Sperm Freezing Research Articles

Evaluation of microRNA expression profiles in human sperm frozen using permeable cryoprotectant-free droplet vitrification and conventional methods.

For sperm cryopreservation, the conventional method, which requires glycerol, has been used for a long time. In addition, the permeable cryoprotectant-free vitrification method has been continuously studied. Although the differences of cryopreservation effects between the two methods have being studied, differences in microRNA (miRNA) profiles between them remain unclear. In this study, we investigated the differences in miRNA expression profiles among conventional freezing sperm, droplet vitrification freezing sperm and fresh human sperm. We also analyzed the differences between these methods in terms of differentially expressed miRNAs (DEmiRs) related to early embryonic development and paternal epigenetics. Our results showed no significant differences between the cryopreservation methods in terms of sperm motility ratio, plasma membrane integrity, DNA integrity, mitochondrial membrane potential, acrosome integrity, and ultrastructural damage. However, sperm miRNA-sequencing showed differences between the two methods in terms of the numbers of DEmiRs (28 and 19 with vitrification using a nonpermeable cryoprotectant and the conventional method, respectively) in postthaw and fresh sperm specimens. DEmiRs related to early embryonic development and paternal epigenetics mainly included common DEmiRs between the groups. Our results showed that the differences between conventional freezing and droplet vitrification were minimal in terms of miRNA expression related to embryonic development and epigenetics. Changes in sperm miRNA expression due to freezing are not always detrimental to embryonic development. This study compared differences in miRNA expression profiles before and after cryopreservation between cryopreservation by conventional and vitrification methods. It offers a new perspective to evaluate various methods of sperm cryopreservation.

Impact of bull age, sperm processing, and microclimatic conditions on the viability and DNA integrity of cryopreserved bovine sperm.

Context Seasonal microclimatic fluctuations can cause changes in sperm quality even in dairy bulls bred under temperate climate. These changes can vary between sires of different age and affect sperm freezability. Aims We aimed to evaluate the modulating effect of bull age and equilibration time before freezing on the seasonal pattern of sperm viability and DNA integrity post-thaw. Methods In the frame of systematic sperm quality control, we assessed the integrity of sperm plasma membrane and acrosome (PMAI) in 15,496 cryopreserved bovine batches, and the percentage of sperm with high DNA fragmentation index (%DFI) after 0h and 3h incubation at 38°C post-thaw (3h) in 3422 batches. Semen was equilibrated for 24h before freezing if collected on Monday or Wednesday and 72h if produced on Friday. We investigated the effect of season, bull age, equilibration, and temperature-humidity index (THI) on the day of semen collection on sperm traits using mixed-effects linear models. Key results PMAI and %DFI (0h and 3h) deteriorated with increasing THI. The effect of THI on %DFI was detected with a 30-day time lag. Seasonal fluctuations of sperm quality were similar between young, mature, and older sires. Prolonged equilibration did not affect PMAI but was linked to elevated %DFI (3h) in summer. Conclusions Extending equilibration from 24 to 72h is compatible with commercial standards of bovine sperm quality post-thaw; however, it could interfere with the seasonal pattern of the latter. Implications Systematic monitoring of bovine sperm quality enables the prompt detection of stress factors related to microclimate and semen processing.

Effect of cholesterol-loaded cyclodextrin treatment on boar sperm cryopreservation.

This study investigated the efficacy of different concentrations of cholesterolloaded cyclodextrin (CLC) on cryopreservation in boar sperm quality. In this study, we treated boar sperm with different concentrations of CLC before freezing and analyzed the sperm cholesterol concentration, plasma membrane, acrosome integrity rate and total motility rate before and after freeze-thawing. We also investigated the levels of reactive oxygen species (ROS), malondialdehyde (MDA), adenosine triphosphate (ATP), and structural- and oxidative-damage related proteins in all groups after thawing. The results revealed that the cholesterol concentration of the CLC-treated groups was higher than that of the control group, both before freezing and after thawing (p<0.05). The plasma membrane integrity rate, acrosome integrity rate, and total motility rate of sperm were also enhanced after thawing in the CLC-treated group (all p<0.05). Moreover, ROS and MDA production and ATP loss were reduced in CLC-treated sperm during freezing and thawing (p<0.05). Finally, CLC pretreatment partially prevented the consumption of various proteins involved in metabolism including capping actin protein of muscle Z-line subunit beta (CAPZB), heat shock protein 90 alpha family class A member 1 (HSP90AA1) and phosphoglycerate mutase 2 (PGAM2) (p<0.05). The CLC treatment increased cholesterol concentration and decreased structural injury and oxidative damage during boar sperm freezing and thawing, improving the efficacy of sperm cryopreservation in boar.

