Membrane Acrosome Integrity Research Articles

The Effect of Resveratrol and Catalase on Post-Thaw Angora Buck Semen

This research aimed to examine the impact of resveratrol and catalase on the motility, plasma membrane integrity, acrosomal membrane integrity, and mitochondrial activity of Ankara buck semen following freeze-thawed process. In this study, semen samples obtained from four mature bucks were divided into four groups: control (C), resveratrol 500 µM/ml (R), catalase 50 IU/ml (CAT), and resveratrol 500 µM/ml + catalase 50 IU/ml (CATR). After dilution with Tris/egg yolk extender, the semen samples were frozen in liquid nitrogen and then thawed for assessment. The CATR group gave the highest values across all evaluated parameters (motility, plasma membrane integrity, acrosomal membrane integrity, and mitochondrial activity) compared to the other groups (61 ± 1.0%, 72.6 ± 0.70%, 70.73 ± 0.67%, 60.9 ± 0.79%, respectively) (p<0.05). In conclusion, the combination of catalase and resveratrol significantly improved the quality of buck semen after freeze-thawed process, thereby contributing to enhanced reproductive outcomes and genetic preservation.

Effect of silver nanoparticles on donkey sperm parameters and ultrastructure.

The aim of this study was to determine the effect of silver nanoparticles (AgNPs) on donkey sperm parameters and ultrastructure. AgNPs were synthesized, purified and resuspended in the extender. Nine frozen-thawed donkey sperm samples were exposed to different concentrations of AgNPs (0, 1.25, 2.5, 5, 12.5, 25 and 50 μg/mL). Sperm parameters: total (TMOT, %) and progressive (PMOT, %) sperm motility, plasma (LIVE, %) and acrosomal membrane integrity (AIS, %), and sperm morphology (MORF, %) were evaluated immediately after AgNPs exposure (T0) and after 2 h of incubation (T2). The interaction beween AgNPs and spermatozoa was visualized by transmission electron microscopy (TEM). At T0, sperm motility and AIS were reduced (p < .05) when using concentrations ≥50 and ≥25 μg/mL, respectively. At T2, sperm motility and LIVE were significantly decreased (p < .05) in concentrations ≥25 and ≥50 μg/mL, respectively. TEM analysis revealed nanoparticle adhesion to the acrosomal region of the plasma membrane. In conclusion, AgNPs at concentrations ≥25 μg/mL impair motility, acrosome and plasma membrane integrity of donkey sperm, which may be mediated by adhesion to the acrosomal region of the sperm surface membrane.

Supplementation of Rooster Semen Extender with Aqueous Extract of Urtica dioicafor a Long Time Preservation by Low Temperature.

The peroxidation of spermatozoa membrane phospholipids is a primary cause of irreversible changes in the preservation of avian semen. To address this issue, the objective of the present study was to assess the potential of Urtica dioica extracts in protecting avian spermatozoa during prolonged storage. Gas chromatography-mass spectroscopic techniques were employed to evaluate the bioactive compounds present in the aqueous and ethanolic extracts obtained from the aerial parts and roots of U. dioica. Semen samples were collected from 16 roosters twice a week and were diluted in Lake's extender containing different concentrations (0, 0.5, and 1 mg/100 mL) of the various extracts. Subsequently, the extended semen samples were cooled and stored at 5°C, and the sperm quality parameters were assessed at 0, 12, 24, and 36 hours of storage. The data from this experiment clearly demonstrate that the addition of nettle root aqueous extracts to the semen diluent, especially at a concentration of 0.5 mg/100 mL, resulted in a significant improvement in various sperm quality parameters. Notably, there were enhancements in total and progressive sperm motilities, viability, fertility, membrane integrity, acrosomal membrane integrity, and a reduction in malondialdehyde production in rooster semen stored in vitro for up to 36 hours. Interestingly, the present study reveals that the beneficial effects of the aqueous extracts from different parts of the nettle were supported not only by the conventional manual method but also by the computer-assisted sperm analysis system. This dual confirmation further emphasizes the positive impact of the aqueous extract on various sperm traits during cooled semen preservation. In conclusion, this study highlights the potential of U. dioica extracts, particularly the aqueous extract from nettle roots at a concentration of 0.5 mg/100 mL, in safeguarding avian spermatozoa during prolonged storage. The significant improvements in various sperm quality parameters and the validation of results through both manual and computer-assisted analysis methods provide strong evidence for the application of U. dioica extracts in avian breeding programs and artificial insemination practices.

