Iodixanol supplementation during sperm cryopreservation improves protamine level and reduces reactive oxygen species of canine sperm

Canine sperm motility is associated with telomere shortening and changes in expression of shelterin genes

BACKGROUND

Motion quality is a critical property for essential functions. Several endogenous and exogenous factors are involved in sperm motility. Here, we measured the relative telomere length and evaluated the gene expression of its binding-proteins, shelterin complex (TRF1, TRF2, RAP1, POT1, TIN2, and TPP1) in sperm of dogs using relative quantitative real-time PCR. We compared them between two sperm subpopulations with poor and good motion qualities (separated by swim-up method). Telomere shortening and alterations of shelterin gene expression result from ROS, genotoxic insults, and genetic predisposition.

RESULTS

Sperm kinematic parameters were measured in two subpopulations and then telomeric index of each parameter was calculated. Telomeric index for linearity, VSL, VCL, STR, BCF, and ALH were significantly higher in sperms with good motion quality than in sperms with poor quality. We demonstrated that poor motion quality is associated with shorter telomere, higher expression of TRF2, POT1, and TIN2 genes, and lower expression of the RAP1 gene in dog sperm. The levels of TRF1 and TPP1 gene expression remained consistent despite variations in sperm quality and telomere length.

CONCLUSION

Data provided evidence that there are considerable changes in gene expression of many shelterin components (TRF2, TIN2, POT1and RAP1) associated with shortening telomere in the spermatozoa with poor motion quality. Possibly, the poor motion quality is the result of defects in the shelterin complex and telomere length. Our data suggests a new approach in the semen assessment and etiologic investigations of subfertility or infertility in male animals.

Iodixanol supplementation in freezing extender improves the antioxidant capacity of semen

The aim of this study was to evaluate the effect of supplementing bovine semen freezing extender with different concentrations of iodixanol on post-thaw sperm characteristics. Six ejaculates of three Nellore bulls were pooled and diluted in commercial extender (BotuBov®) and then divided into 4 groups: control group (without adding iodixanol); groups G1.5, G3, or G6 according to the concentration of iodixanol solution (RedCushion®). After dilution, the samples were cooled and frozen. Post-thaw semen evaluation included sperm motility by CASA immediately after thawing and after 60 min of incubation at 37°C, flow cytometry analysis for integrity of plasma and acrosomal membranes, membrane destabilization and translocation of phosphatidylserine, mitochondrial membrane potential, and formation of intracellular anion superoxide (O 2 - ), hydrogen peroxide (H2 O2 ), and membrane lipid peroxidation. The group G6 presented significantly higher (p < .05) total and progressive motility, percentage of plasma and acrosomal membrane integrity, and H2 O2 than control and group G1.5. Furthermore, group G6 showed lower (p < .05) lipid peroxidation than control. In addition, regardless of the concentration used, the percentage of spermatozoa without phosphatidylserine translocation was higher (p < .05) in all iodixanol supplemented groups. In conclusion, iodixanol supplementation preserved the motility and integrity of sperm membranes during cryopreservation and protected against lipid peroxidation.

Effects of extender filtration and egg yolk concentration on canine semen cryopreservation

