Antagonist effect of DMSO on the cryoprotection ability of glycerol during cryopreservation of buffalo sperm

Effect of Some Plant-Based Substances on Microbial Content and Sperm Quality Parameters of Bull Semen

The rapid emergence of antibacterial resistance requires alternatives to antibiotics to be found, including for semen preservation. One of the possible alternatives would be to use plant-based substances with known antimicrobial effects. The objective of this study was to test the antimicrobial effect of pomegranate powder, ginger, and curcumin extract in two concentrations on bull semen microbiota after exposure for <2 h and 24 h. An additional aim was to evaluate the effect of these substances on sperm quality parameters. The bacterial count in semen was low from the beginning; however, a reduction was present for all tested substances compared with control. A reduction in bacterial count in control samples was also observed with time. Curcumin at a concentration of 5%, reduced bacterial count by 32% and was the only substance that had a slight positive effect on sperm kinematics. The other substances were associated with a decline in sperm kinematics and viability. Neither concentration of curcumin had a deleterious effect on sperm viability parameters measured by flow cytometry. The results of this study indicate that curcumin extract at a concentration of 5% can reduce the bacterial count and does not have a negative influence on bull sperm quality.

EVALUATION OF TWO CRYOPROTECTANTS USED IN A NEW HUMAN SPERM CRYOPRESERVATION TECHNIQUE

OBJECTIVE

The aim: To examine the efficiency of different concentrations of Dimethyl sulfoxide (DMSO) and glycerol as a cytoprotectants in protection of human sperms during cryopres¬ervation in this technique.

PATIENTS AND METHODS

Materials and methods: Thirty oligozoospermic semen samples were used in this study. Samples diagnosed according to WHO 2010 criteria. Sheep's ovarian follicles obtained from local slaughterhouse and prepared by slicing the ovaries and evacuating the follicular fluid and oocyte. Each semen sample divided into six equal parts, and diluted 1:1 with cryosolution contains 5%, 10%, 15% DMSO or glycerol and injected within the emptied follicles. After freezing and thawing, the semen mixture aspired outside the follicles and sperm concentration, progressive motility, total motility, and normal morphology were examined.

RESULTS

Results: The best recovery rate of progressive and total motility post-thawing were with the use of 5% glycerol, and the lowest recovery rate of progressive and total motility and normal morphology were with the use of 15% DMSO.

CONCLUSION

Conclusions: In this technique, glycerol was more efficient than DMSO regarding sperm motility. The best concentration of glycerol for cryopreserve human spermatozoa is 5%.

Carboxylated ε-Poly-l-lysine Improves Post-Thaw Quality, Mitochondrial Functions and Antioxidant Defense of Goat Cryopreserved Sperm

Carboxylated ε-poly-l-lysine (CPLL), a novel cryoprotectant, can protect the sperm membranes by inhibiting ice crystal formation during the cryopreservation process. The present study was conducted to investigate the consequence of CPLL supplementation on the post-thaw quality of cryopreserved goat sperm. For this, different doses (0, 0.5%, 1%, 1.5%, and 2%; v/v) of CPLL were added to the cryopreservation medium, and the motility, membrane and acrosome integrity, mitochondrial membrane potential (MMP), ATP level, ROS production, anti-oxidant defense system, malondialdehyde (MDA) level, and apoptosis in post-thaw sperm were evaluated. It was observed that the addition of 1% CPLL significantly (p < 0.05) increased the total motility, membrane integrity, acrosome integrity, and catalase (CAT) activity of post-thaw sperm compared to those of control and other CPLL doses. The ATP content was observed significantly (p < 0.05) higher in 0.5% and 1% CPLL, however, the SOD activity and progressive motility were significantly (p < 0.05) increased by adding CPLL at 1% and 1.5% level. Moreover, the addition of CPLL at 1% dose not only showed a lower percentage of apoptosis, but also significantly (p < 0.05) increased the MMP while reducing ROS production and MDA levels compared to those of other CPLL doses and/or control. Therefore, it is clear that the supplementation of 1% CPLL can remarkably improve the post-thaw goat sperm motility, membrane and acrosome integrity, antioxidant abundance, mitochondrial potentials, and ATP supply by protecting the sperm from cryodamage and undergoing apoptosis. These findings will provide novel insights into sperm cryobiology.