The contribution of different sperm parameters to better explain ram semen cryoresistance

In order to determine an effective procedure for explaining ram sperm cryoresistance and develop a new model for breeders classification, a retrospective study was conducted using sperm analysis data obtained over two consecutive years from a total of 82 sessions of ram semen cryopreservation. In each session, fresh ejaculates from eight males were collected via artificial vagina, pooled and frozen in liquid nitrogen vapors. After thawing, a total of 19,084 sperm tracks and 11,319 morphometric measurements were analysed. Clustering analyses were applied to establish motile and morphometric sperm subpopulations. Additionally, plasma and acrosome membrane integrity, as well mitochondrial activity using flow cytometry immediately after sperm thawing and following hypoosmotic shock test (HOST) was assessed. To develop a Ram Sperm Cryoresistance Index, Principal Component Analyses (PCA) using 22 variables were conducted. In the first PCA, the parameters that best explain cryoresistance include total motility (TM), motile subpopulation 2 (motSP2, which groups slow, very linear spermatozoa with low lateral head displacement), morphometric subpopulation 1 (morphSP1, grouping spermatozoa with the smallest head size and lowest shape values), sperm plasma membrane integrity immediately after thawing and following hypoosmotic shock test. These parameters collectively account for 77.34 % of the accumulated variance. To emphasize their importance, a second PCA was performed, revealing significant higher weighting coefficients for the quantity (TM) and quality (motSP2) of sperm movement after thawing, compared to the head size and shape of the thawed sperm (morphSP1). Furthermore, HOST Viability played a more decisive role than what was observed under isotonic conditions.

Subtle membrane changes in cryopreserved bull spermatozoa when modified temperature drop rates are used during the first phase of freezing

BACKGROUND: Cryopreservation of spermatozoa involves reduction of temperature to a subzero level, leading to increased longevity. However, temperature reduction has a significant effect on sperm membranes. OBJECTIVE: To evaluate the impact of the rate of temperature drop during the first phase of freezing on subtle membrane changes in cryopreserved bull spermatozoa. MATERIALS AND METHODS: Thirty-two ejaculates from four bulls (eight ejaculates/bull) were collected using artificial vagina while keeping a 3 to 4 days gap between two collections. Diluted semen samples were equilibrated at 5°C for 4 hours. The samples were then placed in a pre-programmed semen freezer. The first phase of freezing, that is, 5°C till −10°C was subjected to three different temperature drop rates: accelerated (F1), moderate (F2), and slow (F3), at 20°C per min, 10°C per min and 5°C per min, respectively. After thawing, spermatozoa were assessed for percentage live, plasma, and acrosomal membrane integrity, along with the external appearance of phosphatidyl serine, indicating apoptosis. RESULTS: A significant difference (p&lt;0.05) in viability, plasma membrane integrity (HOS test), and acrosome membrane integrity (PSA test) was observed between F3 and the other groups. However, the parameters did not significantly differ between F1 and F2. The annexin V-PI assay (AN/PI) categorized four types of sperm populations: non-apoptotic and viable (AN−/PI−), apoptotic and viable (AN+/PI−), non-apoptotic and non-viable (AN−/PI+), and apoptotic and non-viable (AN+/PI+). The proportion of spermatozoa with (AN−/PI−) and (AN+/PI+) differed significantly (p&lt;0.05) between F3 and the other groups. The values for apoptotic and viable (AN+/PI−) and non-apoptotic and non-viable (AN−/PI+) sperm were not significantly different among all freezing categories. CONCLUSION: A slower temperature drop rate (freezing rate) during the first phase of freezing results in less damaging, subtle membrane changes.