The semen cooling and freezing extenders commonly contain the chicken egg yolk (EY) as the main sperm cryoprotectant. Besides its advantages, the EY has large lipoprotein granules that cause several physical and biological interferences. The previous studies have proposed several methods to resolve the problems with the EY-based semen extenders, including mechanical agitation, EY fractionation, replacing the EY with purified EY LDL, and ultrasonication. In the current research, we aimed to evaluate the syringe filtration (220 nm) of an EY-based canine semen freezing extender as a simple and cheap method to remove the EY granules. We also studied the possibility of re-aggregation of EY granules after cooling, freeze/thawing, and lyophilization/rehydration of the filtered extenders. Additionally, we compared the effects of the filtration on lipid profile, turbidity, EY particle size distribution, and osmolality of the EY-based extenders. Next, we examined the effects of filtered extenders containing different levels of EY (5%, 10%, 15%, 20%, and 25%) versus the control extender (20% EY, unfiltered) on post-thaw sperm quality traits. We collected the semen samples from seven clinically healthy mixed-breed adult dogs and pooled them for sperm freezing procedures. Samplings were repeated at least five times, independently. Our results indicated that the syringe filtration could remove the large EY particles and reduce the extender turbidity without affecting the lipid profile of the whole extender solution. The filtered extender supplemented with 25% (v/v) EY led to the best post-thaw canine spermatozoa quality markers. The frozen-thawed spermatozoa evaluations included motility parameters (computer-assisted semen analysis system), membrane and acrosome integrity (hypo-osmotic swelling test, chlortetracycline binding assay), DNA fragmentation (sperm chromatin dispersion assay), membrane lipid peroxidation (MDA levels), apoptosis (Annexin V/propidium iodide assay), and fertility-associated sperm mRNA transcript abundance (protamine 2 and 3). In conclusion, the syringe filtration of the EY-based semen extenders was a simple and cheap method that could effectively remove large EY lipoprotein granules and possibly prevent EY-origin bacterial contamination of the final extender solution. The EY at 25% (v/v) concentration in the filtered extenders resulted in the highest canine spermatozoa cryo-tolerance.

The Association of Oxidative Stress and Reactive Oxygen Species Modulator 1 (ROMO1) with Infertility: A Mini Review

Infertility is one of the disorders that worries many couples around the world, although novel and molecular methods can be used to cure this disease in different stages. One of the factors that causes infertility in men and women is the increased oxidative stress within the cells, which can lead to damage in zygote formation. ROMO1 is one of the most important proteins in the production of reactive oxygen species. This protein can enhance oxidative stress in the cells and body through cellular pathways, such as TNF-α and NF-κB routes, which will eventually lead to many diseases, especially infertility. We engage several international databases by using keywords; ROMO1, Infertility, and Reactive Oxygen Species, and gained a great quantity of information about ROMO1, Infertility, and Oxidative Stress. Although not proven, it is hypothesized that ROMO1 might elevate oxidative stress by activating NF-κB pathway in the cells, furthermore, TNF-α can arouse ROMO1 that can end up with apoptosis and cell death, which consequently can have a lot of disturbing effects on the body, especially the reproductive system. To sum up, revealing the exact cellular and molecular mechanisms of ROMO1-dependent TNF-α and NF-κB pathways in the pathogenesis of infertility might find interesting therapeutic and management strategies for this disorder.

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

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

Antioxidant Activity and Oxidative Stress-Oriented Apoptosis Pathway in Saccharides Supplemented Cryopreserved Sperm of Pacific Abalone, Haliotis discus hannai

The Pacific abalone Haliotis discus hannai is a highly commercialized seafood in Southeast Asia. The aim of the present study was to determine the antioxidant activity and oxidative stress-oriented apoptosis pathway in saccharides supplemented cryopreserved sperm of Pacific abalone. Cryopreserved sperm showed impaired antioxidant defenses due to the reduced mRNA abundance of antioxidant genes (CAT, Cu/Zn-SOD, Mn-SOD, GPx, GR, and BCL-2), apoptosis inhibitor (HSP70, and HSP90) gene, and enzymatic antioxidant activity compared to fresh sperm. Such impaired antioxidant defenses caused an increase in the mRNA expression of apoptosis genes (Bax, and Caspase-3), finally leading to apoptosis. The impaired antioxidant defense also increased O₂^•− production and lipid peroxidation (MDA) levels, which further accelerated apoptosis. Considering all the experimental findings, an apoptosis pathway of cryopreserved sperm has been adopted for the first time. Specifically, sperm cryopreserved using 3% sucrose combined with 8% dimethyl sulfoxide (DMSO) showed improved mRNA stability, enzymatic activity, and DNA integrity with reduced O₂^•− production and MDA levels compared to sperm cryopreserved with the other types of examined cryoprotectants (8% ethylene glycol + 1% glucose, 6% propylene glycol + 2% glucose, 2% glycerol + 3% glucose, and 2% methanol + 4% trehalose). The present study suggests that 3% sucrose combined with 8% DMSO is suitable to cryopreserve the sperm of this valuable species for molecular conservation.

