Effects of Reactive Oxygen and Nitrogen Species on Male Fertility

Significance: In recent decades, male fertility has been severely reduced worldwide. The causes underlying this decline are multifactorial, and include, among others, genetic alterations, changes in the microbiome, and the impact of environmental pollutants. Such factors can dysregulate the physiological levels of reactive species of oxygen (ROS) and nitrogen (RNS) in the patient, generating oxidative and nitrosative stress that impairs fertility. Recent Advances: Recent studies have delved into other factors involved in the dysregulation of ROS and RNS levels, such as diet, obesity, persistent infections, environmental pollutants, and gut microbiota, thus leading to new strategies to solve male fertility problems, such as consuming prebiotics to regulate gut flora or treating psychological conditions. Critical Issues: The pathways where ROS or RNS may be involved as modulators are still under investigation. Moreover, the extent to which treatments can rescue male infertility as well as whether they may have side effects remains, in most cases, to be elucidated. For example, it is known that prescription of antioxidants to treat nitrosative stress can alter sperm chromatin condensation, which makes DNA more exposed to ROS and RNS, and may thus affect fertilization and early embryo development. Future Directions: The involvement of extracellular vesicles, which might play a crucial role in cell communication during spermatogenesis and epididymal maturation, and the relevance of other factors such as sperm epigenetic signatures should be envisaged in the future.

Melatonin/Sericin Wound Healing Patches: Implications for Melanoma Therapy

Melatonin and sericin exhibit antioxidant properties and may be useful in topical wound healing patches by maintaining redox balance, cell integrity, and regulating the inflammatory response. In human skin, melatonin suppresses damage caused by ultraviolet radiation (UVR) which involves numerous mechanisms associated with reactive oxygen species/reactive nitrogen species (ROS/RNS) generation and enhancing apoptosis. Sericin is a protein mainly composed of glycine, serine, aspartic acid, and threonine amino acids removed from the silkworm cocoon (particularly Bombyx mori and other species). It is of interest because of its biodegradability, anti-oxidative, and anti-bacterial properties. Sericin inhibits tyrosinase activity and promotes cell proliferation that can be supportive and useful in melanoma treatment. In recent years, wound healing patches containing sericin and melatonin individually have attracted significant attention by the scientific community. In this review, we summarize the state of innovation of such patches during 2021-2023. To date, melatonin/sericin-polymer patches for application in post-operational wound healing treatment has been only sparingly investigated and it is an imperative to consider these materials as a promising approach targeting for skin tissue engineering or regenerative dermatology.

Melatonin Protects Bovine Spermatozoa by Reinforcing Their Antioxidant Defenses

Cryopreserved semen is widely used in assisted reproductive techniques. Post-thawing spermatozoa endure oxidative stress due to the high levels of reactive oxygen and nitrogen species, which are produced during the freezing/thawing process, and the depletion of antioxidants. To counteract this depletion, supplementation of sperm preparation medium with antioxidants has been widely applied. Melatonin is a hormone with diverse biological roles and a potent antioxidant, with an ameliorative effect on spermatozoa. In the present study, we assessed the effect of melatonin on thawed bovine spermatozoa during their handling. Cryopreserved bovine spermatozoa were thawed and incubated for 60 min in the presence or absence of 100 μΜ melatonin. Also, the effect of melatonin was assessed on spermatozoa further challenged by the addition of 100 μΜ hydrogen peroxide. Spermatozoa were evaluated in terms of kinematic parameters (CASA), viability (trypan blue staining) and antioxidant capacity (glutathione and NBT assay, determination of iNOS levels by Western blot analysis). In the presence of melatonin, spermatozoa presented better kinematic parameters, as the percentage of motile and rapid spermatozoa was higher in the melatonin group. They also presented higher viability and antioxidant status, as determined by the increased cellular glutathione levels and the decreased iNOS protein levels.

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.

Melatonin Supplementation for the Cryopreservation of Canine Sperm

Antioxidants can be used in sperm cryopreservation protocols to reduce oxidative stress that occurs due to the cryopreservation process. The aim of this study was to evaluate the effects of melatonin supplementation on quality and oxidative stress parameters in cryopreserved canine sperm. Eighteen sperm ejaculates were collected from 6 Frenchie Bulldog males (3 collections per male). Sperm motility parameters, membrane integrity, and sperm morphology were analyzed before the cryopreservation process. The extender used in cryopreservation was composed of Tris-egg yolk and ethylene glycol 5% was added as a cryoprotectant. The cryoprotective medium was supplemented with 1.0, 1.5, 2.0, 2.5, and 3.0 mM melatonin, and the control group (without melatonin). Post-thaw sperm was evaluated as described for fresh sperm and oxidative stress parameters (lipid peroxidation, catalase, and superoxide dismutase). Post-thaw sperm motility parameters, membrane integrity, sperm morphology, and oxidative stress parameters did not differ (p > 0.05) among the control group and samples supplemented with melatonin. The results of this study showed that melatonin supplementation had no positive or negative effect on the parameters evaluated. Thus, it is suggested that different concentrations of melatonin be tested to assess its effectiveness as an antioxidant in the cryopreservation process in canine sperm.

Therapeutic effects of melatonin in long-term exposure to 2100MHz radiofrequency radiation on rat sperm characteristics

INTRODUCTION

Radiofrequency electromagnetic fields (RF-EMFs) are one of the risk factors for male reproductive health and melatonin can be an ideal candidate for therapeutic development against RF-induced male fertility problems due to its antioxidant properties. The possible therapeutic role of melatonin in the destructive effects of 2100MHz RF radiation on rat sperm characteristics is investigated in the present study.

METHODS

Wistar albino rats were divided into four groups and the experiment continued for ninety consecutive days; Control, Melatonin (10mg/kg, subcutaneously), RF (2100MHz, thirty minutes per day, whole-body), and RF+Melatonin groups. Left caudal epididymis and ductus deferens tissues were placed in sperm wash solution (at 37°C) and dissected. The sperms were counted and stained. Measurements of the perinuclear ring of the manchette and posterior portion of the nucleus (ARC) were performed and the sperms were examined at an ultrastructural level. All of the parameters were evaluated statistically.

RESULTS

The percentages of abnormal sperm morphology were significantly increased with RF exposure, while the total sperm count was significantly decreased. RF exposure also showed harmful effects on acrosome, axoneme, mitochondrial sheath, and outer dense fibers at the ultrastructural level. The number of total sperms, sperms with normal morphology increased, and ultrastructural appearance returned to normal by melatonin administration.

DISCUSSION

The data showed that melatonin may be a beneficial therapeutic agent for long-term exposure of 2100MHz RF radiation-related reproductive impairments.

Role of Melatonin in Bovine Reproductive Biotechnology

Melatonin has profound antioxidant activity and numerous functions in humans as well as in livestock and poultry. Additionally, melatonin plays an important role in regulating the biological rhythms of animals. Combining melatonin with scientific breeding management has considerable potential for optimizing animal physiological functions, but this idea still faces significant challenges. In this review, we summarized the beneficial effects of melatonin supplementation on physiology and reproductive processes in cattle, including granulosa cells, oocytes, circadian rhythm, stress, inflammation, testicular function, spermatogenesis, and semen cryopreservation. There is much emerging evidence that melatonin can profoundly affect cattle. In the future, we hope that melatonin can not only be applied to cattle, but can also be used to safely and effectively improve the efficiency of animal husbandry.

Effects of Melatonin and Silymarin on Reactive Oxygen Species, Nitric Oxide Production, and Sperm Viability and Motility during Sperm Freezing in Pigs

Sperm during the freezing and thawing process is damaged by oxidative stress. Thus, its antioxidant scavenger is essential for sperm survival and death in frozen-thawed semen. We used melatonin and silymarin in experiments after the dose-dependent experiment. Our study aimed to identify the effect of melatonin and silymarin on the motility and viability of sperm, reactive oxygen species (ROS), and nitric oxide (NO) production in frozen-thawed boar semen. Melatonin and silymarin were treated alone and cotreated in the fresh boar semen. Boar semen was collected using the gloved-hand method from ten crossbred pigs, and samples were used in the experiments. We evaluated sperm viability using SYBR-14 and PI kit, and ROS and NO production were detected by DCF-DA and DAF-2, respectively. The sperm motility was not significantly different between non-treatment and treatment. ROS and NO production in frozen-thawed sperm were decreased by melatonin and silymarin. Moreover, silymarin significantly reduced NO production more than melatonin. Melatonin and silymarin enhanced the viability of sperm. We suggest that melatonin and silymarin are essential antioxidants in semen cryopreservation for protecting sperm damage and maintaining sperm viability. Melatonin and silymarin may be useful antioxidants in freezing boar sperm.

