Sperm Protection Research Articles

Metabolite Support of Long-Term Storage of Sperm in the Spermatheca of Honeybee (Apis mellifera) Queens.

The polyandrous mating system of honeybees (Apis mellifera L.) has garnered widespread attention. Long-lived honeybee queens only mate early in maturation, and the sperm obtained from the aerial mating is stored in the spermatheca. The maintenance of sperm viability in the spermatheca is an intriguing and complex process. However, the key physiological and biochemical adaptations underlying the long-term storage of sperm remain unclear. Analysis of the metabolite profile could help better understand the biology of the spermatheca and offer insights into the breeding and conservation of honeybees and even pest control strategies. Here, the changes in metabolites in the spermatheca were quantified between virgin queens and new-laying queens (with stored sperm) via liquid chromatography–mass spectrometry. Compared with virgin queens, changes occurred in lipids and lipid-like molecules, including fatty acyls and glycerophospholipids (GPL), prenol lipids, and sterol lipids, during storage of sperm in new-laying honeybee queens. Furthermore, the metabolic pathways that were enriched with the differentially expressed metabolites were identified and included GPL metabolism, biosynthesis of amino acids, and the mTOR signaling pathway. The likely roles of the pathways in the maintenance and protection of sperm are discussed. The study identifies key metabolites and pathways in the complex interplay of substances that contribute to the long-term storage of sperm and ultimately reproductive success of honeybee queens.

Photobiomodulation preconditioned human semen protects sperm cells against detrimental effects of cryopreservation

The biological consequences of semen samples preconditioning with photobiomodulation (PBM) were studied on human sperm cells post cryopreservation. Donated semen samples were collected from 22 married men with normal sperm parameters according to World Health Organization (WHO) criteria. Included samples were divided into control and PBM-preconditioning (one session, 810 nm, diode laser, and 0.6 J/cm2) groups before cryopreservation procedure. Progressive sperm motility (PSM), morphology, viability, sperm mitochondrial membrane potential(MMP), intracellular reactive oxygen species (ROS) and lipid peroxidation of sperm cells were assessed post thawing. PBM preconditioning of cryopreserved semen samples most prominently increased the PSM percentage 30 min post thawing (p = 0.000).Application of PBM before cryopreservation significantly increased the number of viable spermatozoa (p = 0.000), increased significantly the number of spermatozoa with high MMP (p = 0.004) and decreased significantly the number of spermatozoa with low MMP post-thawing(P = 0. 007)compared to control group. Cryopreserved human sperm cells with PBM preconditioning showed significant decrease in the levels of intracellular ROS (47.66 ± 2.14 versus 60.42 ± 3.16, p = 0.002) and lipid peroxidation (3.06 ± 0.13 versus 3.68 ± 0.27, p = 0.05)compared to control group.Our findings, as the first evidence, indicated that PBM-preconditioning of human semen before cryopreservation provides a real and substantial advantage. This might lead to a novel strategy in improving PBM application in the procedures of assisted reproductive technologies.

Rosmarinic acid improves boar sperm quality, antioxidant capacity and energy metabolism at 17°C via AMPK activation.

Boar sperm are susceptible to oxidative damage caused by reactive oxygen species (ROS) during storage. Adenosine monophosphate (AMP)-activated protein kinase (AMPK) is an important therapeutic target, because it is a cellular metabolism energy sensor and key signalling kinase in spermatozoa. We evaluated the effects of rosmarinic acid (RA), an antioxidant, on boar sperm during liquid storage to determine whether it protects boar sperm via AMPK activation. Boar ejaculates were diluted with Modena extender with different concentrations of RA and stored at 17°C for 9days. Sperm quality parameters, antioxidant capacity, energy metabolism, AMPK phosphorylation and fertility were analysed. Compared with the control, 40μmol/L significantly improved sperm motility, plasma membrane integrity and acrosome integrity (p<.05). The effective storage time of boar sperm was up to 9days. On the third and seventh days, the sperm with RA exhibited increased total antioxidant capacity (T-AOC), superoxide dismutase (SOD) activity, adenosine triphosphate (ATP) content, mitochondrial membrane potential (ΔΨm) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) activity, whereas malondialdehyde (MDA) content was significantly decreased (p<.05). Western blot showed that RA, as well as AICAR (AMPK activator), promoted AMPK phosphorylation, whereas Compound C (AMPK inhibitor) inhibited this effect. The sperm-zona pellucida binding experiment showed that 40μmol/L RA increased the number of sperm attached to the zona pellucida (p<.05). These findings suggest meaningful methods for improved preservation of boar sperm in vitro and provide new insights into the mechanism by which RA protects sperm cells from oxidative damage via AMPK activation.

