semen. For a better insight, the samples were divided into three groups, according to the breeds used in the study: native Wallachian (NW), improved Wallachian (IW), and Slovak dairy (SD) breeds. The results showed a significantly lower motility and membrane integrity in the NW group in comparison to the IW and SD groups, which was accompanied by a significantly higher concentration of leukocytes, increased reactive oxygen species (ROS) generation, and subsequent oxidative insults to the sperm lipids and proteins. Accordingly, the NW group presented with the highest bacterial load, in which Staphylococcus and Escherichia were the predominant representatives. The Pearson correlation analysis uncovered positive relationships amongst the bacterial load and leukocytospermia (r = 0.613), the extent of lipid peroxidation (r = 0.598), protein oxidation (r = 0.514), and DNA fragmentation (r = 0.638). Furthermore, positive correlations were found between the bacterial load and pro-inflammatory molecules, such as the C-reactive protein (r = 0.592), interleukin 1 (r = 0.709), and interleukin 6 (r = 0.474), indicating a possible involvement of the immune response in the process of bacteriospermia. Overall, our data indicate that ram semen quality may be equally affected by the bacterial load and diversity. Furthermore, we can assume that the presence of bacteria in ejaculates triggers inflammatory processes, causes ROS overproduction, and, thereby, contributes to alterations in the sperm structure, while at the same time compromising the fertilization ability of male gametes.

Evidence for Ovarian and Testicular Toxicities of Cadmium and Detoxification by Natural Substances

Cadmium (Cd) is an environmental toxicant, capable of reducing mitochondrial ATP production and promoting the formation of reactive oxygen species (ROS) with resultant oxidative stress conditions. The ovary and testis are the primary gonads in which female gametes (oocytes) and male gametes (spermatozoa), estrogen and testosterone are produced. These organs are particularly susceptible to Cd cytotoxicity due to their high metabolic activities and high energy demands. In this review, epidemiological and experimental studies examining Cd toxicities in gonads are highlighted together with studies using zinc (Zn), selenium (Se), and natural substances to reduce the effects of Cd on follicular genesis and spermatogenesis. Higher blood concentrations of Cd ([Cd]b) were associated with longer time-to-pregnancy in a prospective cohort study. Cd excretion rate (ECd) as low as 0.8 μg/g creatinine was associated with reduced spermatozoa vitality, while Zn and Se may protect against spermatozoa quality decline accompanying Cd exposure. ECd > 0.68 µg/g creatinine were associated with an increased risk of premature ovarian failure by 2.5-fold, while [Cd]b ≥ 0.34 µg/L were associated with a 2.5-fold increase in the risk of infertility in women. Of concern, urinary excretion of Cd at 0.68 and 0.8 μg/g creatinine found to be associated with fecundity are respectively 13% and 15% of the conventional threshold limit for Cd-induced kidney tubular effects of 5.24 μg/g creatinine. These findings suggest that toxicity of Cd in primary reproductive organs occurs at relatively low body burden, thereby arguing for minimization of exposure and environmental pollution by Cd and its transfer to the food web.

Parkinson Disease Protein 7 (PARK7) Is Related to the Ability of Mammalian Sperm to Undergo In Vitro Capacitation

Parkinson disease protein 7 (PARK7) is a multifunctional protein known to be involved in the regulation of sperm motility, mitochondrial function, and oxidative stress response in mammalian sperm. While ROS generation is needed to activate the downstream signaling pathways required for sperm to undergo capacitation, oxidative stress has detrimental effects for sperm cells and a precise balance between ROS levels and antioxidant activity is needed. Considering the putative antioxidant role of PARK7, the present work sought to determine whether this protein is related to the sperm ability to withstand in vitro capacitation. To this end, and using the pig as a model, semen samples were incubated in capacitation medium for 300 min; the acrosomal exocytosis was triggered by the addition of progesterone after 240 min of incubation. At each relevant time point (0, 120, 240, 250, and 300 min), sperm motility, acrosome and plasma membrane integrity, membrane lipid disorder, mitochondrial membrane potential, intracellular calcium and ROS were evaluated. In addition, localization and protein levels of PARK7 were also assessed through immunofluorescence and immunoblotting. Based on the relative content of PARK7, two groups of samples were set. As early as 120 min of incubation, sperm samples with larger PARK7 content showed higher percentages of viable and acrosome-intact sperm, lipid disorder and superoxide levels, and lower intracellular calcium levels when compared to sperm samples with lower PARK7. These data suggest that PARK7 could play a role in preventing sperm from undergoing premature capacitation, maintaining sperm viability and providing a better ability to keep ROS homeostasis, which is needed to elicit sperm capacitation. Further studies are required to elucidate the antioxidant properties of PARK7 during in vitro capacitation and acrosomal exocytosis of mammalian sperm, and the relationship between PARK7 and sperm motility.