Potential use of soy lecithin or butylated hydroxytoluene as an alternative to powdered egg yolk for ram semen cryopreservation

The aim of this study was to assess the effect of replacing powdered egg yolk (PEY) with soybean lecithin (SL) or butylated hydroxytoluene (BHT) on ram sperm cryopreservation. Two ejaculates/male were collected via artificial vagina from 8 rams during breeding season. Ejaculates were pooled and washed twice by centrifugation. The pellet was divided into three aliquots, diluted in a Tris-based media with 5% glycerol containing PEY (15%), SL (1%) or BHT (0.6 mM) and cooled for 4 h at 5 °C before freezing. Sperm motility, plasma and acrosome membrane integrity and mitochondria activity as lipid peroxidation were assessed immediately after thawing and after 4 h of resilience incubation in a modified PBS at 38 ºC. After thawing, sperm extended in BHT showed the poorest quality compared to sperm extended in PEY and SL. Similar total and progressive motility were observed in sperm preserved in PEY and SL media. Plasma membrane integrity, however, was significantly higher in sperm extended in SL, although most of them with non-functional mitochondria. Acrosome damage was significant lower in SL sperm samples compared to PEY samples. Highest level of lipid peroxidation was found in sperm preserved in PEY. Resilience test had a negative effect (P &lt; 0.05) on plasma and acrosome membrane integrity in all samples, and on progressive motility only in sperm preserved in PEY. In conclusion, soy lecithin could be a potential alternative to PEY for ram cryopreservation, although its adverse effect on sperm mitochondria function has to be strongly considered.

Use of coenzyme Q-10 to improve the pregnancy rate in sheep

One of the factors responsible for less pregnancy rates is the use of frozen semen in sheep due to the oxidative stress created by the process. The aim of this experiment was to test the effects of adding coenzyme Q-10 (CoQ10) to the seminal extender on sperm quality and the pregnancy rate of sheep. In this study, ejaculates from eight Dorper rams of reproductive age were used and tested in four treatments: Control (pure BotuBov®), C1 (175 µM of CoQ10), C3 (350 µM of CoQ10), and C7 (700 µM of CoQ10). Samples were collected in triplicate from each animal, and sperm analysis was performed by CASA after thawing at 0 h and 2 h. The samples were also analyzed by flow cytometry for plasma and acrosomal membrane integrity, stability, lipid peroxidation, mitochondrial potential, and superoxide anion production. In total, 198 ewes were inseminated by laparoscopy and divided into two groups: control (n=98) and C7 (n=100). Pregnancy diagnosis was performed at 30 days. Coenzyme Q10 proved to be safe for semen cryopreservation, not altering sperm kinetic values between the groups post-thawing. In flow cytometry, the C1 and C7 groups achieved a better index of plasma membrane integrity and membrane stability (P<0.05). A increased pregnancy rate was observed in C7 (52 %) compared to the control (38 %). In conclusion, coenzyme Q10 assists in the cryopreservation process, protecting the sperm cell and improving pregnancy rates in ewes.