Alpha Tocopherol Loaded in Liposome: Preparation, Optimization, Characterization and Sperm Motility Protection

Background: Alpha-tocopherol is a potent antioxidant involved in sperm protection particularly during cryopreservation. However, its poor solubility limits the optimal protection in aqueous solutions. Objective: The aim of this study was to enhance the solubility of α-tocopherol by the use of liposomes. Methods: The experimental approach consisted to load vitamin E in liposomes prepared by ethanol injection method and the optimization carried out by an experimental design. The optimum solution was characterized by high performance liquid chromatography and scanning electron microscope. Finely, the impact on sperm motility protection was studied by the freezing technic of bovine sperm. Results: The optimum solution was obtained when using 10.9 mg/ml of phospholipids, 1.7 mg/ml of cholesterol and 2 mg/ml of vitamin E. The liposome size was 99.86 nm, providing 78.47% of loaded efficiency. The results showed also a significant positive impact on sperm motility after hours of preservation. Conclusion: In conclusion, the current results showed the interest of liposome preparation as an alternative to enhance vitamin E solubility and to protect spermatozoa during cryopreservation.

Effect of low-density lipoproteins and trehalose on the quality of cryopreserved bovine semen

Background: In artificial insemination, chicken egg yolk is added to bovine semen to protect it during the cryopreservation process, although it contains substances that can affect the microbiological quality and metabolism of sperm. Objective: To evaluate post-thaw quality of bovine cryopreserved semen added with centrifuged and non-centrifuged egg yolk, low-density lipoproteins (LDL), and trehalose (T). Methods: Ten ejaculates from five bulls were cryopreserved under the treatments T1: pure egg yolk (PEY) at 20% v/v, T2: centrifuged egg yolk (CEY) at 20% v/v, T3: LDL at 8% v/v, T4: T at 100 mM, and T5: T at 100 mM plus LDL at 8% v/v (TLDL). Spermatic motility and kinetics, functional membrane integrity (FMI), structural membrane integrity (SMI), sperm vitality (SV) and abnormal morphology (AM) were assessed using the Sperm Class Analyzer (SCA®) system, hypoosmotic test (HOST), SYBR/PI probes, and eosin–nigrosin staining, respectively. A completely randomized design was used. Normal distribution of the variables was validated through the Kolmogórov– Smirnov test. A generalized linear model was used to determine sources of variation. Means were compared using the Tukey test. Results: Inclusion of CEY or LDL had a similar effect on sperm protection, and were superior for motility, kinetics and membrane integrity compared to the other treatments (p&lt;0.05). CEY was superior for progressive motility (p&lt;0.05). The cryoprotective action of LDL was similar to TLDL for motility and kinetics, SMI, SV, and AM (p&lt;0.05). Inclusion of PEY and T resulted in the lowest semen quality (p&lt;0.05). The use of T resulted in a reduction in FMI and SMI (p&lt;0.05). No differences in AM between treatments were found (p&gt;0.05). Conclusions: Egg yolk can be replaced by centrifuged egg yolk or low-density lipoproteins in the freezing extender used for bovine semen used in artificial insemination.

Maturation of the functional mouse CRES amyloid from globular form

The epididymal lumen contains a complex cystatin-rich nonpathological amyloid matrix with putative roles in sperm maturation and sperm protection. Given our growing understanding for the biological function of this and other functional amyloids, the problem still remains: how functional amyloids assemble including their initial transition to early oligomeric forms. To examine this, we developed a protocol for the purification of nondenatured mouse CRES, a component of the epididymal amyloid matrix, allowing us to examine its assembly to amyloid under conditions that may mimic those in vivo. Herein we use X-ray crystallography, solution-state NMR, and solid-state NMR to follow at the atomic level the assembly of the CRES amyloidogenic precursor as it progressed from monomeric folded protein to an advanced amyloid. We show the CRES monomer has a typical cystatin fold that assembles into highly branched amyloid matrices, comparable to those in vivo, by forming β-sheet assemblies that our data suggest occur via two distinct mechanisms: a unique conformational switch of a highly flexible disulfide-anchored loop to a rigid β-strand and by traditional cystatin domain swapping. Our results provide key insight into our understanding of functional amyloid assembly by revealing the earliest structural transitions from monomer to oligomer and by showing that some functional amyloid structures may be built by multiple and distinctive assembly mechanisms.

Improving native human sperm freezing protection by using a modified vitrification method.

