Sperm Suspensions Research Articles

Challenges in Development of Sperm Repositories for Biomedical Fishes: Quality Control in Small-Bodied Species.

Quality control (QC) is essential for reproducible and efficient functioning of germplasm repositories. However, many biomedical fish models present significant QC challenges due to small body sizes (<5 cm) and miniscule sperm volumes (<5 μL). Using minimal volumes of sperm, we used Zebrafish to evaluate common QC endpoints as surrogates for fertilization success along sequential steps of cryopreservation. First, concentrations of calibration bead suspensions were evaluated with a Makler® counting chamber by using different sample volumes and mixing methods. For sperm analysis, samples were initially diluted at a 1:30 ratio with Hanks' balanced salt solution (HBSS). Motility was evaluated by using different ratios of sperm and activation medium, and membrane integrity was analyzed with flow cytometry at different concentrations. Concentration and sperm motility could be confidently estimated by using volumes as small as 1 μL, whereas membrane integrity required a minimum of 2 μL (at 1 × 106 cells/mL). Thus, <5 μL of sperm suspension (after dilution to 30-150 μL with HBSS) was required to evaluate sperm quality by using three endpoints. Sperm quality assessment using a combination of complementary endpoints enhances QC efforts during cryopreservation, increasing reliability and reproducibility, and reducing waste of time and resources.

Modern human sperm freezing: Effect on DNA, chromatin and acrosome integrity

ObjectivePresence of vitrification method in sperm freezing and the introduction of solid surface vitrification beside rapid freezing in vapour, opens an easy and safe way to help infertility centres. While the effects of cryopreservation on motility, morphology and viability of sperm are documented, the question of the probable alteration of sperm DNA, chromatin and acrosome integrity after freezing and thawing procedures in different methods is still controversial. Materials and methodsNormal sample were collected according to WHO strict criteria. Sperm suspensions were mixed 1:1 with 0.5 M sucrose and divided into four equal aliquots for freezing: fresh, nitrogen direct immersion vitrification (Vit), solid surface vitrification (SSV) and in vapour (Vapour).Sperm suspensions were transferred into a 0.25 ml sterile plastic. Then straw was inserted inside the 0.5 ml straw. For thawing, the straws were immersed in a 42 °C water bath. Beside the sperm parameters, we assessed the acrosome reaction by double staining, chromatin integrity by toluidine blue (Tb) and chromomycin A3 (CMA3) and DNA integrity by terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) respectively. ResultsIn progressive motility, the highest rate occurred in Vit (39.9 ± 13.3). Moreover, the lowest rate of immotile sperm was in Vit (32.7 ± 16.3). In normal morphology, the group Vit was similar to the fresh, while SSV and Vapour were significantly different from the fresh. The percentage of acrosome-reacted sperms was more in Vit (81.3 ± 10.2) than the fresh group. TUNEL+ results showed that DNA fragmentation was significantly increased in Vit (p-value = 0.025). While in SSV and Vapour results were comparable to fresh. There was a significant correlation between TUNEL+ and normal morphology, TB, CMA3 and presence of intact acrosome. ConclusionSperm in Vapour was healthier in terms of DNA, chromatin and acrosome integrity. In contrast of higher motility and normal morphology; DNA, chromatin and acrosome integrity were decreased in Vit. However, these findings were more acceptable in SSV or Vapour.

THE POTENTIAL OF KALANGKALA (Litsea angulata) SEED EXTRACT AS A NATURAL SPERMICIDE MATERIAL

Kalangkala (Litsea angulata) is one of the endemic plants in the wetlands area in Kalimantan which seeds are can reduce the quality of male mice spermatozoa such as motility and mobility. The purpose of this research is to know the potential of kalangkala seed extract on other parameters of spermatozoa quality, which are viability and morphology of male mice spermatozoa in an effort to obtain natural spermicide material. This research used five treatments by using twentyfive male mice. The design of this research was spermatozoa suspensions without being treated (Control = 0), spermatozoa suspensions +Na-CMC 0,5% (P1), spermatozoa suspensions + extract of kalangkala seed 0,1% (P2), spermatozoa suspensions + extract of kalangkala seed 0,3% (P3), and spermatozoa suspensions + extract of kalangkala seed 0,5% (P4), with five repititions for each treatment. The result of this research showed that the kalangkala seed extract reduce the percentage of viability of spermatozoa and increased the percentage of abnormal morphology of spermatozoa male mice. Therefore, kalangkala seed extract has potential as a natural spermicide.