PRM1 Gene Expression and Its Protein Abundance in Frozen-Thawed Spermatozoa as Potential Fertility Markers in Breeding Bulls

Functional genes and proteins in sperm play an essential role in bulls’ reproductive processes. They are more accurate in determining bull fertility than conventional semen quality tests. Protamine-1 (PRM1) is a gene or protein crucial for packaging and protecting sperm DNA until fertilization affects normal sperm function. This study analyzes the genes and proteins potential from PRM1 as fertility markers for different breeds of bulls utilized in the artificial insemination programs, expected to be an accurate tool in interpreting bull fertility in Indonesia. This study used Limousin, Holstein, and Ongole Grade bulls divided into two groups based on fertility, high-fertility (HF) and low fertility (LF). The semen quality assessment included progressive motility (computer-assisted semen analysis), viability (eosin-nigrosine), and plasma membrane integrity (HOS test). Sperm DNA fragmentation (SDF) was assessed using the acridine orange staining and the Halomax test. Sperm PRM deficiency was evaluated with the chromomycin A3 method. Moreover, PRM1 gene expression was measured using qRT-PCR, and the PRM1 protein abundance was measured with the enzyme immunoassay method. Semen quality values, relative expression of PRM1 gene, and quantity of PRM1 protein were significantly higher (p < 0.05) in HF bulls than in LF bulls. The SDF and PRM deficiency values in LF bulls were significantly higher (p < 0.05) than HF bulls. Additionally, PRM1 at the gene and protein levels correlated significantly (p < 0.01) with fertility. Therefore, PRM1 is a potential candidate for fertility markers in bulls in Indonesia.

The potential of sperm bovine protamine as a protein marker of semen production and quality at the National Artificial Insemination Center of Indonesia

Background and Aim:

Protamine (PRM) is the major protein in the sperm nucleus and plays an essential role in its normal function. Moreover, PRM has great potential as a protein marker of semen production and quality. This study aimed to assess the potential of sperm bovine PRM as a protein marker of semen production and quality in bulls at the National Artificial Insemination (AI) Center of Indonesia.

Materials and Methods:

The semen production capacity of each bull was collected from frozen semen production data at the Singosari AI Center for 6 months, and was then divided into two groups (high and low). A total of 440 frozen semen straws from six Limousin (LIM), six Friesian Holstein (FH), six Peranakan Ongole (PO), and four Aceh bulls aged 4-5 years were used in the study. The frozen semen was used to measure the concentration of PRM1, PRM2, and PRM3 using the enzyme immunoassay method. The frozen semen was also used to assess the quality of the semen, including progressive motility (PM) through computer-assisted semen analysis, sperm viability through eosin–nigrosin analysis, and the DNA fragmentation index through Acridine Orange staining.

Results:

PRM1 was significantly higher in all bull breeds included in the study (p<0.00), followed by PRM2 (p<0.00) and PRM3 (p<0.00). PRM1 significantly affected semen production in LIM, FH, PO, and Aceh bulls (p<0.05). Moreover, PRM2 significantly affected semen production only in FH and Aceh bulls (p<0.05), whereas PRM3 affected this parameter in PO and Aceh bulls exclusively (p<0.05). Consistently and significantly, PRM1 was positively correlated with the PM and viability of sperm and negatively associated with its DNA fragmentation in LIM, FH, PO, and Aceh bulls (p<0.05; p<0.01). The correlation analysis between PRM2 and PRM3 and semen quality parameters varied across all bull breeds; some were positively and negatively correlated (p<0.05; p<0.01), and some were not correlated at all.

Conclusion:

PRM1 has excellent potential as a protein marker of semen production and quality in bulls at the National AI Center of Indonesia.