Demonstration of Solute-specific Synergism in Binary Solvents

The structure and solvation behavior of binary liquid mixtures of Methanol (MeOH) and N, N-Dimethylformamide (DMF) are explored by ascertaining their intermolecular interactions with either Rhodamine-B (RhB) or Rhodamine101 (Rh101) dye through steady-state absorption, emission, and two-photon induced fluorescence. Specifically, in the present investigation, we examine the strong synergistic solvation observed for the combinations of hydrogen bond donating (MeOH) and accepting (DMF) solvent pairs. Solvatochromism causes the solvatochromic probe molecules to sense increased polarity compared to their bulk counterparts. The origin of synergism was explained in terms of solute-solvent and solvent-solvent interactions in binary solvent mixtures interactions, as evidenced by probe dependence. The solvation behavior of the Methanol and DMF binary solvent mixture shows strong probe dependence, with Rh101 showing synergism while RhB does not.

PCR investigation of the vertical transmission of Mycobacterium bovis in Montbéliarde cattle in Gonbad, northeast of Iran

Bovine tuberculosis is an important global zoonosis. The causative agent of the disease is Mycobacterium bovis, belonging to the Mycobacterium tuberculosis complex. This study aimed to identify vertical transmission of Mycobacterium bovis in tuberculin positive pregnant dairy cows referred to the slaughterhouse and commercial sperm used to inseminate them in Gonbad, Gorgan province, Iran, by PCR assay. From March to September 2016, one thousand and seven hundred artificially inseminated cows were subjected to the tuberculin test; then, tuberculin positive cows were referred to the Gonbad slaughterhouse. Samples containing milk, lymph node, placenta, foetal abomasal fluid, and amniotic fluid were prepared from all affected cows and stored at -80 °C until analysis. Bacterial DNA was extracted from all specimens by a commercial kit. Detection was performed by amplifying pncATB gene using special primers via the polymerase chain reaction method. Results of tuberculin test revealed 144 positive cases (8.47%). PCR results for 48 milk samples, 120 biopsy samples, 63 samples of foetuses showed 9, 93 and 43 positive cases, respectively which all belonged to tuberculin positive samples. No positive sperm samples were identified. It was concluded that the infection rate with M. bovis in Montbéliarde cattle was high and also, that vertical transmission was not seen.

Effect of turmeric extract and dimethyl sulfoxide on buffalo semen freezability and fertility

The freeze-thaw process results in structural and functional damages caused by overaccumulation of reactive oxygen species (ROS). Addition of antioxidants to semen extenders is of a great importance to overcome this oxidative damage. The study objective was to evaluate the consequence of using Tris-citric acid fructose egg yolk (TCFY) extender supplemented with a combination of turmeric extract and dimethyl sulfoxide (DMSO) [TTD] on sperm freezability and fertility. From five tubes (each containing 5 mL TCFY), the first tube contained neither turmeric extract nor DMSO and was kept as control. The other four tubes contained 1.5% DMSO plus 100 µL/5 mL, 200 µL/5 mL, 300 µL/5 mL and 400 µL/5 mL turmeric extract. Semen samples were pooled and extended to reach an application of 60×106 sperm/mL (TT1D to TT4D, respectively). Diluted semen was exposed to the freezing protocol. The post cooling results revealed significant improvement in percent of alive spermatozoa in TT1D, significant decrease in sperm abnormalities in all concentrations used, significant improvement in intact acrosome percentage in TT1D, TT2D and TT4D. The post thawing results exhibited significant improvement in sperm motility in TT1D, TT2D and TT4D; significant amelioration of sperm membrane integrity (HOST) in TT1D, TT2D, TT3D and TT4D. Acrosome integrity was maintained in all concentrations as in the control. It was concluded that TT1D revealed the best semen quality in cooled semen; and TT1D, TT2D exhibited the superior post thawing semen quality. In addition, conception rate (CR) of the post-thawed semen was ameliorated in TT1D, TT2D, TT3D and TT4D with TT1D being the best one with this regard.