Effects of sperm concentration on the quality of cryopreserved sperm in Yangtze sturgeon (Acipenser dabryanus)

The Yangtze sturgeon (Acipenser dabryanus) is extinct in the wild; however, artificial propagation in captivity under fully controlled conditions has been successful. Sperm cryopreservation is an effective method for germplasm conservation and aquaculture. Sperm concentration affects the quality of cryopreserved spermatozoa. Thus, in this study, we optimized the concentration (0.25 × 109, 0.5 × 109, 1.0 × 109, and 2.0 × 109 spermatozoa [spz]/mL) for Yangtze sturgeon sperm cryopreservation in a 0.5 mL plastic straw. The greatest value for the kinetic parameters was achieved when sperm were cryopreserved at 0.5 × 109 spz/mL. In comparison to other concentrations, there was a notable increase in both acrosomal and plasma membrane integrity when sperm was cryopreserved at a concentration of 0.5 × 109 spz/mL. No significant difference of superoxide dismutase and glutathione peroxidase enzyme activity was present in post-thaw sperm, except in sperm cryopreserved at a concentration of 2.0 × 109 spz/mL. Catalase activity was significantly higher in post-thaw sperm at a concentration of 0.5 × 109 spz/mL than at other concentrations. Excluding sperm cryopreserved at 2.0 × 109 spz/mL, the fertilization rate of cryopreserved sperm was not significantly different among the different concentrations. This concentration optimization improves cryopreserved sperm quality and standardizes sperm cryopreservation procedures for the Yangtze sturgeon. These findings are especially beneficial for the establishment of a sperm cryobank.

The kinetics of goat sperm is negatively affected after freezing in an extender including zinc oxide nanoparticles

BACKGROUND: Nanotechnology can benefit livestock industries, especially through postharvest semen manipulation. Zinc oxide nanoparticles (Np-ZnO) are potentially an example. OBJECTIVE: To investigate how the addition of zinc oxide nanoparticles (Np-ZnO) affected the characteristics of postthawed goat semen. MATERIALS AND METHODS: Seminal pools from four Saanen bucks were used. Semen was diluted in Tris-egg yolk extender, supplemented with Np-ZnO (0, 50, 100 or 200 μg/mL), frozen and stored in liquid nitrogen (−196°C), and thawed in a water bath (37°C/30s). Semen samples were evaluated for sperm kinetics by computer-assisted sperm analysis (CASA), and assessed for other functional properties by epifluorescence microscopy, such as plasma membrane integrity (PMi), acrosomal membrane integrity (ACi) and mitochondrial membrane potential (MMP). RESULTS: For total motility (TM), the group treated with 200 μg/mL Np-ZnO was superior to the control. In straight-line velocity (VSL), the control was better than the group containing 200 μg/mL of Np-ZnO. For average path velocity (VAP), the control was higher than with 100 μg/mL Np-ZnO. For linearity (LIN), the control was higher than with 200 μg/mL Np-ZnO. In straightness (STR), the control and 100 μg/mL Np-ZnO were higher than with 200 μg/mL Np-ZnO. In wobble (WOB), the control was better than the 50 μg/mL Np-ZnO treatment. In PMi, ACi and MMP no significant differences were found. CONCLUSION: The addition of Np-ZnO (200 μg/mL) to the goat semen freezing extender improved the total motility of cells, whilst negatively affecting sperm kinetics.

Studies on Fresh and Cryopreserved Seminal Attributes in Beetal Bucks Outside their Breeding Tract

The objectives of the present research were to assess fresh and cryopreserved. seminal characteristics of breeding Beetal buck semen outside of its breeding tract. Semen was collected twice in a week from twelve Beetal bucks for 6 weeks. The mean value of ejaculate volume(ml), mass motility(o-5 scale), progressive motility(%), sperm viability (%), intact acrosome(%), sperm abnormality(%) and plasma membrane integrity(%) were ranged from 0.73 ± 0.08 ml to 1.17 ± 0.27 ml; 4.17+ to 4.67+, 80.83 ± 1.54 to 87.50 ± 2.14; 83.83 ± 0.95 to 90.33 ± 0.80; 87.00 ± 0.86 to 94.67 ± 0.33; 6.83 ± 0.31 to 10.33 ± 0.67 and 59.33 ± 1.52 to 66.67 ± 1.17, respectively. The mean value of post thaw sperm motility, post thaw sperm viability, post thaw acrosome integrity, post thaw sperm abnormalities and post thaw plasma membrane integrity were ranged from 52.50± 1.12 to 66.67 ± 1.67; 60.00 ± 1.24 to 69.67 ± 1.05; 66.00 ± 0.77 to 78.83 ± 2.15; 9.00 ± 0.45 to 12.83 ± 0.60 and 41.50 ± 1.18 to 53.50 ± 1.23, respectively. It was determined that, even outside of the breeding tract, the foundational characteristics of Beetal bucks are within the range defined for other Indian breeds of goat.