Human Sperm as an In Vitro Model to Assess the Efficacy of Antioxidant Supplements during Sperm Handling: A Narrative Review

Spermatozoa are highly differentiated cells that produce reactive oxygen species (ROS) due to aerobic metabolism. Below a certain threshold, ROS are important in signal transduction pathways and cellular physiological processes, whereas ROS overproduction damages spermatozoa. Sperm manipulation and preparation protocols during assisted reproductive procedures-for example, cryopreservation-can result in excessive ROS production, exposing these cells to oxidative damage. Thus, antioxidants are a relevant topic in sperm quality. This narrative review focuses on human spermatozoa as an in vitro model to study which antioxidants can be used to supplement media. The review comprises a brief presentation of the human sperm structure, a general overview of the main items of reduction-oxidation homeostasis and the ambivalent relationship between spermatozoa and ROS. The main body of the paper deals with studies in which human sperm have been used as an in vitro model to test antioxidant compounds, including natural extracts. The presence and the synergic effects of different antioxidant molecules could potentially lead to more effective products in vitro and, in the future, in vivo.

Antioxidant additive melatonin in tris-based egg yolk extender improves post-thaw sperm attributes in Hariana bull

In the study, melatonin, a known antioxidant pineal peptide was used as an additive in the tris-egg yolk glycerol-based semen extender in Hariana bull semen and post-thaw sperm characters were evaluated. In the study, Group I was a control without melatonin; and Group II, III, and IV were having 0.5 mM, 1 mM, and 2 mM melatonin/80 × 10⁶ spermatozoa, respectively were treatment groups. Thirty-two semen ejaculates from 4 Hariana bulls were processed for freezing and post-thaw sperm characteristics were evaluated. Sperm motility, velocity, the viability with intact membrane, and total antioxidant capacity were markedly (P < 0.05) improved in Group IV compared to all other groups. The lipid peroxidation and total protein carbonylation were substantially (P < 0.05) decreased in Group IV compared to all other groups. The population of cryocapacitated, acrosome-reacted, and apoptotic-like spermatozoa were significantly (P < 0.05) decreased in Group IV. Further, the relative band intensity of 74 kDa protein and percent of spermatozoa showing positive immune reactivity to tyrosine-phosphorylated proteins was decreased in Group IV. The progesterone-receptor ligand binding, in vitro capacitation response, and Vanguard distance were markedly (P < 0.05) improved in Group IV. In summary- Group IV having 2 mM melatonin was found to be optimal in providing cryoprotective effects to Hariana bull spermatozoa after freezing-thawing and can be suitably used as a semen additive during semen cryopreservation.

Influence of trans-ferulic acid on the quality of ram semen upon cold preservation

BACKGROUND

Due to lower antioxidant capacity and higher amounts of polyunsaturated fatty acids, ram spermatozoa are very susceptible during cooling process.

OBJECTIVES

The objective was to examine the effect of the trans-ferulic acid (t-FA) on the ram semen during liquid preservation.

METHODS

Semen samples were collected from the Qezel rams, pooled, and extended with the Tris-based diluent. Pooled samples enriched with different amounts of the t-FA (0, 2.5, 5, 10, and 25 mM) and preserved at 4°C for 72 h. Spermatozoa's kinematics, membrane functionality, and viability were assessed by CASA system, hypoosmotic swelling test, and eosin-nigrosin staining, respectively. Moreover, biochemical parameters were measured at 0, 24, 48, and 72 h.

RESULTS

Results showed that 5 and 10 mM t-FA improved forward progressive motility (FPM) and curvilinear velocity compared to the other groups at 72 h (p < 0.05). Samples treated with 25 mM t-FA showed the lowest total motility, FPM, and viability at 24, 48, and 72 h of storage (p < 0.05). Higher total antioxidant activity levels were observed in the 10 mM t-FA-treated group compared to the negative control at 72 h (p < 0.05). Treatment with 25 mM t-FA increased malondialdehyde amounts and decreased superoxide dismutase activity compared to other groups at the final time assessment (p < 0.05). Nitrate-nitrite and lipid hydroperoxides values were not affected by treatment.

CONCLUSIONS

The current study indicates the positive and negative influences of different concentrations of t-FA on the ram semen upon cold storage.

Improvement of the Seminal Characteristics in Rams Using Agri-Food By-Products Rich in Phytomelatonin

The aim of this study was to evaluate the effect of a phytomelatonin-rich diet, including by-products from the food industry, on ram sperm quality and seminal plasma composition. Melatonin content in several by-products before and after in vitro ruminal and abomasal digestion was determined by HPLC-ESI-MS/MS. Finally, 20% of a mix of grape pulp with pomegranate and tomato pomaces was included in the rams' diet, constituting the phytomelatonin-rich diet. Feeding the rams with this diet resulted in an increase in seminal plasma melatonin levels compared with the control group (commercial diet) in the third month of the study. In addition, percentages higher than those in the control group of morphologically normal viable spermatozoa with a low content of reactive oxygen species were observed from the second month onwards. However, the antioxidant effect does not seem to be exerted through the modulation of the antioxidant enzymes since the analysis of the activities of catalase, glutathione reductase and glutathione peroxidase in seminal plasma revealed no significant differences between the two experimental groups. In conclusion, this study reveals, for the first time, that a phytomelatonin-rich diet can improve seminal characteristics in rams.

Effect of melatonin and nitric oxide on capacitation and apoptotic changes induced by epidermal growth factor in ram sperm

CONTEXT

Apart from the canonical cAMP-PKA pathway, ram sperm capacitation can be achieved by the MAPK ERK1/2 signalling cascade, activated by epidermal growth factor (EGF).

AIMS

This study aims to investigate the effect of melatonin and nitric oxide (NO·) on capacitation and apoptotic-like changes in EGF-capacitated ram spermatozoa.

METHODS

In vitro capacitation was induced by EGF in the absence or presence of melatonin (100pM or 1μM). Also, a NO· precursor, L-arginine, or a NOS inhibitor, NG-nitro-L-arginine methyl ester (L-NAME), were added to capacitation media to study the interaction of NO· and melatonin during EGF-capacitation. Sperm functionality parameters (motility, viability, capacitation state), apoptotic markers (caspase activation and DNA damage), NO· levels, and phosphorylated c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (assessed by Western blot), were evaluated in swim-up and capacitated samples with EGF.

KEY RESULTS

NO· levels and the apoptotic-related markers were raised after EGF incubation. Melatonin had a bimodal role on sperm EGF-capacitation, preventing it at high concentration and promoting acrosome reaction at low concentration, but neither of the two concentrations prevented the increase in apoptotic-like markers or NO· levels. However, melatonin at 1μM prevented the activation of JNK.

CONCLUSIONS

NO· metabolism does not seem to modulate the apoptosis-like events in ram spermatozoa. Melatonin at 1μM prevents ram sperm capacitation induced by EGF independently from nitric oxide metabolism, and it could be exerted by limiting the JNK mitogen-activated protein kinase (MAPK) activation.

IMPLICATIONS

This study improvesour understanding of the biochemical mechanisms involved in sperm capacitation, and ultimately, fertility.