Slow freezing is the most commonly used technique for the cryopreservation of spermatozoa in clinical practice. However, it has been shown to have a negative impact on sperm function and structure. Vitrification as a successful alternative method has been proved to have better protective effects on human embryos, but vitrification of spermatozoa is still subject to low recovery rates. In this study, a modified vitrification method for native spermatozoa was developed. A total of 28 semen samples were included; each sample was divided into three equal parts and assigned to fresh, slow freezing, and vitrification groups. Sperm vitality, motility, morphology, DNA integrity, and acrosome reaction were assessed for each of the groups. The results showed that vitrification achieves better results for several sperm protection parameters than slow freezing; vitrification achieves a higher recovery rate (P < 0.05), motility (P < 0.05), morphology (P < 0.05), and curve line velocity (P < 0.05) than slow freezing. Furthermore, DNA fragmentation was decreased (P < 0.05) and better acrosome protection (P < 0.05) was exhibited in the spermatozoa after vitrification. Principal component analysis of all sperm parameters revealed that the vitrification cluster was closer to the fresh cluster, indicating that spermatozoa are better preserved through vitrification. In conclusion, while both slow freezing and vitrification have negative effects on sperm function and structure, the vitrification protocol described here had a relatively better recovery rate (65.8%) and showed improved preservation of several sperm quality parameters compared with slow freezing.

THE ACTIVITY AND ISOFORMS OF SUPEROXIDE DISMUTASE IN TISUES OF REPRODUCTIVE ORGANS OF RATS

The aсtivity of superoxide dismutase, the content of its isoforms in testis, epididimis, and in epididimal spermatozoa of pubescent rat males were studied. The experiments were performed on adult male rats (age 5 - 6 months). After decapitation, the testes and the epididimis were taken, from which the spermatozoa were washed with 0.9 % sodium chloride solution. The total protein and activity of superoxide dismutase (SOD) were determined in the supernatant and the sperm suspension. SOD isoforms were detected after electrophoresis in 10 % polyacrylamide gel by specific staining of gel plates with nitrosine tetrazolium. The highest activity was found to be in the tissue of the testes (18.2 ± 2.59 IU/mg of protein), less on 34.6% in the epididymis and the lowest on 46.7% in epididymal sperm. Electrophoresis in 10 % polyacrylamide gel and specific staining in the tissues of testis, epididymis, and epididymal sperm of rats revealed five major SOD isoforms, which, depending on the speed of movement in PAAG, were labeled, from maximum to least mobile, such as S1, S2, S3, S4 and S5. The specifity of testicular tissue is the presence of two minor isoforms (S1a- and S1b-isoforms), which are characterized by high electrophoretic mobility and lower intensity of manifestation, and the color disappears over time, unlike other proteins of the enzyme. It was found that the SOD isoenzyme spectrum is characterized by tissue specificity and depended on the physiological and functional features of the tissue of the reproductive organs of males and spermatozoa. In the testis tissue, S2 isoform was in the largest amount– 36.7 ± 1.91%, less and almost the same content of S1-, S3- and S4-isoforms (18.0 ± 3.27, 19.3 ± 3.98 and 15.7 ± 2.15%) and the least – S5-, S1a- and S1b-isoform (6.2 ± 1.20%; 2.2 ± 0.03 and 1.9 ± 0.01%). In the epididimis tissue, the content of the S3-isoform was higher on 17.9% and S2- and S1- respectively on 7.9% and 4.9%, respectively, compared to the testis. SOD isoenzymes of epididymal spermatozoa are characterized by a high content of S2 isoforms, which is more on 11.2% than in the testis, and the content of S1 isoforms, by contrast, is lower on 10.0%. The established differences in the content and activity of individual isoforms of the enzyme indicate the existence of tissue specificity of SOD proteins, due to the functional characteristics of the studied tissues. Optimal protection of sperm from O2• - in the process of their differentiation and maturation is ensured by the activity of different SOD isoforms, confirming the established differences in the isoenzyme spectrum.

Canine semen cryoconservation: Emerging data over the last 20 years.