EFFECT OF SPERMS FREEZABILITY ON SOME SEMEN ATTRIBUTES AND AMINO ACID CONCENTRATIONS IN SEMINAL PLASMA OF HOLSTEIN BULLS

This study investigated the effect of different sperm freezability on some semen characteristics and amino acid concentrations in the seminal plasma of Holstein bulls cryopreserved for two years. The semen straws (0.25 ml) that cryopreserved for two years were divided into three equal groups (7 bulls per group) according to the sperm’s freezability: medium (73.02%; F1), good (83.76%; F2), and high (91.20%; F3). The F1 bulls were superior (P≤ 0.05) in sperm’s cell individual motility (SCIM) for fresh semen as compared with F2 and F3 bulls. The F2 and F3 groups were superior (P≤ 0.01) to the F1 group in live sperm percentage at cryopreservation. The sperm’s DNA damage percentage was lesser (P≤ 0.05) in the F1 and F3 groups as compared with the F2 group. The differences among groups in normal sperm percentage, sperm’s plasma membrane and acrosome integrity percentage, malondialdehyde, and total antioxidant concentrations lacked significance. The essential and non-essential amino acid concentrations in seminal plasma did not differ among groups. In conclusion, sperm freezability influenced some semen attributes but did not affect amino acid concentrations in the seminal plasma of Holstein bulls.

Effects of Long-Term Cryopreservation on the Transcriptomes of Giant Grouper Sperm.

The giant grouper fish (Epinephelus lanceolatus), one of the largest and rarest groupers, is a fast-growing economic fish. Grouper sperm is often used for cross-breeding with other fish and therefore sperm cryopreservation is important. However, freezing damage cannot be avoided. Herein, we performed a transcriptome analysis to compare fresh and frozen sperm of the giant grouper with frozen storage times of 0, 23, 49, and 61 months. In total, 1911 differentially expressed genes (DEGs), including 91 in El-0-vs-El-23 (40 upregulated and 51 downregulated), 251 in El-0-vs-El-49 (152 upregulated and 69 downregulated), and 1569 in El-0-vs-El-61 (984 upregulated and 585 downregulated), were obtained in the giant grouper sperm. DEGs were significantly increased at 61 months of cryopreservation (p < 0.05). GO and KEGG enrichment analyses of the DEGs revealed significant enrichment in the pilus assembly, metabolic process, MAPK signaling pathway, apoptosis, and P53 signaling pathway. Time-series expression profiling of the DEGs showed that consistently upregulated modules were also significantly enriched in signaling pathways associated with apoptosis. Four genes, scarb1, odf3, exoc8, and atp5f1d, were associated with mitochondria and flagella in a weighted correlation network analysis. These genes may play an important role in the response to sperm freezing. The experimental results show that long-term cryopreservation results in freezing damage to the giant grouper sperm. This study provides rich data for studies of the mechanism underlying frozen fish sperm damage as well as a technical reference and evaluation index for the long-term cryopreservation of fish sperm.

Mechanisms underlying human sperm cryodamage: the role of reactive oxygen species (ROS) and antioxidants

Sperm cryopreservation is an efficient procedure for male fertility preservation, although the freeze-thaw procedure causes irreversible structural and functional changes in human spermatozoa. Indeed, the procedure is responsible for harmful changes that may affect sperm biology. In mammalian cells, cryopreservation induces a shift of redox homeostasis towards increasing generation of reactive oxygen species (ROS). The characteristics of ROS and the cellular outcomes depend on the cell type. Supra-physiological ROS levels during cryopreservation severely impact sperm survival, reproductive potential and DNA integrity, the latter a fundamental factor for fertilisation and transmission of paternal genetic information to offspring. The aim of this review is to summarise current knowledge of the main molecular mechanisms underlying ROS generation during sperm cryopreservation and its subsequent effects. In addition, we report current experimental approaches based on the supplementation of cryopreservation media with enzymatic and non-enzymatic antioxidants with the aim of minimising the harmful effects of ROS, and thus improving post-thaw sperm quality. Current data indicate that the potential use of antioxidants as constituents of the sperm freezing solution in clinical settings would require considerable attention. KEY WORDS: Spermatozoa, cryopreservation, ROS, oxidative stress, antioxidants.