Effects of partially replacing glycerol with cholesterol-loaded cyclodextrin on protamine deficiency, in vitro capacitation and fertilization ability of frozen-thawed Yanbian Yellow cattle sperm

Glycerol is widely used as a cryoprotectant to protect the sperm from freezing damage during cryopreservation. However, glycerol at a high concentration has toxic effects on the sperm. Therefore, we explored the effects of partially replacing glycerol with cholesterol-loaded cyclodextrin (CLC) in a cryoprotectant on protamine deficiency, in vitro capacitation, and fertilization ability of freeze-thawed Yanbian Yellow cattle sperm. We used fresh semen, control (6% glycerol), and four treatment-I, II, III, and IV (3% glycerol + 0, 0.75, 1.5, and 3 mg/mL CLC, respectively)-groups. Computer-assisted semen analysis; JC-1, CMA3, and FluoZin-3-AM staining; flow cytometry; and IVF were conducted. Replacing a portion of glycerol with 1.5 mg/mL CLC significantly improved sperm motility, viability, plasma membrane integrity, acrosome integrity, and membrane lipid disorders, mitochondrial membrane potential (MMP), capacitation, and fertilization ability (P < 0.05) compared with the control. Additionally, in group I and III, the protamine deficiency were significantly lower (P < 0.05) than in the control group. It was found that 6% glycerol has a higher degree of damage to sperm DNA integrity than 3% glycerol. Overall, this study revealed that partial replacement of glycerol with CLC can be used as a novel cryoprotection method to reduce the toxicity of glycerol and improve the quality of thawed Yanbian Yellow cattle sperm.

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

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

Strategies for Highly Efficient Rabbit Sperm Cryopreservation

The rabbit is a valuable animal for both the economy and biomedical sciences. Sperm cryopreservation is one of the most efficient ways to preserve rabbit strains because it is easy to collect ejaculate repeatedly from a single male and inseminate artificially into multiple females. During the cooling, freezing and thawing process of sperms, the plasma membrane, cytoplasm and genome structures could be damaged by osmotic stress, cold shock, intracellular ice crystal formation, and excessive production of reactive oxygen species. In this review, we will discuss the progress made during the past years regarding efforts to minimize the cell damage in rabbit sperms, including freezing extender, cryoprotectants, supplements, and procedures.

Relationship of frozen-thawed semen quality with the fertility rate after being distributed in the Brahman Cross Breeding Program

BACKGROUND AND AIM

Various factors can reduce the quality of semen used for artificial insemination and have an impact on fertility decline, such as poor handling during frozen semen distribution. This study was aimed at assessing the quality of frozen-thawed semen after distribution in the field and its importance in maintaining fertility.

MATERIALS AND METHODS

The Brahman Cross (BX) breeding program of PT Lembu Jantan Perkasa, Indonesia, was used. This program was preferred due to its adherence to guidelines that limit the effects of extraneous factors that may affect semen quality. Frozen-thawed semen samples from eight bulls with the same production code were analyzed and compared between the production site (artificial insemination [AI] center) and the field (BX breeding program). Total and progressive motility (PM) of sperm were determined using computer-assisted semen analysis. Plasma membrane integrity (PMI) was assessed using hypoosmotic swelling test, sperm viability using Eosin-Nigrosin staining, acrosome integrity using trypan blue-Giemsa staining, morphological abnormalities using William staining, and DNA fragmentation using toluidine blue staining. The fertility rate was determined using the conception rate (%) derived from AI data based on 502 AI services and 478 cows in the BX breeding program. A t-test was used to compare the quality of frozen-thawed semen before and after distribution. The relationship between the qualities of frozen semen after distribution in the field with fertility was analyzed using Pearson correlation.