Assessment of the Impact of Corpus luteum on In Vitro Maturation and Developmental Competence of Dromedary Camel Oocytes

To ascertain the effect of corpus luteum (CL) on the oocytes retrieval, quality and in vitro developmental competence in camels, ovaries were collected from apparent healthy slaughtered she-camel during breeding season and categorized according to the presence (group I) or absence (Group II) of CL. Oocytes were aspirated from 2-5 mm antral follicles on the surface of pathological free-ovaries, quantified and morphologically graded depending upon the cumulus investment and cytoplasmic distribution. Oocytes from each group were matured in vitro and examined for nuclear maturation in fixed slides after 30 hours of incubation.In vitro matured oocytes from each group were fertilized with epididymal sperm suspension and assessed for the cleavage and development to morula and blastocyst stages at 3rd, 5th and 7th day, respectively. Under the present experimental conditions, the accessible data showed a significant influence of CL presence on the quantity, quality and in vitro nuclear maturation of retrieved oocytes in camels. While the rate of excellent and poor quality oocytes retrieval was higher (p

The effect of antioxidants on sperm motility activation in the Booroolong frog

Motile sperm can generate high levels of reactive oxygen species (ROS) post activation, and ROS can quickly accumulate to levels that impair motility and fertilising ability. The addition of antioxidants to sperm suspensions has been suggested as a means of reducing oxidative stress and enhancing sperm motility during and after sperm storage. Despite this, very few studies have attempted to experimentally test the effects of antioxidants on sperm motility activation in animals that use an external mode of fertilisation, espcially in amphibians. The present study aimed to investigate the effect of vitamin C and vitamin E on sperm motility activation in the Booroolong frog. Spermatozoa were activated in media containing either vitamin C (0, 0.05, 0.10, 0.15, 0.20, 0.25μgμL−1) or vitamin E (0, 0.25, 0.50, 0.75, 1.0, 1.25 1.50, 1.75μgμL−1). Sperm performance parameters (percent motility and velocity) were assessed using CASA at 0, 1, 2, 3, 4, 5 and 6h post-activation. Contrary to expectations, vitamin C supplementation was detrimental to sperm motility across all tested concentrations, while vitamin E had no effect. Further investigation on the endogenous antioxidant system of anuran sperm is required to ascertain whether alternative antioxidants may be more suitable at reducing ROS produced during sperm activation and improving sperm motility activation in vitro.

Participation of phosphofructokinase, malate dehydrogenase and isocitrate dehydrogenase in capacitation and acrosome reaction of boar spermatozoa

The aim of this work was to determine the enzymatic activity of phosphofructokinase (PFK), malate dehydrogenase (MDH) and isocitrate dehydrogenase (IDH) in boar spermatozoa and study their participation in bicarbonate-induced capacitation and follicular fluid-induced acrosome reaction. Enzymatic activity of these enzymes was determined spectrophotometrically in extracts of boar spermatozoa. Sperm suspensions were incubated in the presence of bicarbonate (40 mM), a well-known capacitation inducer, or follicular fluid (30%), as an acrosome reaction inducer, and different concentrations of oxoglutarate, oxalomalate and hydroxymalonate, inhibitors of PFK, IDH and MDH, respectively. Capacitation percentages were determined by the fluorescence technique of chlortetracycline (CTC), and true acrosome reaction was determined by trypan blue and differential-interferential contrast, optical microscopy. The activity of PFK in boar spermatozoa enzymatic extracts was 1.70±0.19 U/1010 spermatozoa, the activity of NAD- and NADP-dependent IDH was 0.111±0.005 U/1010 and 2.22±0.14 U/1010 spermatozoa, respectively, and the activity of MDH was 4.24±0.38 U/1010 spermatozoa. The addition of the specific inhibitors of these enzymes prevented sperm capacitation and decreased sperm motility during capacitation and inhibited the acrosome reaction (AR), without affecting the sperm motility during this process. Our results demonstrate the participation of PFK, IDH and MDH in bicarbonate-induced capacitation and follicular fluid-induced acrosome reaction in boar spermatozoa, contributing to elucidate the mechanisms that produce energy necessary for these processes in porcine spermatozoa.

