Canine sperm vitrification with sucrose: effect on sperm function

The ability of sucrose to protect spermatozoa against mitochondrial damage, artificial acrosome reaction and DNA fragmentation during ultra‐rapid cryopreservation in canine sperm was investigated. Swim‐up selected spermatozoa of second‐fraction semen were vitrified with different concentrations of sucrose (0.1, 0.25 and 0.4 m ) in proportion 1 : 1 v/v with HTF–BSA 1%. From each group, 30‐μl suspensions of cells were dropped directly into liquid nitrogen and stored for at least 24 h. Cells were thawed by submerging the spheres in HTF with 1% BSA at 37 °C. The number of progressively motile spermatozoa was significantly higher in the sucrose 0.25 m + HTF–BSA 1% (42.5 ± 2.3%, P < 0.01) than in HTF only (1.66 ± 0.3%). The same combination of sucrose 0.25 m + HTF–BSA 1% (42.7 ± 1.5%) had a stronger cryoprotective effect on the integrity of mitochondrial membrane potential (P < 0.05) and decreased the DNA fragmentation (2.8 ± 0.5%) as compared with HTF only (1.93 ± 0.6% and 5.6 ± 0.6% respectively). With respect to acrosome‐reacted spermatozoa, no significant difference was found between the groups investigated (P > 0.05). It is concluded that sucrose, a nonpermeable cryoprotectant, can effectively preserve important physiological parameters such as mitochondrial membrane potential and DNA integrity during ultra‐rapid cryopreservation.     

High temperature is essential for preserved human sperm function during the devitrification process

Sperm vitrification is a cryopreservation method based on high‐speed freezing by direct exposure of cells in liquid nitrogen (N₂L), thereby avoiding the traditional cooling curves of freezing. The objective of this work was to determine the optimal warming temperature for vitrified human spermatozoa in order to maintain their fertilisation potential. Spermatozoa were cryopreserved by direct plunging into N₂L and warmed at different temperatures for 5 and 10 s at 38, 40 and 42 °C. Sperm motility was evaluated by the CASA system and the sperm membrane function by HOST test. It was detected that progressive motility of sperm warmed at 38, 40 and 42 °C was 26.4 ± 8.4%; 56.6 ± 16.3% and 65.4 ± 15%, respectively, with statistically significant differences between the temperatures of 38 and 40 °C and 38 and 42 °C (P < 0.05). The plasma membrane function evaluated by HOST test was better preserved at 42 °C (76.3 ± 2.0%) compared to 40 °C (43 ± 2%) and 38 °C (65.6 ± 1.5%). The temperature in the thawing process can affect the motility and plasma membrane integrity and function. The warming at 42 °C for thawed vitrified sperm is the optimum temperature to preserve the sperm physiological parameters.     

Trehalose sustains a higher post‐thaw sperm motility than sucrose in vitrified human sperm

One of the cryopreservation methods that best preserves sperm function is vitrification. However, comparative studies have not been performed to evaluate the effect of nonpermeable cryoprotectors on sperm function for prolonged periods of time post‐devitrification. These times are necessary, especially in in vitro fertilisation and intrauterine insemination, for gamete interaction and then fertilisation to occur, while maintaining motility to arrive at the fertilisation site. In this study, sucrose (.25 m ) and trehalose (.1 and .05 m ) were compared in essential parameters like motility and plasma membrane integrity for 12 hr. Post‐devitrification sperm motility using .1 m trehalose was 68.9%, higher than that obtained with .05 m trehalose (59.9%, p < .0081) and .25 m sucrose (57.9%, p < .0002). Similar results were obtained at 6 and 12 hr with .1 m trehalose (58.0% and 42.3% respectively) compared to .05 m trehalose (p < .0184 and p < .033) and .25 m sucrose (p < .0001 and p < .0012).There was no difference between .25 m sucrose and .05 m trehalose. Membrane integrity was best preserved at time 0 by .1 m trehalose (p < .05), but there was no significance at 6 and 12 hr compared to sucrose. Our results suggest that for assisted reproduction techniques that require motile spermatozoa for a longer period of time, use of .1 m trehalose is recommended in the sperm vitrification technique.     