Cryopreservation of ram semen: baicalein efficiency on oxidative stress, chromatin integrity, viability and motility post thaw.

Baicalein (B) has potential antioxidant properties, but it has not been tested as a ram semen extender. This study aimed to assess the impact of B on various sperm parameters and determine its potential influence on semen quality after the freeze-thawing process. During the breeding season, ejaculates were obtained from four rams with the aid of an artificial vagina. The collected mixed semen samples were divided into four groups: control (C; 0), B0.5 (0.5 mM), B1 (1 mM), and B2 (2 mM). After semen extension, the samples were loaded into 0.25 mL straws and stored for 2 h at 4°C prior to freezing in liquid nitrogen vapor and thawed in a water bath at 37°C. Among the groups, B0.5 demonstrated the highest progressive motility results, while B1 and B2 exhibited reduced motility (p < 0.05). In terms of high mitochondrial membrane potential, plasma membrane and acrosome integrity, and viability, B0.5 showed significantly superior outcomes to the other B groups (p < 0.05), although it was not significantly better than C. B1 displayed the highest plasma membrane integrity levels (p < 0.05). Notably, B2 displayed the lowest total antioxidant status levels among the groups (p < 0.05). The findings of this study suggested that the in vitro spermatological characteristics of ram spermatozoa such as progressive motility and chromatin integrity can be protected from the freeze-thawing process by using the 0.5 mM dose of baicalein as a semen extender. The treatment of sperm freezing might benefit from further in-depth research on the role of B in the improvement of cryoinjury and its underlying processes.

In Vitro Effects of Charged and Zwitterionic Liposomes on Human Spermatozoa and Supplementation with Liposomes and Chlorogenic Acid during Sperm Freezing.

Semen handling and cryopreservation induce oxidative stress that should be minimized. In this study, human semen was supplemented during cryopreservation with formulations of handmade liposomes and chlorogenic acid (CGA), an antioxidant compound. Zwitterionic (ZL), anionic (AL), and cationic (CL) liposomes were synthesized and characterized. Three aliquots of swim-up-selected sperm were incubated with ZL, AL, and CL (1:10,000), respectively. The percentages of sperm with progressive motility, high mitochondrial membrane potential (MMP; JC-1), double-stranded DNA (dsDNA acridine orange), and acrosome integrity (Pisum sativum agglutinin) were assessed. Then, human semen was frozen using both 1:10,000 ZL and CGA as follows: freezing medium/empty ZL (EL), freezing medium/empty ZL/CGA in the medium (CGA + EL), freezing medium/CGA loaded ZL (CGA), freezing medium (CTR). The same sperm endpoints were evaluated. ZL were the most tolerated and used for semen cryopreservation protocols. All the supplemented samples showed better endpoints versus CTR (p < 0.001). In particular, spermatozoa from the CGA and CGA + EL A samples showed increased motility, dsDNA, and acrosome integrity versus CTR and EL (p < 0.001; motility EL vs. CGA + EL p < 0.05). ZL and CGA can improve post-thaw sperm quality, acting on both cold shock effect management and oxidative stress. These findings open new perspectives on human and animal reproduction.

Evaluation of Sperm DNA Fragmentation Using Halosperm Technique after the Freezing-Thawing Process in Men: A Study on the Validation of the SCD Protocol.

DNA fragmentation index (DFI) enhances routine semen analysis by providing valuable insights into male reproductive potential. Utilizing Halosperm test, a sperm chromatin dispersion (SCD) assay based on induced condensation. The purpose of this study was to assess sperm DNA damage both before and after freezing. By following the specified kit instructions, an attempt was made to validate the SCD test protocol, with a particular emphasis on the implications of sperm freezing on its DNA integrity. In total, 380 fresh human semen samples from normozoospermic patients were frozen at -20°C for 10 days, using SCD cryopreservation reagent. Routine semen analysis and DNA fragmentation index (DFI) were determined for each sample before freezing and after thawing. Semen morphology and sperm DFI were compared before and after freezing/thawing process. There was a significant decrease in sperm normal morphology after thawing (9.31±2.42% vs. 7.1±1.53%, p<0.05, respectively). The sperm head, midpiece, and tail defect rate increased after freezing at -20°C. Moreover, DFI was significantly higher after thawing compared to before freezing (20.71±1.61% before freezing vs. 29.1±0.21% after thawing with p<0.001). Cryoconservation of semen samples at -20°C for 10 days using SCD cryopreservation reagent seems to damage sperm morphology, resulting in a reduction in sperm DNA integrity. The measurement of DFI on a fresh sample remains the most reliable technique for obtaining accurate results.