Ascorbic acid reduces redox potential in human spermatozoa subjected to heat-induced oxidative stress.

Oxidation-reduction potential (ORP) is a new measure of oxidative stress. It is a balance between the total available oxidants and reductants. This study measures the efficiency of ascorbic acid (AA) against oxidative stress induced by either heat alone or heat and hydrogen peroxide in sperm suspensions using the MiOXSYS System. Two concentrations of ascorbic acid (400 and 600μmol/L) were tested against heat- and heat plus hydrogen peroxide-induced oxidative stress in sperm suspensions after 2 and 4hr of incubation. Sperm motility and static oxidation reduction potential (sORP) were measured at 2 and 4hr of incubation at three different temperatures. A significant decrease in sORP was observed as a function of AA concentration. The 600μmol/L AA had more pronounced reduction in sORP compared to 400μmol/L AA (p=.001). Significant decreases in sperm motility ranging from 4.89% to 14.02% were observed both as a function of incubation time and addition of H2 O2 (p<.001). Ascorbic acid is efficacious to reduce heat-induced oxidative stress in sperm preparations in vitro. The supplementation of ascorbic acid may be advantageous for semen preparations in IUI, IVF and ICSI.

Cryoprotectant effect of trehalose in extender on post-thaw quality and in vivo fertility of water buffalo (Bubalus bubalis) bull spermatozoa.

This study was designed to ascertain the cryoprotectant effects of different concentrations of trehalose [0 (T0), 25 (T25), 35 (T35), 45 (T45) mm], egg yolk [20% (E20), 15% (E15) v/v] and glycerol [7% (G7), 5% (G5) v/v] in Tris-citric acid-based extender on post-thaw quality and in vivo fertility of buffalo bull spermatozoa. Twenty-five ejaculates were collected from five bulls and split into four parts. After that, the split ejaculates from each of the bull were diluted either in T0E20G7 (control) or T25E20G5 or T35E15G5 or T45E15G5 extender. Finally, the sperm suspension was frozen in 0.54-ml French straws. Post-thaw sperm total motility (%), progressive motility (%), rapid velocity (%), average path velocity (μm/s), straightline velocity (μm/s), curvilinear velocity (μm/s), linearity (%), plasma membrane and acrosome integrities (%) were higher (p<.05) in T45E15G5 extender as compared to other treatment groups and control. The fertility rate (56.8% versus 41.3%) was higher (p<.05) in buffaloes inseminated with semen doses cryopreserved in extender containing T45E15G5 combination of cryoprotectants than the control. In conclusion, addition of 45mm trehalose along with 15% egg yolk and 5% glycerol in extender improves the post-thaw quality and in vivo fertility of buffalo bull spermatozoa.

Rosmarinic acid reverses the effects of metronidazole-induced infertility in male albino rats.

Rosmarinic acid (RA) is a natural antioxidant that has many biological activities. In the present study we investigated the potential of RA to reverse the negative effects of the widely used antibiotic and antiprotozoal agent metronidazole (MTZ), which is known to induce reversible male infertility. Two doses of RA (5 and 15mg kg-1) were studied in sexually mature rats with and without MTZ-induced infertility. Rats were intraperitoneally injected with 5mg kg-1 RA or 15mg kg-1 RA (in distilled water) and, 45min later, they were intraperitoneally injected with 40mg kg-1 MTZ (in distilled water). Cauda epididymidal sperm suspensions were used to assess sperm count, motility and morphology. Histological and ultrastructural studies were performed on the testes and cauda epididymidis. In rats in which infertility was not induced, neither dose of RA affected the parameters assessed. However, in sexually mature rats in which infertility was induced by 40mg kg-1 MTZ, RA at both 5 and 15mg kg-1 ameliorated the damaging effects of MTZ on final bodyweight (30 days later), sperm motility and morphology. Only 5mg kg-1 RA, and not 15mg kg-1 RA, improved the harmful effects of MTZ on the sperm count and testis ultrastructure. The findings of the present study have considerable clinical implications and suggest a possible use for RA to reverse the negative effects of MTZ on male fertility, the male reproductive system and spermatogenesis.