Bacterial communities in bovine ejaculates and their impact on the semen quality

Although bacterial contamination of ejaculates may cause difficulties in cattle reproduction, standard protocols for a routine microbiological analysis of bovine semen are still missing. Understanding of the mechanisms of bacterial damage to spermatozoa may contribute to the prevention and management of bacteriospermia in the future. Therefore, this study was designed to investigate bacterial profiles of fresh bovine ejaculates (n = 30), while at the same time we focused on assessing the relationships between bacteriospermia and selected sperm quality parameters as well as an array of oxidative stress and inflammatory markers. The samples were divided into three quality groups according to the sperm motility: Excellent (EX) - over 90% > Good (GO) - between 89% and 80% > Moderate (MO) - under 80%. The results showed a significant increase in reactive oxygen species (ROS) generation in the GO group when compared to the EX group. In the MO group, a deterioration of almost all quality parameters was observed when compared to the EX group. In particular, sperm motility, mitochondrial membrane potential, ROS production and IL-6 concentration exhibited a significant decline. Pearson correlation analysis revealed positive associations among bacterial load and the presence of leukocytes in semen (r = 0.965), malondialdehyde concentration (r = 0.816) and DNA fragmentation (r = 0.784). MALDI-TOF MS Biotyper analysis showed a prevalence of the Staphylococcus genus. The quantification of bacterial colonies revealed a significantly increased (P < 0.01) bacterial load in the MO group when compared with the EX as well as the GO group. Overall, our results suggest that sperm quality may be affected by both, bacterial composition, and bacterial load. It appears that an increased presence of bacterial species triggers the immune response, causes oxidative stress, and thereby contributes to sperm structural alterations while diminishing their fertilization ability.Abbreviations: EX: Excellent; GO: Good; MO: Moderate; MOT: Motility; ROS: Reactive Oxygen Species; MMP: Mitochondrial Membrane Potential; IL-1: Interleukin 1; IL-6: Interleukin 6; IL-8: Interleukin 8; IL-12: Interleukin 12; CRP: C-reactive protein; DNA: Deoxyribonucleic acid; MALDI-TOF MS: Matrix-assisted Laser Desorption/Ionization-Time of Flight Mass Spectrometry; LPO: Lipid peroxidation; CFU: Colony-forming units MDA: Malondialdehyde; CASA: Computer-assisted Sperm Analysis; WS: Working solution; RIPA: Radio-immunoprecipitation assay; TBARS: Thiobarbituric Acid Reactive Substances; BHB: D-β-hydroxybutyrate.

Comparative analysis of the detrimental in vitro effects of three fusariotoxins on the selected structural and functional characteristics of rabbit spermatozoa

In this study, we evaluated the in vitro effects of 1-50 μM zearalenone (ZEA), deoxynivalenol (DON) and T-2 toxin (T-2) on rabbit spermatozoa for as much as 8 h of in vitro exposure. Our results indicate that all sperm quality parameters were negatively affected by these fusariotoxins in a time- and dose-dependent manner. The most prominent structure affected by ZEA was the plasma membrane, exhibiting alterations consistent with the onset of apoptosis and reactive oxygen species (ROS) overproduction. This correlated with the most prominent decline of the sperm motility among all selected fusariotoxins. Significant necrotic changes and mitochondrial dysfunction were primarily responsible for the sperm damage in the presence of T-2. Finally, exposure of spermatozoa to DON led to a significant decrease in the DNA integrity. This study may provide new information on the specific mechanisms of action involved in the in vitro toxic behavior of fusariotoxins on male gametes.

Impact of Oxidative Stress on Male Reproduction in Domestic and Wild Animals

Oxidative stress occurs when the levels of reactive oxygen species (ROS) overcome the antioxidant defenses of the organism, jeopardizing several biological functions, including reproduction. In the male reproductive system, oxidative stress not only impairs sperm fertility but also compromises offspring health and survival, inducing oxidative damage to lipids, proteins and nucleic acids. Although a clear link between oxidative stress and male fertility disorders has been demonstrated in humans and laboratory rodents, little information is available about the implications of impaired redox homeostasis in the male fertility of domestic and wild animals. Therefore, this review aims to provide an update regarding the intrinsic and extrinsic factors that are associated with oxidative stress in the male reproductive system and their impact on the reproductive performance of domestic and wild animals. The most recent strategies for palliating the detrimental effects of oxidative stress on male fertility are reviewed together with their potential economic and ecological implications in the livestock industry and biodiversity conservation.

Oxidative stress in response to heat stress in wild caught Namaqua rock mice, Micaelamys namaquensis

Modelling of anthropogenic induced climate suggests more frequent and severe heatwaves in the future, which are likely to result in the mass die-off of several species of organisms. Oxidative stress induced by severe heat stress has previously been associated with a reduction in animal cognitive performance, depressed reproduction and lower life expectancy. Little is known about the non-lethal consequences of species should they survive extreme heat exposure. We investigated the oxidative stress experienced by the Namaqua rock mouse, a nocturnal rodent, using two experimental heat stress protocols, a 6 hour acute heat stress protocol without access to water and a 3-day heatwave simulation with ad libitum water. Oxidative stress was determined in the liver, kidney and brain using malondialdehyde (MDA) and protein carbonyl (PC) as markers of oxidative damage, and superoxide dismutase (SOD) and total antioxidant capacity (TAC) as markers of antioxidant defence. Incubator heat stress (heat and dehydration stress) was brought about by increasing the body temperatures of animals to 39-40.8 °C for 6 hours. Following incubator heat stress, significantly higher levels of MDA were observed in the liver. Dehydration did not explain the variation in oxidative markers and is likely a combined effect of thermal and dehydration stress. Individual body mass was significantly negatively correlated to kidney SOD and lipid peroxidation. A heatwave was simulated using a temperature cycle that would naturally occur during a heatwave in the species' local habitat, with a maximal ambient temperature of 38 °C. Following the simulated heatwave, SOD activity of the kidney demonstrated significantly lowered activity suggesting oxidative stress. Current heat waves in this species have the potential of causing oxidative stress. Heat and dehydration stress following exacerbated temperatures are likely to incur significant oxidative stress in multiple tissues demonstrating the importance of water availability to allow for rehydration to prevent oxidative stress.

Protective effects of ethyl acetate extract from Shorea roxburghii against diabetes induced testicular damage in rats

Diabetic mellitus is a chronic metabolic disorder that is associated with several complications including testicular dysfunction. This research investigated the protective action of the ethyl acetate extract from Shorea roxburghii (SRE) on diabetes induced testicular damage in rats. Diabetic rats were orally administered with SRE at doses of 100 and 400 mg/kg for 4 weeks. SRE improved the body weight gain, testes weight, testes index and increased serum concentration of testosterone. Furthermore, SRE increased the testicular antioxidant enzymes including superoxide dismutase, catalase and glutathione peroxidase. In addition, SRE ameliorated testicular inflammatory mediators such as myeloperoxidase, tumor necrosis factor alpha, interleukin 6, p38 MAPK and nuclear factor kappa B activation and decreased testicular cell apoptosis in the treated diabetic rats. SRE also raised sperm parameters after treatment of diabetic rats. Conclusively, our results suggested that SRE ameliorated diabetes induced testicular damage by inhibiting oxidative stress and inflammation.