RESULTS

There was no significant difference (p>0.05) in the quality of frozen-thawed semen (sperm motility, PMI, viability, acrosome integrity, abnormalities, and DNA fragmentation) between the production site (AI center) and after distribution in the field (BX breeding program). The semen met the minimum standards for AI programs. Total motility (r=0.986), PM (r=0.961), sperm viability (r=0.971), PMI (r=0.986), and acrosome integrity (r=0.992) were all positively correlated (p<0.05) with fertility rate; while sperm abnormalities (r=-0.996) and sperm DNA fragmentation (r=0.975) were negatively correlated (p<0.05) with fertility rate.

CONCLUSION

The study showed that to achieve the maximal and optimal fertility rate in bulls in an AI program, the overall quality of frozen-thawed semen in all aspects is critical. This can be achieved if the handling during distribution and storage, as well as the various factors that may affect the quality of semen in the field, can be controlled properly.

Two-Photon-Induced Fluorescence Study of Rhodamine-6G Dye in Different Sets of Binary Solvents

This study deals with the effects of different sets of binary solvents on the Two-Photon Induced Fluorescence (TPIF), a non-linear process, of the Rhodamine-6G (Rh6G) dye, which is a well-known xanthene dye. This work examines the importance of inter-molecular interactions, which results in the modulation of the TPIF of the Rh6G. In this work, we have investigated three binary solvent mixtures representing varying polarity and intermolecular interactions. Specific solvent mixtures used are methanol-water, methanol-dimethyl formamide, and methanol-chloroform. Since the solvent polarity across these binary solvents differs, there are significant intermolecular interactions in the binary mixture solvents, which modulate the two-photon process of Rh6G when irradiated with high-intensity laser light at 780 nm. In our studies, we find that Rh6G in the MeOH-H₂O binary solvent has maximum red-shift and minimum intensity as compared to other pairs of binary liquids when the volume fraction of methanol decreases due to more extensive hydrogen bonding between the two components. Additionally, at 1:1 ratio of binary mixtures, Rh6G is found to have the highest TPEACS value for methanol-chloroform binary solvent and reason for that is related to the formation of weak H-bond networks between proton donor chloroform and proton acceptor methanol.

Antioxidative effect of BHA in soya bean lecithin-based extender containing Glycerol or DMSO on freezing capacity of goat semen

The aim of this study was to evaluate the effects of butylated hydroxyanisole (0 or 4 mM) along with different concentrations (5 or 7%) of glycerol (G) and dimethyl sulphoxide (DMSO) as cryoprotectant (CPAs) on freezability of goat semen. Semen was collected from four bucks (3-4 years) twice a week for five weeks. The pooled ejaculates were diluted with extender containing two different concentrations of G or DMSO in combination with BHA. Afterwards, the diluted samples were loaded into 0.25 ml straws and frozen using a standard protocol. After thawing motility parameters, viability, membrane integrity and total abnormality were assessed. The Results showed that the presence of BHA in extender, type and level of CPAs as main factors had significant effects on goat sperm viability, total and progressive motility after freezing-thawing processes (p < .05). Also, the interaction of BHA (0 and 4 mM) and levels of G or DMSO (5 or 7%) had a significant effects (p < .05) on total motility, viability and some characteristic. In this case, the addition of 5% G or DMSO with BHA resulted in highest motility and viability than the other groups (p < .05). The addition of G5 (with and without BHA) increased VSL and reduced abnormality than the other groups (p < .05). The results showed that the main effects of CPAs and CPAs level on membrane functionality were significant (p < .05). Also there were no significance differences in the interactive effects of MDA, VCL, VAP, ALH, LIN and STR among the groups (p > .05). Finally, it can be concluded that the use of 5% CPAs with or without BHA may result in better post-thaw sperm quality of goat.