The effect of gentamicin on sperm motility and bacterial abundance during chilled sperm storage in the Booroolong frog

Antibiotics can inhibit bacterial contamination and extend sperm longevity during storage; a primary goal of captive facilities conducting biobanking and artificial fertilisation (AF). This study evaluated the effects of gentamicin on the short-term storage of Booroolong frog sperm. Sperm suspensions were obtained via either testis maceration, or as spermic urine, following hormonal induction of sperm-release. The effect of 0, 1, 2, 3 or 4mgmL−1 gentamicin on bacterial abundance (CFUmL−1) was determined and sperm motility assessed. In both testis macerate samples and spermic urine samples, gentamicin administered at intermediate-to-high doses (2, 3 & 4mgmL−1) eliminated, or significantly reduced, bacterial abundance. Sperm samples obtained via testis maceration exhibited significantly lower sperm motility at the highest doses (3 & 4mgmL−1). All remaining treatments (0, 1 & 2mgmL−1) were statistically similar and maintained sperm motility >55%. Sperm samples obtained as spermic urine exhibited no difference in sperm motility or velocity when treated with gentamicin at any dose. While antibiotic treatment did not improve sperm longevity as predicted, this is the first study to demonstrate that antibiotic treatment can reduce bacterial abundance without compromising sperm motility in an anuran amphibian. Antibiotic supplementation may be an important tool for reducing pathogen transmission where sperm samples are transferred between captive institutions for biobanking and AF.

The effect of freeze-drying media and storage temperature on ultrastructure and DNA of freeze-dried buffalo bull spermatozoa

ObjectiveThe present study intended for displaying the effect of different freeze-drying media and temperature of storage on the ultrastructure and DNA of freeze-dried buffalo bull spermatozoa. The semen samples undergone freeze-drying were raw semen and frozen-thawed semen extended in Tris-Fructose-Egg yolk-Glycerol. MethodsSemen samples were processed in two portions: First portion was cryopreserved with Tris-Fructose-Egg yolk-Glycerol extender to be freeze-dried with the different media used in this study. Second portion was freeze-dried immediately with the different media used in this study. Semen samples were centrifuged in a percoll gradient (45–90%) for 20 min at 700 × g to remove seminal plasma. Subsequently, sperms were washed twice in Tyrode's albumen lactate pyruvate (TALP) to remove percoll remains, and allocated into the four freeze-drying media (media 1, 2, 3 and 4) respectively. The media tested were: medium 1 (EGTA solution), medium 2 (EDTA solution), medium 3 (TCM199 with Hanks salts and 10% FCS) and medium 4 (TCM199 with Hanks salts and 10% FCS and trehalose). For all the media used, samples were diluted, placed in tubes of 1.5 ml and kept at room temperature for 30 min. Then sperm cell suspensions were cooled in liquid nitrogen vapor (approximately −80 °C for 1 h), by keeping the tubes at a distance of 5 cm from liquid nitrogen surface before plunged into it. Frozen samples were immediately inserted into the freeze-drying machine, previously stabilized at (−40 °C) and 350 × 10−3 Mbar pressure. After 12–16 h of freeze-drying, the tubes containing the samples were covered with aluminum foil and stored for 3 months at different temperatures; 4 °C, −20 °C and −80 °C. Freeze-dried sperm samples were re-hydrated by adding 100 μL of milli-Q water at room temperature. To evaluate sperm ultrastructure, transmission electron microscopy was done. For detection of DNA fragmentation, commet assay was performed. ResultsElectron microscopy showed that the sperm cell component most affected by freeze-drying was the plasma membrane, which was destroyed in all media either in raw or frozen thawed sperm. Microtubules organization was also disorganized in the majority of the sperm from freeze-drying medium 2 and 3, diverging from freeze-drying media 1 and 4, in which microtubules were intact. Conversely, the acrosome and mitochondria were well protected in all media. However, the storage temperature has no effect. The freeze-drying medium with EDTA solution exhibited and the lowest percent of DNA damage (9.3) while the freeze-drying medium (TCM with trehalose) exhibited the highest percent of DNA damage (13.6) at temperature of storage (4 °C). In contrast, the freeze-drying medium with EGTA solution exhibited the lowest percent of DNA damage (15.3) while the freeze-drying medium (TCM with trehalose) exhibited the highest percent of DNA damage (18) at temperature of storage (−20 °C). On the other hand, the freeze-drying medium with EDTA solution exhibited the lowest percent of DNA damage (11.3) while the freeze-drying medium (TCM with trehalose) exhibited the highest percent of DNA damage (20) at temperature of storage (−80 °C). Consequently, the freeze-drying medium (TCM without trehalose) exhibited the lowest percent of DNA damage (6.5) while the freeze-drying medium with EDTA solution exhibited the highest percent of DNA damage (13.9) at temperature of storage (4 °C). On the contrary, the freeze-drying medium with EGTA solution exhibited the lowest percent of DNA damage (13.2) while the freeze-drying medium (TCM without trehalose) exhibited the highest percent of DNA damage (20.8) at temperature of storage (−20 °C). Conversely, the freeze-drying medium with EDTA solution exhibited the lowest percent of DNA damage (6) while the freeze-drying medium (TCM with trehalose) exhibited the highest percent of DNA damage (12) at temperature of storage (−80 °C). ConclusionFrom the present study, we demonstrated that the freeze-drying medium containing EGTA and EDTA solution were more efficient in avoiding damage to components of buffalo bull sperm, especially the nuclei. Therefore, the medium used for freeze-drying process directly affected sperm nuclear integrity. Also, the storage temperature of freeze-dried sperm affects sperm nuclear integrity.