Sperm quality assessment in Ficopomatus enigmaticus (Fauvel, 1923): Effects of selected organic and inorganic chemicals across salinity levels

Contamination by organic and inorganic compounds remains one of the most complex problems in both brackish and marine environments, causing potential implications for the reproductive success and survival of several broadcast spawners. Ficopomatus enigmaticus is a tubeworm polychaete that has previously been used as a model organism for ecotoxicological analysis, due to its sensitivity and ecological relevance. In the present study, the effects of five trace elements (zinc, copper, cadmium, arsenic and lead), one surfactant (sodium dodecyl sulfate, SDS) and one polycyclic aromatic hydrocarbon (benzo(a)pyrene, B(a)P) on the sperm quality of F. enigmaticus were investigated. Sperm suspensions were exposed in vitro to different concentrations of each selected contaminant under four salinity conditions (10, 20, 30, 35). Possible adverse effects on sperm function were assessed by measuring oxidative stress, membrane integrity, viability and DNA damage. Sperm quality impairments induced by organic contaminants were more evident than those induced by inorganic compounds. SDS exerted the largest effect on sperm. In addition, F. enigmaticus sperm showed high tolerance to salinity variation, supporting the wide use of this species as a promising model organism for ecotoxicological assays. Easy and rapid methods on polychaete spermatozoids were shown to be effective as integrated sperm quality parameters or as an alternative analysis for early assessment of marine and brackish water pollution.

Heat and dehydration induced oxidative damage and antioxidant defenses following incubator heat stress and a simulated heat wave in wild caught four-striped field mice Rhabdomys dilectus

Heat waves are known for their disastrous mass die-off effects due to dehydration and cell damage, but little is known about the non-lethal consequences of surviving severe heat exposure. Severe heat exposure can cause oxidative stress which can have negative consequences on animal cognition, reproduction and life expectancy. We investigated the current oxidative stress experienced by a mesic mouse species, the four striped field mouse, Rhabdomys dilectus through a heat wave simulation with ad lib water and a more severe temperature exposure with minimal water. Wild four striped field mice were caught between 2017 and 2019. We predicted that wild four striped field mice in the heat wave simulation would show less susceptibility to oxidative stress as compared to a more severe heat stress which is likely to occur in the future. Oxidative stress was determined in the liver, kidney and brain using malondialdehyde (MDA) and protein carbonyl (PC) as markers for oxidative damage, and superoxide dismutase (SOD) and total antioxidant capacity (TAC) as markers of antioxidant defense. Incubator heat stress was brought about by increasing the body temperatures of animals to 39-40.8°C for 6 hours. A heat wave (one hot day, followed by a 3-day heatwave) was simulated by using temperature cycle that wild four striped field mice would experience in their local habitat (determined through weather station data using temperature and humidity), with maximal ambient temperature of 39°C. The liver and kidney demonstrated no changes in the simulated heat wave, but the liver had significantly higher SOD activity and the kidney had significantly higher lipid peroxidation in the incubator experiment. Dehydration significantly contributed to the increase of these markers, as is evident from the decrease in body mass after the experiment. The brain only showed significantly higher lipid peroxidation following the simulated heat wave with no significant changes following the incubator experiment. The significant increase in lipid peroxidation was not correlated to body mass after the experiment. The magnitude and duration of heat stress, in conjunction with dehydration, played a critical role in the oxidative stress experienced by each tissue, with the results demonstrating the importance of measuring multiple tissues to determine the physiological state of an animal. Current heat waves in this species have the potential of causing oxidative stress in the brain with future heat waves to possibly stress the kidney and liver depending on the hydration state of animals.

Quercetin and Naringenin Provide Functional and Antioxidant Protection to Stored Boar Semen

In this study, we evaluated the impact of 5-50 μM quercetin (QUE) and naringenin (NAR) on extended boar spermatozoa in the BTS (Beltsville Thawing Solution) medium for 72 h. Spermatozoa motion, membrane, acrosome, and DNA integrity were investigated immediately after sample dilution (0 h) as well as after 24 h, 48 h, and 72 h of semen storage. Furthermore, reactive oxygen species (ROS) and superoxide production, as well as the extent of oxidative damage to the sperm proteins and lipids, were assessed to determine the potential of QUE and NAR to prevent a potential loss of sperm vitality due to oxidative stress development. Our results indicate that the most notable parameter influenced by QUE was the mitochondrial activity, which remained significantly higher throughout the experiment (p < 0.001 and p < 0.0001; 10 μM), and which correlated with the most prominent maintenance of sperm motility (p < 0.01, 48 h; p < 0.05, 72 h). A significant membrane stabilization (p < 0.01, 24 h and 48 h; p < 0.0001, 72 h) and prevention of lipid peroxidation (p < 0.05, 24 h and 48 h; p < 0.01, 72 h) was primarily observed following administration of 10 and 25 μM NAR; respectively. Administration of 10 μM QUE led to a significant decrease of superoxide (p < 0.0001, 48 h and 72 h) while the most notable decline of ROS generation was recorded in the case of 10 and 25 μM NAR (p < 0.001). This study may provide new information on the specific mechanisms of action involved in the favorable effects of natural biomolecules on spermatozoa.