Selection of normal spermatozoa with a vacuole‐free head (x6300) improves selection of spermatozoa with intact DNA in patients with high sperm DNA fragmentation rates

Intracytoplasmic morphologically selected sperm injection (IMSI, 6300× magnification with Nomarski contrast) of a normal spermatozoon with a vacuole‐free head could improve the embryo's ability to grow to the blastocyst stage and then implant. However, the most relevant indications for IMSI remain to be determined. To evaluate the potential value of IMSI for patients with a high degree of sperm DNA fragmentation (n = 8), different types of spermatozoa were analysed in terms of DNA fragmentation. Motile normal spermatozoa with a vacuole‐free head selected at 6300× magnification had a significantly lower mean DNA fragmentation rate (4.1 ± 1.1%, n = 191) than all other types of spermatozoa: non‐selected spermatozoa (n = 8000; 26.1 ± 1.5% versus 4.1 ± 1.1%; P < 0.005), motile spermatozoa (n = 444; 20.8 ± 2.7% versus 4.1 ± 1.1%; P < 0.001) and motile, normal spermatozoa selected at 200× magnification (n = 370; 18.7 ± 2.7% versus 4.1 ± 1.1%; P < 0.001) and then motile, morphometrically normal spermatozoa with anterior vacuoles (n = 368; 15.9 ± 2.9% versus 4.1 ± 1.1%; P < 0.05) or posterior vacuoles (n = 402; 22.5 ± 3.6% versus 4.1 ± 1.1%; P < 0.001) selected at 6300× magnification. For patients with high sperm DNA fragmentation rates, selection of normal spermatozoa with a vacuole‐free head (6300×) yields the greatest likelihood of obtaining spermatozoa with non‐fragmented DNA.     

Effect of cysteine and glutamine added to extender on post‐thaw sperm functional parameters of buffalo bull

Amino acids seem to be crucial components for semen freezing extender due to antioxidant properties. Therefore, this study aimed to assess motility parameters, membrane integrity, intracellular reactive oxygen species (ROS), mitochondrial membrane potential (MMP) and DNA damage to detect the optimum concentrations of cysteine and glutamine for buffalo semen cryopreservation. Twenty ejaculates of four buffalo bulls were diluted in tris‐egg yolk extender and divided into seven equal groups consisting of cysteine (5, 7.5 and 10 mmol), glutamine (10, 15 and 20 mmol) and no additive. Supplementation of 5 and 7.5 mmol cysteine and 15 mmol glutamine in cryopreservation extender significantly increased post‐thaw motility and plasma membrane integrity of spermatozoa with significant reduction in intracellular ROS when compared with control groups (P < 0.05). Cysteine at 7.5 mmol concentration elevated progressive motility and MMP, compared with control (P < 0.05). No significant differences were observed for motion patterns and DNA damage of frozen–thawed buffalo spermatozoa in extender containing amino acids. The findings of this study showed that supplementation of 7.5 mmol cysteine and 15 mmol glutamine in semen cryopreservation extender has more potential to decrease intracellular ROS, and subsequently elevate motility and membrane integrity of buffalo frozen–thawed spermatozoa.     