Canine semen cryoconservation was used since 1969, and this process is still nowadays in progress. This review aims to have an overview of two factors leading to a successful freezing-thawing semen. The success and efficiency of freezing process can be measured by the post-thawing sperm mobility. The first factor is the best extender used as a cryoprotectant to have a similar osmolarity and pH compared to the seminal plasma to enable sperm survival. Historically, chicken egg yolk was used since 1940, but due to microbial risks and to the presence of granules (which interfere with counting dead spermatozoa and inhibits a spermatozoal respiration), despite these disadvantages, egg yolk is considered an excellent cryoprotectant for sperm of different animal species. The low-density lipoproteins (LDL), contained in EY, when used at a concentration of 6% in a freezing medium associated with 20mM of glutamine, show a mobility up to 54.5%, which is the best combination found. However, the sperm protection mechanism by LDL during freezing-thawing process only begins to be decrypted. But extraction protocols of LDL are not efficient for an industrial use. Therefore, egg yolk plasma is used within liquid or lyophilized state, and offering similar efficiency as the 6% LDL middle. The equilibration step, in which the diluted sperm is placed for a variable period of time at a temperature of +4°C, before freezing it. The studies show that 6hr is the optimal duration for the canine sperm equilibration. The future of canine sperm cryopreservation is expected in liposome use and synthetic substances, which mimics LDL role.

Gelatin Microcartridges for Onboard Activation and Antioxidant Protection of Sperm.

Sperm-driven micromotors are promising devices for developing autonomous, noninvasive diagnostic and therapeutic tools, specifically in reproductive biology and medicine. In this article, we present template-based microstructures fabricated from gelatin for sperm capture, activation, and antioxidant protection. The cartridge-like structures with one closed end-capture single bovine sperm cells and are propelled by the sperm's flagellum. We demonstrate the pH-dependent release of heparin from the gelatin microcartridges to induce capacitation, a crucial maturation process prior to fertilization. Further, the gelatin cartridges exhibit a protection against oxidative stress, one of the main causes for sperm damage. Finally, we investigate the stability and degradability of the microstructures in various physiological environments, such as endometrial cell culture, different pH, and in the presence of proteases. Overall, we prove that these gelatin spermbots display great potential for the development of noninvasive theranostic tools in reproductive biology and medicine for the protection and activation of sperm, especially useful for studying sperm migration. We present their beneficial features which comprise not only biocompatibility and biodegradability but also pH response, loading stability, and antioxidant protection.

Transcriptional profiling and physiological roles of Aedes aegypti spermathecal-related genes

BackgroundSuccessful mating of female mosquitoes typically occurs once, with the male sperm being stored in the female spermatheca for every subsequent oviposition event. The female spermatheca is responsible for the maintenance, nourishment, and protection of the male sperm against damage during storage. Aedes aegypti is a major vector of arboviruses, including Yellow Fever, Dengue, Chikungunya, and Zika. Vector control is difficult due to this mosquito high reproductive capacity.ResultsFollowing comparative RNA-seq analyses of spermathecae obtained from virgin and inseminated females, eight transcripts were selected based on their putative roles in sperm maintenance and survival, including energy metabolism, chitin components, transcriptional regulation, hormonal signaling, enzymatic activity, antimicrobial activity, and ionic homeostasis. In situ RNA hybridization confirmed tissue-specific expression of the eight transcripts. Following RNA interference (RNAi), observed outcomes varied between targeted transcripts, affecting mosquito survival, egg morphology, fecundity, and sperm motility within the spermathecae.ConclusionsThis study identified spermatheca-specific transcripts associated with sperm storage in Ae. aegypti. Using RNAi we characterized the role of eight spermathecal transcripts on various aspects of female fecundity and offspring survival. RNAi-induced knockdown of transcript AeSigP-66,427, coding for a Na+/Ca2+ protein exchanger, specifically interfered with egg production and reduced sperm motility. Our results bring new insights into the molecular basis of sperm storage and identify potential targets for Ae. aegypti control.

How to Reduce the Potential Harmful Effects of Light on Blastocyst Development during IVF

Purpose: Earlier findings revealed the damaging effect of visible light on zygotes and gametes. The aim of our study is to eliminate or significantly reduce the potentially harmful effects of light exposure during in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) and to investigate the effect of light protection on embryo development and implantation. Materials and Methods: To protect sperm cells, oocytes, and embryos from the potential harmful effects of light exposure during laboratory procedures, we created a dark environment for the cells and applied red filters on laboratory lamps and UV or infrared filters in the microscopes in order to eliminate white light exposure of the cells throughout all work stages. Results: The fertilization rate was significantly (p = 0.011) higher in light-protected ICSI cycles. Blastocyst development rates (blastocyst/embryo) were significantly (p < 0.001) higher in light-protected embryos than in those manipulated in conventional light conditions both in IVF (20.9% difference) and ICSI (38.6% difference). Numbers of clinical pregnancies/transfers of ICSI fertilized day 5 blastocysts were also significantly (p = 0.040) higher in light-protected conditions. Conclusions: These data show that light protection has a positive effect on fertilization rate and increases the blastocyst development as well as the number of clinical pregnancies/transfers. Implementation of this light protection method in IVF centers may improve the success rate while maintaining maximal embryo safety.