Fumaria parviflora regulates oxidative stress and apoptosis gene expression in the rat model of varicocele induction

Varicocele is one of the leading causes of male infertility in which oxidative stress induces DNA damages in spermatozoa of patients with varicocele. Recent studies indicated that the treatment with antioxidant agents has protective effects against the formation of reactive oxygen species (ROS). Our research aimed to evaluate the impact of Fumaria Parviflora (FP) on the varicocele-induced testicular injury. For this purpose, 32 adult male Wistar rats (n = 8 per group) were randomly assigned to four groups as follows: sham group, varicocele group, varicocele treatment group and the control treatment group. The experimental groups daily received FP (250 mg/kg) for 8 weeks. The induction of varicocele was conducted by partial occlusion on the left renal vein. The diameter of seminiferous tubules, Johnsen's score and the epithelium thickness improved in the treated-varicocele group as compared to the varicocele group. FP extract could increase the biochemical parameters including superoxide dismutase and glutathione peroxidase, and also decrease malondialdehyde level in the varicocele group. Furthermore, varicocele markedly increased both mRNA and intensity of Bax, while treatment with FP could alleviate them. We concluded that FP could alleviate varicocele, possibly by lowering oxidative stress and testicular damage.

Characterization of the Omija (Schisandra chinensis) Extract and Its Effects on the Bovine Sperm Vitality and Oxidative Profile during In Vitro Storage

Schisandra chinensis is a woody vine native to China, Korea, and Russia, which has been used as a traditional herbal remedy to treat male infertility. As very little information is available concerning its effects on ejaculated spermatozoa, the aim of this study was to investigate the chemical, antioxidant, and antibacterial properties of the S. chinensis berry (Omija) extract followed by an assessment of its in vitro effects on bovine sperm function and oxidative balance. Phytochemical components of the Omija extract were determined by high performance liquid chromatography. The content of polyphenols, flavonoids, and carotenoids was assessed by spectrophotometric protocols. Antioxidant characteristics of the Omija extract were determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and molybdenum-reducing antioxidant power (MRAP) assays. The disc diffusion method and determination of the minimal inhibitory concentration were applied to study the antibacterial properties of Schisandra. Thirty semen samples were exposed to different concentrations of Omija (1, 5, 10, 25, 50, and 75 µg/mL) for 0, 2, and 24 h. Sperm motility, mitochondrial activity, and superoxide and reactive oxygen species production, as well as total antioxidant capacity and oxidative damage to proteins and lipids were determined. Our data reveal that the Omija extract, particularly at a concentration range within 5-50 µg/mL, exhibited dose-dependent motion-promoting and metabolism-enhancing properties, accompanied by significant antioxidant effects. We may conclude that the biomolecules present in the Omija extract such as schisandrins and phenolic molecules offer protection to critical sperm structures against oxidative insults and/or possible bacterial contamination, leading to a higher preservation of mammalian sperm viability and functional activity.

Endogenous and Exogenous Antioxidants As a Tool to Ameliorate Male Infertility Induced by Reactive Oxygen Species

Significance: Antioxidants are essential for the maintenance of cellular redox homeodynamics in the male reproductive tract, playing a key role in fertilizing potential. Reactive oxygen species (ROS), at physiological levels, are essential for sperm function and fertilization. Under pathological conditions, abnormal production of ROS may occur. Redox control is primarily regulated by the inner antioxidant system. However, these endogenous antioxidants may be present at abnormal amounts or may be insufficient. Exogenous antioxidants obtained through the diet may have an important role, particularly in specific pathological conditions. This review addresses the regulation of redox homeodynamics in the male reproductive tract by endogenous and exogenous antioxidants and the importance of their cooperation for the maintenance of fertility. Recent Advances: Many studies have shown the importance of antioxidants for the preservation of male fertility, mostly under pathological conditions. Excessive antioxidants can inhibit ROS-induced signaling pathways that are essential for the reproductive system. The challenge is to keep the balance between oxidants and antioxidants to maintain ROS-amount at physiological concentration. Critical Issues: Although antioxidant therapies are gaining popularity and showing promising results in the improvement of male fertility, there is a lack of knowledge regarding the type of exogenous antioxidant, the doses and time to be administered. Future Directions: It would be of great importance to find a way to restore redox homeostasis under stress conditions. Understanding the poorly studied mechanisms by which exogenous antioxidants cooperate with the inner cellular antioxidant system to counteract free radicals may help in the development of new fertility therapies.

Divergent effect of fast- and slow-releasing H2S donors on boar spermatozoa under oxidative stress

Hydrogen sulphide (H₂S) is involved in the physiology and pathophysiology of different cell types, but little is known about its role in sperm cells. Because of its reducing properties, we hypothesise that H₂S protects spermatozoa against the deleterious effects of oxidative stress, a condition that is common to several male fertility disorders. This study aimed i) to determine the total antioxidant capacities of Na₂S and GYY4137, which are fast- and slow-releasing H₂S donors, respectively, and ii) to test whether H₂S donors are able to protect spermatozoa against oxidative stress. We found that Na₂S and GYY4137 show different antioxidant properties, with the total antioxidant capacity of Na₂S being mostly unstable and even undetectable at 150 µM. Moreover, both H₂S donors preserve sperm motility and reduce acrosome loss, although the effects were both dose and donor dependent. Within the range of concentrations tested (3–300 µM), GYY4137 showed positive effects on sperm motility, whereas Na₂S was beneficial at the lowest concentration but detrimental at the highest. Our findings show that Na₂S and GYY4137 have different antioxidant properties and suggest that both H₂S donors might be used as in vitro therapeutic agents against oxidative stress in sperm cells, although the optimal therapeutic range differs between the compounds.

Possible therapeutic effects of vindoline on testicular and epididymal function in diabetes-induced oxidative stress male Wistar rats

OBJECTIVE

The study evaluated the effects of vindoline on testicular and epididymal oxidative stress in diabetes-induced male Wistar rats.