不同浓度的蔗糖溶液快速冻存人类精子的实验研究

目的:探讨使用非渗透性冷冻保护剂蔗糖快速冻存人类精子的可行性。方法:收集正常精液标本40份,经上游法处理后,收集上游精子悬液,分成6份,1份作为对照,其余5份分别用常规精子冷冻法,0.15、0.20、0.25、0.30 mol/L蔗糖溶液冷冻精子,复苏后比较6组精子活动率、前向运动精子活动率及精子质膜完整性。结果:所有冷冻组复苏后精子活动率、前向运动精子活动率及膜完整率与冷冻前上游组(96.2±1.8)%,(93.8±2.8)%,(99.0±0.8)%比较均显著下降,差异有显著性(P<0.05)。精子活动率结果:蔗糖冷冻组之间比较,0.20 mol/L组解冻后精子活动率高于0.15、0.25、0.30 mol/L组,分别为(55.5±6.3)%、(45.9±6.6)%、(50.4±9.4)%、(45.5±11.2)%,差异有显著性(P<0.05)。0.20、0.25 mol/L蔗糖冷冻组与常规慢速冷冻组(53.6±5.0)%比较,差异均无显著性(P>0.05);0.15、0.30 mol/L蔗糖组均低于常规慢速冷冻组(P<0.05)。前向运动精子活动率结果:0.20 mol/L蔗糖冷冻组与常规冷冻组比较差异无显著性[(44.4±7.4)%vs(42.3±8.1)%,P>0.05];以上两组均高于0.15、0.25、0.30 mol/L蔗糖冷冻组,分别为(37.1±8.3)%、(33.1±9.2)%、(22.0±9.1)%,差异有显著性(P<0.05)。精子膜完整率结果:0.20 mol/L蔗糖冷冻组(70.1±6.9)%高于常规冷冻组、0.15、0.25、0.30 mol/L蔗糖冷冻组,分别为(63.1±6.8)%、(57.7±8.3)%、(63.5±10.7)%、(57.8±12.9)%,差异有显著性(P<0.05);常规冷冻组与0.15、0.25、0.30 mol/L蔗糖冷冻组比较差异无显著性(P>0.05)。结论:终浓度为0.20 mol/L的蔗糖溶液作为人类精子冷冻保护剂是可行的,快速冷冻方法简便、快速、经济、安全有效。     

Large volume cryoprotectant‐free vitrification: an alternative to conventional cryopreservation for human spermatozoa

Vitrification is a simple and cost‐effective method for the storage of human spermatozoa without the use of conventional cryoprotectants, by plunging the sperm suspension directly into liquid nitrogen. As a result, solidification of living cells without the formation of ice crystals is achieved during cooling. This study aimed to compare cryoprotectant‐free vitrification to conventional cryopreservation protocols. Semen samples (n = 35) were collected from patients seeking diagnostic assistance at the Reproductive and Endocrine Unit at Steve Biko Academic Hospital. Samples were processed using a discontinuous density‐gradient centrifugation method. Washed samples were split into two aliquots and cryopreserved either by means of cryoprotectant‐free vitrification (sucrose + 1% albumin) or conventional slow freezing (TEST‐yolk buffer). Post‐thawing, the sperm motion parameters, mitochondrial membrane potential (Δψm) and DNA fragmentation were compared between the two groups. No significant differences were observed in the sperm motility parameters (P > 0.05). Significantly higher percentages of Δψm (11.99% ± 4.326% versus 6.58% ± 1.026%; P < 0.001) and lower percentages of DNA fragmentation (2.79% ± 1.017% versus 3.86% ± 1.38%; P < 0.01) were observed when comparing cryoprotectant‐free vitrification to conventional cryopreservation. Cryoprotectant‐free vitrification is a rapid and promising alternative to conventional methods resulting in good‐quality spermatozoa post‐thaw.     

Cryoprotectant‐free ultra‐rapid freezing of human spermatozoa in cryogenic vials

The objective of this study was to investigate the effect of ultra‐rapid freezing (direct immersion in liquid nitrogen) on human spermatozoa in cryogenic vials (≥0.5 ml) at different concentrations of sucrose. After swim‐up, the sperm suspensions (N = 58) were diluted with sperm preparation medium and divided into six aliquots: swim‐up (fresh), conventional freezing group (slow freezing) and four ultra‐rapid freezing groups containing sucrose at different concentrations (0.15 m , 0.20 m , 0.25 m and 0.30 m ). Sperm motility, progressive motility, plasma membrane integrity, DNA stability and acrosome integrity of fresh and cooled‐warmed spermatozoa were analysed. The progressive motility, plasma membrane and acrosome integrity of spermatozoa in the 0.20 m sucrose group were significantly higher than those of the slow freezing group (47.5 ± 6.8% versus 36.4 ± 8.7%, 73.2 ± 6.9% versus 63.9 ± 6.3%, 53.7 ± 10.0% versus 35.9 ± 9.7% respectively, P < 0.05). However, no differences were found in sperm motility or DNA stability (58.5 ± 6.3% versus 54.2 ± 5.3%, 90.1 ± 2.8% versus 87.2 ± 4.7%, P > 0.05 respectively) between the 0.20 m sucrose and the slow freezing group. No differences were found between the ultra‐rapid and slow freezing group at the other concentrations of sucrose. Our findings suggest that the method of ultra‐rapid freezing of human spermatozoa in cryogenic vials with a solution containing 0.20 m sucrose results in recovery of spermatozoon of superior qualities. In contrast to slow freezing, the ultra‐rapid freezing technique of human spermatozoa seems to reduce cryoinjuries and maintain important physiological characteristics of the spermatozoa after warming.     