Effects of Melatonin Supplementation on the Aortic Wall in a Diet-Induced Obesity Rat Model

Background Cardiovascular disease (CVD) is still the leading cause of death globally. Alterations in the arterial wall architecture predict CVD morbidity and mortality and are associated with other CVD risk factors. Aortic wall thickness is closely linked to short- and long-term CVD morbidity and mortality, even without pronounced atherosclerotic changes. Obesity increases the risk of a broad spectrum of pathologies with vascular manifestation, which are often pathogenically associated with chronic oxidative stress and inflammatory response. Hence, as an antioxidant and anti-inflammatory agent, the pineal gland hormone melatonin is expected to have vasoprotective effects. This study evaluated the effects of melatonin supplementation on aortic wall thickness by assessing the cross-sectional associations of abdominal obesity with aortic intima-media thickness in a diet-induced obesity rat model. Methodology The model comprised of male Wistar rats that were on a high-fructose diet (HFD) (20% glucose-fructose corn syrup) for 12 weeks; the rats were divided into four groups (n = 8): control, HFD, HFD and melatonin supplementation (per os - 4 mg/kg/24h), and control and melatonin supplementation. All rats received a standard rodent diet and tap water. Zoometric measurements and the Lee index were calculated. Morphometric analysis of the abdominal aorta was performed by staining with hematoxylin-eosin and measuring the thickness of the abdominal aortic wall. For this, we used the Aperio Image Scope software. To evaluate the functional properties of the abdominal aorta, the modified Kernogan's index (KI) was employed. Results The results showed significantly elevated body weight (Lee index), KI, and wall thickness of the aorta abdominalis with morphometric changes in the vessel wall in HFD rats compared to the control group. Melatonin supplementation prevented these changes. Conclusions The administration of HFD to Wistar rats led to pathomorphological and morphometric changes in their abdominal aorta, which constitute the main diagnostic criteria of endothelial dysfunction. Melatonin supplementation regressed vascular wall remodeling and restored its functional capacity.

Coping with Oxidative Stress in Reproductive Pathophysiology and Assisted Reproduction: Melatonin as an Emerging Therapeutical Tool

Infertility is an increasing global public health concern with socio-psychological implications for affected couples. Remarkable advances in reproductive medicine have led to successful treatments such as assisted reproductive techniques (ART). However, the search for new therapeutic tools to improve ART success rates has become a research hotspot. In the last few years, pineal indolamine melatonin has been investigated for its powerful antioxidant properties and its role in reproductive physiology. It is considered a promising therapeutical agent to counteract the detrimental effects associated with oxidative stress in fertility treatments. The aim of the present narrative review was to summarize the current state of the art on the importance of melatonin in reproductive physiology and to provide a critical evaluation of the data available encompassing basic, translational and clinical studies on its potential use in ART to improve fertility success rates.

CircRNA Samd4 induces cardiac repair after myocardial infarction by blocking mitochondria-derived ROS output

Reactive oxygen species (ROS) derived from oxygen-dependent mitochondrial metabolism are the essential drivers of cardiomyocyte (CM) cell-cycle arrest in adulthood. Mitochondria-localized circular RNAs (circRNAs) play important roles in regulating mitochondria-derived ROS production, but their functions in cardiac regeneration are still unknown. Herein, we investigated the functions and underlying mechanism of mitochondria-localized circSamd4 in cardiac regeneration. We found that circSamd4 was selectively expressed in fetal and neonatal CMs. The transcription factor Nrf2 controlled circSamd4 expression by binding to the promoter of circSamd4 host gene. CircSamd4 overexpression reduced while circSamd4 silenced increased mitochondrial oxidative stress and subsequent oxidative DNA damage. Moreover, circSamd4 overexpression induced CM proliferation and prevented CM apoptosis, which reduced the size of the fibrotic area and improved cardiac function after myocardial infarction (MI). Mechanistically, circSamd4 reduced oxidative stress generation and maintained mitochondrial dynamics by inducing the mitochondrial translocation of the Vcp protein, which downregulated Vdac1 expression and prevented the mitochondrial permeability transition pore (mPTP) from opening. Our findings suggest that circSamd4 is a novel therapeutic target for heart failure after MI.

The Interplay of Oxidative Stress and ROS Scavenging: Antioxidants as a Therapeutic Potential in Sepsis

Oxidative stress resulting from the disproportion of oxidants and antioxidants contributes to both physiological and pathological conditions in sepsis. To combat this, the antioxidant defense system comes into the picture, which contributes to limiting the amount of reactive oxygen species (ROS) leading to the reduction of oxidative stress. However, a strong relationship has been found between scavengers of ROS and antioxidants in preclinical in vitro and in vivo models. ROS is widely believed to cause human pathology most specifically in sepsis, where a small increase in ROS levels activates signaling pathways to initiate biological processes. An inclusive understanding of the effects of ROS scavenging in cellular antioxidant signaling is essentially lacking in sepsis. This review compiles the mechanisms of ROS scavenging as well as oxidative damage in sepsis, as well as antioxidants as a potent therapeutic. Direct interaction between ROS and cellular pathways greatly affects sepsis, but such interaction does not provide the explanation behind diverse biological outcomes. Animal models of sepsis and a number of clinical trials with septic patients exploring the efficiency of antioxidants in sepsis are reviewed. In line with this, both enzymatic and non-enzymatic antioxidants were effective, and results from recent studies are promising. The usage of these potent antioxidants in sepsis patients would greatly impact the field of medicine.

Melatonin pretreatment on exosomes: Heterogeneity, therapeutic effects, and usage

The therapeutic outcomes of exosome-based therapies have greatly exceeded initial expectations in many clinically intractable diseases due to the safety, low toxicity, and immunogenicity of exosomes, but the production of the exosomes is a bottleneck for wide use. To increase the yield of the exosomes, various solutions have been tried, such as hypoxia, extracellular acidic pH, etc. With a limited number of cells or exosomes, an alternative approach has been developed to improve the efficacy of exosomes through cell pretreatment recently. Melatonin is synthesized from tryptophan and secreted in the pineal gland, presenting a protective effect in pathological conditions. As a new pretreatment method, melatonin can effectively enhance the antioxidant, anti-inflammatory, and anti-apoptotic function of exosomes in chronic kidney disease, diabetic wound healing, and ischemia-reperfusion treatments. However, the current use of melatonin pretreatment varies widely. Here, we discuss the effects of melatonin pretreatment on the heterogeneity of exosomes based on the role of melatonin and further speculate on the possible mechanisms. Finally, the therapeutic use of exosomes and the usage of melatonin pretreatment are described.

A microplate-based DCFH-DA assay for the evaluation of oxidative stress in whole semen

Aims

The well-documented relationship between sperm oxidation and male infertility strongly encourages the development of assays for reactive oxygen species detection in semen samples. The present study aims to apply the microplate-based 2’,7’-dichlorofluorescein diacetate assay to the evaluation of oxidative stress in unprocessed whole semen, thus avoiding sample centrifugations and other manipulations that may cause significant reactive oxygen species increments.

Main methods

The fluorescence assay consisted in the quantification of both intracellular and extracellular reactive oxygen species levels in unwashed semen specimens by using the probe 2’,7’-dichlorofluorescein diacetate into a 96-well plate. The method was useful for the preliminary assessment of the oxidation levels of whole semen samples from men undergoing standard sperm analysis as well as to evaluate the effect of some pro-glutathione molecules on semen oxidative status.

Key findings

The 2’,7’-dichlorofluorescein diacetate assay was successfully adapted to the evaluation of oxidative stress in whole semen, effectively revealing the perturbation of the redox homeostasis of the sample. Accordingly, specimens with abnormal sperm parameters (n = 10) presented oxidation indexes significantly higher than those with normospermia (n = 10) [7729 (range 3407–12769) vs. 1356 (range 470–2711), p < 0.001]; in addition, semen oxidation indexes negatively correlated to sperm motility and morphology. Noteworthy, whole semen exposure to pro-glutathione compounds led to reduced semen oxidation levels and sperm protection against oxidative damage.

Significance

Based on our pilot experimental data, the microplate-based 2’,7’-dichlorofluorescein diacetate assay appears to be a convenient method for the detection of reactive oxygen species levels in whole semen samples, avoiding artifacts due to semen centrifugation steps. At the same time, the test could be a helpful tool for the basic and quick screening of antioxidant molecules able to preserve semen quality.