METHODS

Forty-eight (48), 6-week old male Wistar rats weighing between 190-230g were divided into 6 groups (n = 8) and used for this study. Group 1 was the normal control, group 2 comprised non-diabetic rats treated with vindoline, and group 3 was the non-diabetic group of rats treated with glibenclamide-the standard drug for the treatment of diabetes. Group 4 was the diabetic control, group 5 comprised diabetic rats treated with vindoline and group 6 was the diabetic rats treated with glibenclamide. Diabetes was induced in group 4, group 5 and group 6 rats by subjecting them to 10% fructose water over a period of 2 weeks, followed by administration of a single intraperitoneal injection of 40 mg/kg b.w streptozotocin (STZ). Testicular and epididymal lipid peroxidation levels, antioxidant enzymes, scavenging activity and total antioxidant capacity were measured.

RESULTS

Diabetes-induced male Wistar rats demonstrated chronic hyperglycaemia, oxidative stress and reduced oxygen radical absorption capacity in both testicular and epididymal tissues. Short-term treatment of diabetic rats with vindoline for 5 weeks significantly reduced fasting blood glucose levels, minimise testicular oxidative stress, increased testicular and epididymal catalase and epididymal SOD and increase total antioxidant activity capacity.

CONCLUSION

Treatment with vindoline showed protective effects against diabetes-induced oxidative stress in both testicular and epididymal tissues of male Wistar rats, hence can be considered potential agent in the management of diabetes-induced oxidative stress male sexual dysfunction.

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

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

Effect of heavy metals on oxidative markers and semen quality parameters in HF crossbred bulls

The study was conducted to assess the effect of toxic heavy metals on seminal antioxidants, trace minerals and semen quality parameters in crossbred breeding bulls. Semen samples were collected from breeding bulls (82) maintained at bull rearing unit of the institute. Toxic heavy metals (Pb and Cd), trace minerals (Zn, Cu, Co and Fe) and oxidative stress markers (SOD, catalase and MDA) were determined in semen samples of breeding bulls. Sperm motility and concentration were measured in fresh ejaculates. Significant levels of Pb (0.23±0.006 μg/ml) and Cd (0.11±0.005 μg/ml) were detected in semen samples of breeding bulls. On analysis of the data between good and poor bull categories, significantly higher concentration of Pb and Cd was present in semen samples of poor bulls as compared to good bulls. There was significantly higher malondialdehyde (MDA) and low superoxide dismutase (SOD) and catalase in seminal plasma of poor bulls compared to good bulls. A significant decrease in Zn and Cu was observed in poor bulls as compared to good bulls. Cobalt and iron values did not show any significant variation between good and poor quality bulls. On correlation analysis, lead and cadmium showed significant negative correlation with Zn, Cu, SOD, catalase, motility and sperm concentration while significant positive correlation was seen with MDA respectively. The study concludes that increased Pb and Cd in bull semen may increase the risk of seminal oxidative stress development and a subsequent reduction in male fertility.

Oxidative damage induced by copper in testis of the red swamp crayfish Procambarus clarkii and its underlying mechanisms

Copper (Cu) is one of the most widespread environmental pollutants and is known to exert multiple toxic effects including reproductive toxicity. In this study, we investigated the toxic effect of Cu on reproduction of the red swamp crayfish (Procambarus clarkii), an economic crustacean species, by exposing adult male crayfish to 0.03 and 3.00 mg/L Cu²⁺ for 7 days. The results showed that Cu²⁺ exposure induced oxidative stress accompanied by elevated reactive oxygen species (ROS) and malondialdehyde (MDA) levels in testes, and resulted in decreased sperm quality and abnormal testicular structures with apoptotic germ cells and vacuolisation in Sertoli cells. To reveal the molecular mechanism of Cu²⁺-induced oxidative damage in crayfish testes, we sequenced, assembled and annotated the transcriptome for crayfish testes, using the Illumina sequencing approach. After the 3.00 mg/L Cu²⁺ treatment, 6745 genes with differentially expressed profile were identified, of which many genes were involved in cellular response to ROS based on Gene Ontology enrichment analysis. Further, KEGG analysis demonstrated that genes with up-regulated expression levels significantly enriched in mitochondria oxidative phosphorylation pathway, suggesting disturbed mitochondrial electron transport chain was probably a main source of Cu²⁺-induced ROS production in testes. This study represented the first use of transcriptome to investigate the toxic effect of Cu²⁺ on male crayfish reproduction, and the pathways identified underlying Cu²⁺ toxicity at molecular level provide a novel insight into the reproductive toxicity of Cu in crustaceans.

Aminoguanidine Protects Boar Spermatozoa against the Deleterious Effects of Oxidative Stress

Aminoguanidine is a selective inhibitor of the inducible nitric oxide synthase (iNOS) and a scavenger of reactive oxygen species (ROS). Numerous studies have shown the antioxidant properties of aminoguanidine in several cell lines, but the in vitro effects of this compound on spermatozoa under oxidative stress are unknown. In this study, we tested the hypothesis that aminoguanidine may protect against the detrimental effects of oxidative stress in boar spermatozoa. For this purpose, sperm samples were incubated with a ROS generating system (Fe²⁺/ascorbate) with or without aminoguanidine supplementation (10, 1, and 0.1 mM). Our results show that aminoguanidine has powerful antioxidant capacity and protects boar spermatozoa against the deleterious effects of oxidative stress. After 2 h and 3.5 h of sperm incubation, the samples treated with aminoguanidine showed a significant increase in sperm velocity, plasma membrane and acrosome integrity together with a reduced lipid peroxidation in comparison with control samples (p < 0.001). Interestingly, except for the levels of malondialdehyde, the samples treated with 1 mM aminoguanidine did not differ or showed better performance than control samples without Fe²⁺/ascorbate. The results from this study provide new insights into the application of aminoguanidine as an in vitro therapeutic agent against the detrimental effects of oxidative stress in semen samples.