Optimization of the cryopreservation of dromedary camel semen: Cryoprotectants and their concentration and equilibration times

Research into an optimal cryoprotectant, its concentration and equilibration time underlies the successful cryopreservation of dromedary camel spermatozoa. This study assessed the cryo-efficiency of different cryoprotectants, their concentration and equilibration time and any interactions. In experiment 1, semen samples (n = 4 males; 2 ejaculates/male) were frozen using Green Buffer containing one of four cryoprotectants (3% glycerol, ethylene glycol, methyl formamide, dimethyl sulfoxide) and using 4 equilibration times (10 min, 0.5, 1 and 2 h). Glycerol and ethylene glycol provided the best motility recovery rates and different equilibration times were not significant for any cryoprotectant nor were any interactions noted. However different equilibration times were pertinent for improved kinematic parameters BCF and VSL. In experiment 2, glycerol and ethylene glycol were evaluated at 4 concentrations (1.5, 3, 6, 9%) with 0.5 h equilibration (n = 4 males, 3 ejaculates/male). Sperm motility recoveries, kinematics and acrosome status were assessed. Higher values for LIN and STR were found with ethylene glycol. At 0 and 1 h post thaw 3 and 6% of either cryoprotectant resulted in better motility values than 1.5%. Acrosome integrity was compromised at 9% cryoprotectant. There were interactions between cryoprotectant and concentration in total motility at 0 and 1 h. For glycerol, total motility recoveries were best at 3-9%; for ethylene glycol 1.5-6% were best at 0 h and 3-6% at 1 h. In conclusion, 3-6% glycerol or ethylene glycol offered the best cryoprotection for camel sperm while different equilibration times were not critical.

Cryoprotection synergism between glycerol and dimethyl sulfoxide improves the mitochondrial transmembrane potential, plasmalemma, acrosomal and DNA integrities, and in vivo fertility of water buffalo (Bubalus bubalis) spermatozoa

The objective of the study was to devise a cryoprotection synergism between glycerol and dimethyl sulfoxide (DMSO) for water buffalo spermatozoa. Additionally, the effect of best evolved concentrations of glycerol and DMSO in extender was assessed on in vivo fertility of buffalo spermatozoa. Ejaculates (n = 30) were equally distributed into five aliquots; first aliquot was diluted at 37 °C in extender having 7 % glycerol (control); second aliquot was diluted at 37 °C as well as at 4 °C in extender having 3.5 % DMSO (Group 1); third aliquot was diluted at 37 °C in extender having 3.5 % glycerol and then at 4 °C in extender having 3.5 % DMSO (Group 2); fourth aliquot was diluted at 37 °C in extender having 3.5 % DMSO and then at 4 °C in extender having 3.5 % glycerol (Group 3); fifth aliquot was diluted in extenders having 1.75 % glycerol and 1.75 % DMSO at 37 as well as at 4 °C (Group 4). At post thawing, sperm progressive motility (%), rapid velocity (%), average path velocity (µm/s), curved line velocity (µm/s), in vitro longevity (%), structural and functional integrity of plasmalemma (%), mitochondrial transmembrane potential (%) and viable sperm with intact acrosome (%) were higher (P < 0.05) in Group 4 compared to other treatment groups and control. Regarding sperm DNA integrity (%); it was higher (P < 0.05) in Group 4 compared to Group 1, 3 and control. The in vivo fertility (%) of buffalo spermatozoa was significantly higher with Group 4 compared to control (69.45 vs. 59.81). In conclusion, synergism exists between glycerol and DMSO (Group 4) in improving the quality and in vivo fertility of cryopreserved water buffalo spermatozoa.

A deeper insight into an intriguing acetonitrile–water binary mixture: synergistic effect, dynamic Stokes shift, fluorescence correlation spectroscopy, and NMR studies

An insight study reveals the strong synergistic solvation behaviours from reporter dye molecules within the acetonitrile (ACN)–water (WT) binary mixture.

Direct observation of coherent oscillations in solution due to microheterogeneous environment

We report, for the first time, direct observation of coherent oscillations in the ground-state of IR775 dye due to microheterogeneous environment. Using ultrafast near-infrared degenerate pump-probe technique centered at 800 nm, we present the dynamics of IR775 in a binary mixture of methanol and chloroform at ultra-short time resolution of 30 fs. The dynamics of the dye in binary mixtures, in a time-scale of a few fs to ~740 ps, strongly varies as a function of solvent composition (volume fraction). Multi-oscillation behavior of the coherent vibration was observed, which increased with decreasing percentage of methanol in the dye mixture. Maximum number of damped oscillations were observed in 20% methanol. The observed vibrational wavepacket motion in the ground-state is periodic in nature. We needed two cosine functions to fit the coherent oscillation data as two different solvents were used. Dynamics of the dye molecule in binary mixtures can be explained by wavepacket motion in the ground potential energy surface. More is the confinement of the dye molecule in binary mixtures, more is the number of damped oscillations. The vibrational cooling time, τ₂, increases with increase in the confinement of the system. The observed wavepacket oscillations in ground-state dynamics continued until 1.6 ps.