Characterisation of ADAMs (protein)of bovine seminal plasma by Mass Spectrometry

This study has been designed to analyse the secreted and soluble proteins in bovine seminal plasma by mass spectrometry. The majority of these proteins are produced by accessory glands, and partially by testis, epididymis, ductus deferens and vas deferens of male reproductive tract.&#x0D; Seminal plasma of bovine was collected freshly and isolated after centrifuged and removed the sperm. Non boiled and boiled seminal plasma lysate were run to identify and detect the total proteins, as well as the individual single member of ADAMs protein is determined.&#x0D; The non-boiled lysate of seminal plasma was displayed diversity of proteins more than boiled sample lysate of seminal plasma.&#x0D; However, boiled and non-boiled seminal plasma have distinguished several types of ADAMs protein which are included: ADAM10, ADAM9, ADAM7, ADAM15 in non-boiled samples, while boiled lysate of bovine seminal plasma was displayed ADAM10, ADAM9, ADAM28, and ADAM22.&#x0D; Our finding concluded that bovine seminal plasma is very rich in different types of soluble, cleaved and shed proteins such ADAMs protein which could potentially have a biological and physiological role in protection and interactions of sperm during motility inside female reproductive tract, as it might support it to fertilise the ovum. This protection might be via immunosuppression behaviour or by block specific receptors in female reproductive tract for enhancing sperm motility, and avoid sperm the singling response of immunity.

Influence of Coconut Powder Water-Based Conservation Medium (APC-102c) for Maintaining Mitochondrial Activity of Cryopreserved Ram Sperm

Background: Semen extenders are required to protect and preserve semen, and the development of suitable extenders is key for artificial insemination. Although the use of Tris-based diluent is widespread, new diluents such as powdered coconut water have been developed for better sperm protection. One way to evaluate the effectiveness of diluents is through microscopic analyses that evaluate sperm motility, vigor, and concentration. However, these analyses are limited, and may not provide accurate results. New evaluation techniques have been studied, and one of the tests that can be used to add reliability to these analyses is mitochondrial activity evaluation, which can sum all the parameters, and provide a more accurate evaluation. Thus, the present study aimed to evaluate the efficacy of ACP-102c in cryopreserved ram semen.Materials, Methods &amp; Results: Five semen samples were collected from two ram breeders using artificial vagina (n = 10). Each ejaculate was divided into the following two treatments: T1 - ACP-102c + 20% egg yolk + 7% glycerol and T2 - TRIS + 20% egg yolk + 7% glycerol. Extended semen samples were then packed in 0.5 mL plastic straws, subjected through the refrigeration curve up to 4°C (0.35° C/min), and equilibrated for 2 h at 4°C. Subsequently, the straws were placed at 4 cm above liquid nitrogen level (-60°C) for 15 min, immersed, and then finally stored in the liquid nitrogen at -196°C. Both fresh and thawed samples were evaluated for total and progressive sperm motility using conventional microscopy (40x), and the same evaluator on each occasion. For plasma membrane integrity (IMP), the smear staining technique with the Eosin-Nigrosin staining was used; 200 sperms were counted and classified as whole (unstained) and unhealthy (stained). Mitochondrial activity was evaluated using a cytochemical technique based on the oxidation of 3,3'-diaminobenzidine (DAB); 200 sperms were counted, and classified into four classes (I, II, III, and IV) according to the degree of coloration of the intermediate part. Fresh semen showed no significant difference (P &gt; 0.05) between treatments with respect to motility parameters; however, T2 showed significantly inferior results regarding plasma membrane integrity. After thawing, T2 was significantly higher in sperm motility parameters compared to T1. The mitochondrial activity and plasma membrane integrity parameters did not show any significant difference between the treatments.Discussion: The TRIS-based diluent showed higher motility values than ACP-102c; however, motility rates in ACP-102c diluent, although lower, are considered satisfactory for insemination, which requires semen with minimal progressive motility of 30%. Notably, the cryopreservation protocol used in this study is the standard for TRIS-based diluent, and it is known that the optimal rate of refrigeration and cryopreservation may differ according to the composition of the storage medium; therefore, we may assume that the protocol used is not yet appropriate for the ACP-102c diluent, and further studies are required. IMP is an essential attribute for fertilization, and cryopreservation can affect the plasma membrane as observed in this study. Cryopreserved semen reduced the percentage of class I mitochondrial reaction sperms in both treatments, demonstrating that cryopreservation affects the mitochondrial activity of the intermediate portion of the sperm; however, there was no difference between treatments in thawed semen. Thus, we concluded that the ACP-102c conservation medium maintains seminal quality after thawing, and it can be used in artificial insemination processes.