In vitro exposure of human spermatozoa to bisphenol A induces pro-oxidative/apoptotic mitochondrial dysfunction

As bisphenol A (BPA) exerts oxidative/pro-apoptotic effects in several cell types, we explored whether the in vitro exposure to BPA could affect human sperm integrity through the induction of pro-oxidative/apoptotic mitochondrial dysfunction. The exposure of motile sperm suspensions to scalar BPA concentrations for 4h produced a decrease in the mitochondrial membrane potential, starting from 300μM. It was associated with an increased mitochondrial generation of superoxide anion, caspase-9 and caspase-3 activation and motility decrement. Vitality decline was observed at BPA≥400μM. Twenty hours exposure to 300μM BPA, but not to lower concentrations, produced a significant loss in sperm vitality associated with a complete sperm immobilization. Finally, 300μM BPA also produced a significant DNA oxidative damage, as revealed by the formation of oxidized base adduct 8-hydroxy-2′-deoxyguanosine. In conclusion, BPA affected human sperm integrity by inducing pro-oxidative/apoptotic mitochondrial dysfunction.

A comparative analysis of sperm selection procedures prior to cryopreservation for Nili-Ravi buffalo bull (Bubalus bubalis) semen-: Assessment of its impact on post-thaw sperm functional quality

Sperm selection techniques have been developed to get sperm suspensions enriched in motile and functional cells. Studies show that selection before cryopreservation improves post-thaw quality of cryopreserved sperm but information on buffalo bull sperm is scarce. The study was aimed to 1) perform a comparative analysis of sperm selection procedures; Swim-Up (SU), Sephadex™-G15 Filtration (S-G15) or Glass Wool Filtration (GWF) for total and motile cell recovery, 2) to assess the impact of sperm selection prior to cryopreservation on sperm quality (motility, morphology, cell membrane and normal apical ridge, viability and livability, chromatin integrity) and sperm functionality (Embryo Cleavage after IVF with selected sperm) in post-thawed suspensions of buffalo bull sperm. Semen was collected from 5 Nili Ravi buffalo bulls maintained at the Semen Production Unit Qadirabad, District Sahiwal, Pakistan. Ejaculates were divided into four aliquots for SU, S-G15 and GWF and control. After sperm selection, total and motile sperm recovery was highest in GWF samples (total sperm=84.08±8.39%; motile sperm=80.42±3.57%). An improvement (P<0.05) in all post-thaw parameters was observed in S-G15-selected sperm and, in some parameters in GWF-filtered sperm suspensions compared to control. The highest (P<0.05) embryo cleavage rate (%) was achieved with frozen-thawed sperm selected with S-G15 prior to cryopreservation (44.72±4.18) compared to control (21.98±3.00). In conclusion, post thaw sperm quality was improved after sperm selection from fresh buffalo bull semen through S-G15 and GWF procedures compared to SU and control while, the fertility rate (cleavage rate) was improved with sperm processed using the S-G15 procedure.