Percentage change of FSH value: new variable to predict the seminal outcome after varicocelectomy

In the literature, there is no good agreement with variables to predict seminal outcome after varicocelectomy. The purpose of this study was to evaluate the FSH percentage change (Δ% FSH) as a predictor of the seminal outcome after varicocelectomy together with other known predictors. We evaluated 118 patients who underwent varicocelectomy. We assessed factors that could be predictors of the improvement of semen characteristics: LH, FSH, total and free testosterone before operation, testis volume, age, testicular pain, body mass index (BMI), Δ% FSH, varicocele Doppler ultrasound grade using regression analysis. Mean sperm concentration increased from 27 ± 12 to 52 ± 15 million per ml post‐operatively (P < 0.003), mean sperm motility increased from 31 ± 12 to 40 ± 13 million per ml following the operation (P < 0.02), also mean FSH value changed from 10.2 ± 8.3 to 6.7 ± 7.2 UI/L (P < 0.01). In unvaried regression analysis, Δ% FSH, BMI and age were predictors of the improvement of semen characteristics. In multiple regression analysis, only Δ% FSH and age were predictors. Negative correlation with age and positive correlation with Δ% FSH were observed. Our findings suggest that Δ% FSH (before and after varicocelectomy) and age are significant factors predicting the improvement of semen characteristics.     

Addition of caffeine to equine thawed sperm increases motility and decreases nitrite concentration

The aim of this study was to improve the quality of frozen-thawed equine sperm by the addition of caffeine to it. Semen from nine stallions was frozen and different concentrations of caffeine (3, 5 and 7.5 mM) were added to frozen-thawed semen. The sperm kinetic parameters, membrane functionality and integrity, and acrosome integrity and spontaneous acrosome reacted sperm were evaluated with a computer-assisted sperm analysis, a hypoosmotic swelling test and epifluorescent microscopy, respectively. Nitrite and hydroperoxide concentrations of frozen-thawed semen were measured using spectrophotometry. Sperm fertility was evaluated by artificial insemination (AI) of 16 mares with thawed ejaculates (control and 5 mM caffeine-treated groups). Compared to that in the control, the addition of 5 mM caffeine induced an increase in sperm motility (38.9 ± 2.8 versus 32.6 ± 3.4%), and a decrease in nitrite concentration (11.4 ± 2.1 versus 12.8 ± 2.9 µM/µg protein, p < .05). Moreover, the pregnancy rate from AI in the caffeine group was significantly higher (62.5%) than that in the control group (12.5%). These data suggest that caffeine reduced the nitrite concentration and enhanced sperm motility in thawed equine sperm, thus increasing the fertility rate in mares inseminated with caffeine-treated equine semen.     

Giant panda (Ailuropoda melanoleuca) sperm morphometry and function after repeated freezing and thawing

This work examines the effects of subsequent cycles of freezing–thawing on giant panda (Ailuropoda melanoleuca) sperm morphometry and function, and assesses whether density‐gradient centrifugation (DGC) can increase the number of freezing–thawing cycles this sperm can withstand. A sperm sample was collected by electroejaculation from a mature giant panda and subjected to five freezing–thawing cycles. Although repeated freezing–thawing negatively affected (P < 0.05) sperm motility and membrane integrity, in both nonselected and DCG‐selected sperm samples, >60% of the sperm cells in both treatments showed acrosome integrity even after the fifth freezing cycle. In fresh semen, the sperm head length was 4.7 μm, the head width 3.6 μm, area 14.3 μm² and perimeter length 14.1 μm. The present results suggest that giant panda sperm trends to be resistant to repeated freezing–thawing, even without DGC selection.     