Quantitative phosphoproteomics explain cryopreservation-induced reductions in ram sperm motility

Sperm cryopreservation decreases motility, probably due to changes in protein phosphorylation. Our objective was to use quantitative phosphoproteomics for systematic comparative analyses of fresh versus frozen-thawed sperm to identify factors causing cryo-injury. Ejaculates were collected (artificial vagina) from six Dorper rams, pooled, extended, and frozen over liquid nitrogen. Overall, 915, 3382, and 6875 phosphorylated proteins, phosphorylated peptides, and phosphorylation sites, respectively, were identified. At least two modified sites were present in 57.94% of the 6875 phosphosites identified, of which AKAP4 protein contained up to 331 modified sites. There were 732 phosphorylated peptides significantly up-regulated and 909 significantly down-regulated in frozen-thawed versus fresh sperm. Moreover, the conserved motif [RxxS] was significantly down-regulated in frozen-thawed sperm. Phosphorylation of sperm-specific proteins, e.g., AKAP3/4, CABYR, FSIP2, GSK3A/B, GPI, and ODF1/2 make them potential biomarkers to assess the quality of frozen-thawed ram sperm. Furthermore, these differentially phosphorylated proteins and modification sites were implicated in cryopreservation-induced changes in sperm energy production, fiber sheath composition, and various biological processes. We concluded that abnormal protein phosphorylation modifications are key regulators of reduced sperm motility. These novel findings implicated specific protein phosphorylation modifications in sperm cryo-injury. SignificanceThis study used phosphorylated TMT quantitative proteomics to explore regulation of epigenetic modifications in frozen-thawed ram sperm. This experiment demonstrated that ram sperm freezing affects phosphorylation site modifications of proteins, especially those related to functions such as sperm motility and energy production. Furthermore, it is important to link functions of phosphorylated proteins with changes in sperm quality after freezing and thawing, and to clarify intrinsic reasons for sperm quality changes, which is of great importance for elucidating mechanisms of sperm freezing damage. Based on these protein markers and combined with cryoprotectant design theory, it provides a theoretical basis and data reference to study sperm cryoprotectants.

Apigenin supplementation substantially improves rooster sperm freezability and post-thaw function

This pioneering research investigated apigenin potential to augment rooster sperm cryosurvival in an extender model. Apigenin is a natural antioxidant flavonoid showing promise for improved post-thaw sperm function. However, its effects on avian semen cryopreservation remain unexplored. This first study supplemented rooster sperm Lake extender with 0, 50, 100, 200, 400 μmol/L apigenin to determine the optimal concentrations for post-thaw quality. Supplementation with 100 μmol/L apigenin resulted in significant enhancements in total motility (from 41.5% up to 71.5%), progressive motility (18.1% to 29.1%) (p < 0.05), membrane integrity (40% to 68%), mitochondrial function (p < 0.001), viability (37% to 62%) and total antioxidant capacity (p < 0.001) compared to the control. It also substantially reduced percentages of abnormal morphology, reactive oxygen species and apoptosis (p < 0.001). Although 200 μmol/L apigenin significantly enhanced some attributes, effects were markedly lower than 100 μmol/L. Higher doses did not improve cryoprotective parameters. This indicates 100 μmol/L as the optimal apigenin concentration. This represents the first report of apigenin protecting rooster sperm from cryodamage. The natural antioxidant improved post-thaw sperm quality, likely by suppressing oxidative stress and apoptosis. Apigenin shows promise for enhancing rooster sperm cryosurvival.

Cryopreservation of Limited Sperm Using A Combination of Sucrose and Taurine, Loaded on Two Different Devices, and Thawed at Two Different Temperatures.

