Melatonin affects the motility and adhesiveness of in vitro capacitated boar spermatozoa via a mechanism that does not depend on intracellular ROS levels (original) (raw)
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Andrologia, 2000
The aim of the present study was to investigate the effect of melatonin on plasminogen activator activity (PAA), plasminogen activator inhibition (PAI) and plasmin inhibition (PI) in ram spermatozoa and seminal plasma, in correlation with changes in blood testosterone. Melatonin implants (18 mg) were placed subcutaneously in sixteen Chios rams in autumn and spring. Semen samples for spectrophotometrical assays were collected 36 h before the implantation of melatonin and thereafter once a week, for 17 weeks. Blood samples for testosterone assay (RIA) were collected 8 h before implantation (one sample/30 min  7.5 h) and thereafter every 15 days for 105 days after implantation. For each ram, six parameters of testosterone were estimated: mean value, basal level, number of peaks, peak amplitude, peak duration and mean testosterone concentration during peaks. Melatonin implantation during autumn induced an increase in PAA and t-PAI in spermatozoa; melatonin implantation in spring induced an additional increase in u-PAI and PI; no change in PAA, PAI or PI was found in seminal plasma, during autumn or spring. The melatonin-induced increase of PAA, PAI and PI in spermatozoa was in positive correlation with the increase of testosterone mean value, basal level and number of peaks; the increase of testosterone parameters was greater in autumn compared to spring. Changes of PAA, PAI and PI of spermatozoa, under the influence of melatonin, might indicate changes in the fertilizing ability of spermatozoa, since plasminogen activators and their inhibitors are present on the plasma and the outer acrosomal membrane of spermatozoa and are released during the acrosome reaction. #
Does Melatonin Exert Its Effect on Ram Sperm Capacitation Through Nitric Oxide Synthase Regulation?
International Journal of Molecular Sciences, 2020
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 capacitatin...
The effect of melatonin on the quality of extended boar semen after long-term storage at 17 °C
Theriogenology, 2011
In order to enhance the life span of refrigerated boar semen, our aim was to evaluate the effects of addition of 1 M MLT to commercially produced pig semen (33 seminal doses from 14 boars) that had been preserved at 17°C for 7 days. Samples without MLT served as controls. On Days 1, 4 and 7, we evaluated motility parameters and the percentage of total motile and progressively motile spermatozoa by a computer-aided sperm analysis system. Viability (SYBR-14/PI), acrosomal status (FITC-PNA/PI), membrane fluidity (M-540/YoPro-1) and mitochondrial membrane potential status (JC-1) were evaluated by flow cytometry. MLT treatment significantly enhanced the percentage of static spermatozoa after 7 days of storage and significantly reduced the percentage of progressively motile spermatozoa on Day 7. The velocity characteristics (VCL, VSL and VAP) were significantly higher for MLT-treated samples on Day 1 and were their lowest on Day 7. With regard to flow cytometry results, the percentage of viable spermatozoa with an intact acrosome was higher in MLT samples throughout the entire storage period. In addition, there was a significantly higher proportion of live spermatozoa on Day 7 in the samples that had not been treated with MLT. The proportion of spermatozoa showing a high mitochondrial membrane potential remained at similar levels (P Ͼ 0.05) throughout the trial. Although the findings of the present study revealed that 1 M MLT increased the proportion of live sperm with an intact acrosome, this treatment did not enhance the spermatic quality of refrigerated boar semen.
NADPH Oxidase 5 and Melatonin: Involvement in Ram Sperm Capacitation
Frontiers in Cell and Developmental Biology, 2021
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...
Melatonin Protects Bovine Spermatozoa by Reinforcing Their Antioxidant Defenses
Cryopreserved semen is widely used in Assisted Reproductive Technologies (ART) enabling the conservation and broad use of genetically superior semen. The quality of semen post-thawing determines the success of ART and despite the great advances in cryopreservation methods, the quality of frozen/thawed semen is still sub-optimal. Post-thawing spermatozoa endure oxidative stress (OS) 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, the effect of melatonin on bovine spermatozoa was evaluated during in vitro sperm handling and under oxidative conditions in terms of sperm quality parameters and antioxidant capacity. Melatonin ...
Melatonin diminishes oxidative damage in sperm cells,improving assisted reproductive techniques
TURKISH JOURNAL OF BIOLOGY
Sperm preparation procedures are a potential generator of oxidative stress-induced DNA damage, which leads to a dramatic drop in fertility. An increasing number of studies suggest that melatonin reduces the oxidative stress induced by manipulation. However, very little is known about the preservative role of melatonin in sperm preparation medium during assisted reproduction procedures. For this aim to be achieved, semen was divided into two fractions and preincubated with and without 1 mM melatonin. Afterwards, both fractions were divided into two subfractions to perform swim-up in the presence and absence of 1 mM melatonin. Labeling with anti-CD46 and antiactive caspase-3 allowed the monitoring of acrosome reaction and apoptosis by flow cytometry. Sperm DNA fragmentation and compaction were analyzed through propidium iodide staining. The normozoospermic and oligozoospermic samples that were preincubated with melatonin underwent a significant increase in the ratio of adequate spermatozoa and a reduction of caspase-3 activation. Additionally, preincubation with melatonin enhanced the migration of sperm cells with compacted DNA in oligozoospermic samples (P < 0.05) and prevented DNA fragmentation in normozoospermic samples (P < 0.05). In light of the current results, the cytoprotective capacity and innocuousness of melatonin make it a great candidate to be applied in assisted reproduction techniques in order to prevent iatrogenic oxidative damage.
The Role of Melatonin to Ameliorate Oxidative Stress in Sperm Cells
Makris A, Alevra AI, Exadactylos A, Papadopoulos S, 2023
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 Effect on Cryopreserved Sperm Cells of Crioulo Stallions
Open Access Journal of Veterinary Science & Research, 2020
The freezing/thawing process of spermatozoa can cause cellular damage to the male gamete, decreasing the fertilization potential due to the increase in the production of reactive oxygen species (ROS). Melatonin is a potent endogenous antioxidant that protects the body against the damage caused by ROS. This study has evaluated different melatonin concentrations on the sperm viability of cryopreserved semen of Crioulo stallions. For that, three ejaculates were collected from five stallions diluted in a commercial extender followed by centrifugation and resuspension in a commercial freezing extender supplemented with 0; 1.25; 2.5. 5mM of Melatonin before the cryopreservation process. After thawing, the evaluation was performed assessing motility and flow cytometry evaluations: the plasma membrane integrity (PI), the integrity of the acrosomal membrane (FITC-PNA), mitochondrial membrane potential (JC1), and ROS generation (DCF-DA). Our results showed that sperm motility in the group wit...