Shielding effect of melatonin improves seminal quality and oxidative stress indices during chilled storage of ram semen

Supplementation of antioxidant to semen extender maintains seminal quality by reducing oxidative stress during preservation time period. The main aim of this study was to investigate the effect of different concentrations of melatonin supplementation on liquid storage of Magra ram semen. This study was performed on adult Magra ram (n = 8), and seminal ejaculates (48) were collected and evaluated for various macroscopic and microscopic seminal quality parameters for further processing. After preliminary evaluation, ejaculates of each collection session were mixed and divided into four equal aliquots. All the aliquots were diluted (1:10) with Tris-citric fructose egg yolk extender contained sans melatonin served as control, whereas the other three aliquots were supplemented with 0.5, 1 and 2 mM MLT which were grouped as MLT0.5, MLT1 and MLT2, respectively. Thereafter, the samples were stored at 4 ºC for 72 h, and various seminal parameters (individual sperm progressive motility, viability, abnormalities, plasma membrane functionality) along with oxidative stress parameters (total antioxidant capacity (TAC), malondialdehyde (MDA)) were evaluated at 0, 24, 48 and 72 h of preservation. The results indicated that the mean percent values for progressive sperm motility, viability, plasma membrane functionality and TAC were significantly higher (p < 0.05) in treated groups with the highest values in MLT1 group. Significantly lower (p < 0.05) percentage of total sperm abnormalities and MDA level was observed in treatment groups compared to control group. The results report that supplementation of 1 mM melatonin efficiently maintains the seminal quality and ameliorates oxidative stress during preservation at 4 ºC to 72 h.

New Insight on the In Vitro Effects of Melatonin in Preserving Human Sperm Quality

Spermatozoa (SPZ) are sensitive to stressful conditions, particularly oxidative stress, which alters their quality; thus, the use of protective molecules as an antioxidant is encouraged. Herein, we used melatonin (MLT) to investigate its in vitro effects on human sperm parameters under conditions of oxidative stress induced by cadmium (Cd). Fifteen human semen samples were divided into control, Cd-treated, MLT-treated, and Cd+MLT-treated groups and analyzed after 30 min, 6 h, and 24 h of exposure. Results showed a time-dependent decrease in SPZ motility, DNA integrity, and increased apoptosis induced by oxidative stress, and these effects were counteracted by MLT co-treatment. Based on these data, we further explored additional parameters just at 24 h. The induced oxidative stress, highlighted by the increased lipid peroxidation, reduced the percentage of SPZ able to undertake acrosome reaction and altered the levels and localization of some protein markers of motility (PREP, RSPH6A), morphology (DAAM1), and acrosome membrane (PTMA, IAM38); all these effects were counteracted by MLT co-treatment. Interestingly, MLT alone was able to ameliorate motility at 30 min of incubation compared to the control, while at 24 h, it prevented the physiological alteration in terms of motility, DNA integrity, and apoptosis. Collectively, the data encourage MLT use as an integrative molecule to ameliorate human gamete quality when compromised by stressful conditions.

Melatonin epigenetic potential on testicular functions and fertility profile in varicocele rat model is mediated by Silent information regulator1

BACKGROUND AND PURPOSE

Varicocele is a leading cause of male infertility. Melatonin is a highly pleiotropic neurohormone. We aimed to characterize the melatonin epigenetic potential in varicocele and the involved molecular mechanisms.

EXPERIMENTAL APPROACH

Fifty-two male albino rats were randomly divided into four groups (13 rats each): control (I), melatonin (II), varicocele (III) and melatonin treated varicocele (IV) groups. Left varicocele was induced by partial left renal vein ligation. Reproductive hormones, epididymal sperm functional parameters, testicular 3/17 β-hydroxysteroid dehydrogenases, antioxidant enzymes, malondialdehyde, nicotinamide adenine dinucleotide phosphate oxidase, 8-hydroxy-2'-deoxyguanosine and histopathological/Johnsen's score were evaluated. Flow cytometry and Comet were carried out to explore extent of sperm and testicular DNA damage. Testicular expression of silent information regulator 1 (SIRT1), forkhead transcription factors-class O (type1) (FOXO1), tumour suppressor gene, P53, cation channels of sperm (CatSper) and steroidogenic acute regulatory protein was evaluated by western blot technique. Testicular expression of Bcl-2 and its associated X protein and nuclear factor kappa-light-chain-enhancer of activated B cells were assayed by immunohistochemical staining. Testicular miR-34a expression was quantified by quantitative reverse transcription-polymerase chain reaction.

KEY RESULTS

The varicocele induced testicular histological injury, enhanced oxidative stress, P53-mediated apoptosis, DNA damage and increased testicular miR-34a expression paralleled with down-regulated SIRT1/FOXO axis. Melatonin treatment of varicocele rats displayed antioxidant/anti-apoptotic efficacy and improved reproductive hormones axis, CatSper expression and fertility parameters. MiR-34a/SIRT1/FOXO1 epigenetic axis integrates testicular melatonin mediated intracellular transduction cascades in varicocele.

CONCLUSION AND IMPLICATIONS

Melatonin can be used as an adjuvant therapy to improve varicocele and its complication.

Factors Affecting the Survival of Ram Spermatozoa during Liquid Storage and Options for Improvement

Semen preservation is an essential component of reproductive technologies, as it promotes genetic gain and long-distance semen transport and multiplies the number of ewes able to be inseminated per single ejaculate. However, the reduced temperature during cold storage at 5 or 15 °C inflicts sub-lethal damage to spermatozoa, compromising sperm quality and the success of artificial breeding. New and emerging research in various species has reported the advantages of storing spermatozoa at higher temperatures, such as 23 °C; however, this topic has not been thoroughly investigated for ram spermatozoa. Despite the success of storing spermatozoa at 23 °C, sperm quality can be compromised by the damaging effects of lipid peroxidation, more commonly when metabolism is left unaltered during 23 °C storage. Additionally, given the biosafety concern surrounding the international transport of egg-yolk-containing extenders, further investigation is critical to assess the preservation ability of synthetic extenders and whether pro-survival factors could be supplemented to maximise sperm survival during storage at 23 °C.

A systematic review on the role of melatonin and its mechanisms on diabetes-related reproductive impairment in non-clinical studies

BACKGROUND

Diabetes-induced reproductive complications can lead to subfertility and infertility, raising the need to protect reproductive organs. There are limited medications used to improve reproductive health in diabetic patients. Melatonin, mainly produced by the pineal gland, may improve diabetes-associated reproductive complications through various mechanisms and may be a preferred candidate to protect the reproductive system. The present review aims to elucidate the underlying mechanisms of melatonin's effect on the reproductive system adversely affected by diabetes mellitus (DM).

METHODS

A comprehensive systematic literature electronic search was done using the PRISMA guidelines. Web of Science, PubMed, Embase, and Scopus were searched for publications up to June 2022. Search terms were selected based on the study purpose and were explored in titles and abstracts. After screening, out of a total of 169 articles, 14 pertinent articles were included based on our inclusion and exclusion criteria.

RESULTS

The results of studies using rats and mice suggest that DM adversely affects reproductive tissues, including testes and epididymis, prostate, corpus cavernosum, and ovary leading to alterations in histological and biochemical parameters compared to the normal groups. Treatment with melatonin improves oxidative stress, blocks apoptosis induced by endoplasmic reticulum stress and caspase activation, reduces pro-inflammation cytokines, and enhances steroidogenesis.

CONCLUSION

Melatonin exerted a protective action on the impaired reproductive system in in-vivo and in-vitro models of DM. The topic has to be followed up in human pregnancy cases that will need more time to be collected and approved.

Lycopene protects sperm from oxidative stress in the experimental varicocele model

Oxidative stress (OS) is an important parameter in the evaluation of infertility caused by varicocele. Antioxidants are the most commonly prescribed drugs in these patients. Lycopene molecule, as the powerful antioxidant in the carotenoid family, has beneficial effects on improving fertility in males. Therefore, we investigated the effects of lycopene on induced OS by varicocele in an animal model. Forty-five adult male Wistar rats were divided into two groups: control (n = 12) and varicocele (n = 33). Two months after induced varicocele, five rats in each group were sacrificed randomly and induced varicocele was investigated. Remained rats were divided into five groups (n = 7), including the control (I), varicocele (II), varicocele reserving solvent (III), varicocele reserving lycopene 4 mg/kg (IV), and 10 mg/kg (V) for two months. At the end of the experiment, intracellular reactive oxygen species (ROS), malondialdehyde (MDA), total antioxidant capacity (TAC), %DNA damage, and antioxidant enzymatic levels were measured. The results indicated that there were significant increases in the levels of ROS, MDA, DNA damage, superoxide dismutase (SOD), sperm concentration, and motility in the varicocele groups compared with the control group. In the lycopene group (10 mg/kg), sperm concentration, the levels of TAC, and catalase (CAT) activity were improved so the levels of ROS, MDA, and %DNA damage were reduced compared with varicocele group. Our findings indicated that the administration of lycopene especially at a dose of 10 mg/kg in the varicocele group could protect sperm from OS and sperm DNA damage by increasing antioxidant activity and reducing ROS.