Assisted reproductive techniques for canines: preservation of genetic material in domestic dogs

Assisted reproductive techniques (ARTs), such as artificial insemination, in vitro fertilization, and cryopreservation of gametes/zygotes, have been developed to improve breeding and reproduction of livestock and for the treatment of human infertility. Their widespread use has contributed to improvements in human health and welfare. However, in dogs, only artificial insemination using frozen semen is readily available as an ART to improve breeding and control genetic diversity. A recent priority in sperm cryopreservation is the development of alternatives to egg yolk, which is widely used as a component of the sperm extender. Egg yolk can vary in composition among batches and is prone to contamination by animal pathogens. The latter can be a problem for international exchange of cryopreserved semen. Low-density lipoprotein and skim milk are promising candidates for use as extenders, to ensure fertility after artificial insemination. Although not tested for its effects on fertility following artificial insemination, polyvinyl alcohol may also be a useful alternative to egg yolk as an extender. The development of cryopreservation techniques for canine embryos lags behind that for other mammals, including humans. However, given the success of non-surgical embryo transfer in 2011, studies have sought to refine this approach for practical use. Research on sperm cryopreservation has yielded satisfactory results. However, investigation of other approaches, such as cryopreservation of oocytes and gonadal tissues, remains insufficient. Techniques for the efficient induction of estrus may aid in the development of successful canine ARTs.

Overview on the Antioxidants, Egg Yolk Alternatives, and Mesenchymal Stem Cells and Derivatives Used in Canine Sperm Cryopreservation

Sperm cryopreservation is a widely used assisted reproductive technology for canine species. The long-term storage of dog sperm is effective for the breeding of dogs living far apart, scheduling the time of artificial insemination that suits the female, and preventing diseases of the reproductive tract. However, spermatozoa functions are impaired during the freeze-thaw processes, which may decrease reproductive performance. Numerous attempts have been made to restore such impairments, including the use of cryoprotectants to prevent the damage caused by ice crystal formation, and supplementation of antioxidants to reduce reactive oxygen species generation due to osmotic stress during the procedure. Egg yolk derivatives, antioxidants, and, more recently, mesenchymal stem cells (MSCs) and their derivatives have been proposed in this research field. This review article will summarize the current literature available on the topic.

Effect of Bovine Serum Albumin Supplementation in Tris-Soybean Lecithin-Based Extender on Quality of Chilled Ram Epididymal Spermatozoa

Objective: This study was designed to assess the effects of using tris-soybean lecithin (TSL)-based extender supplemented with bovine serum albumin (BSA) on the quality of ram epididymal spermatozoa during refrigerated storage. Method: Epididymal sperm were collected from 22 Zandi rams, diluted in TSL-based extender at different concentrations (0%, 2.5%, 5%, 7.5%, and 10%) of BSA, and stored for 5 days at 4°C. Sperm parameters including motility, viability, plasma membrane integrity, chromatin protamination, and malondialdehyde (MDA) content were evaluated at 0, 24, 72, and 120 hours of refrigeration. Results: The addition of 10% BSA to the extender significantly improved sperm viability at 24 and 120 hours of refrigerated liquid storage (p < 0.05). An enhancement in plasma membrane integrity was observed along with a decrease in MDA level by increasing the concentration of BSA from 0% to 10% (p > 0.05). Sperm motion characteristics were higher in the BSA-free group at 120 hours of preservation (p < 0.05). No statistical difference was found for nuclear protamination between experimental groups (p > 0.05). Conclusion: BSA supplementation in TSL-based extender can preserve the viability of epididymal ram spermatozoa during liquid storage at 4°C.