The effect of cysteine and glutamine on human sperm functional parameters during vitrification

Assuming the adverse effects of reactive oxygen species (ROS) on sperm function, this study was conducted to assess the effects of cysteine and glutamine as effective antioxidants on human sperm parameters under vitrification. Twenty normozoospermic samples were used. The samples were subjected to a vitrification process and cysteine (5 and 10 mM) and glutamine (10 and 15 mM). The sperm motility parameters, mitochondrial membrane potential (MMP), plasma membrane integrity (PMI), DNA damage and intracellular ROS damage were assessed for each sample. Statistical analyses showed that motility, mitochondrial membrane potential and DNA damage decreased in the vitrified groups with cysteine 5, 10 mM and glutamine 10, 15 mM separately. Also intracellular ROS increased significantly compared to the fresh group (p < .05). No significant differences were observed for PMI compared with the fresh group (p > .05). Supplementation of cysteine and glutamine in both concentrations separately decreased intracellular ROS and DNA damage of spermatozoa with significant increase in PMI, MMP and progressive motility compared to vitrified control group (p < .05). The results showed no significant effect of a specific concentration in cysteine and glutamine on sperm parameters compared to other concentrations. Both amino acids have the potential to improve the harmful effects of freezing on sperm parameters.     

Effect of egg yolk plasma on dog sperm cryopreservation

This study evaluated the quality of frozen‐thawed dog spermatozoon after the inclusion of egg yolk plasma (EYP) instead of whole egg yolk (EY) in the cryopreservation extender and after distinct periods of exposure to EYP. Seven mongrel dogs were used as sperm donors, and EYP was obtained by centrifugation. In Experiment 1, post‐thawing sperm motility (MOT) and integrity of membrane (INT) and acrosome (ACR) were superior for spermatozoon extended with 20% EYP T2 than with 20% EY (P < 0.05), although normal sperm morphology (MOR) did not differ (P > 0.05). In Experiment 2, after ejaculates extended with 20% EYP were cooled at 5°C for 2, 6 and 10 h before freezing, MOT, INT and ACR were similar among periods (P > 0.05). Thus, dog spermatozoon extended with 20% EYP can be kept cooled for up to 10 h prior to freezing, achieving post‐thawing quality greater than that obtained with the inclusion of EY in freezing extenders.     

Goat semen cryopreservation with rainbow trout seminal plasma supplemented lecithin-based extenders

The objective of this study was to determine the optimum concentrations of rainbow trout seminal plasma (RTS) supplemented extenders for goat semen quality at post-thaw and after incubation. Five sexually mature Saanen goat (Capra aegagrus hircus) were used for semen collection. Pooled semen was diluted with soybean lecithin-based extender without RTS (control) or supplemented with different concentrations of RTS (1%, 2%, 4% or 8%), at a final concentration of 150 × 10⁶ spermatozoon/ml. Sperm motility, plasma membrane functional integrity (HOST), damaged acrosome (PSA-FITC), mitochondrial activity (rhodamine123) and DNA integrity (TUNEL) were evaluated. Spermatological parameters were evaluated at post-thaw and after 6 hr incubation. RTS8 group preserved sperm motility, acrosomal integrity, plasma membrane functional integrity and mitochondrial function better than the control group (p < .05). The study demonstrated that RTS supplemented lecithin-based extenders have useful effects on goat spermatozoa. In addition, the results of the current study represented the positive effect of using 8% RTS supplemented extender.     