Pharmacological and philosophical considerations for the around-the-clock use of scheduled melatonin to promote sedation and reduce aggression in individuals with serious mental illness: a case report

Melatonin, the endogenous hormone that helps maintain circadian rhythm, has been used exogenously for both primary and secondary sleep disorders. While the effects of melatonin given prior to planned sleep and to restore normal circadian sleep phases have been well studied, there is little information on the use of melatonin as a pharmacotherapeutic intervention for around-the-clock sedation to prevent agitation and aggressive patient behaviors. This is the first case report to our knowledge of melatonin used throughout the day, as a scheduled dose for prolonged treatment duration, to reduce aggression in a patient with severe mental illness.

The initial maturation status of marmoset testicular tissues has an impact on germ cell maintenance and somatic cell response in tissue fragment culture

Successful in vitro spermatogenesis was reported using immature mouse testicular tissues in a fragment culture approach, raising hopes that this method could also be applied for fertility preservation in humans. Although maintaining immature human testicular tissue fragments in culture is feasible for an extended period, it remains unknown whether germ cell survival and the somatic cell response depend on the differentiation status of tissue. Employing the marmoset monkey (Callithrix jacchus), we aimed to assess whether the maturation status of prepubertal and peri-/pubertal testicular tissues influence the outcome of testis fragment culture. Testicular tissue fragments from 4- and 8-month-old (n = 3, each) marmosets were cultured and evaluated after 0, 7, 14, 28 and 42 days. Immunohistochemistry was performed for identification and quantification of germ cells (melanoma-associated antigen 4) and Sertoli cell maturation status (anti-Müllerian hormone: AMH). During testis fragment culture, spermatogonial numbers were significantly reduced (P < 0.05) in the 4- but not 8-month-old monkeys, at Day 0 versus Day 42 of culture. Moreover, while Sertoli cells from 4-month-old monkeys maintained an immature phenotype (i.e. AMH expression) during culture, AMH expression was regained in two of the 8-month-old monkeys. Interestingly, progression of differentiation to later meiotic stage was solely observed in one 8-month-old marmoset, which was at an intermediate state regarding germ cell content, with gonocytes as well as spermatocytes present, as well as Sertoli cell maturation status. Although species-specific differences might influence the outcome of testis fragment experiments in vitro, our study demonstrated that the developmental status of the testicular tissues needs to be considered as it seems to be decisive for germ cell maintenance, somatic cell response and possibly the differentiation potential.

Fluorescent probes for the detection of reactive oxygen species in human spermatozoa

Reactive oxygen species (ROS) production is a by-product of mitochondrial activity and is necessary for the acquisition of the capacitated state, a requirement for functional spermatozoa. However, an increase in oxidative stress, due to an abnormal production of ROS, has been shown to be related to loss of sperm function, highlighting the importance of an accurate detection of sperm ROS, given the specific nature of this cell. In this work, we tested a variety of commercially available fluorescent probes to detect ROS and reactive nitrogen species (RNS) in human sperm, to define their specificity. Using both flow cytometry (FC) and fluorescence microscopy (FM), we confirmed that MitoSOX™ Red and dihydroethidium (DHE) detect superoxide anion (as determined using antimycin A as a positive control), while DAF-2A detects reactive nitrogen species (namely, nitric oxide). For the first time, we also report that RedoxSensor™ Red CC-1, CellROX^® Orange Reagent, and MitoPY1 seem to be mostly sensitive to hydrogen peroxide, but not superoxide. Furthermore, mean fluorescence intensity (and not percentage of labeled cells) is the main parameter that can be reproducibly monitored using this type of methodology.

NADPH Oxidase 5 and Melatonin: Involvement in Ram Sperm Capacitation

Reactive oxygen species (ROS) play an essential role in mammalian sperm capacitation. NADPH oxidase 5 (NOX5) has been described as the main source of ROS production in some mammalian spermatozoa, such as human and equine. On the other hand, melatonin can decrease cellular ROS levels and regulates NOX activity in somatic cells. Therefore, the objectives of this work were (1) to identify NOX5 in ram spermatozoa and analyze its possible changes during in vitro capacitation and (2) to investigate the effect of melatonin on NOX5 expression and localization and on superoxide levels in capacitated ram spermatozoa. Protein bands associated with NOX5 were detected by Western blot analysis. Likewise, indirect immunofluorescence (IIF) revealed six different immunotypes for NOX5, which varied throughout in vitro capacitation. Superoxide (O₂^⋅–), evaluated by DHE/Yo-Pro-1, rose after in vitro capacitation and in the presence of the calcium ionophore A23187 but decreased in the presence of the NOX inhibitor GKT136901. GKT also reduced the percentage of capacitated and acrosome-reacted spermatozoa that had increased during incubation in capacitating conditions. The presence of melatonin at micromolar concentrations avoided the increment in O₂^⋅– and the changes in NOX5 immunotypes provoked by capacitation. In conclusion, NOX5 is present in ram spermatozoa and the changes in its distribution, associated with sperm capacitation, can be prevented by melatonin. To this extent, it could imply that melatonin exerts its antioxidant role, at least in part, by modulating NOX5 activity during ram sperm capacitation.

Melatonin Treatment in Rams and Their Replacement with Novel Treated Rams Advance First Lambing and Increase Fertility in Sarda Ewe Lambs

Simple Summary

The goals of this study were to advance first mating in ewe lambs and to shorten the period ranging from weaning to first lambing. Sarda ewe lambs (n = 400) were separated into four groups of 100 and exposed for a 50-day breeding period to fertile, adult rams as follows: (1) RMR (Rams–Melatonin–Replacement) group: exposed to melatonin-treated rams which were replaced every 10 days; (2) RM (Rams–Melatonin) group: exposed to melatonin-treated rams which were not replaced; (3) RCR (Rams–Controls–Replacement) group: exposed to untreated rams which were replaced every 10 days; and (4) RC (Rams–Controls) group: exposed to untreated rams which were not replaced. In each group, lambing dates, fertility rate, litter size, and distance in days from ram introduction to lambing (DRIL) were recorded. The RMR group showed the highest fertility rate, whilst shorter DRIL and higher number of ewes that lambed in a shorter time frame were recorded both in RM and RMR groups, compared to controls. The findings highlighted that melatonin treatment in rams and their replacement allowed advancing first mating, increasing fertility rate, and improving lambing concentration.

Abstract

This study aims to find reliable strategies for advancing first mating and shortening the period from weaning to first lambing in ewe lambs. Sarda ewe lambs (n = 400) were selected from two farms and allocated into four separated groups of 100, all of which were exposed to fertile, adult rams over the course of a 50-day breeding period. The first treatment group (RMR) was exposed to four melatonin-treated rams which were replaced every ten days, whilst the second treatment group (RM) was exposed to four melatonin-treated rams which were not replaced. Alternatively, the first control group (RCR) was exposed to four untreated rams which were replaced every ten days, whilst the second control group (RC) was exposed to four untreated rams which were not replaced. In each group, lambing dates, fertility rate, litter size, and distance in days from ram introduction to lambing (DRIL) were recorded. The highest fertility rate was recorded in the RMR group (p ≤ 0.05). Shorter DRIL (p ≤ 0.01) and higher lambing concentrations were recorded in the RM and RMR groups as compared to the controls. The findings indicate that melatonin treatment of rams and their replacement at 10-day intervals results in earlier onset of first mating, increased fertility rate in ewe lambs, and a higher number of ewes that lambs in a shorter time frame.