Conditioned Medium from Canine Amniotic Membrane-Derived Mesenchymal Stem Cells Improved Dog Sperm Post-Thaw Quality-Related Parameters

Simple Summary

Mesenchymal stem cells and their derivatives are used in clinical studies for their anti-apoptotic, anti-oxidant, immunomodulatory, and regenerative properties. Their use in reproductive medicine is increasing as they have been proved to be beneficial for infertility treatment. Mesenchymal stem cells can secrete factors that influence biological processes in target tissues or cells; these factors are either directly secreted by the cells or mediated through their derivatives. Although the amniotic membrane is easy to obtain and is a good source of stem cells, clinical trials using amniotic membrane-derived mesenchymal stem cells are still uncommon, especially in reproductive medicine or artificial reproductive technologies. The objective of the present study was to demonstrate the effects of conditioned medium prepared from amniotic membrane-derived stem cells on dog sperm cryopreservation. Our results showed that 10% of the conditioned medium enhanced the quality-related parameters of frozen–thawed sperm cells because of the presence of antioxidants and growth factors in the medium, which probably protected spermatozoa during the freeze–thaw process. These results suggest that conditioned media prepared from amniotic membrane-derived mesenchymal stem cells might have clinical applications in assisted reproductive technologies.

Abstract

This study investigated the effects of conditioned medium (CM) from canine amniotic membrane-derived MSCs (cAMSCs) on dog sperm cryopreservation. For this purpose, flow cytometry analysis was performed to characterize cAMSCs. The CM prepared from cAMSCs was subjected to proteomic analysis for the identification of proteins present in the medium. Sperm samples were treated with freezing medium supplemented with 0%, 5%, 10%, and 15% of the CM, and kinetic parameters were evaluated after 4–6 h of chilling at 4 °C to select the best concentration before proceeding to cryopreservation. Quality-related parameters of frozen–thawed sperm were investigated, including motility; kinetic parameters; viability; integrity of the plasma membrane, chromatin, and acrosome; and mitochondrial activity. The results showed that 10% of the CM significantly enhanced motility, viability, mitochondrial activity, and membrane integrity (p < 0.05); however, the analysis of chromatin and acrosome integrity showed no significant differences between the treatment and control groups. Therefore, we concluded that the addition of 10% CM derived from cAMSC in the freezing medium protected dog sperm during the cryopreservation process.

Does resveratrol affect prepared sperm parameters and chromatin quality in normozoospermic and asthenozoospermic patients before and after freezing? A lab trial study

Background

Previous studies have examined the effect of resveratrol as a potent antioxidant for free radicals in semen. While, the prepared spermatozoa are more affected by ROS factors due to centrifugation and incubation.

Objective

To evaluate the RSV's effects on the prepared sperm parameters and chromatin quality in both normozoospermic and asthenozoospermic cases before and after freezing.

Materials and Methods

The sample of 10 normozoospermic and asthenozoospermic men was prepared through the swim-up method. The groups were then divided into two samples of control and experimental (exposure to 30 µmol/l of RSV) to evaluate and compare the sperm parameters and chromatin quality before and after freezing.

Results

The motility and viability of spermatozoa were seen to be significantly different before and after freezing separately in the control and treatment samples of the groups (p ≤ 0.001 and p = 0.001, respectively). However, the stated difference between the control and treatment samples of normozoospermic and asthenozoospermic patients were not significant (p > 0.05). In addition, the sperm morphology and chromatin quality were not significantly different between the two samples of each group; nonetheless, chromatin quality of the treated sample was better than that of the control before and after freezing.

Conclusion

Despite the protective effects of RSV on the semen samples, RSV cannot affect significantly the prepared sperms parameters and chromatin quality in normozoospermic and asthenozoospermic patients.