Cytotoxicity and genotoxicity of CuO nanoparticles in sea urchin spermatozoa through oxidative stress

Copper oxide nanoparticles (CuO NPs) are extensively used in various industrial and commercial applications. Despite their wide application may lead to the contamination of marine ecosystem, their potential environmental effects remain to be determined. Toxicity assessment studies have primarily focused on investigating the effects of CuO NPs on fertilization success and embryo development of different sea urchin species while the impact on sperm quality have never been assessed. In this line, this study aims to assess the effects of CuO NPs on the spermatozoa of the sea urchin Paracentrotus lividus. After sperm exposure to CuO NPs, biomarkers of sperm viability, cytotoxicity, oxidative stress, and genotoxicity as well as morphology were evaluated. Results showed that CuO NPs exposure decreased sperm viability, impaired mitochondrial activity and increased the production of reactive oxygen species (ROS) and lipid peroxidation. Furthermore, CuO NPs exposure caused DNA damage and morphological alterations. Together with the antioxidant rescue experiments, these results suggest that oxidative stress is the main driver of CuO NP spermiotoxic effects. The mechanism of toxicity is here proposed: the spontaneous generation of ROS induced by CuO NPs and the disruption of the mitochondrial respiratory chain lead to production of ROS that, in turn, induce lipid peroxidation and DNA damage, and result in defective spermatozoa up to induce sperm cytotoxicity. Investigating the effects of CuO NPs on sea urchin spermatozoa, this study provides valuable insights into the mechanism of reproductive toxicity induced by CuO NPs.

Effects of Astaxanthin on Miniature Pig Sperm Cryopreservation

The purpose of this study is to evaluate the effects of astaxanthin added to freezing buffer on semen parameters, total sperm oxidation stress after postthawing of boar sperm, and lipid peroxidation (LPO) which is caused by reactive oxygen species (ROS) in sperm membrane. Varying concentrations of astaxanthin (0, 10, 50, 100, and 500 μM) were used in the freezing buffer during cryopreservation to protect the DNA of thawed miniature pig sperm. Semen parameter was measured using computer-assisted sperm analysis (CASA) for sperm motility, and then ROS rate and oxidative stress of boar sperm were determined using fluorescence-activated cell sorting (FACS). Sperm motility was higher (p < 0.05) in the astaxanthin group than in the control group. Sperm motility and the number of progressive motile sperm were higher (p < 0.05) in the astaxanthin 500 μM group than in the control group. In ROS evaluation, the astaxanthin group had lower intracellular O₂ and H₂O₂ in viable sperm. Yo-Pro-I/HE and PI/H2DCFDA staining as revealed using flow cytometry was lower in astaxanthin groups than in the other groups. As a result, we found that astaxanthin could protect the sperm plasma membrane from free radicals and LPO during boar sperm postthawing.

A novel epididymal quiescence factor inhibits sperm motility by modulating NOS activity and intracellular NO-cGMP pathway

Mature and potentially motile spermatozoa stored in cauda epididymis in an inactive state for approximately 30 days; however, during ejaculation they regain motility. To understand the actual molecular mechanism of the sperm quiescence during caudal stay, a proteinaceous quiescence factor (QF) has been purified from caprine epididymal plasma to apparent homogeneity. In the present study complete purification, detailed characterization as well as mechanistic pathway of QF has been described. QF is purified to 215-fold with 45% activity recovery. It is a 59 kDa monomeric protein with isoelectric point 5.8 and optimally active at pH 7.5. Circular dichroism spectroscopy and atomic force microscopy study confirm its α-helical secondary structure and globular tertiary conformation. QF is a thermo-stable protein as higher temperature does not alter its helical structure. N-terminal amino acid sequencing and MALDI analysis of QF did not find 100% similarity with any available protein of the database, proved its novelty. QF at 2 μM dose inhibits sperm progressive forward motility within 10 min. This motility inhibitory activity of QF is mediated by reducing NOS enzyme activity and subsequently decreasing the intracellular NO and cGMP concentration. It does not modulate intracellular Ca⁺⁺ and cAMP concentration. QF has no adverse effect on DNA integrity and morphology of spermatozoa. Motility inhibitory action of QF is reversible. Thus, the role of QF in maintaining energy saving quiescence state of mature cauda spermatozoa and its reactive nitrogen species reducing activity may lead to a new direction for storage of spermatozoa and idiopathic male infertility.

Testicular toxicity and sperm quality following copper exposure in Wistar albino rats: ameliorative potentials of L-carnitine