Resveratrol Improves the Frozen-Thawed Ram Sperm Quality.

Cryopreservation generates a substantial quantity of ROS in semen, leading to a decline in sperm quality and fertilization capacity. The objective of this study was to investigate the effects of resveratrol and its optimal concentration on ram sperm quality after cryopreservation. Ram semen was diluted with a freezing medium containing different concentrations of resveratrol (0, 25, 50, 75, and 100 μM). After thawing, various sperm parameters such as total motility, progressive motility, acrosome integrity, plasma membrane integrity, mitochondrial membrane potential, glutathione (GSH) content, glutathione synthase (GPx) activity, superoxide dismutase (SOD) activity, catalase (CAT) activity, lipid peroxidation (LPO) content, malondialdehyde (MDA) content, ROS level, SIRT1 level, DNA oxidative damage, and AMPK phosphorylation level were assessed. In addition, post-thaw sperm apoptosis was evaluated. Comparatively, the addition of resveratrol up to 75 μM significantly improved the sperm motility and sperm parameters of cryopreserved ram sperm. Specifically, 50 μM resveratrol demonstrated a notable enhancement in acrosome and plasma membrane integrity, antioxidant capacity, mitochondrial membrane potential, adenosine triphosphate (ATP) content, SIRT1 level, and AMPK phosphorylation levels compared to the control group (p < 0.05). It also significantly (p < 0.05) reduced the oxidative damage to sperm DNA. However, detrimental effects of resveratrol were observed at a concentration of 100 μM resveratrol. In conclusion, the addition of 50 μM resveratrol to the cryopreservation solution is optimal for enhancing the quality of cryopreserved ram sperm.

The protective effect of zinc oxide and selenium oxide nanoparticles on the functional parameters of rat sperm during vitrification.

While sperm freezing (cryopreservation) is an effective method for preserving fertility, it can potentially harm the structure and function of sperm due to an increase in the production of reactive oxygen species. This study aimed to assess the impact of zinc oxide nanoparticles (ZnONPs) and selenium oxide nanoparticles (SeONPs) on various sperm functional parameters, including motility, plasma membrane integrity (PMI), mitochondrial membrane potential (MMP), acrosome membrane integrity (ACi), and malondialdehyde (MDA) levels. Semen samples were collected from 20 Albino Wistar rats. These samples were then divided into six groups: fresh, cryopreservation control, and groups supplemented with SeONPs (1, 2, 5 μg/mL) and ZnONPs (0.1, 1, 10 μg/mL). Statistical analysis revealed that all concentrations of SeONPs increased total motility and progressive reduction of MDA levels compared to the cryopreservation control group (p<0.05). However, supplementation with ZnONPs did not affect these parameters (p>0.05). Conversely, supplements of 1 and 2 μg/mL SeONPs and 1 μg/mL ZnONPs contributed to the improvement of PMI and ACi (p<0.05). Yet, no significant change was observed in MMP with any concentration of SeONPs and ZnONPs compared to the cryopreservation control group (p>0.05). The findings suggest that optimal concentrations of SeONPs may enhance sperm parameters during the freezing process.