26 Baobab oil supplemented extender preserves post-thaw bull sperm quality parameters

The processes of semen cryopreservation and thawing affect sperm membrane integrity and motility and increases morphological defects as well as DNA damage. The most influential cause of this is oxidative stress. When endogenous antioxidant capacity of seminal plasma is reduced during the freeze-thawing process, plant extracts exhibiting strong antioxidant activity can be used as supplements for compensation. Baobab oil has gained interest because it is rich in powerful antioxidants, which could protect sperm cells from oxidative damage during cryopreservation. Our study aimed to assess the effects of baobab oil on post-thaw sperm quality parameters in an egg-yolk-based extender. Thirty semen ejaculates were collected from 15 Nguni bulls using an electro ejaculator. Semen samples were randomly allocated to control (no baobab oil), 20μL (1%), 50μL (2.5%), and 100μL (5%) baobab oil per millilitre extender. Following dilution, semen samples were loaded into 0.25-mL semen straws, equilibrated for 4h at 5°C, and transferred into a controlled rate programmable freezer. The frozen semen straws were stored in a liquid nitrogen tank (−196°C) until thawing. Semen straws were thawed (37°C/60 minutes) after 1 week of cryopreservation and analysed for (1) sperm motility using a computer-aided sperm analyser, (2) morphological defects and viability using eosin-nigrosin stain, (3) membrane integrity by hypo-osmotic swelling test, and (4) DNA integrity by terminal deoxynucleotidyl transferase dUTP nick end labelling assay. Data was analysed using analysis of variance. Treatment means were compared in relation to the control group by Dunnett's test. We found that supplementing semen extender with baobab oil at 1% significantly (P&amp;lt;0.05) preserved sperm DNA integrity (88.3±3.7) and membrane integrity (74.0±4.2) when compared with the control group (71.7±3.7 and 55.8±4.4, respectively). Baobab oil supplementation either at 1% (5.9±0.5), 2.5% (7.2±0.5), or 5% (6.0±0.5) significantly reduced sperm morphological defects compared with control (9.5±0.5). Total motility (1% (72.7%), 2.5% (72.7%), 5% (71.9%), control (59.3%)) and viability (1% (79.1%), 2.5% (79.8%), 5% (77.8%), control (67.6%)) were also improved by supplementation; however, the difference was not significant. In conclusion, it was demonstrated that supplementing bull semen extender with 1% baobab oil protects sperm from morphological defects, maintains membrane integrity, as well as preserves sperm DNA. All the baobab oil supplementation levels preserved post-thaw bull-sperm quality parameters.

38 Ram sperm longevity after cryopreservation in extender containing L-carnitine

The cryopreservation process causes oxidative stress to the sperm cell, and the addition of antioxidants to the extender for semen freezing helps sperm protection. This study assessed the effect of L-carnitine (LC) concentrations (0, 5, or 10mM LC) on two ram semen extenders (Tris-egg yolk or the commercial optiXcell IMV medium (IMV Technologies)) for semen cryopreservation. Four Santa Inês rams were used during the breeding season. After semen collection, macroscopic and microscopic evaluations were performed, and a pool of semen was formed. The semen was diluted, and the final concentration was 100×106 per 0.25-mL straw. Cryopreservation was performed with a cooling rate of 0.25°C min−1 until 5°C, and the freezing rate used was 20°C min−1 from 5 to −120°C. After the freezing-thawing process and throughout incubation (38°C in 5% CO2) in Fert-Tyrode's albumin lactate pyruvate medium, every 1h for up to 3h, several parameters were evaluated: sperm kinetics, hypo-osmotic test, plasma membrane integrity, capacitation status, and lipid peroxidation level. We did not find any protective effect of LC on plasma membrane integrity, hypo-osmotic test, and capacitation status. The sperm kinetics values throughout incubation showed that Tris extender promoted better indices of staight-line velocity, linearity, wobble, and straightness than IMV extender along incubation, regardless of the presence of LC. There were no benefits of the LC addition throughout the incubation, and 10mM was deleterious to few parameters (amplitude of lateral head displacement, linearity, and wobble) compared with the control (0mM) in the Tris extender group. The plasma membrane integrity analysis revealed no differences (P&amp;gt;0.05) among the groups. The average number of intact cells (hypo-osmotic) was higher in Tris extender groups supplemented with 10mM LC at 1h and 5mM LC at 2h compared to the respective extender IMV groups. Regarding capacitation status, the Tris 5mM LC group had more acrosome-reacted cells when compared with the IMV 5mM LC group at 2h. At 3h, the percentage of acrosome-reacted cells was higher in the Tris 0-mM group when compared with the IMV 0-mM group. Regardless the presence of LC, IMV had higher (P&amp;lt;0.05) lipoperoxidation than the Tris treatments. In conclusion, LC supplementation in semen extender had no beneficial effect on freezing-thawing ram sperm and throughout incubation for up to 3h, with no difference in each time point evaluated. Under the conditions of this study, the use of Tris extender was superior to IMV extender for ram sperm. Financial support for this work came from the Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (Young Scientist Program of Our State; E-26/203.168/2017).