Heterogeneity in binary mixtures of dimethyl sulfoxide and glycerol: fluorescence correlation spectroscopy

Diffusion of four coumarin dyes in a binary mixture of dimethyl sulfoxide (DMSO) and glycerol is studied using fluorescence correlation spectroscopy (FCS). The coumarin dyes are C151, C152, C480, and C481. In pure DMSO, all the four dyes exhibit a very narrow (almost uni-modal) distribution of diffusion coefficient (Dt). In contrast, in the binary mixtures all of them display a bimodal distribution of Dt with broadly two components. One of the components of D(t) corresponds to the bulk viscosity. The other one is similar to that in pure DMSO. This clearly indicates the presence of two distinctly different nano-domains inside the binary mixture. In the first, the micro-environment of the solute consists of both DMSO and glycerol approximately at the bulk composition. The other corresponds to a situation where the first layer of the solute consists of DMSO only. The burst integrated fluorescence lifetime (BIFL) analysis also indicates presence of two micro-environments one of which resembles DMSO. The relative contribution of the DMSO-like environment obtained from the BIFL analysis is much larger than that obtained from FCS measurements. It is proposed that BIFL corresponds to an instantaneous environment in a small region (a few nm) around the probe. FCS, on the contrary, describes the long time trajectory of the probes in a region of dimension ~200 nm. The results are explained in terms of the theory of binary mixtures and recent simulations of binary mixtures containing DMSO.

Sperm-egg interaction and functional assessment of springbok, impala and blesbok cauda epididymal spermatozoa using a domestic cattle in vitro fertilization system

The study assesses the possibility to estimate the potential fertility of post-thawed antelope (Antidorcas marsupialis), impala (Aepyceros melampus) and blesbok (Damaliscus dorcus phillipsi) epididymal sperm using homologous and heterologous IVF and the functioning of cattle IVF system to produce antelope embryos. Cauda epididymal sperm were collected from the antelope and cryopreserved under field conditions. In vitro matured domestic cow, blesbok and springbok oocytes were co-incubated in modified-Tyrode Lactate (m-TL) IVF media with springbok, impala and blesbok sperm for heterologous IVF and springbok and blesbok sperm for homologous IVF. A group of presumptive zygotes from each treatment were examined for sperm penetration and male pronuclear formation after 18h and the remainder were cultured and evaluated for embryo cleavage 22h later. The study shows that Modified Tyrode Lactate in vitro fertilization media supports survivability, capacitation and hyperactivation of springbok, impala and blesbok sperm. Springbok, impala and blesbok post-thawed epididymal spermatozoa are capable of fertilizing domestic cow oocytes under conditions that support domestic cattle IVF. Penetration, male pronuclear formation and embryo cleavage did not differ (p>0.05) between cow oocytes inseminated with sperm from springbok, impala or blesbok however these parameters were higher (p<0.05) for oocytes inseminated with bull sperm. Modified Tyrode Lactate IVF media supported homologous fertilization and embryo development in springbok and blesbok however did not support blastocyst development. These findings suggest that cattle provide a useful model for evaluating springbok, impala and blesbok post-thawed cauda epididymal sperm functionality. Domestic cattle embryo culture conditions need to be modified to promote blastosyst development in these antelope species. Such research provides an important tool in assisted reproductive technology development when high biological value material is utilized for wild species recovery plans.