Gallic and carnosic acids improve quality of frozen‐thawed ram spermatozoa

The objective was to determine effects of gallic acid (GA) and carnosic acid (CA), present in carob pods and rosemary extract respectively, on frozen‐thawed ram spermatozoa. Thirty ejaculates were collected from five Merino rams, pooled, diluted in Tris‐based extender and divided into five equal portions containing: 0.05 or 2 mM of GA; 0.05 or 0.2 mM of CA; or no additive (control). Extended semen was equilibrated at +4°C, loaded into straws, held 5 cm above liquid nitrogen for 12 min then plunged. Computer‐aided sperm analysis was used to assess motility, whereas flow cytometry was used to assess high mitochondrial membrane potential (HMMP) and percentages of spermatozoa with plasma membrane and acrosome integrity (PMAI). Spermatozoa supplemented with 2 mM GA had greater total motility than control spermatozoa (39.9 ± 3.01 vs. 29.2 ± 1.31%, mean ± SEM, p < .05). The PMAI was greatest in 0.2 mM CA (13.3 ± 0.68%), whereas HMMP was highest in 0.05 mM CA but lowest in control (22.9 ± 4.95 and 11.4 ± 3.64% respectively; p < .05). In conclusion, for cryopreservation of ram semen in Tris‐based extender, supplementation with 2 mM GA increased post‐thaw motility, whereas supplementation with 0.05 mM CA enhanced mitochondrial function.     

Prolonged incubation of processed human spermatozoa will increase DNA fragmentation

One of the causes of failure in ART is sperm DNA fragmentation which may be associated with long period of spermatozoa incubation at 37 °C. The objective was to evaluate the rate of sperm DNA fragmentation using the sperm chromatin dispersion (SCD) test after swim‐up at different time intervals prior to use. In this prospective study, 21 normozoospermic specimens were analysed. The samples were incubated at 37 °C after preparation by direct swim‐up. DNA fragmentation was assessed at different time intervals (0, 1, 2 and 3 h) using SCD test. Spermatozoa with no DNA fragmentation showed large‐ or medium‐sized halos, and sperm cells with DNA fragmentation showed either a small halo or no halo . The rates of normal morphology and progressive motility after sperm processing were 72.33 ± 2.53% and 90 ± 1.02%, respectively. The rate of sperm DNA fragmentation was significantly higher after 2 h (8.81 ± 0.93%, P = 0.004) and 3 h (10.76 ± 0.89%, P < 0.0001) of incubation compared to 0 h (4.38 ± 0.8%). A positive correlation was found between the incubation time and sperm DNA damage (P < 0.0001). Prolonged incubation of prepared normozoospermic samples at 37 °C is associated with higher rates of sperm DNA fragmentation. Therefore, sperm samples intended for ART procedures should be used within 2 h of incubation at 37 °C.     

Supplementation of IVF medium with melatonin: effect on sperm functionality and in vitro produced bovine embryos

Gamete co‐incubation generates high free radical levels surrounding growing zygotes which may impair subsequent embryo viability. Melatonin eliminates a wide variety of free radicals; hence, we tried to improve in vitro embryo production by adding melatonin to in vitro fertilisation (IVF) media in high (Exp. 1) and low concentrations (Exp. 2), and we evaluated its effect on bull sperm function during IVF co‐incubation time (Exp. 3). In Experiment 1, we supplemented IVF media culture with 0.01, 0.1 and 1 mmol of melatonin, along with a no melatonin control group. In Experiment 2, melatonin levels were reduced to 10, 100 and 1000 nmol, with a no melatonin control group. In Experiment 3, spermatozoa were incubated in IVF media with melatonin (as Exp. 2) and functional parameters were analysed at 0, 4 and 18 h. In Experiment 1, only 1 mmol melatonin showed lesser blastocyst rates than control (C: 23.2 ± 6.7% versus 1 mmol: 2.0 ± 1.7%). In Experiment 2, no statistical differences were found in cleavage percentage, blastocyst percentage and total cell count for any melatonin treatment. In Experiment 3, sperm samples with 1000 nmol melatonin had a significantly higher wobbler (WOB) coefficient, a lower percentage of intact acrosomes, a lower percentage of viable spermatozoa with ROS, greater DNA fragmentation and higher DNA oxidation than controls. Total fluorescence intensity for ROS at 10 nmol melatonin was significantly greater than controls (P < 0.05). IVF media with 1 mmol melatonin is deleterious for embryo development, and in lower concentrations, it modulated sperm functionality, but had no effects on embryo production.     