Cryopreservation of sperm is essential for patients with low sperm counts and couples undergoing infertility treatment. The aim of this study was to compare the effects of Taurine (T) and Sucrose (S) in individual sperm cryopreservation utilizing cryotop and petri dish and thawing at 37 and 42°C. In this experimental study, 17 normospermic semen samples were processed using the "Swim-up" procedure and progressively motile sperm were then isolated from these samples using an inverted microscope. Sperm were added to droplets of "sucrose medium" with 25 mM Taurine antioxidant (S+T) and the commercial cryoprotectant "Sperm Freeze" (CPA), loaded on a petri dish and cryotop. After rapid freezing of the samples, they were thawed at two different temperatures (37°C and 42°C), and the sperm classical parameters, viability, and DNA fragmentation were assessed. Statistical analysis displayed a significant increase in total and progressive motility in individual sperm freezing on cryotop with CPA and thawing at 42°C (P<0.05). Other parameters did not show any differences between the CPA and S+T groups and two thawing temperatures in either of the cryopreservation methods. Although, both cryoprotectants (CPA and S+T) may preserve individual sperm effectively using cryotop, the CPA and thawing at 42°C showed a better effect on the motility percentage of the small number of sperm.

Freezing Stallion Semen-What Do We Need to Focus on for the Future?

Artificial insemination (AI) is used frequently in the breeding of sport horses, apart from Thoroughbreds. Most AIs are carried out with cooled semen rather than frozen semen because of the difficulties in identifying a protocol that is suitable for freezing most ejaculates and the necessity to inseminate close to ovulation because of the short life of the thawed spermatozoa. More widespread use of frozen semen would improve biosecurity, allow greater choice of stallions, and offer more flexibility when managing deliveries of semen to the stud. It would even decrease the amount of antibiotics used in semen extenders, since the volume of frozen semen is smaller than when cooled semen is inseminated. However, there is considerable variability in the cryosurvival of spermatozoa from different stallions, leading to the classification of stallions as good or bad freezers. Improvements could be made at the level of stallion nutrition, the semen collection regimen, the extender, the removal of seminal plasma, and the cooling protocol, among others. Stallion sperm membranes are highly susceptible to lipid peroxidation, but research on antioxidants has failed to identify an additive that would benefit all stallions. In the future, biomarkers for sperm freezability could be used as an aid in identifying suitable ejaculates for cryopreservation.

Evaluation of the effect of mitoquinone on functional parameters, DNA structure, and genes expression related to the apoptotic and antioxidants of human sperm after freezing-thawing.

Sperm freezing is considered as an effective way in assisted reproductive technology (ART) programs, it has detrimental effects on sperm function, due to the production of reactive oxygen species (ROS). This study aimed to investigate the potential of Mitoquinone (MitoQ) in inhibiting the production of mitochondrial ROS during sperm freezing. A total of 20 human normozoosperm samples were collected for this study. The samples were divided into four groups, each containing different concentrations of MitoQ (0, 0.2, 2, and 20 nM), and then subjected to the freezing process. After thawing, the sperm suspensions were evaluated for parameters including motility, morphology, acrosome integrity, adenosine triphosphate (ATP) level, intracellular ROS, viability, chromatin packaging, DNA denaturation, DNA fragmentation, as well as the expression of antioxidants (GPX, SOD) and apoptotic (Bax, Bcl2) genes. The results showed that total and progressive mobility of sperms significantly increased in the 2 nM group, while significantly decreased in the 20 nM group (p ≤ 0.05). Sperm morphology did not significantly improve across all the tested concentrations (p ≥ 0.05). Intracellular ROS levels showed a significant decrease and increase in the concentrations of 2 and 20 nM, respectively (p ≤ 0.05). Furthermore, a significant increase was observed in viability, ATP, acrosome integrity, chromatin packaging, and non-denatured and non-fragmented DNA after treatment with 2 nM of MitoQ, compared with the control group (p ≤ 0.05). Regarding gene expressions, the relative expressions of oxidative stress genes were increased in the 2 nM group and decreased in the 20 nM group (p ≤ 0.05), while no significant difference was observed in the expressions of apoptotic genes compared with the control group (p ≥ 0.05). All the comparisons were made with respect to the control group. Adding the optimal concentration of MitoQ (2 nM) to the sperm freezing medium not only improves sperm functional parameters and reduces DNA damages, but also stimulates the expression of antioxidant genes, leading to even greater benefits for sperm cryopreservation.

