Combination of fetuin and trehalose in presence of low glycerol has beneficial effects on freeze-thawed ram spermatozoa

Extender development for optimal cryopreservation of buck sperm to increase reproductive efficiency of goats

Preservation of sperm significantly contributes to the advancement of assisted reproductive technologies, genetic conservation and improvement efforts, and precision breeding of livestock. This review distills knowledge from the existing information and emerging patterns in the field of buck sperm cryopreservation. The primary focus is on the challenges and opportunities associated with improving extender formulations and freezing techniques in order to enhance the vitality of sperm after thawing and to increase the potential for conception. This review assesses the efficacy and limitations of conventional extenders derived from egg yolk or soybean lecithin, and the adverse impacts of seminal plasma enzymes on sperm quality during the processes of chilling and cryopreservation. Significant progress has been made in the fields of molecular biology namely lipidomics, proteomics, metabolomics, DNA methylation providing valuable knowledge regarding the unique reactions of sperm to cryopreservation. The utilization of the "omics" technologies has shown intricate molecular transformation that occur in sperm during freezing and thawing. Moreover, detection of molecular biomarkers that indicate the quality of sperm and their ability to withstand freezing provides opportunities to choose the best sperm samples for cryopreservation. This, in turn, enhances the results of artificial insemination and genetic conservation endeavors. This review emphasizes the necessity for adopting a comprehensive approach that combines molecular and cellular knowledge with practical methods in the field of sperm cryopreservation to ensure production of goats as major food animals in the global scale.

A review on the functional roles of trehalose during cryopreservation of small ruminant semen

Sperm cryopreservation is an approach to preserve sperm cells in liquid nitrogen or other cryogenic media for future use in assisted reproductive technologies, such as in vitro fertilization or artificial insemination. Sperm cryopreservation has been extensively used in the dairy industry and has attained excellent results after artificial insemination. However, for small ruminants the application of sperm cryopreservation is limited, due to the poor quality of frozen semen and special characteristics of the reproductive female tract. In order to improve post-thaw semen quality various cryoprotectants are used. Currently, many types of cryoprotectants, such as permeable organic solvents, sugars, antioxidants, and natural or synthetic ice blockers, have been tested on small ruminants' sperm cryopreservation. Among them, trehalose; has shown potential acting as an excellent cryoprotectant for semen freezing. While, the exact roles and action mechanisms of trehalose during cryopreservation remain unclear. In this review, we systematically summarized the present usage status, potential action mechanisms, and future application prospects of trehalose in small-ruminant sperm cryopreservation.

Lipid mixtures (from a liposome kit) and melatonin improve post-thawed Angora goat sperm parameters

Semen freezing and storing has been widely used in reproductive biotechnology, being applied to certain males of livestock breeds or animal species with economic value such as the Angora goat. The development of a semen extender with the cryoprotective agents can prevent the deterioration of sperm parameters after thawing. This study aimed to investigate lipid mixtures (from a liposome kit, Lps) and melatonin (Mel) at different doses to prevent the deterioration of sperm parameters and to provide the cryoprotective effects on sperm DNA. The Angora goat ejaculates were collected and pooled. They were divided into seven equal volumes, and each of them was diluted with the extenders of the experimental groups with additives (Lps 321.99 μg/mL, Lps 841.33 μg/mL, Mel 0.25 mM, Mel 1 mM, Lps 321.99 μg/mL + Mel 1 mM, Lps 841.33 μg/mL + Mel 0.25 mM) and no additives (control group). After the freeze-thawing process, motility, viability, acrosome integrity, DNA double-strand breaks, and abnormal DNA integrity were assessed for different extender groups. It was determined that the use of Lps alone at low dose or the combination of Lps and Mel had significant cryoprotective effects on motility, viability, acrosome integrity, and DNA damage in Angora goat sperm. This study will help us to understand the effects of Lps and Mel used alone or in combination at different doses and which doses give the optimum spermatological parameter rates following the freeze-thawing process, and hence it will shed light on further studies.