Melatonin protects rats testes against bleomycin, etoposide, and cisplatin-induced toxicity via mitigating nitro-oxidative stress and apoptosis

There is growing concern that some cytotoxic regimens for cancer adversely affect spermatogenesis and male fertility. Increasing evidence demonstrated that melatonin has beneficial impacts on reproductive processes; however, whether melatonin can protect against bleomycin, etoposide, and cisplatin (BEP) chemotherapy regimen-induced testicular toxicity, remains obscure. The present study aimed to explore the effect of melatonin on BEP-evoked testicular injury in rats. Adult male Wistar rats (n = 10/group) were intraperitoneally (i.p.) injected with one cycle of 21 days of 0.33 therapeutically relevant dose levels of BEP (.5 mg/kg bleomycin, 5 mg/kg etoposide, and 1 mg/kg cisplatin) with or without melatonin. At the end of the study, sperm parameters, testosterone level, stereology of testes, testicular levels of malondialdehyde (MDA), nitric oxide (NO), and total antioxidant capacity (TAC), the expression of apoptosis-associated genes such as Bcl2, Bax, Caspase-3, p53, and TNF-α (Real-time PCR and Immunohistochemistry) were evaluated. Our findings showed that melatonin restored spermatogenesis by improving sperm count, motility, viability, and morphology. Testosterone level, histopathology, and stereology of testes were significantly improved in melatonin-administrated groups. Furthermore, melatonin recovered the oxidative status of the testes through elevating TAC and ameliorating MDA and NO levels. More importantly, melatonin therapy suppressed BEP-evoked apoptosis by modulating Bcl-2, Bax, Caspase-3, p53, and TNF-α expression in testes. In conclusion, melatonin protects the testes against BEP-induced testicular damage by attenuating nitro-oxidative stress, apoptosis, and inflammation, which provides evidence for melatonin as a possible clinical therapy against BEP-associated gonadotoxicity and male sub/infertility.

Melatonin alleviates heat stress-induced oxidative stress and apoptosis in human spermatozoa

Oxidative stress generates a large amount of reactive oxygen species (ROS) and affects sperm quality via damaging sperm DNA and compromising the intracellular homeostasis in human spermatozoa. In assisted reproductive technology (ART), it is substantial to prevent spermatozoa from ROS attack. The pineal hormone melatonin has the natural antioxidant capacity and can scavenge ROS. To the best of our knowledge, however, there are presently no studies investigating if melatonin can protect human spermatozoa from heat-induced oxidative damage. Herein, we induced oxidative stress in human spermatozoa with heat treatment, and determined that melatonin could protect human spermatozoa from heat-induced oxidative stress. We first confirmed that heat stress-induced oxidative stress damaged human spermatozoa by decreasing sperm motility and viability. Furthermore, the pretreatment of human spermatozoa by melatonin was able to alleviate such damage by suppressing sperm mitochondrial ROS generation, increasing mitochondrial membrane potential, reducing the formation of the lipid peroxidation product, 4-HNE, and reducing sperm DNA damage and apoptosis. Collectively, these findings suggest that melatonin is useful as a potential treatment option for male infertility caused by heat-induced oxidative stress.

Oxidative and nitrosative stress in frozen-thawed pig spermatozoa. I: Protective effect of melatonin and butylhydroxytoluene on sperm function

The addition of antioxidants to the cryopreservation medium has been shown to exert a positive effect on the quality of frozen-thawed sperm in different species. The objective of the present study was to evaluate the effects of supplementing the freezing medium with butylhydroxytoluene (BHT) and melatonin (MEL) in frozen-thawed pig spermatozoa. With this purpose, six ejaculates coming from six separate boars were cryopreserved in traditional freezing medium (i.e. lactose/egg-yolk/glycerol; Control) supplemented with 1.0 mM BHT (BHT-1), 2.0 mM BHT (BHT-2), 0.01 μM MEL (MEL-1) and 1.0 μM MEL (MEL-2). We evaluated sperm viability, membrane lipid disorder, acrosome integrity, mitochondrial membrane potential, lipid peroxidation, oxidation of thiol groups, and levels of total reactive oxygen species (ROS), peroxynitrite and superoxide anion (·O₂^-). We also analysed total (TM) and progressive sperm motilities (PM), and kinetic parameters at post-thaw (T0, T30 and T60). The BHT-2 and MEL-2 groups presented higher viability and acrosome integrity, and lower levels of peroxynitrite, ·O₂^- and lipid peroxidation than the control (P < 0.05), whereas MEL-2 diminished the levels of total ROS (P < 0.05). TM and PM were not affected by the treatment, while, LIN and STR shows differences between experimental groups. In conclusion, the addition of BHT and MEL to cryopreservation medium diminishes oxidative and nitrosative stress markers, which has repercussions for the integrity of plasma and acrosomal membranes of frozen-thawed spermatozoa.

Protective Role of Natural Products in Glioblastoma Multiforme: A Focus on Nitric Oxide Pathway

In spite of therapeutic modalities such as surgical resection, chemotherapy, and radiotherapy, Glioblastoma Multiforme (GBM) remains an incurable fatal disease. This necessitates further therapeutic options that could enhance the efficacy of existing modalities. Nitric Oxide (NO), a short-lived small molecule, has been revealed to play a crucial role in the pathophysiology of GBM. Several studies have demonstrated that NO is involved in apoptosis, metastasis, cellular proliferation, angiogenesis, invasion, and many other processes implicated in GBM pathobiology. Herein, we elaborate on the role of NO as a therapeutic target in GBM and discuss some natural products affecting the NO signaling pathway.

Maternal pineal melatonin in gestation and lactation physiology, and in fetal development and programming

Pregnancy and lactation are reproductive processes that rely on physiological adaptations that should be timely and adequately triggered to guarantee both maternal and fetal health. Pineal melatonin is a hormone that presents daily and seasonal variations that synchronizes the organism's physiology to the different demands across time through its specific mechanisms and ways of action. The reproductive system is a notable target for melatonin as it actively participates on reproductive physiology and regulates the hypothalamus-pituitary-gonads axis, influencing gonadotropins and sexual hormones synthesis and release. For its antioxidant properties, melatonin is also vital for the oocytes and spermatozoa quality and viability, and for blastocyst development. Maternal pineal melatonin blood levels increase during pregnancy and triggers the maternal physiological alterations in energy metabolism both during pregnancy and lactation to cope with the energy demands of both periods and to promote adequate mammary gland development. Moreover, maternal melatonin freely crosses the placenta and is the only source of this hormone to the fetus. It importantly times the conceptus physiology and influences its development and programing of several functions that depend on neural and brain development, ultimately priming adult behavior and energy and glucose metabolism. The present review aims to explain the above listed melatonin functions, including the potential alterations observed in the progeny gestated under maternal chronodisruption and/or hypomelatoninemia.

Melatonin can be, more effective than N-acetylcysteine, protecting acute lung injury induced by intestinal ischemia-reperfusion in rat model

OBJECTIVES

The current study compared the impact of pretreatment with melatonin and N-acetylcysteine (NAC) on the prevention of rat lung damage following intestinal ischemia-reperfusion (iIR).

METHODS

Twenty-eight Wistar rats were subjected to intestinal ischemia induced by a 60 min occlusion of the superior mesenteric artery, followed by reperfusion for 120 min. Animals were divided into the following groups (n=7 per group): sham, only abdominal incision; SS+iIR, pretreated with saline solution and iIR; NAC+iIR, pretreated with NAC (20 mg/kg) and iIR; MEL+iIR, pretreated with melatonin (20 mg/kg) and iIR. Oxidative stress and inflammatory mediators were measured and histological analyses were performed in the lung tissues.

RESULTS

Data showed a reduction in malondialdehyde (MDA), myeloperoxidase (MPO), and TNF-alpha in the animals pretreated with NAC or MEL when compared to those treated with SS+iIR (p<0.05). An increase in superoxide dismutase (SOD) levels in the NAC- and MEL-pretreated animals as compared to the SS+iIR group (34±8 U/g of tissue; p<0.05) was also observed. TNF-α levels were lower in the MEL+iIR group (91±5 pg/mL) than in the NAC+iIR group (101±6 pg/mL). Histological analysis demonstrated a higher lung lesion score in the SS+iIR group than in the pretreated groups.

CONCLUSION

Both agents individually provided tissue protective effect against intestinal IR-induced lung injury, but melatonin was more effective in ameliorating the parameters analyzed in this study.