Copper is a persistent toxic and bio-accumulative heavy metal of global concern. Continuous exposure of copper compounds of different origin is the most common form of copper poisoning and in turn adversely altering testis morphology and function and affecting sperm quality. L-carnitine has a vital role in the spermatogenesis, physiology of sperm, sperm production and quality. This study was designed to examine whether the detrimental effects of long-term copper consumption on sperm quality and testis function of Wistar albino rat could be prevented by L-carnitine therapy. The parameters included were sperm quality (concentration, viability, motility, and morphology), histopathology, serum aspartate aminotransferase (AST), serum alanine aminotransferase (ALT), serum urea, serum creatinine, serum testosterone and testis antioxidant enzyme levels (superoxide dismutase and glutathione-S-transferase), and biomarkers of oxidative stress (lipid peroxidation and expression of heat shock protein 70 in testis). Three-month-old male Wistar rats (n = 30) were divided into six groups as group 1 (G1, 0.9% saline control), group 2 (G2, CuSO4 200 mg/kg dissolved in 0.9% saline water), groups 3 and 4 (G3 and G4, L-carnitine 50 and 100 mg/kg dissolved in 0.9% saline water, respectively), and groups 5 and 6 (G5 and G6, CuSO₄ 200 mg/kg plus L-carnitine, 50 and 100 mg/kg dissolved in 0.9% saline water, respectively). Doses of copper (200 mg/kg) and L-carnitine (50 and 100 mg/kg) alone and in combinations along with untreated control were administered orally for 30 days. The following morphological, physiological, and biochemical alterations were observed due to chronic exposure of copper (200 mg/kg) to rats in comparison with the untreated control: (1) generation of oxidative stress through rise in testis lipid peroxidation (12.21 vs 3.5 nmol MDA equivalents/mg protein) and upregulation of heat shock protein (overexpression of HSP70 in testis), (2) liver and kidney dysfunction [elevation in serum ALT (81.65 vs 48.08 IU/L), AST (156.82 vs 88.25 IU/L), ALP (230.54 vs 148.16 IU/L), urea (12.65 vs 7.45 mmol/L), and creatinine (80.61 vs 48.25 μmol/L) levels], (3) significant decrease in body (99.64 vs 106.09 g) and organ weights (liver-3.48 vs 4.99 g; kidney-429.29 vs 474.78 mg; testes-0.58 vs 0.96 g), (4) imbalance in hormonal and antioxidant enzyme concentrations [significant decline in serum testosterone (0.778 vs 3.226 ng/mL), superoxide dismutase (3.07 vs 8.55 μmol/mg protein), and glutathione-S-transferase (59.28 vs 115.58 nmol/mg protein) levels], (5) severe alterations in the testis histomorphology [sloughed cells (90.65%, score 4 vs 15.65%, score 1), vacuolization (85.95%, score 4 vs 11.45%, score 1), cellular debris along with degenerative characteristics, accentuated germ cell depletion in the seminiferous epithelium, severe damage of spermatogonia and Sertoli cells (73.56%, score 3 vs 0%, score 1)], (6) suppression of spermatogenic process [hypospermatogenesis (low Jhonsen testicular biopsy score 4 vs 9.5), decrease in tubules size (283.75 vs 321.25 μm in diameter), and no. of germ cells (81.8 vs 148.7/100 tubules), Leydig cells (5.2 vs 36.65/100 tubules), and Sertoli cells (8.1 vs 13.5/100 tubules)], (7) sperm transit time was shorter in caput and cauda and ensued in incomplete spermatogenic process and formation of immature sperm leading to infertility, (8) sperm quality was affected significantly [decreased daily sperm production (13.21 vs 26.9 × 10⁶ sperms/mL), sperm count (96.12 vs 154.25 × 10⁶/g), sperm viability (26.88 vs 91.65%), and sperm motility (38.48 vs 64.36%)], and (9) increase of head (32.82 vs 2.01%) and tail (14.85 vs 0.14%) morphologic abnormalities and DNA fragmentation index (88.37 vs 11.11%). Oxidative stress and their related events appear to be a potential mechanism involved in copper testicular toxicity and L-carnitine supplementation significantly modulated the possible adverse effects of copper on seminiferous tubules damage, testes function, spermatogenesis, and sperm quality. It was validated that the use of L-carnitine at doses of 50 and 100 mg/kg protects against copper-induced testicular tissue damage and acts as a therapeutic agent for copper heavy metal toxicity.

Acute myeloid leukaemia at an early age: Reviewing the interaction between pesticide exposure and KMT2A-rearrangement

Acute myeloid leukaemia (AML) in early childhood is characterised by a high frequency of recurrent genomic aberrations associated with distinct myeloid subtypes, clinical outcomes and pathogenesis. Genomic instability is the first step of pathogenic mechanism in early childhood AML. A sum of adverse events is necessary to the development of infant AML (i-AML), which includes latency of biochemical-molecular and cellular effects. Inherited genetic susceptibility associated with exposures to biotransformation substances can modulate the risk of DNA damage and it is a very important piece in the pathogenic puzzle. In this review, we have aimed to explore the chain of events in the time-points of the natural history of i-AML, which includes maternal exposures during pregnancy, the speculations about the formation of somatic mutations during foetal life and the secondary genomic aberrations associated with i-AML. The modulation of risk conferred by xenobiotic metabolism´s genes variants is the bottom line of the pathogenic process. Since we have conducted observational and molecular investigations in early childhood leukaemia, the data focused here is based on Brazilian findings with summarised results of our experience with epidemiological and molecular studies in early-age leukaemia.

Effect of Pollen, Pit Powder, and Gemmule Extract of Date Palm on Male Infertility: A Systematic Review

Pollen, pit powder, and gemmule extract of the date palm are rich in flavonoids. Antioxidant characteristics of the flavonoids have a significant effect on prevention and treatment of infertility. The aim of the present study was to review studies investigating the effects of pollen, pit powder, and gemmule extract of the date palm on male infertility. Articles that were published about the topic between 2005 and 2016 were reviewed from different databases in Turkish and English. The search engines used included PubMed, Science Direct, Clinical Key, Google Scholar, Springer, Dergipark, Ulakbim, and Akademik Dizin. The studies found that pollen, pit powder, and gemmule extract of the date palm created positive changes in hormone levels that have a role in male fertility and increased sperm motility and quality, spermatogenesis, and weights of testes and epididymis. Date palm pollen, pit powder, and gemmule extract have a high antioxidant capacity because of phenolic formations in the composition. Such characteristics have a positive effect on prevention and treatment of male infertility. Furthermore, gonadotropic and steroidal compounds within date palm pollen play a role in treatment of male infertility. The limited number of studies conducted on this topic indicates that more research is needed.