Reduction of cryopreservation-induced structural, functional and molecular damages in ram sperm by hydrated C60 fullerene

This study aimed to investigate the morphological, functional and molecular changes in frozen-thawed ram sperm using an extender containing different concentrations of hydrated carbon 60 fullerene (C60 HyFn), a nanotechnological product. Semen taken from each of the seven Akkaraman rams were pooled. Semen collection was done twice a week and it continued for 3 weeks. Each pooled semen sample was divided into six equal groups and diluted with tris + egg yolk extender including 0 (control), 200, 400, 800 nM, 1 and 5 μM concentrations of C60 HyFn at 37°C. They were then frozen in liquid nitrogen vapour at -140°C, stored in liquid nitrogen container (-196°C) and thawed at 37°C for 25 s before analysis. In comparison with control, C60 HyFn addition prior to freezing procedure provided significant increases in total and progressive motility rates, glutathione peroxidase, catalase activities and percentage of highly active mitochondria, and significant decreases in dead and abnormal sperm rates, lipid peroxidation, caspase-3 and DNA fragmentation levels in frozen-thawed ram semen. When compared to control, C60 HyFn supplementation significantly down-regulated the expression levels of miR-200a and KCNJ11, and significantly up-regulated the expression levels of miR-3958-3p (at the concentrations of 200, 400, 800 nM and 1 μM), CatSper1 (at the concentrations of 200, 400 nM and 5 μM), CatSper2 (at the concentrations of 1 and 5 μM), CatSper3 (at the concentrations of 200, 400 nM, 1 and 5 μM), CatSper4 (at all concentrations), ANO1 (at the concentrations of 800 nM, 1 and 5 μM) and TRPV5 (at the concentrations of 200, 400 and 800 nM). The addition of C60 HyFn had no effect on global DNA methylation rates. As a result, C60 HyFn supplementation to ram semen extenders may be beneficial in reducing some of the functional, structural and molecular damages in sperm induced by the freeze-thawing procedure.

Comparative RNA isolation methods from fresh ejaculated spermatozoa in Sahiwal cattle (Bos indicus) and Murrah buffalo (Bubalus bubalis) bulls for high quality and enhanced RNA yield

Sperm mRNA transcriptional profiling can be used to evaluate the fertility of breeding bulls. The aim of the study was to compare the modified RNA isolation methods for higher RNA yield and quality from freshly ejaculated sperm of cattle and buffalo bulls. Ten fresh ejaculates from each Sahiwal (n = 10 bulls × 10 ejaculates) and Murrah bulls (n = 10 bulls x 10 ejaculates) were used for RNA isolation. From the recovered live sperm, total sperm RNA was isolated by conventional methods (TRIzol, Double TRIzol), membrane-based methods combined with TRIzol (RNeasy + TRIzol) with the addition of β-mercaptoethanol (BME) and Kit (RNeasy mini) methods in fresh semen. Among different isolation methods; the membrane-based modified methods combined with TRIzol (RNeasy + TRIzol) with the addition of β-mercaptoethanol (BME) resulted significantly (p < .05) higher total RNA quantity (300-340 ng/µL) and better purity in different concentrations of spermatozoa viz., 30-40 million, 70-80 million and 300-400 million sperm. The study concluded that the inclusion of BME to the combined membrane-based methods with somatic cell lysis buffer solution was best for constant increased yield and purity of RNA isolation from Sahiwal cattle and Murrah buffalo bull sperm.

The Effects of Different Doses of ROCK Inhibitor, Antifreeze Protein III, and Boron Added to Semen Extender on Semen Freezeability of Ankara Bucks

In the presented study, the effects of ROCK inhibitor Y-27632, antifreeze protein III, and boron at two different doses were investigated on the spermatological parameters of Ankara buck semen after freeze−thawing. Ejaculates were collected from bucks using an electroejaculator during the breeding season. The ejaculates that showed appropriate characteristics were pooled and used in the dilution and freezing of semen. The extender groups were formed by adding two different doses of three different additives (ROCK inhibitor Y-27632, 5 and 20 µM; antifreeze protein III, 1 and 4 µg/mL; boron, 0.25 and 1 mM) to the control extender. The semen was diluted with the different extenders at 35−37 °C and loaded into straws. Sperm samples frozen in liquid nitrogen vapors, following equilibration, were stored in liquid nitrogen. It was observed that extender supplementation improved post-thaw motility of Ankara buck semen after freeze−thawing. Differences were significant (p < 0.01) for 5 and 10 µM doses of ROCK inhibitor (71.82% and 74.04 % motility), as well as for 0.25 and 1 mM doses of boron (76.36% and 72.08% motility), compared to the control group (66.15% motility). With respect to the evaluation of acrosomal integrity and mitochondrial activity after freeze−thawing, although supplementation provided protection at all doses, the efficacy was not statistically significant (p > 0.05). It was observed that DNA damage was improved by antifreeze protein III at 1 µg/mL (1.23% ± 0.23%) and by boron at all doses (0.25 mM: 1.83% and 1 mM: 1.18%) compared to the control group (3.37%) (p < 0.01), following the thawing process. In the present study, it was determined that some additives added to the extender provided significant improvements in buck spermatozoa motility and DNA damage after thawing.