A comparison of the biological properties of European red deer (Cervus elaphus elaphus) spermatozoa stored in the epididymides and in a liquid state at 5 °C

The biological properties of European red deer (Cervus elaphus elaphus) spermatozoa stored in the epididymides and in a liquid state were compared. Spermatozoa were collected from the epididymides harvested post-mortem. In the first variant, spermatozoa were diluted in two extenders (Bovidyl® and Salomon's), and were stored at 5 °C for up to 144 h. In the second variant, spermatozoa were stored in the epididymides at 5 °C for up to 144 h, and then diluted in the same extenders. Biological properties were evaluated after 0, 48, 96, and 144 h of storage. Sperm motility parameters were determined in the CASA system. Plasma and acrosomal membrane integrity, mitochondrial activity, apoptotic changes, and DNA integrity were assessed by the fluorescence method. Most variables were significantly influenced by the storage method and time. At 144 h, differences (P ≤ 0.05) in sperm parameters were observed between storage variants. Total motility (TMOT), plasma membrane integrity, and mitochondrial activity decreased below 50% of baseline values in the spermatozoa stored in the epididymides, but remained above 70% of baseline values in the spermatozoa stored in a liquid state. The compared storage variants did not differ in TMOT, mitochondrial activity, or the percentage of viable spermatozoa without apoptotic-like changes up to 96 h of storage, regardless of the applied extender. The earliest significant changes were noted in sperm motility parameters. In conclusion, European red deer spermatozoa can be stored in the epididymides at 5 °C for up to 96 h, but their biological parameters are more effectively preserved during liquid storage.

Effects of Methionine Restriction from Different Sources on Sperm Quality in Aging Mice.

Decreased sperm quality causing poor pregnancy outcomes in aging males is a common problem. The aim of this study was to investigate the ameliorative effect of methionine restriction on sperm quality in aging mice, using methionine or 2-hydroxy-4-(methylthio)butanoate (HMTBA) as the methionine source, with a view to providing nutritional strategies to mitigate the decline in sperm quality in aging livestock. Fifty-one 6-week-old male mice were randomly divided into four groups: the non-aging group (NA, 0.86% methionine), the control diet group (CD, 0.86% methionine), the methionine-restricted group (MR, 0.17% methionine) and the HMTBA-restricted group (HR, 0.17% methionine). The mice in the CD, MR and HR groups were injected with a daily dose of 0.25 mL/20 g body weight of 10% D-galactose to establish an aging model. The test period was 42 days. The results showed that aging mice in the CD group had impaired testicular morphology and significantly decreased sperm quality compared to those in the NA group. Aging mice in the MR and HR groups showed attenuated impaired testicular morphology and improved sperm quality, especially sperm acrosomal integrity and membrane integrity, compared to mice in the CD group. In addition, mice in the MR and HR groups had reduced testicular inflammation and oxidative stress, increased spermidine levels, and reduced sperm RNA N6-methyladenosine (m6A) and DNA 5-methylcytosine (5mC) levels. Spermidine levels were positively correlated, whereas sperm RNA m6A and DNA 5mC levels were negatively correlated with sperm quality parameters. Our study suggests that methionine restriction alleviates the decline in sperm quality in aging mice, which may be related to changes in methionine metabolism and inhibition of sperm DNA and RNA methylation.

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 ( ), 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.

The Effect of Mycotoxins and Their Mixtures on Bovine Spermatozoa Characteristics.