АНАЛИЗ ВОСПРОИЗВОДИМОСТИ РЕЗУЛЬТАТОВ ПРИ ИССЛЕДОВАНИИ ЦИТОТОКСИЧНОСТИ С ИСПОЛЬЗОВАНИЕМ КРАТКОВРЕМЕННОЙ СУСПЕНЗИОННОЙ КУЛЬТУРЫ СПЕРМАТОЗОИДОВ БЫКА

Cytotoxicity of urine (n=29), soil and snow (n=13) using bull spermatozoa short-term suspension culture and analyzer AT-5 was studied. For each sample, 3 to 4 repeated series of tests were carried out with new test and control solutions as well as with newly defrosted bull spermatozoa suspension. To assess reproducibility of results, a variation factor for the index of toxicity (It) was determined. It is shown that It is highly variable. Repeated series of tests allow to lower probability of error in the research.

Cryoprotectant‐free vitrification of human spermatozoa in new artificial seminal fluid

Vitrification is a new method that has been recently introduced in Assisted Reproduction Technique programs. The aim of this study was to design a new medium similar to normal human seminal fluid (SF), formulation artificial seminal fluid (ASF), and to compare the cryoprotective potency of this medium with SF and human tubal fluid (HTF) medium. Thirty normal ejaculates were processed with the swim-up technique and sperm suspensions were divided into four aliquots: (i) fresh sample (control); (ii) vitrification in HTF medium supplemented with 5mg/mL human serum albumin and 0.25mol sucrose (Vit HTF); (iii) vitrification with patients' SF (Vit SF); and (iv) vitrification in ASF (Vit ASF). After warming, sperm parameters of motility, viability, and morphology were analyzed using WHO criteria. Also, sperm pellets were fixed in 2.5% glutaraldehyde and processed for scanning electron microscopy and transmission electron microscopy observations. The results showed that progressive motility (46.09±10.33 vs. 36.80±13.75), grade A motility (36.59±11.40 vs. 16.41±11.24), and normal morphology (18.74±8.35 vs. 11.85±5.84) and viability (68.22±10.83 vs. 60.86±11.72) of spermatozoa were significantly higher in Vit ASF than in Vit HTF. All parameters were better in Vit ASF than in Vit SF, but only viability was significantly different (p=0.006). After cryopreservation, deep invagination in cytoplasm and mechanically weak point sites and folded tail were commonly observed. But, this phenomenon was more significant in Vit HTF and Vit SF than in ASF (p<0.05). In transmission electron microscopy evaluation, acrosome damage, plasma membrane loss, chromatin vacuolation, and disruption of mitochondria arrangement and structures were observed in all vitrified groups. Adherence of several tail sections together was also seen in all cryo groups. But this was seen more in Vit HTF and Vit SF than in ASF (p<0.05). In conclusion, vitrification of human spermatozoa with ASF can effectively preserve the quality of sperm motility in comparison with Vit HTF.

Alkaline phosphatase added to capacitating medium enhances horse sperm-zona pellucida binding

Alkaline phosphatase (AP) is present in equine seminal plasma and spermatozoa, but its functional role is not fully understood yet. Being that, sperm-oocyte interaction in equine species has been reported to be enhanced at a slightly basic pH, this work aimed at verifying whether exogenous alkaline phosphatase exerts any role on stallion spermatozoa and sperm-oocyte interaction at different pHs (7.4; 8.0; 9.0). Stallion spermatozoa were capacitated in Tyrode's medium at pH 7.4, 8.0, and 9.0 for 4 hours at 38 °C, 5% CO2 with 2.5-IU AP (AP group) or without AP (capacitated spermatozoa group); viability with mitochondrial activity, motility, and acrosome integrity were measured. In addition, a homologous binding assay was carried out: stallion spermatozoa were capacitated 1 hour at 38 °C, 5% CO2 with 2.5-IU AP (AP group) or without AP (capacitated spermatozoa group). Oocytes were then added to sperm suspensions and coincubated for 1 hour. Our results indicate that AP at pH 9.0 significantly increases the percentage of living cells with active mitochondria, whereas it significantly reduces the percentage of acrosome-damaged cells at pH 8.0. No significant differences were registered in motility parameters. The homologous binding assay showed a strong effect of AP, that increased the number of sperm bound to the oocyte's zona pellucida at all pHs tested. In conclusion, AP can induce some modifications on sperm membranes thus enhancing their capacity to bind to the zona pellucida of equine oocytes.