Metabolomics analysis of buck semen cryopreserved with trehalose

Trehalose is commonly used as an impermeable cryoprotectant for cryopreservation of cells, but its cryoprotective mechanism has now not but been determined. This study investigated the cryopreservation impact of trehalose on buck semen cryopreservation and finished metabolic profiling of freeze-thawed media by way of the GC–MS-based metabolomics for the first time. Metabolic pattern recognition and metabolite identification by means of principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA) and metabolic pathway topology analysis revealed the results of trehalose on buck sperm metabolism at some point of cryopreservation. The results confirmed that trehalose drastically progressed sperm motility parameters and structural integrity after thawing. PCA and PLS-DA analysis discovered that the metabolic patterns of the freezing-thawing media of buck semen cryopreserved with trehalose (T group) or without trehalose (G group, Control) were certainly separated. Using screening conditions of VIP >1.5 and p vaule <0.05, a total of 48 differential metabolites have been recognized, whithin l-isoleucine, L-leucine, L-threonine, and dihydroxyacetone were notably enriched in valine, leucine and isoleucine biosynthesis, glycerolipid metabolism, and aminoacyl-tRNA biosynthesis pathways. In brief, trehalose can efficiently improve membrane structural integrity and motion parameters in buck sperm after thawing, and it exerts a cryoprotective impact with the aid of changing sperm amino acid synthesis and the glycerol metabolism pathway.

Proteomic profiling of cryopreserved Trichormus variabilis using various cryoprotectants

Algae, which may be unicellular or multicellular, can carry out photosynthesis just like plants as they effectively utilize light energy. They contain various physiologically active substances and are, therefore, widely used commercially to produce healthy food and feed additives, cosmetics, and energy supplements. For useful applications, the cryopreservation technique has been used in various fields. Recently, to develop suitable cryopreservation methods for algal applications, various studies have been performed. However, adequate investigations have not been conducted to understand the mechanism underlying algal cryopreservation at the molecular level. Therefore, this study examined the profile alteration of the proteome using cryopreservation with various cryoprotectants (CPAs). Trichormus variabilis was cultured and then cryopreserved with 10% dimethyl sulfoxide, methanol, and glycerol, after which, proteome profiling was done. Finally, signaling pathway search was performed, and a new signaling pathway was established based on differentially expressed proteins. As a result, the expression levels of 17 proteins were observed. Additionally, it was confirmed that the differentially expressed proteins were related to 16 signaling pathways and that they were capable of interacting with each other. The findings suggest that the differentially expressed proteins may be applied as biomarkers for algal cryopreservation and to understand the mechanism underlying T. variabilis cryopreservation. Moreover, it is anticipated that the results from this study would be useful in selecting suitable CPAs and in upgrading the cryopreservation techniques.

Trehalose can effectively protect sheep epididymis epithelial cells from oxidative stress

Trehalose, a naturally nontoxic disaccharide that does not exist in mammals, stabilizes cell membrane integrity under oxidative stress conditions, the mechanism of which is still unclear. Here, we analyzed the effects of trehalose on sheep epididymis epithelial cell (EEC) proliferation and its possible mechanisms. To study the effect of trehalose on EECs, EECs were isolated from testes of 12-month-old sheep; cell counting kit-8 (CCK-8) was used to measure the growth of the cells. Cell proliferation was evaluated by assaying cell cycle and apoptosis, and RT-PCR was utilized to identify the epididymal molecular markers glutathione peroxidase 5 (GPX5) and androgen receptor (AR). Next, reactive oxygen species (ROS) content was evaluated by a dichloro-dihydro-fluorescein diacetate (DCFH-DA) probe. Superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities were evaluated by enzyme chemistry methods, and GPX5 expression was evaluated by qRT-PCR and enzyme-linked immunosorbent assay (ELISA). The results showed that 100 mM trehalose significantly improved the proliferation potential of EECs, in which the cells could be serially passaged 14 times with continued normal GPX5 and AR marker gene expression in vitro. The trehalose can increase significantly a proportion of EECs in S phase (P<0.01) and decrease significantly the apoptotic rate of EECs (P<0.01) compared to the control. Moreover, the trehalose decreased ROS significantly (P<0.01) and increased CAT (P<0.01) and GSH-Px (P<0.05) activities significantly in EECs. GPX5 mRNA and protein expression were also significantly upregulated in trehalose-treated EECs (P<0.05 and P<0.01 respectively). Our study suggested that exogenous trehalose exhibited antioxidant activity through increasing the activities of CAT, GSH-Px, and the expression level of GPX5 and could be employed to maintain vitality of sheep EECs during long-term in vitro culture.