The effect of astaxanthin supplementation on the post-thaw quality of dog semen

Astaxanthin is a member of the carotenoid family well known for its anti-cancer, anti-diabetic, anti-inflammatory and antioxidant nature. This study was designed to investigate the effects of astaxanthin supplementation of the extender (buffer 2) on post-thaw dog semen quality. Semen from four healthy dogs was collected by digital manipulation twice a week. The ejaculates were pooled, washed, divided into four equal aliquots, diluted with the extender supplemented with different concentrations of astaxanthin (0, 0.5, 1 and 2 µM) and cryopreserved. The results showed that 1 µM astaxanthin was the optimum concentration that led to significantly higher (p < .05) post-thaw motility, kinematic parameters and viability than the other groups. In comparison with the control group, sperm samples supplemented with 1 µM astaxanthin showed significantly higher (p < .05) sperm counts with intact membranes (55.7 ± 0.6% vs. 51.3 ± 0.9%), intact acrosome (58.4 ± 0.7% vs. 53.5 ± 0.6%), active mitochondria (54.9 ± 0.5% vs. 42.6 ± 0.6%) and normal chromatin (67.6 ± 0.9% vs. 61.7 ± 0.6%). Furthermore, astaxanthin-supplemented samples showed significantly lower expression levels (p < .05) of pro-apoptotic (BAX), oxidative induced DNA damage repair (OGG1), oxidative stress-related (ROMO1) genes and higher expression levels of anti-apoptotic (BCL2), and sperm acrosome-associated (SPACA3) genes compared to the control. Thus, supplementation of 1 µM astaxanthin in semen extender results in improved freeze-thaw sperm quality of the dog.

Effects of kinetin supplementation on the post-thaw motility, viability, and structural integrity of dog sperm

Oxidative stress is one of the major issues associated with cryopreservation because it causes a marked reduction in the post-thaw quality of semen. This study investigated the ability of kinetin to preserve the structural and functional integrity of dog sperm during cryopreservation. Pooled ejaculates were divided into 5 equal aliquots, diluted with buffer 2 supplemented with different concentrations of kinetin (0, 25, 50, 100, and 200 μM), and finally cryopreserved. The optimal concentration of kinetin was 50 μM based on the significantly improved (P < 0.05) motion characteristics and viability of post-thaw sperm samples. Moreover, kinetin-supplemented samples exhibited significantly higher (P < 0.05) sperm counts with the intact plasma membrane, normal acrosomes, mitochondria, and chromatin than control. The beneficial effects of kinetin were also reflected by the significant increase in the expression levels of anti-apoptotic (B-cell lymphoma, BCL2) and protamine-related genes (protamine 2, PRM2; protamine 3, PRM3), and decrease in the expression of pro-apoptotic (BCL2-associated X, BAX) and mitochondrial reactive oxygen species-modulating genes (ROS modulator 1, ROMO1) in kinetin-supplemented sperm samples than in control. The results demonstrated that supplementation of buffer 2 with 50 μM kinetin is ideal for reducing the magnitude of oxidative damage during semen cryoprocessing and improving the post-thaw quality of dog semen.

Oviductal Extracellular Vesicles Improve Post-Thaw Sperm Function in Red Wolves and Cheetahs

Artificial insemination (AI) is a valuable tool for ex situ wildlife conservation, allowing the re-infusion and dissemination of genetic material, even after death of the donor. However, the application of AI to species conservation is still limited, due mainly to the poor survival of cryopreserved sperm. Recent work demonstrated that oviductal extracellular vesicles (oEVs) improved cat sperm motility and reduced premature acrosomal exocytosis. Here, we build on these findings by describing the protein content of dog and cat oEVs and investigating whether the incubation of cryopreserved red wolf and cheetah sperm with oEVs during thawing improves sperm function. Both red wolf and cheetah sperm thawed with dog and cat oEVs, respectively, had more intact acrosomes than the non-EV controls. Moreover, red wolf sperm thawed in the presence of dog oEVs better maintained sperm motility over time (>15%) though such an improvement was not observed in cheetah sperm. Our work demonstrates that dog and cat oEVs carry proteins important for sperm function and improve post-thaw motility and/or acrosome integrity of red wolf and cheetah sperm in vitro. The findings show how oEVs can be a valuable tool for improving the success of AI with cryopreserved sperm in threatened species.