Deduction of a calcium ion circuit affecting rooster sperm in vitro.

Four premises for rooster sperm preservation were outlined previously. Understanding mitochondrial Ca cycling in terms of whole-cell Ca flux was one premise. The present work tested the hypothesis that sperm mitochondria can be damaged by intracellular as well as extracellular Ca. Sperm were washed by centrifugation through 12% (wt/vol) Sperm were washed by centrifugation through 12%(at/vol) Accudenz to procure sperm at a physiological concentration within a chemically-defined suspension. Five solutions were tested. Each solution contained 30 m glucose, and had an osmolality of 320 mmol/kg and a pH of 7.4. Washed sperm were diluted to 2.0 × 10 sperm/mL. Each replicate sperm suspension was cooled to 10°C. Sperm mobility was measured after 1, 2, 4, 8, 12, and 24 h. Data were plotted as a function of time in each experiment. Function type was confirmed by lack of fit analysis. A parabola with a maximum at 3.7 h was observed when sperm were suspended in 205 m taurine buffered with 50 m-tris[hydroxyl-methyl]methyl-2-amino-ethanesulfonic acid (TES). This effect was attributed to a Ca flux from the nuclear envelope into mitochondria. An exponential decay was observed when TES-buffered taurine contained 2 m Ca. This effect was attributed to mitochondrial Ca overload induced by uptake of extracellular Ca. Exponential decay also was observed when TES-buffered taurine contained a Ca chelator. This effect was attributed to a Ca flux from the nuclear envelope through mitochondria and then into an extracellular Ca sink. This possibility was supported by the response of sperm to thapsigargin. Specifically, inhibition of sarcoendoplasmic reticulum Ca-ATPase compromised sperm mobility relative to a buffer control. Finally, a 60 m phosphate buffer containing 2 m citrate yielded a linear relationship in contrast to the TES-buffered solutions tested. Sperm mobility after 24 h of storage in the phosphate buffer was 92% of that observed for prewashed sperm. The linear response was attributed to weak chelators providing resistance within a Ca circuit and thereby preventing mitochondrial Ca overload. Fertility, however, was compromised when hens were inseminated with mobile sperm recovered after either 8 or 24 h of storage at 10°C. In conclusion, sperm cell Ca homeostasis was proven to be critical for maintaining sperm mobility in vitro, but mitochondrial Ca uptake is not the sole phenomenon that compromises sperm function during in vitro storage.

Cryopreservation of Atlantic salmon Salmo salar sperm: effects on sperm physiology.

The objective of this study was to determine the effect of freezing on the function in Atlantic salmon Salmo salar spermatozoa. The semen was frozen in Cortland's medium + 1.3M dimethyl sulphoxide + 0.3M glucose + 2% bovine serum albumin (final concentration) in a ratio of 1:3 (semen:cryoprotectant) as the treatment (T) and fresh semen as the control (F). Straws of 0·5 ml of sperm suspension were frozen in 4 cm of N2 L. They were thawed in a thermoregulated bath (40° C). After thawing, the percentage of spermatozoa with fragmented DNA [transferase dUTP (deoxyuridine triphosphate) nick-end labelling (TUNEL)], plasma membrane integrity (SYBR-14/PI) and mitochondrial membrane potential (ΔΨMMit, JC-1) were evaluated by flow cytometry and motility was evaluated by optical microscope under stroboscopic light. The fertilization rates of the control and treatment semen were tested at a sperm density of 1·5 × 10(7) spermatozoa oocyte(-1) , by observation of the first cleavages after 16 h incubation at 10° C. In the cryopreserved semen (T), the mean ± s.d. DNA fragmentation was 4·8 ± 2·5%; plasma membrane integrity 75·2 ± 6·3%; mitochondrial membrane potential 51·7 ± 3·6%; motility 58·5 ± 5·3%; curved line velocity (VCL ) 61·2 ± 17·4 µm s(-1) ; average-path velocity (VAP ) 50·1 ± 17·3 µm s(-1) ; straight-line velocity (VSL ) 59·1 ± 18·4 µm s(-1) ; fertilization rate 81·6 ± 1·9%. There were significant differences in the plasma membrane integrity, mitochondrial membrane potential, motility, fertilization rate, VCL , VAP and VSL compared with the controls (P < 0·05). Also the mitochondrial membrane potential correlated with motility, fertilization rate, VCL and VSL (r = 0·75; r = 0·59; r = 0·77 and r = 0·79, respectively; P < 0·05); and the fertilization rate correlated with VCL and VSL (r = 0·59 and r = 0·55, respectively).