Synergistic effect of royal jelly in combination with glycerol and dimethyl sulfoxide on cryoprotection of Romanov ram sperm

Sperm fertility decreases significantly after freezing. Providing a suitable and useful diluent compound for freezing ram sperm can increase the efficiency of artificial insemination and consequently, the reproductive performance of sheep. Various biological properties such as antibacterial, anti-cancer, immunosuppressive, antioxidant and reproductive properties of royal jelly (RJ) are well known. The aim of this study was to investigate the possible synergistic effect of royal jelly in combination with glycerol and dimethyl sulfoxide (DMSO) in sperm cryopreservation extender of Romanov ram. The pooled semen samples from 5 Romanov rams were allocated into 3 experiments. The effect of 6% DMSO, 6% glycerol and a combination of 3% DMSO +3% glycerol co-supplemented with 1, 2 and 3% RJ was evaluated in 3 experiments. Samples were frozen by conventional slow freezing method and post-thaw parameters of total motility, progressive motility, plasma membrane integrity, DNA damage, apoptosis, enzyme activity of superoxide dismutase (SOD) and glutathione peroxidase (GPx), total antioxidant capacity (TAC) and malondialdehyde (MDA) were evaluated. The results showed that the percentage of motility, progressive motility, TAC, GPx, SOD and all sperm kinematic parameters except LIN in the group containing 2% RJ + 6% DMSO was higher than the control group (p < 0.05). Some parameters such as progressive motility, sperm membrane integrity, TAC, GPx, VAP, VCL, STR and SRT in the group containing 2% RJ + 6% DMSO were more than (p < 0.05) in the sperm group containing 1% RJ + 6% DMSO. MDA values in sperm groups containing 2% RJ + 6% DMSO were significantly (p < 0.05) lower than the sperm containing 1% royal jelly and the control group. In the sperm group containing 2% RJ + 6% glycerol, sperm membrane integrity, TAC, GPx, SOD, progressive motility and all sperm kinematic parameters except VAP were higher and MDA values and sperm abnormalities were lower than the control group (p < 0.05). The sperm group containing 1% RJ and 3% DMSO +3% glycerol had higher motility, progressive motility, membrane integrity, and all sperm kinematic parameters except VSL; and lower sperm abnormalities, DNA damage, apoptosis and MDA than the control group (p < 0.05). As a general conclusion of this study, the addition of 2% RJ + 3% DMSO and 3% glycerol to the freezing extender improved microscopic and biochemical ram sperm parameters after the freeze-thaw process. Hence, moderate concentrations of royal jelly (2%) are sufficient to protect sperm from freezing damage, and high (3%) and low (1%) concentrations do not have a good cryoprotective effect.

Trehalose modifies the protein profile of ram spermatozoa during cryopreservation

As a magical oligosaccharide, trehalose has been revealed to enhance the post-thaw quality of stock semen. However, information regarding the cryoprotective mechanism of trehalose during cryopreservation has not yet been determined. This study was designed to observe the effects of trehalose on the proteome of ram frozen spermatozoa by applying the isobaric tag for relative and absolute quantification (iTRAQ) strategy combined with parallel reaction monitoring (PRM). A total of 1269 proteins were identified. Among them, there were 21 differentially expressed proteins (DEPs), with 9 up-regulated proteins and 11 down-regulated proteins in spermatozoa frozen with trehalose. These DEPs were primarily located in nucleus, cytoplasm, and extracellular region. The Gene Ontology (GO) enrichment analysis demonstrated the involvement of the DEPs in signal transduction, ion binding, oxidoreductase activity, response to stress, and catabolic processes. Based on the STRING analysis, tight functional correlations were observed between 6-phosphogluconate dehydrogenase, fructose-bisphosphate aldolase A isoform 1, 14-3-3 protein epsilon, tyrosine-protein kinase Fer, and beta-hexosaminidase subunit alpha precursor. Furthermore, 10 DEPs were verified using PRM, confirming the accuracy of the iTRAQ data acquired in this study. In conclusion, trehalose can modify the protein profile of ram spermatozoa during cryopreservation, which may be associated with its cryoprotective effects. Additionally, trehalose may function on frozen spermatozoa through antioxidation, involvement in glycolysis, and increment of spermatozoa tolerance to various stresses.