Melatonin can improve viability and functional integrity of cooled and frozen/thawed rabbit spermatozoa

Melatonin is known to protect sperm against freezing-inflicted damage in different domestic species. The aim of the study was to evaluate the effect of supplementation of semen extender with melatonin on the quality and DNA integrity of cooled and frozen/thawed rabbit spermatozoa. We also investigated whether the addition of melatonin to the semen extender could improve the fertility of rabbit does artificially inseminated with frozen/thawed semen. Semen samples collected from eight rabbit bucks were pooled and then diluted in INRA-82 supplemented either with (0.5, 1.0 or 1.5 mM) or without (0.0 mM) melatonin. Diluted semen was cooled at 5°C for 24 hr. For cryopreservation and based on the first experiment's best result, semen samples were diluted in INRA-82 in the presence or absence of 1.0 mM melatonin and then frozen in 0.25 ml straws. Following cooling or thawing, sperm quality and DNA integrity were evaluated. Furthermore, the fertility of frozen/thawed semen was investigated after artificial insemination. Supplementation of semen extender with 1.0 mM melatonin improved (p < .05) motility, viability, membrane and acrosome integrities in cooled semen compared with other groups. Sperm quality and DNA integrity were higher (p < .05) in frozen/thawed semen diluted in 1.0 mM melatonin-supplemented extender than in the control group. Conception and birth rates were higher in does inseminated with 1.0 mM melatonin treated semen compared with the controls. In conclusion, supplementation of semen extender with 1.0 mM melatonin improved the quality of cooled and frozen/thawed rabbit spermatozoa. Melatonin can preserve DNA integrity and enhance the fertility of frozen/thawed rabbit spermatozoa.

The effect of melatonin on testis histological changes and spermatogenesis indexes in mice following treatment with dexamethasone

Dexamethasone is a common medicine that is capable of causing malformation in the male reproductive system. The aim of this study was to investigate the effect of melatonin on testis histological changes and Spermatogenesis indexes in adult mice following treatment with dexamethasone. Adult male NMRI mice were divided randomly into four groups: control, dexamethasone (i.p injections, 7 mg/kg/day), dexamethasone + melatonin and melatonin (i.p injections, 20 mg/kg/day). After 7 days of treatment, the right testes were studied stereologically and the left testes were used to measure the daily sperm production (DSP). The serum levels of malondialdehyde (MDA), testosterone and total antioxidant capacity (TAC) were also measured. The left caudal epididymis was used to analyze sperm parameters. Data were analyzed using one way ANOVA and means were considered significantly different at p < 0.05. A significant decrease in the testis volume, seminiferous tubules volume, the number of spermatocytes, round and long spermatids, Spermatogenesis indexes, sperm parameters such as motility, count, viability, tail length and DSP, serum testosterone level, TAC and the body weight was found in the dexamethasone group compared to the control. Meanwhile a significant swelling of the interstitial tissue and a significant increase in the MDA level was found in the dexamethasone group compared to the control. The above parameters reached the control level in the dexamethasone + melatonin group. Melatonin can compensate for the adverse effects of dexamethasone on sperm parameters and the histology of the seminiferous tubules in mice.

"Emerging role of Novel Seminal Plasma Bio-markers in Male Infertility: A Review"

Male infertility has emerged as an important cause of infertility worldwide. There are many factors affecting male fertility and research is going on to know impact of various factors on sperm functions. Semen analysis is gold standard diagnostic test for male infertility, but it is crude method for estimation of male infertility as seminal composition gets affected by environmental factors, infections, other pathologies, hence, results of semen analysis either becomes normal/ambiguous, leading to failure of diagnosis and delayed treatment. Hence, with need of newer, better tests for assessing male factor infertility, seminal plasma is being tested for biomarkers. Seminal plasma is considered gold mine for male fertility as it contains molecules from male reproductive glands which play important role in sperm function. Study of seminal plasma molecules can give an idea about sperm concentration, motility, morphology and cause of infertility and can serve as biomarkers for male infertility. Present review briefs on some of these novel seminal plasma biomarkers which may play significant role in male fertility and can be used in future for better identification, assessment of infertile males.

METHODOLOGY

Literature from 1985 to 2019 was searched from various databases including PUBMED, SCOPUS, Google Scholar on seminal plasma biomarkers using keywords: "seminal plasma protein biomarkers", "novel seminal plasma markers and male infertility", "hormones in seminal plasma and male infertility", "oxidative stress and male infertility", "Reactive Oxygen Species and sperm DNA", "immunoinfertility".

INCLUSION CRITERIA

All full length original or review articles or abstracts on seminal plasma markers and male infertility published in English language in various peer-reviewed journals were considered.

EXCLUSION CRITERIA

Articles published in languages other than English were excluded from the study.

RESULTS

Seminal plasma is a big reservoir of molecules derived from the various male reproductive glands which can be used as potential biomarkers of male fertility.

CONCLUSION

Hence, seminal plasma biomarkers can be used in future for better assessment of male factor infertility, its causes and may play an important role in management of male factor infertility.

Synthesis of new ferulic/lipoic/comenic acid-melatonin hybrids as antioxidants and Nrf2 activators via Ugi reaction

Aim: Oxidative stress has been implicated in the pathogenesis of many neurodegenerative diseases, and particularly in Alzheimer's disease. Results: This work describes the Ugi multicomponent synthesis, antioxidant power and Nrf2 pathway induction in antioxidant response element cells of (E)-N-(2-((2-(1H-indol-3-yl)ethyl)amino)-2-oxoethyl)-N-(2-(5-(benzyloxy)-1H-indol-3-yl)ethyl)-3-(4-hydroxy-3-methoxyphenyl)acryl amides 8a-d, N-(2-((2-(1H-indol-3-yl)ethyl)amino)-2-oxoethyl)-N-(2-(5-(benzyloxy)-1H-indol-3-yl)ethyl)-5-(1,2-dithiolan-3-yl)pentanamides 8e-h and N-(2-((2-(1H-indol-3-yl)ethyl)amino)-2-oxoethyl)-N-(2-(5-(benzyloxy)-1H-indol-3-yl)ethyl)-5-hydroxy-4-oxo-4H-pyran-2-carboxamides 8i,j. Conclusion: We have identified compounds 8e and 8g, showing a potent antioxidant capacity, a remarkable neuroprotective effect against the cell death induced by H₂O₂ in SH-SY5Y cells, and a performing activation of the Nrf2 signaling pathway, as very interesting new antioxidant agents for pathologies that curse with oxidative stress.

El-Taieb M, N. Fares N, M. Fayed H, Toghan R, M. Ibrahim H. Men with idiopathic oligoasthenoteratozoospermia exhibit lower serum and seminal plasma melatonin levels: Comparative effect of night-light exposure with fertile males

Melatonin is a darkness hormone secreted by the pineal gland, which serves a role in idiopathic oligoasthenoteratozoospermia (iOAT). The present study aimed to evaluate the seminal plasma and serum melatonin levels of 50 patients with iOAT and 50 normal fertile controls and the effects of exposure to light at night on semen parameters. Semen analyses were performed according to the World Health Organization 2010 guidelines. Measurements of serum and seminal plasma melatonin, serum TSH, FT3, FT4, free testosterone, prolactin, FSH and LH were performed using ELISA. The overall results revealed that the serum and seminal plasma levels of melatonin were lower in patients with iOAT compared with the control subjects (P=0.0004 and 0.01, respectively). Patients with iOAT who were exposed to light at night exhibited lower serum and seminal plasma melatonin levels compared with those who were not exposed to light at night (P<0.0001 and 0.02, respectively). Additionally, similar significant differences were identified in control subjects exposed to light at night when compared to non-exposed controls. There was a significantly positive correlation between serum melatonin levels and sperm motility in the entire iOAT patient cohort (r=0.614; P<0.0001) and a significantly positive correlation between the serum and seminal plasma melatonin levels in the non-exposed iOAT patient subgroup (r=0.753; P<0.001). Thus, darkness and sleep at night may improve the semen parameters of patients with iOAT, as evidenced by the effects of light exposure at night on the serum and seminal plasma levels of melatonin and, consequently, on semen parameters.

Does Melatonin Exert Its Effect on Ram Sperm Capacitation Through Nitric Oxide Synthase Regulation?

Nitric oxide (NO·), synthesized from L-arginine by nitric oxide synthase (NOS), is involved in sperm functionality. NOS isoforms have been detected in spermatozoa from different species, and an increment in NOS activity during capacitation has been reported. This work aims to determine the presence and localization of NOS isoforms in ram spermatozoa and analyse their possible changes during in vitro capacitation. Likewise, we investigated the effect of melatonin on the expression and localization of NOS and NO· levels in capacitated ram spermatozoa. Western blot analysis revealed protein bands associated with neuronal NOS (nNOS) and epithelial NOS (eNOS) but not with inducible NOS (iNOS). However, the three isoforms were detected by indirect immunofluorescence (IFI), and their immunotypes varied over in vitro capacitation with cAMP-elevating agents. NO· levels (evaluated by DAF-2-DA/PI staining) increased after in vitro capacitation, and the presence of L-arginine in the capacitating medium raised NO· production and enhanced the acrosome reaction. Incubation in capacitating conditions with a high-cAMP medium with melatonin modified the NOS distribution evaluated by IFI, but no differences in Western blotting were observed. Melatonin did not alter NO· levels in capacitating conditions, so we could infer that its role in ram sperm capacitation would not be mediated through NO· metabolism.