Cushioned centrifugation during sperm selection increases the fertilization and cleavage rates of cattle embryos produced in vitro

This study was conducted to evaluate the effect of utilization of an iodixanol-based solution as a cushioning method during the sperm selection utilizing discontinuous Percoll gradient centrifugation in in vitro production (IVP) of cattle embryos. In Experiment I, all aliquots of thawed semen were subjected to sperm selection using the same discontinuous Percoll® gradients, except for the following four conditions: presence of cushioning solution (Cushion Fluid, Minitube) during the first centrifugation process (C1), presence of cushioning solution during the second centrifugation process (C2), inclusion of cushioning solution in both centrifugation steps (C1-2), and no addiction of cushioning solution (C; control group). Recovery rates, sperm kinetics, and reactive oxygen species (ROS) production were evaluated. In Experiment II, sperm cells were processed using sperm selection conditions C and C1, and fertilization rates and embryonic development kinetics were compared between experimental groups. With use of condition C1, there was improvement in fertilization and cleavage rates when compared to use of condition C (56.4% compared with 45.5% and 80.0% compared 64.7%, respectively). In conclusion, results indicate the use of a cushioning solution during sperm selection positively affects the developmental potential of embryos.

Improved viability and fertility of frozen-thawed dog sperm using adipose-derived mesenchymal stem cells

Cryopreservation procedures negatively affect the quality traits of sperm, causing certain changes at structural and molecular levels due to thermal, mechanical, osmotic, and oxidative damage. The objective of this study was to examine the potential of canine adipose-derived mesenchymal stem cells (Ad-MSCs) for providing protection to the dog sperm against cryo-damage. Canine Ad-MSCs were selected on the basis of the significantly higher gene expression for different proteins actively involved in the cell repair including annexin 1 (ANX1), histone H3 (H3) and high mobility group B (HMGB) protein compared to skin fibroblasts. Semen was collected from four healthy dogs by digital manipulation. The washed pooled ejaculates were diluted with buffer 2 (extender) supplemented without Ad-MSCs (Control), with 2.5 × 10⁶ Ad-MSCs/mL (Group 1) or with 5 × 10⁶ Ad-MSCs/mL (Group 2). Group 1 exhibited significantly higher post-thaw motility, live sperm, intact plasma membrane and normal acrosomes than the other groups. Additionally, Group 1 showed significantly higher expression levels of genes related to the repair of membranes (ANX1, dysferlin; DYSF, and fibronectin; FN1) and chromatin material (H3 and HMGB). Protein expression of ANX1, H 3, and FN1 was also statistically more in Group 1 than in Control. The results confirm that canine Ad-MSCs can effectively preserve the quality of frozen-thawed sperm by a reduction in cryoinjury. At an appropriate concentration, Ad-MSCs significantly improve the quality of post-thaw dog sperm.

Myoinositol Supplementation of Freezing Medium Improves the Quality-Related Parameters of Dog Sperm

Simple Summary

The generation of free radical reactive oxygen species during freeze–thaw procedures is one of the major factors affecting the function and survival of sperm. Myoinositol is the most important natural form of inositol produced in the human body. Researchers have attempted to exploit the antioxidant nature of myoinositol to treat human infertility issues via the improvement of sperm quality traits and fertilization rates. We investigated the potential role of myoinositol neutralizing free radicals produced during the cryopreservation of dog semen. Myoinositol supplementation in the freezing medium resulted in improved quality-related parameters of dog semen including percentage motility, viability, plasma membrane integrity, and chromatin integrity. Improvement in post-thaw semen quality was confirmed by the expression of genes related to apoptosis, nuclear integrity, and reactive oxygen species generation.

Abstract

Oxidative stress during freeze–thaw procedures results in reduced semen fertility. A decrease in free radical levels can improve the post-thaw sperm quality. We examined the effects of myoinositol supplementation in freezing medium on the structure and function of cryopreserved dog sperm. Pooled ejaculates were diluted with buffer without or with myoinositol (1 or 2 mg/mL). Analysis of fresh semen revealed that the optimal concentration of myoinositol was 1 mg/mL, and this concentration was used in further experiments. Post-thaw semen quality in the myoinositol-supplemented group was superior (p < 0.05) compared with that in the control group in terms of motility (57.9 ± 0.4% vs. 47.8 ± 0.2%), sperm viability (57.5 ± 0.5% vs. 44.6 ± 0.6%), intact plasma membrane (56.6 ± 0.4% vs. 46.2 ± 0.6%), and acrosome membrane (59.3 ± 0.5% vs. 51.8 ± 0.5%). In addition, sperm in the myoinositol-supplemented group showed a significantly lower expression of pro-apoptotic (BAX) and mitochondrial reactive oxygen species (ROS) modulator (ROMO1) genes but higher expression of anti-apoptotic (BCL2), and protamine-related (PRM2 and PRM3) genes compared with that in the control group. Therefore, myoinositol supplementation before freezing can protect against oxidative stress and improve post-thaw dog sperm quality.