Action of Cholesterol-Loaded Cyclodextrin on Viability of Ram Semen

Background: Studies report that cyclodextrins have the property of carrying cholesterol to the membrane, but in some cases can also remove this cholesterol from the plasma membrane. The mechanism of action of CLC is not well understood, however, it seems to involve sperm protection during the freezing and thawing process. Studies show that its use enhancing increased osmotic tolerance and reduced premature sperm capacitation reaction. In this sense, studies report that cyclodextrins have the property of carrying cholesterol to the membrane, but in some cases can also remove this cholesterol from the plasma membrane. Improvements were reported in the sperm parameters of buffaloes, bulls, stallions and sheep. Ram naturally present less lipids in their membrane, on average 27%, while bulls have 31%, rabbits 62%, and humans 50%. The aimed of the present study was to evaluate the use of cholesterol-loaded cyclodextrin (CLC), a commercial diluent, in the kinetics and viability of frozen and thawed ram spermatozoa. Materials, Methods &amp; Results: Five ejaculates, from five rams of Dorper breed were collected and divided into three groups: control, 1 mg CLC and 2 mg CLC. Semen was diluted in different concentrations of CLC (0, 1, and 2 mg/120×106 spermatozoa), and incubated at room temperature (21°C) for 10 min. Samples were conditioned in 0.5 mL straws and incubated at 5°C for 4 h, exposed to LN2 vapor for 10 min and storing a cryogenic container. The parameters as spermatic kinetics, plasma membrane, acrosomal membrane (MPAI, %), and intracellular levels of superoxide anion (O2-) were evaluated. Sperm progressive motility (PM), rapid spermatozoa percentage (RAP), linearity (LIN, %), average path velocity (VAP, μm/s) and MPAI (%) were more satisfactory with the use of 1 mg compared to 2 mg (P &lt; 0.05). In addition, 1 mg CLC showed decreased levels of superoxide anion formation (O2-), a free radical detrimental to spermatozoa (P &lt; 0.05). The use of 2 mg of CLC reduce VAP (P &lt; 0.05) and did not have any beneficial effect on the evaluated parameters. Discussion: Authors did not observe improvement in the parameters of progressive motility when using 1 mg of CLC in goat semen and 2 mg in bull semen with the slow freezing protocol. This differs from our work, as we found that 1 mg of CLC improved the PM parameters, but not at the concentration of 2 mg CLC. Additionally, authors verified that cyclodextrin at 3 mg concentration was effective in protecting the sperm against the deleterious effects of H2O2. They obtained superior plasma membrane motility, viability, and integrity of the CLC-treated samples compared to the control group. The superoxide anion (O2-) is a free radical formed from molecular oxygen by the addition of an electron. It is generated spontaneously, mainly in the membrane of the mitochondria, by the respiratory chain and by flavoenzimes, lipoxygenases, and cicloxygenases. In our study, we found a difference between the study group with 1 mg CLC and the control group. Thus, we suggest that CLC may have a beneficial effect in stabilizing the sperm plasma membrane. Use of CLC at a concentration of 1 mg was found to be effective for the improvement of parameters of sperm progressive motility, rapid sperm percentage, and plasma and acrosomal membrane integrity. In addition, the study group with 1 mg of CLC showed decreased levels of superoxide anion formation, a free radical detrimental to spermatozoa.

Deletion of a Seminal Gene Cluster Reinforces a Crucial Role of SVS2 in Male Fertility.