There is growing concern about the effects of mycotoxins on mammalian reproduction. Although the effects of single mycotoxins have been well documented, the impact of their mixtures on spermatozoon quality is less known. Here, frozen-thawed semen (n = 6 bulls) was in-vitro-cultured (2 h) without (control) or with (i) a single mycotoxin [zearalenone (ZEN), ochratoxin A (OTA), toxin 2 (T2), and diacetoxyscirpenol (DAS)] in a dose-response manner; (ii) binary mixtures (OTA + T2, OTA + ZEN, OTA + DAS, ZEN + T2, DAS + T2 and ZEN + DAS); or (iii) ternary mixtures (OTA + DAS + T2, OTA + ZEN + T2, and ZEN + DAS + T2). Then, the spermatozoa quality was characterized according to its plasma- and acrosome-membrane integrity, mitochondrial membrane potential, and oxidation status by a flow cytometer. Exposure to single mycotoxins or binary mixtures did not affect the spermatozoa characteristics. However, exposure to the ternary mixtures, OTA + DAS + T2 and OTA + ZEN + T2, reduced (p < 0.05) the mitochondrial membrane potential relative to the control. In addition, OTA + ZEN + T2 increased (p < 0.05) the proportion of spermatozoa with reactive oxygen species relative to the control. The most suggested interaction effect between the mycotoxins was found to be an additive one. A synergistic interaction, mainly regarding the oxidation status of the spermatozoa, was also found between the mycotoxins. The current study sheds light on the potential risk of exposing spermatozoa to a mycotoxin mixture.

Cryopreservation of equine spermatozoa reduces plasma membrane integrity and phospholipase C zeta 1 content as associated with oocyte activation.

Phospholipase C zeta (PLCZ1) is considered the major sperm-borne oocyte activation factor. Cryopreserved stallion spermatozoa are commonly used for intracytoplasmic sperm injection (ICSI). However, plasma membrane damage and protein modifications caused by cryopreservation could impair sperm structure and function, leading to a reduction of PLCZ1 and oocyte activation after ICSI. We compared membrane integrity and PLCZ1 abundance in populations for fresh, frozen, and refrozen stallion spermatozoa, either thawed and refrozen at room or low temperature; and examined the effect of relative PLCZ1 content on cleavage after ICSI. Western blotting, ELISA, and immunofluorescence were conducted in stallion spermatozoa, freezing extenders, and detergent-extracted sperm fractions to detect and quantify PLCZ1. Retrospectively, PLCZ1 content and cleavage rate were analyzed. Fresh, frozen, and refrozen at room and low temperatures spermatozoa were evaluated for acrosomal and plasma membrane integrity and PLCZ1 content using flow cytometry. Western blotting, ELISA, and immunofluorescence revealed significant reduction of PLCZ1 in spermatozoa after cryopreservation and confirmed PLCZ1 detection in extenders. After detergent extraction, a PLCZ1-nonextractable fraction remained in the postacrosomal region of spermatozoa. Plasma membrane integrity was significantly reduced after freezing. Acrosomal and plasma membrane integrity were similar between frozen and refrozen samples at low temperature, but both were significantly higher than samples refrozen at room temperature. Acrosomal and plasma membrane integrity significantly correlated to PLCZ1 content. Percentages of PLCZ1-labeled spermatozoa and PLCZ1 content were reduced after freezing but not after refreezing. Relative content and localization of PLCZ1 were associated with cleavage rates after ICSI. Sperm PLCZ1 content associates with cleavage rates after ICSI. Cryopreservation is detrimental to sperm plasma membrane integrity and PLCZ1 retention. However, refreezing did not result in additional PLCZ1 loss. Refreezing stallion spermatozoa at a low temperature resulted in better survival but did not improve PLCZ1 retention.

Egg Yolk-Supplemented Tris-Citric Acid Extender Improves the Prefreezing and Post-Thaw Sperm Quality Indices of Guinea Pig (Cavia porcellus) Epididymal Spermatozoa.