Cytoskeletal proteins F-actin and β-dystrobrevin are altered by the cryopreservation process in bull sperm

The cryopreservation process has an important impact on sperm structure and physiology. The negative effects have been mainly observed on the plasma membrane, which is directly stabilized by the cytoskeleton. Since cytoskeleton proteins are osmosensitive and thermosensitive, the aim of this study was to evaluate the damage caused to the bull sperm cytoskeleton by cryopreservation (freezing-thawing). Fresh and frozen-thawed bull semen samples were exposed to a treatment with the neutral detergent Brij 36-T. Electron microscopy evidenced important damages at the sperm perinuclear theca after the protein extraction protocol; the perinuclear theca was partially solubilized, the perinuclear theca substructure disappeared in the cryopreserved samples. Furthermore, the sperm head's shape was significantly altered on the cryopreserved samples. Fluorescence analysis showed a decrease of the intensity of actin and dystrobrevin on the frozen-thawed samples. Western blot assays revealed a stronger signal for actin and β-dystrobrevin in the frozen-thawed sperm samples than in the fresh ones. Our results suggest that the cryopreservation process highly alters the sperm cytoskeleton stability, causing its proteins to become more fragile and therefore more susceptible to be extracted.

Response of buffalo spermatozoa to low temperatures during cryopreservation

This is the first detailed report on the response of buffalo spermatozoa to low temperatures during freezing. The study determined the critical temperature zone for buffalo spermatozoa and developed a suitable freezing rate for this species. Semen from four Nili-Ravi buffalo bulls diluted in Tris-citric acid was frozen in a programmable freezer. Motion characteristics, plasma membrane integrity and acrosome morphology were determined at +4, 0, –5, –10, –20, –30, –40, –50, –80 and –196°C by removing semen straws from the freezer at exactly these temperatures and rewarming them at 37°C. The first statistical decline in sperm motility and lateral head displacement was observed at –40°C. For all other parameters, there was biphasic decline: for curvilinear velocity, at 0°C and –50°C; and for plasma membrane integrity and acrosome morphology, at –30°C and –50°C. In a second series of experiments, buffalo spermatozoa were frozen using slow (–10°C min–1), medium (–20°C min–1) or fast (–30°C min–1) freezing rates, between –10°C and –80°C. Freezing of buffalo spermatozoa at a rate of –30°C min–1 yielded higher post-thaw motion characteristics, plasma membrane integrity and normal acrosomes. In conclusion, different sperm characteristics respond differently at low temperatures and the freezing of buffalo spermatozoa at a higher rate ensures higher post-thaw semen quality.

The effect of different concentrations of glycerol and DMSO on viability of Markhoz goat spermatozoa during different freezing temperatures steps

The present study was conducted to determine the following; (1) the influence of different concentrations of glycerol (1, 3, 5 or 7%, v/v) in experiment 1 and DMSO (1, 1.25, 1.5 or 1.75% v/v) in experiment 2 added either at 37 or 5 degrees C and (2) the comparing of best concentration of glycerol with the best of DMSO, obtained in this study, on post-thaw motility, progressive motility, viability and normal acrosome of Markhoz goat sperm. In experiment 1, motility, progressive motility and viability of sperm were improved significantly (p < 0.05) by increasing of glycerol concentrations in the extenders, with the best results obtained with glycerol at 7% added at 37 degrees C. However, the rate of normal acrosome showed an opposite trend, i.e., the extender containing 1% glycerol added at 5 degrees C showed better results (p < 0.05). In experiment 2, the observed results showed similar tendencies to experiment 1. The data showed that the extender containing 1.75% DMSO concentration (the highest level) added at 37 degrees C was significantly (p < 0.05) better than others. The percentage of intact acrosomes decreased significantly (p < 0.05) by increasing of DMSO concentrations, when added at 37 degrees C. Further, the results of 1% DMSO added at 5 degrees C was (p < 0.05) better than other groups. In regard to all evaluated parameters, the observed results in experiment 3 showed that extender containing 7% glycerol added at 37 degrees C was significantly (p < 0.05) better than 7% glycerol added at 5 degrees C and extender containing 1.75% DMSO added at both temperatures. In conclusion, the results of presented study indicated that glycerol is still the cryoprotectant of choice for freezing of Markhoz goat sperm.