Exposure by males to light emitted from media devices at night is linked with decline of sperm quality and correlated with sleep quality measures

The last several decades have been characterized by the widespread usage of digital devices, especially smartphones. At the same time, there have been reports of both decline in sleep duration and quality and male fertility decline. The aim of this study was to assess the relationship between evening exposure to the light-emitting screens of digital media devices and measures of both sleep and sperm quality. Semen samples were obtained from 116 men undergoing fertility evaluation for the following sperm variables: volume (mL), pH, sperm concentration (million/mL), motility percentage (progressive% + non-progressive motility%), and total sperm count. Exposure to the screens of electronic devices and sleep habits was obtained by means of a questionnaire. Smartphone and tablet usage in the evening and after bedtime was negatively correlated with sperm motility (-0.392; -0.369; p < .05), sperm progressive motility (-0.322; -0.299; p < .05), and sperm concentration (-0.169; p < .05), and positively correlated with the percentage of immotile sperm (0.382; 0.344; p < .05). In addition, sleep duration was positively correlated with sperm total and progressive motility (0.249; 0.233; p < .05) and negatively correlated with semen pH (-0.349; p < .05). A significant negative correlation was observed between subjective sleepiness and total and progressive motility (-0.264; p < .05) as well as total motile sperm number (-0.173; p < .05). The results of this study support a link between evening and post-bedtime exposure to light-emitting digital media screens and sperm quality. Further research is required to establish the proposed causative link and may lead to the future development of relevant therapeutic and lifestyle interventions.

Melatonin reduces cAMP-stimulated capacitation of ram spermatozoa

The presence of melatonin receptors on the surface of ram spermatozoa has led to speculation about melatonin having a role in sperm functionality. The aim of this study was to elucidate the mechanism through which melatonin regulates ram sperm capacitation induced by a cocktail containing cAMP-elevating agents. Cocktail samples capacitated in the presence of 1µM melatonin showed lower percentages of capacitated spermatozoa (chlortetracycline staining; P<0.001) together with a decrease in protein tyrosine phosphorylation (P<0.01) and lower levels of reactive oxygen species (ROS) and cAMP (P<0.05) compared with cocktail samples without the hormone. Determination of kinematic parameters, together with principal component and cluster analyses, allowed us to define four sperm subpopulations (SP). After 3h of incubation with cAMP-elevating agents, the percentages of spermatozoa belonging to SP1 (high straightness) and SP4 (less-vigorous spermatozoa with non-linear motility) increased while SP2 and SP3 (rapid spermatozoa starting hyperactivation or already hyperactivated) decreased compared with the control sample. The presence of melatonin at 100 pM and 10nM restored these subpopulations to values closer to those found in the control sample. These results indicate that melatonin at micromolar concentrations modulates ram sperm capacitation induced by cAMP-elevating agents, reducing ROS and cAMP levels, whereas at lower concentrations melatonin modifies motile sperm subpopulations. These findings warrant further studies on the potential use of melatonin for controlling capacitation in artificial insemination procedures.

Cryoprotective effect of melatonin supplementation on post-thawed rooster sperm quality

Reactive oxygen species (ROS) and free radicals are one of the major detrimental factors that can negatively affect the quality of sperm during cryopreservation. Melatonin is an effective antioxidant and free radical scavenger in various cells. In this study, therefore, the aim was to evaluate the post-thawed quality of spermatozoa after cryopreservation of rooster semen in freezing extender supplemented with melatonin. Semen samples from seven Green-legged Partridge roosters were pooled and diluted with EK extender supplemented with 10^-3, 10^-6, or 10^-9 M melatonin (control sample was prepared without supplementation with melatonin), and the pooled sample was subjected to cryopreservation. Post-thawed sperm motility was determined using the IVOS system, whereas plasma membrane status, acrosome integrity, mitochondrial activity, lipid peroxidation, chromatin status, and apoptotic-like changes were determined using fluorochromes and flow cytometry. Results, indicate post-thaw motile sperm cell count was greater (P < 0.05) in the frozen samples supplemented with melatonin (10^-3 and 10^-6 M) than the control sample. Although no significant differences were observed in post-thawed acrosomal integrity, plasma membrane integrity and mitochondrial activity were greater (P < 0.05) in samples frozen with melatonin (10^-3 and 10^-6 M) than that of the control sample. In addition, with supplementation of melatonin there was a decrease (P < 0.05) in the amount of lipid peroxidation, DNA fragmentation, and apoptotic-like changes after thawing. These results indicate there is a positive effect of melatonin supplementation in rooster semen freezing extenders on post-thaw sperm quality.

Melatonin supplementation improves the intactness of plasma membrane and acrosomal membrane of cryopreserved spermatozoa in Hariana bull

Supplementation of MT @ 2 mM was more beneficial in cryopreservation of Hariana bull spermatozoa as evidenced from post-thawed sperm membrane integrity and acrosomal intactness. Melatonin can be recommended to be used @ 2 mM concentration into the semen extender to increase the post thaw sperm functional attributes in Hariana bull.

Melatonin-improved buffalo semen quality during nonbreeding season under tropical condition

The role of melatonin in protecting spermatozoa from different kinds of injury has been widely reported. The present study aimed to test whether treatment of buffalo bulls with melatonin could ameliorate sperm function during nonbreeding season under tropical condition. Ten Murrah buffalo bulls were randomly allocated into control and treated groups of equal numbers of bulls to study the effect of melatonin on semen characteristics, seminal plasma constituents, blood plasma hormonal levels, and antioxidant enzyme activities during nonbreeding season. Treated bulls were implanted with melatonin (18 mg/50 kg of body weight) for a period of 2 mo. During this period, semen was collected twice a week, and blood samples were collected weekly to determine plasma concentration of melatonin and LH and activities of antioxidant enzymes. During nonbreeding season, melatonin implantation improved semen characteristics by increasing (P < 0.05) percentages of sperm with forward motility, viability, total motile sperm, and rapid motility, average path, curvilinear, and straight-line velocity and amplitude of lateral head displacement and decreasing (P < 0.05) percentages of abnormal sperm and linearity index as compared to the control group. Furthermore, melatonin implantation increased (P < 0.05) seminal plasma concentrations of total protein, albumin, and cholesterol and decreased (P < 0.05) seminal plasma aspartate aminotransferase activity. In addition, melatonin-implanted bulls exhibited an increase (P < 0.05) in red blood cells superoxide dismutase activity compared to untreated bulls. In conclusion, melatonin implantation successfully improved semen quality of buffalo bulls during nonbreeding season under tropical condition.

Effect of addition of melatonin on liquid storage of ram semen at 4°C

Adding a certain amount of antioxidants to semen extender has been shown to improve semen quality. The aim of present study was to elucidate whether the supplementation of melatonin to the Tris-based extender (CTR) could enhance the quality of ram spermatozoa during storage at 4°C. Ram semen samples were collected and diluted with CTR extender containing different concentrations (0, 0.05 (M 0.05), 0.1 (M 0.1), 0.2 (M 0.2) or 0.4 (M 0.4) mM) of melatonin. Sperm routine indicators, mitochondrial activity, total antioxidant capacity (T-AOC) and malondialdehyde (MDA) content were analysed in control and melatonin treatment groups. The higher per cent of motility, plasma membrane integrity, mitochondrial activity and T-AOC activity was observed in M 0.05, M 0.1 and M 0.2 groups compared to control group at 5 days of storage (p < 0.05), while lower percentage of MDA content was observed among these groups (p < 0.05). In addition, there were no significant differences in acrosome integrity among the control and M 0.05, M 0.1 and M 0.2 groups during the experiment. The above results show that the addition of 0.05, 0.1, 0.2 mM of melatonin is beneficial to the preservation of ram semen during liquid storage at 4°C mainly through antioxidative stress.