Zaozao Xu’s case: Chinese women’s appeal for the right to freeze their eggs

China’s regulatory framework on assisted reproductive technologies (henceforth ARTs) has remained unchanged and unchallenged for over two decades, prohibiting unmarried women from accessing any form of ARTs. Section 1 Article 4(1) of the Ethical Principles for Human Reproductive Technologies and Human Sperm Banks explicitly stipulates that ‘couples who do not comply with national population and family planning laws and regulations and single women’ are prohibited from accessing ARTs. However, unmarried men are allowed to freeze sperm regardless of their marital status, constituting direct discrimination against women. Furthermore, significant legislative conflicts exist between local regulations and departmental rules in this area, hindering the consistent application of ART norms in China and substantially limiting the reproductive rights of Chinese women. Zaozao Xu’s case is the first case in China directly challenging the current prohibitive regulations on egg freezing and may signify a crucial turning point in China’s reform of ARTs legislation. This commentary provides an overview of the case and examines various issues associated with the existing regulatory framework, including the vagueness of the legislation and regulation, legislative conflicts in the current framework, deeply rooted discrimination against women, and the regulator’s problematic conception of ARTs. This commentary emphasises the urgent need for China to re-evaluate and reform its ARTs regulatory framework to allow unmarried women to access ARTs, or at least egg-freezing services as the first step.

Dog sperm cryopreservation using cryovials and different dilution steps

BACKGROUND: The conventional sperm freezing method for dog sperm is with straws and includes two-step dilution and a long equilibration time. OBJECTIVE: To develop a more efficient freezing method using cryovials. MATERIALS AND METHODS: Three freezing protocols using cryovials (0.5 mL) were conducted with dog spermatozoa at 1 × 108 sperm/mL: Group 1 spermatozoa were cooled in cryovials and extender 1 (E1) and extender 2 (E1 +1 M glycerol) at 4°C for 50 min and then frozen over LN2 for 20 min; Group 2 sperm was cooled and frozen in cryovials with a mixture of E1 and E2 (1:1) in a deep freezer (−80°C) for 30 min; Group 3 sperm in cryovials and E1 were cooled at 4°C for 20 min, cooled for an additional 20 min after addition of E2 (E1:E2, 1:1), and then frozen using LN2 vapour for 20 min. The control (Group 4) consisted of spermatozoa in straws being frozen using the conventional freezing method using two-step dilution. All groups were plunged and stored in LN2 after freezing and their functional performance and gene expression determined. RESULTS: Progressive motility and acrosome integrity were highest (P &lt; 0.05) in Groups 2, 3 and 4 (only acrosome integrity). Viability in Group 3 was significantly better that in the other Groups, and the reactive oxygen species (ROS) level and phosphatidylserine (PS) translocation index were significantly lower in Group 2 than the other Groups. The expression of sperm mitochondria-associated cysteine-rich protein (SMCP) and anti-apoptotic B-cell lymphoma 2 (BCL2) genes was highest (P &lt; 0.05) in Group 2 and the expression of pro-apoptotic Bcl2-associated X protein (BAX) was lowest (P &lt; 0.05) in Group 4. CONCLUSION: The sperm frozen using cryovials, one step dilution and the deep freezer (Group 2) proved to be a simple and suitable cryopreservation method for dog sperm.

Successful transposition of sperm freezing, in vitro fertilization and artificial insemination methodologies in the Tadjik markhor species (Capra falconeri heptneri).

The objective of the present study was to transpose sperm freezing methodology from domestic goat to the Tadjik markhor (Capra falconeri heptneri) and to address the feasibility to develop IVP and artificial insemination using such frozen semen. Semen of different adult markhor males were successfully recovered by electro-ejaculation and were then frozen using caprine methodology. Frozen semen showed good survival rates at thawing and good fertility rates were assessed in heterologous in vitro fertilization system with goat oocytes. LOPU/IVF was applied for Tadjik markhor females allowing the first successful blastocyst production in vitro. In an applied program, we also transposed successfully intrauterine AI method with frozen/thawed semen to the Tadjik markhor.