The presence of seminal plasma,especially derived from stallion semen,helps preserve chilled Asian elephant (Elephas maximus) sperm motility

The effects of seminal plasma (SP), derived from autologous, homologous and heterologous species (stallion, boar and dog) on chilled Asian elephant sperm quality, were determined. Semen was collected from eight males and samples with ≥30% motile spermatozoa were used in the study. Semen was diluted with Tris–glucose–egg yolk extender, supplemented with different SP types and preserved at 4°C for 48 hr. Experiment 1 (n = 31), showed that the presence of SP (autologous) helped to preserve sperm quality in terms of sperm motility and acrosome integrity (p < .05). Homologous SP did not result in better sperm quality than autologous SP. Heterologous SP from stallion provided higher sperm motility and velocities compared to autologous SP (p < .05). Experiment 2 (n = 14) determined the effect of different SP from four stallions. All stallion SP gave higher (p < .05) results for motile spermatozoa and sperm velocities than autologous SP. In conclusion, the presence of SP helps preserve Asian elephant sperm quality and stallion SP supports the motility of Asian elephant spermatozoa during cold storage.     

Study on correlation of sperm quality parameters with antioxidant and oxidant status of buffalo bull semen during various stages of cryopreservation

This investigation was carried out to study the correlation of sperm quality parameters with antioxidant and oxidant status of buffalo bull semen during various stages of cryopreservation. Semen samples were evaluated for sperm parameters (mass motility [MM], concentration [CON], progressive motility [PM], viability [VIB], acrosomal integrity [AI] and hypo‐osmotic swelling [HOS] response), antioxidants (superoxide dismutase [SOD], catalase [CAT], glutathione peroxidase [GPx] and total antioxidant capacity [TAC]) and oxidants (Lipid peroxidation [LPO] and reactive oxygen species [ROS]) at fresh, pre‐freeze and post‐thaw stages. Sperm parameters (PM, VIB, AI and HOS response) and antioxidants (SOD, CAT and TAC) were significantly (p < .05) reduced at fresh stage, and oxidants (LPO and ROS) were significantly (p < .05) increased at pre‐freeze and post‐thaw stages. At fresh stage, MM was negatively correlated with LPO (p < .05), and CON was positively correlated with SOD, TAC and CAT, negatively correlated with LPO and CAT was positively (p < .01) correlated with VIB and HOS response. At pre‐freeze stage, CAT was positively correlated with PM and AI (p < .05), and AI was negatively (p < .05) correlated with ROS. At post‐thaw stage, CAT was positively correlated with PM, VIB, HOS response and AI,, and LPO was negatively correlated with HOS, AI and VIB. The study of correlations of these parameters at different preservation stages with bull fertility may play an important role in developing models for predicting future fertility of bulls in the absence of conception rate data.     

Comparative study of fertility parameters in vitrified human spermatozoa in the presence or absence of EmbryORP®: A novel antioxidant

The cryopreservation of spermatozoa has the main purpose of preserving male fertility. However, current preservation techniques have shown to produce lesions in the structure and alter sperm functions, probably due to the production of reactive oxygen species (ROS) during cryopreservation. To overcome the damage provoked by ROS, we introduced a novel antioxidant called EmbryORP^® in a vitrification protocol and compared eight fertility parameters: motility, viability, morphology, concentration, the semen pH, the oxidation-reduction potential (ORP), the spontaneous acrosomal reaction (AR) and the mitochondrial membrane potential (MMP), in the presence or absence of EmbryORP^®. We analysed 20 samples from healthy human sperm donors and observed that the antioxidant significantly decreased the semen pH as well as the MMP and the ORP affecting the balance of ROS. The antioxidant also lowered the motility and viability of the cells, but preserved the acrosome and sperm morphology in general. We concluded that EmbryORP^® lowered the ORP, but to a suboptimal level that may be harmful to spermatozoa. Despite these results, our work opens new perspectives on how to improve cryopreservation media. Therefore, we recommend exploring the EmbryORP^® potential benefit by reducing its concentration or changing the exposure time during the cryopreservation protocol.