Reactive Oxygen Species Modulator 1 (ROMO1), a New Potential Target for Cancer Diagnosis and Treatment

Today, the incidence of cancer in the world is rising, and it is expected that in the next several decades, the number of people suffering from cancer or (the cancer rate) will double. Cancer is defined as the excessive and uncontrolled growth of cells; of course (in simple terms), cancer is considered to be a set of other diseases that ultimately causes normal cells to be transformed into neoplastic cells. One of the most important causes of the onset and exacerbation of cancer is excessive oxidative stress. One of the most important proteins in the inner membrane of mitochondria is Reactive Oxygen Species (ROS) Modulator 1 (ROMO1) that interferes with the production of ROS, and with increasing the rate of this protein, oxidative stress will increase, which ultimately leads to some diseases, especially cancer. In this overview, we use some global databases to provide information about ROMO1 cellular signaling pathways, their related proteins and molecules, and some of the diseases associated with the mitochondrial protein, especially cancer.

The roles of reactive oxygen species and antioxidants in cryopreservation

Cryopreservation has facilitated advancement of biological research by allowing the storage of cells over prolonged periods of time. While cryopreservation at extremely low temperatures would render cells metabolically inactive, cells suffer insults during the freezing and thawing process. Among such insults, the generation of supra-physiological levels of reactive oxygen species (ROS) could impair cellular functions and survival. Antioxidants are potential additives that were reported to partially or completely reverse freeze-thaw stress-associated impairments. This review aims to discuss the potential sources of cryopreservation-induced ROS and the effectiveness of antioxidant administration when used individually or in combination.

Use of polyvinyl alcohol as a chemically defined compound in egg yolk-free extender for dog sperm cryopreservation

The objectives of this study were to investigate the effects of polyvinyl alcohol (PVA) as a chemically defined compound in egg yolk (EY)-free extender by determining the appropriate concentration of PVA and the effect of pH adjustment in EY-free PVA extenders on dog spermatozoa. Spermatozoa (1 × 10⁸  cells/ml) were frozen with EY-free extenders supplemented with 0 (control), 0.025, 0.05, 0.1, 0.2 or 0.3 g/100 ml PVA. Sperm progressive motility (PM) was assessed immediately after thawing (IAT) and post-thaw incubation (PTI), while viability, acrosome integrity and reactive oxygen species (ROS) levels were evaluated after PTI. Additionally, spermatozoa were frozen using EY-free PVA extenders before pH adjustment (6.45) and after adjustment of pH (6.85). Viability, PM, ROS and gene expression (BCL2 and SMCP) were assessed. Supplementation with 0.05 g/100 ml or more PVA significantly increased PM compared to the control group in the IAT and PTI. Post-thaw incubation significantly increased sperm motility in all groups. The acrosome integrity in all PVA groups was higher (p < .05) than the control without an effect on ROS and viability. Adjustment of the pH to 6.85 improved (p < .05) sperm PM compared to the non-adjusted groups without affecting viability, ROS or expression of BCL2 and SMCP. We suggest that PVA supplementation in EY-free Tris extenders can effectively protect dog spermatozoa during freezing and can maintain higher motility and acrosome integrity. Adjustment of pH in EY-free PVA extenders can improve post-thaw sperm motility. Therefore, PVA can be used as a compound in EY-free extender for the cryopreservation of dog spermatozoa.