Assessing the efficacy of different semen extenders on post-thaw quality of Bangladeshi buffalo sperm under a manual cryopreservation protocol

Cryopreservation has been used extensively for cattle in Bangladesh, albeit no study was conducted on the cryopreservation of buffalo sperm in Bangladesh. This study aimed to evaluate the suitability of different semen extenders for improving the post-thaw quality of Bangladeshi buffalo sperm under a manual cryopreservation protocol. The manual cryopreservation protocol was compared and optimized with a commercial biofreezer protocol. Then, the efficacy of different diluters was evaluated using the optimized manual cryopreservation protocol. Meanwhile, the post-thaw sperm quality in terms of motility and morphology was evaluated by CASA during the optimization process. During manual cryopreservation, the first cooling from 37 °C to 5 °C was done in a BLRI-developed equilibration chamber and the second cooling from 5 °C to -120 °C in a Styrofoam box using liquid nitrogen vapor from different distances (0.5, 1.5, 1.6, 2 and 3 inches). Simultaneously, another batch of sperm was cryopreserved using a programmable freezer. The highest number of motile sperms (62.67±1.12; P&lt;0.01) and progressive motility (38.97±1.10; P&lt; 0.001) was observed at 1.6 inches above liquid nitrogen, which are similar to the results obtained from automated biofreezer protocol (65.94±4.65 and 45.54 ± 3.64, respectively). To evaluate the semen extenders’ efficacy, one locally developed Tris-fructose-egg yolk-based diluter and two commercial diluters (Andromed, Triladyl) were used in the freezing of buffalo sperm. The highest recovery and conception rates were observed in sperm diluted with TFE (82.4% and 80%, respectively). Therefore, it is clear that this manual cryopreservation protocol and the TFE diluter could be a suitable and inexpensive alternative for Bangladeshi buffalo sperm considering post-thaw sperm quality and fertility.

Sambucus Nigra: black fruits that makes sperms come out ahead in in vitro fertilization

Freezing is a non-physiological method that includes a series of processes such as dilution, incubation, cooling, freezing and thawing, which affect the structure, biochemistry and function of sperm. Human sperm freezing has overcome many spatial and temporal limitations and is now an integral part of assisted reproductive technologies (ART). Freezing causes biochemical, functional and structural changes in sperm. These changes include plasma and sperm acrosome membranes, which increase their permeability and leads to disruption of morphology, motility and chromatin structure. Therefore, freezing causes irreversible damage to sperm, which leads to the loss of movement and biological function of most sperm. Sperm health is one of the important factors in the fertility of couples. Therefore, reducing the harmful effects caused by freezing and properly performing the in vitro Fertilization (IVF) process, the development of useful solutions is inevitable. The extract from black fruits of Elderberry (Sambucus nigra) has potent in vitro effect on the sperm motility, vitality and oxidative profile. This extract can largely improve the sperms parameters and stereological parameters (spermatogonia, primary spermatocyte, round spermatid, and Leydig cells), decrease of TNF-a and caspase-3 expression, increase of the serum testosterone, increase of mitochondrial activity, and reduction of reactive oxygen species. So, it can also be used as in vivo status. We suggested that black fruits of Sambucus nigra makes sperms come out ahead in IVF techniques.

Insights into alternative cryoprotectants to freeze sperm of domestic cats.

Globalization and habitat destruction pose a significant threat to wildlife felids. Even though conservation banks for genetic materials have been created, the sperm cryopreservation with minimal cell damage is still a great challenge. Thus, this study aimed to compare the effects of two commercial extenders with different concentrations of alternative cryoprotectants on thawed sperm quality of domestic cats. Five adult cats were anaesthetized (using a combination of 40 μg/kg medetomidine associated to 5 mg/kg ketamine), and the semen was collected by electroejaculation (electrical stimulation of 2-3 V). Semen samples were evaluated for sperm characteristics (kinetics, morphology, membrane integrity and morphometry). Subsequently, they were sorted into two aliquots and centrifuged. The aliquots were added to a commercial extender containing 3% glycerol and 2% methylformamide (extender I) or 2% glycerol and 3% methylformamide (extender II), frozen, thawed (37°C/30 s) and reevaluated. Comparatively, the sperm kinetics and membrane integrity of fresh semen were higher (p < .002) than frozen samples in extender I and II. Total and progressive motility were lowest in the thawed samples. However, the subjective analysis indicated high sperm motility, since the kinetics evaluation was impaired by the low cell number in the thawed samples. There were no differences in sperm morphology between the groups. In the sperm morphometric analysis, a significant difference (p = .04) was identified in the length of the intermediate piece in extender II samples compared with fresh and extender I. Thus, it can be concluded that although the concentrations tested did not maintain the kinetic parameters and membrane integrity of spermatozoa after thawing, the extender with a lower concentration of glycerol was less toxic for maintaining the midpiece length.