Does air pollution play a role in infertility?: a systematic review

BACKGROUND

Air pollution is involved in many pathologies. These pollutants act through several mechanisms that can affect numerous physiological functions, including reproduction: as endocrine disruptors or reactive oxygen species inducers, and through the formation of DNA adducts and/or epigenetic modifications. We conducted a systematic review of the published literature on the impact of air pollution on reproductive function. Eligible studies were selected from an electronic literature search from the PUBMED database from January 2000 to February 2016 and associated references in published studies. Search terms included (1) ovary or follicle or oocyte or testis or testicular or sperm or spermatozoa or fertility or infertility and (2) air quality or O3 or NO2 or PM2.5 or diesel or SO2 or traffic or PM10 or air pollution or air pollutants. The literature search was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We have included the human and animal studies corresponding to the search terms and published in English. We have excluded articles whose results did not concern fertility or gamete function and those focused on cancer or allergy. We have also excluded genetic, auto-immune or iatrogenic causes of reduced reproduction function from our analysis. Finally, we have excluded animal data that does not concern mammals and studies based on results from in vitro culture. Data have been grouped according to the studied pollutants in order to synthetize their impact on fertility and the molecular pathways involved.

CONCLUSION

Both animal and human epidemiological studies support the idea that air pollutants cause defects during gametogenesis leading to a drop in reproductive capacities in exposed populations. Air quality has an impact on overall health as well as on the reproductive function, so increased awareness of environmental protection issues is needed among the general public and the authorities.

Addition of insulin-like growth factor I to the maturation medium of bovine oocytes subjected to heat shock: effects on the production of reactive oxygen species, mitochondrial activity and oocyte competence

This study was performed to investigate the effects of insulin-like growth factor-I (IGF-I) addition to in vitro maturation (IVM) medium on apoptosis, mitochondrial membrane potential, ROS production, and developmental competence of bovine oocytes subjected to heat shock. Two temperatures (conventional: 24 h at 38.5°C, or heat shock: 12 h at 41°C followed by 12 h at 38.5°C) and 3 IGF-I concentrations (0, 25, and 100 ng/mL) were tested during IVM. The oocytes were then fertilized in vitro, and the presumptive zygotes were cultured until reaching the blastocyst stage. There was no interaction between temperature and IGF-I concentration for any variable evaluated (P > 0.05). The addition of IGF-I did not alter the proportion of nuclear maturation, TUNEL-positive oocytes and caspase-3 activity, or blastocyst proportion on Days 7 and 8 post-fertilization. Furthermore, the total number of cells and the number of cells in the inner cell mass (ICM) in the blastocyst were not altered (P > 0.05). However, IGF-I increased (P < 0.05) the mitochondrial membrane potential and the production of ROS in oocytes and decreased (P < 0.05) the proportion of apoptotic cells in the ICM in blastocysts. Heat shock increased (P < 0.05) the proportion of TUNEL-positive oocytes and ROS production and reduced (P < 0.05) the mitochondrial membrane potential. Moreover, heat shock increased (P < 0.05) the apoptosis proportion in the ICM cells. In conclusion, supplementing IVM medium with IGF-I may increase the mitochondrial membrane potential and ROS production in oocytes and decrease apoptosis in the ICM in blastocysts. Heat shock for 12 h compromised oocyte developmental competence and increased apoptosis within the ICM cells of the blastocysts.

Free radical and superoxide reactivity detection in semen quality assessment: past, present, and future

Oxidative stress is a well-established cause of male infertility, with reactive oxygen species (ROS) impairing sperm production, motility, membrane, and DNA integrity. Currently, most clinics do not test infertile patients for the imbalance between ROS generation and the ability of the antioxidants to scavenge them, although there is a clear need for andrology laboratories to be able to identify and/or quantify seminal oxidative stress. As such there is a clinical urgency for an inexpensive and easy-to-perform assay able to identify oxidative stress in semen. The aim of this review is to provide information on the currently available methods to assess and quantify ROS and particularly superoxide in male reproductive cells, tissues, and fluids which may have a significant clinical utility in identifying men with impaired fertility associated with oxidative stress. Through a deeper understanding of oxidative stress and its assessment options, clinical andrology labs may better assist patients to achieve increased rates of fertility and pregnancy.

Seasonal variations in the blood concentration of selected heavy metals in sheep and their effects on the biochemical and hematological parameters

The main objective of this study was to assess the concentration of various heavy metals (Cd, Pb, Zn, Cu, Hg) in the blood of sheep, followed by biochemical and hematological analysis in order to reveal possible associations. Blood was collected in two different seasons: winter (fed by fodder) and spring (grazing animals). The higher concentrations of Pb (p < 0.01), Cu (p < 0.05) and Hg, but lower of Cd and Zn were found in spring. Evaluation of the biochemical and hematological parameters during different seasons showed a possible environmental effect on the health of animals. A statistically significant increase of Ca (p < 0.001), Mg (p < 0.05), urea (p < 0.001), TP (p < 0.05), glucose (p < 0.01), AST (p < 0.001), ALT (p < 0.001), ALP (p < 0.01), cholesterol (p < 0.001), bilirubin (p < 0.05), triglycerides (p < 0.001) and a decrease of P (p < 0.05), HGB (p < 0.05), MCHC (p < 0.05) and RDWc (p < 0.05) in spring was detected. The results of this study showed statistically significant correlations between Pb and ALP (r = 0.53) level in winter and between Pb and Ca (r = -0.73) in the spring. The hematological analysis revealed a significant correlation between Zn and RBC (r = 0.61), MCV (r = -0.74), MCH (r = -0.71) and between Pb and MCH (r = -0.55), PCT (r = -0.66), PDWC (r = -0.55) in the winter. A high positive significant correlations were found between Cd and RDWC (r = 0.77) and Cu and RDWC (r = 0.75). The significance of this work is the use the data in the preventive diagnosis of metabolic and production diseases. The collected data may serve as a control indicator to detect toxic hazards related to the heavy metal occurrence on animal health status.