Multiple genes, whose functions or expression are overlapping, compensate for the loss of one gene. A gene cluster in the mouse genome encodes five seminal vesicle proteins (SVS2, SVS3, SVS4, SVS5, and SVS6). These proteins are produced by male rodents and function in formation of the copulatory plug following mating. SVS2 plays an essential role in the successful internal fertilization by protecting the sperm membrane against a uterine immune attack. We hypothesized that the four remaining seminal vesicle proteins (SVPs) of this gene cluster may partially/completely compensate for the deficiency of SVS2. For confirming our hypothesis, we generated mice lacking the entire SVP-encoding gene cluster and compared their fecundity with Svs2-deficient (Svs2−/−) mice; that is, mice deficient in Svs2 alone. A single loxP site remained after the deletion of the Svs2 gene. Therefore, we inserted another loxP site by combining the CRISPR/Cas9 system with single-stranded oligodeoxynucleotides (ssODN). Male mice lacking the entire SVP-encoding gene cluster (Svs2–6−/− mice) and thereby all five SVP proteins, generated by the deletion of 100kbp genomic DNA, showed low fecundity. However, the fecundity level was comparable with that from Svs2−/− male mice. Our results demonstrate that SVS3, SVS4, SVS5, and SVS6 do not function in the protection of sperm against a uterine immune attack in the absence of SVS2. Thus, Svs2 is the critical gene in the SVP gene cluster.

Ready for the journey: a comparative proteome profiling of porcine cauda epididymal fluid and spermatozoa

In the present study, we describe the proteome of porcine cauda epididymis fluid and spermatozoa by means of Multidimensional Protein Identification Technology (MudPIT). Ten sexually mature healthy boars were surgically castrated and epididymides were dissected to obtain the cauda epididymal content. Polled protein extracts of cauda epididymal fluid (CEF) and spermatozoa (CESperm) were loaded in an Agilent 1100 quaternary HPLC and peptides eluted from the microcapillary column were electro-sprayed directly into a LTQ Orbitrap XL mass spectrometer. Using bioinformatics, identified proteins were classified by their molecular functions, involvement in biological processes and participation in relevant metabolic pathways associated with spermatozoa physiology, fertility potential and protection. A total of 645 proteins were identified in the CEF, with epididymal-specific lipocalin-5, beta-hexosaminidase subunit beta precursor and phosphatidylethanolamine-binding protein 4 being the most abundant proteins found. A total of 2886 proteins were identified in the CESperm proteome with 81 proteins being considered more abundant (spectral counts > 100). CEF and CESperm data were compared and 345 proteins were present in both proteomes. Phosphatidylethanolamine-binding protein 4 precursor was the only protein found most abundant in both CEF and CESperm proteomes. Based on Gene Ontology analysis, we identified CEF and CESperm proteins associated with sperm protection against ROS and immune mediated response, glycosaminoglycan degradation, ubiquitin-proteasome system, metabolic process and maturation, modulation of acrosome reaction and ZP binding and oocyte penetration. These results provide a better comprehension about the molecular process and biological pathways involved in sperm epididymis maturation and establishment of the cauda epididymis sperm reservoir.

Impact of semen-derived amyloid (SEVI) on sperm viability and motility: its implication in male reproductive fitness.

Human semen contains a large number of macromolecules, including proteins/enzymes and carbohydrates, regulating and protecting sperm cells. Proteomic analysis of human seminal fluid led to the discovery of semen amyloids derived from short peptide fragments of the proteins prostatic acid phosphatase (PAP) and semenogelin (SG) which are known to play a crucial role in enhancing HIV infection. However, the relevance of their existence in human semen and role in maintaining sperm behavior remains unclear. Distinct physiological, biochemical, and biophysical attributes might cause these amyloids to influence sperm behavior positively or negatively, affecting fertilization or other reproductive processes. We assessed the direct effect of amyloids derived from a PAP248-286 fragment, on sperm motility and viability, which are crucial parameters for assessment of sperm quality in semen. Co-incubation of human sperm with PAP248-286 amyloids at normal physiological concentrations formed in buffer led to significant reduction in sperm viability, though approximatelya 10× higher concentration was needed to show a similar effect with amyloid formed in seminal fluid. Both forms of PAP248-286 amyloid also had a significant impact on sperm motility at physiological levels, in agreement with a previous report. Our study suggests that PAP248-286 amyloids can directly influence sperm motility and viability in a concentration-dependent manner. We hypothesise that the direct toxic effect of PAP248-286 amyloid is normally mitigated by other seminal fluid ingredients, but that in pathological conditions, where PAP248-286 concentrations are elevated and it plays a role in determining sperm health and viability, with relevance for male fertility as well as sterility.