This study aimed to assess the suitability of egg yolk (EY) supplementation to a tris-citric acid-based extender on cryosurvival of guinea pig (Cavia porcellus) epididymal spermatozoa. Two synthetic-based extenders, tris-citric acid-glucose plus 20% EY (TCG-EY) and tris-citric acid-fructose (TCF) both with 5% glycerol, were compared. Thirty-two epididymides were recovered from 16 adult guinea pig males by gonadectomy, and then the sperm samples were retrieved by retrograde flushing using TCG-EY and TCF extenders for left or right epididymis, respectively. TCG-EY and TCF sperm samples were frozen in static liquid nitrogen vapors through a two-step cooling procedure. Before freezing, the percentage of progressive sperm motility and sperm with intact plasma and acrosome membranes from TCG-EY sperm samples were higher (p < 0.05) than those diluted with TCF. Post-thaw sperm kinematic variables and membrane integrity were drastically reduced (p < 0.001) compared with prefreezing samples, regardless of extender type. The post-thaw plasmatic and acrosome membrane integrity from TCG-EY sperm samples was higher (p < 0.05) than those from TCF samples. Except for the length, the morphometric head dimensions of sperm diluted with TCG-EY or TCF did not vary (p > 0.05) after the freezing-thawing process compared with the prefreezing samples. In conclusion, despite greater cell cryoinjury with both extenders, the EY supplementation exerted greater cell membrane protection before and after the freezing-thawing process. This research shows an in-depth analysis of guinea pig sperm cryopreservation; however, more studies are recommended.

Soybean lecithin and cholesterol-loaded cyclodextrin in combination to enhances the cryosurvival of dairy goat semen

The objective of the study was to examine the effect of soy lecithin (SL) and cholesterol loaded cryclodestrin (CLC) on cryo-survival of sperm cryopreserved in the presence or absence of seminal plasma in Saanen dairy goats. Tris-based dilutions containing various concentrations of SL (0, 0.5%, 1.0% or 2.0%) and CLC (0, 2.0 g/L, 4.0 g/L or 6.0 g/L CLC) were used to cryopreserve Saanen dairy goat sperm. The quality of frozen-thawed sperm, including progressive motility, viability, acrosome and plasma membrane integrity, as well as fertility were detected. Results found that the optimal combination of the two cryoprotectants was 1.0% SL+4.0 g/L CLC, which significantly increased progressive motility, viability, acrosome and plasma membrane integrity of frozen thawed sperm. The impact of the two cryoprotectants in combination was not affected by the presence of seminal plasma. The conception rates obtained after artificial insemination using sperm cryopreserved with and without seminal plasma were 88.89% and 91.67% (P > 0.05), respectively. The respective values for average number of litter sizes were 1.55 ± 0.17 and 1.56 ± 0.21 (P > 0.05). Therefore, this study improved the cryopreservation efficiency of goat semen, enhanced the sperm cryosurvival, and layed a foundation for the wide application of frozen goat semen.

Phosphocreatine addition to extender enhances the quality and antioxidant capacity of cryopreserved boar sperm.

Boar sperm are less resistant to drastic changes in the external environment during cryopreservation, mainly because their plasma membranes are rich in unsaturated fatty acids but lack cholesterol and are thus susceptible to lipid peroxidation caused by the attack of reactive oxygen species. This study evaluated the effect of adding phosphocreatine to cryopreservation extenders on boar sperm quality and antioxidant capacity. Different concentrations (0, 5.0, 7.5, 10.0 and 12.5 mmol/L) of phosphocreatine were added to the cryopreservation extender. After thawing, sperm were analysed for morphological parameters, kinetic parameters, acrosome integrity, membrane integrity, mitochondrial activity, DNA integrity and antioxidant enzyme activity. The results showed that 10.0 mmol/L phosphocreatine samples enhanced the boar sperm motility, viability, average path velocity, straight-line velocity, curvilinear velocity and beat cross frequency after cryopreservation and reduced the malformation rate compared to the control group (p < .05). The acrosome integrity, membrane integrity, mitochondrial activity and DNA integrity of boar sperm were higher than those of the control group after adding 10.0 mmol/L phosphocreatine to the cryopreservation extender (p < .05). Extenders containing 10.0 mmol/L phosphocreatine maintained high total antioxidant capacity; elevated the activities of catalase, glutathione peroxidase and superoxide dismutase; reduced malondialdehyde and H2 O2 content (p < .05). Therefore, adding phosphocreatine to the extender is potentially beneficial for boar sperm cryopreservation at an optimal 10.0 mmol/L concentration.