Effect of dilution in sperm maturation media and time of storage on sperm motility and fertilizing capacity of cryopreserved semen of sex-reversed female rainbow trout

Masculinized females, also called neomales or sex-reversed females have a male phenotype but retain the female genotype (XX). Therefore, all spermatozoa produced in their functional testes carry an X chromosome, which is desired for the production of all-female rainbow trout populations. Semen of sex-reversed female rainbow trout is of low quality and in vitro maturation is required, which includes dilution of sperm suspensions with specially formulated maturation solutions. The aim of this study was to determine the effect of dilution in different maturation media on sperm quality (sperm motility characteristics and fertilizing capacity) of frozen/thawed sperm of sex-reversed female rainbow trout. The effect of time of post-thaw storage (0, 15, 60 and 120min) on semen quality was also tested. Sperm motility parameters and fertilization rate at the eyed and hatching stages were assessed for post-thaw semen diluted in different media. The cryopreservation procedure resulted in high post-thaw sperm motility of about 57% and did not differ from fresh semen. Unexpectedly, maturation media decreased sperm activation capacity immediately after dilution; however, sperm motility increased over time. Fertilization rates of frozen/thawed semen were high (71–87%) and did not differ significantly between experimental variants at any of tested periods of storage. Our results demonstrated that the effect of the maturation media on frozen/thawed sperm is different from that of fresh sperm. The progressive increase in post-thaw sperm motility in maturation media can potentially be applied to routine hatchery practice.

Amine reactive dyes: An alternative to estimate membrane integrity in fish sperm cells

Fluorescent dyes that binds irreversibly to cellular amines, come in several available emission spectra, and do not poses health concerns were used to evaluate membrane integrity in fish sperm cells. The objectives of the present study were to determine: (1) a working dye concentration for fish sperm samples, and (2) if the traditional propidium iodide/SYBR-14 staining combination was comparable with the amine reactive dye (ARD) methods at identifying cell populations with intact and compromised membranes after sperm activation, refrigerated storage, and exposure to cryoprotectant and surfactant. Zebrafish (Danio rerio) sperm were obtained by stripping, and pooled samples (in triplicate) were used in all tests. Six dilutions of the amine dye (ranging from 0.625 to 0.02μl/ml) were evaluated, and compared with the traditional staining protocol. A concentration of 0.5μl/ml ARD was selected to be used in subsequent assays.Sperm suspensions were activated with deionized water to simulate urine contamination. After 10s, osmolality was increased to stop activation, and the procedure was repeated in 10-s intervals until the sperm remained activated for 120 consecutive sec; membrane integrity was analyzed at each time interval. For the storage assay, sperm suspensions were prepared in Hanks' balanced salt solution at 302mOsm/kg osmolality (HBSS302), HBSS354 and HBSS402, and evaluated every 2h for 8h, and every 24h for 72h. Cryoprotectant toxicity was tested by diluting sperm suspensions in HBSS340 with methanol at 5, 10 and 15% final concentrations. Surfactant toxicity was tested by diluting sperm suspensions in HBSS354 with Triton X-100 at 0.2, 0.15 and 0.1mM final concentrations. In each toxicity assay, membrane integrity was tested every 20min for 80min. The number of membrane-intact cells significantly decreased across time in all treatments (P<0.05). Significant differences between staining protocols were observed after activation and after exposure to methanol at 10 and 15%, and to Triton X-100 (P<0.05). The average difference, however, was minor (between 1 and 6% in average) in relation to the typical values used for decision making based on this assay. Results showed that this method has the potential to contribute greatly to the standardization of cryopreservation in aquatic species. Statement of relevanceQA-QC for repository development in aquatic species.