Quantitative and qualitative characteristics of frozen-thawed bovine spermatozoa recovered via a conventional and a standardized swim-up technique

Ram Sperm Selection by a Dextran/Swim-Up Procedure Increases Fertilization Rates Following Intrauterine Insemination in Superovulated Ewes

The objective of this study was to compare the efficacy of 2 dextran/swim-up media to increase the sperm quality parameters and the maintenance of these parameters at 15 degrees C and 30 degrees C over 6 hours. Additionally, this study examined whether differences in sperm quality reflect different reproductive efficiencies following intrauterine insemination in superovulated ewes. The study involved 2 selected samples (SS) obtained by dextran/swim-up, performed either with (SS+) or without (SS-) capacitating compounds, and a control sample consisting of raw semen diluted in the same medium. The efficacies of the swim-up sperm selection procedures were similar in both media, and no significant differences were found among the evaluated parameters. Conversely, we found important differences between selected and control samples. Sperm motility, viability (as assessed by carboxifluorescein diacetate/propidium iodide [PI] staining), and mitochondrial activity (as assessed by rhodamine 123/PI) were significantly higher in the selected samples than in the control. Additionally, following incubation at 15 degrees C, the preservation of sperm quality was significantly better in the selected samples than in the control samples. After 6 hours of incubation at 15 degrees C, selected samples had a motility value of 46%, which was significantly (P < .001) higher than the value observed in control samples (27%). The percentage of viable cells observed after 6 hours of incubation at 15 degrees C was significantly (P < .0001) higher in selected samples than in the control samples. Furthermore, after 2 hours of incubation at 30 degrees C, swim-up samples had viability values that were significantly (P < .0001) higher than those of the control samples. SS+ and SS- samples did not differ significantly in spermatozoa yield, sperm quality, or survival. Differences between selected samples and controls were reflected in the fertilization rate obtained following intrauterine insemination in superovulated ewes that experienced a 52-hour interval between progestagen removal and artificial insemination. A restricted criterion for fertilization rate evaluation was established, and only the percentage of embryos recovered from the uterine horns 6 days after insemination was considered with respect to the total number of corpora lutea counted in the ovaries. The fertilization rate of SS- samples (50%) was significantly higher (P > .001) than those of the SS+ (2%) and control samples (5%).

VIABILITY AND FECUNDITY OF HUMAN SEMEN SPECIMENS CRYOSTORED AND TRANSPORTED AT 5°C USING THE BIO–TRANZTMSHIPPING

This study was designed to assess the viability and fecundity of semen stored at 5 degrees C for 24 hours using the Bio-Tranz shipping system. Semen specimens were assessed for motility and sperm membrane integrity at the time of collection and 24 hours after storage in the Bio-Tranz. In group 1 (n = 61), specimens were diluted in TYB, processed and used for intrauterine insemination (IUI), leaving an aliquot for storage for 24 hours in the Bio-Tranz. In group 2 (n = 67), specimens were diluted in TYB, stored for 24 hours in the Bio-Tranz and then processed and used for IUI. In both groups, the total motile sperm used for IUI was similar and the women that underwent IUI were standardized for ovulation prediction and time of insemination. The overall sperm characteristics between the two groups were within normal range. Significant decreases were noted in sperm motility and membrane integrity in both groups after storage. Similar pregnancy rates were obtained between the two patient populations. The use of the Bio-Tranz shipper is extremely convenient for patients requiring semen evaluation, cryostorage or IUI and other assisted reproductive technologies.

Assessment of two devices for in vitro preparation of human sperm

The aim of the study was to assess and compare the efficiency of the ZSC-II versus the Sperm Select techniques in preparing human sperm from normozoospermic patients for use in intrauterine insemination and other assisted reproductive technologies. Twenty-five patients were included in the study. Semen was collected at intercourse and processed via 2 sperm preparation methods. Recovery of motile sperm and other sperm qualitative measurements were evaluated before and after ZSC-II and Sperm Select sperm preparation. Sperm qualitative measurements were not significantly different after the ZSC-II and Sperm Select procedures (p > .05). Differences (p < .05) were noted between the 2 procedures in the number of sperm recovered. A higher survival rate (longevity test, 72 h) was observed after ZSC-II sperm preparation and recovery. The ZSC-II procedure yielded higher total motile sperm than the Sperm Select. The superiority in longevity may suggest possible advantages in obtaining higher fertilization and pregnancy rates.

Evaluation of techniques for the cryopreservation of washed spermatozoa: comparisons between Ham's F-10 and TEST-yolk media

The objective of this study was to develop new techniques for the cryopreservation of washed spermatozoa. Two media (Ham's F-10 and nonthermoprecipitated TEST-yolk buffer [NT-TYB]) containing 7% (v/v) glycerol were compared to semen cryopreservation by adding glycerol directly to the semen. Twenty four men collected a semen specimen each after 4 days of sexual abstinence via the use of a semen collection device at intercourse. Specimens were assessed for volume (ml), count (x 10(6)), percentage and grade of motility, morphology (% normal) and acrosomal status (% intact acrosomes). Each ejaculate was split into 3 aliquots (Aliquots 1 to 3) and processed for freezing. Aliquot 1 was prepared for cryopreservation by adding glycerol (7% [v/v] final concentration) directly via a dropwise mode. Aliquot 2 and 3 were diluted 1:1 (v/v) with Ham's F-10 and NT-TYB, respectively. Aliquots 2 and 3 were then centrifuged (400 x g for 10 minutes) and resuspended into the corresponding media containing 7% (v/v) glycerol to complete the sperm wash procedure. All aliquots were frozen in 0.5 ml french straws. Sperm specimens were frozen in liquid nitrogen (LN2) vapor from +23 degrees C to -68 degrees C at a slow rate (2.3 degrees C/minute), after which the specimens were plunged directly into LN2 and stored for 30 days. The quality of the spermatozoa were monitored throughout each step of the overall procedure by measuring the motility characteristics of the spermatozoa. Straws corresponding to each aliquot were thawed in a water bath at 37 degrees C for 2 minutes, followed by assessment of sperm motility and acrosomal status. The percentage of motility after thawing was 31.6 +/- 5.6%, 32.8 +/- 1.8% and 37.3 +/- 1.9% in Aliquots 1 to 3, respectively. Similarly, the grade of motility was 2.4 +/- 0.2, 2.6 +/- 0.1 and 3.0 +/- 0.1 in Aliquots 1 to 3, respectively. The acrosomal status (% intact acrosomes) in Aliquots 1 to 3 was 41.2 +/- 2.6, 43.1 +/- 3.6 and 51.6 +/- 4.5, respectively. The results suggest that the characteristics of spermatozoa washed and frozen in NT-TYB (Aliquot 3) were improved over those spermatozoa prepared via direct addition of glycerol to the semen (Aliquot 1) or by using Ham's F-10 (Aliquot 2). The most significant reduction noted during freezing was in the loss of acrosomal integrity. The results obtained in this study point out that washed spermatozoa can be cryopreserved with some success and that the recovered spermatozoa could be used for intrauterine insemination in an artificial insemination program using husband's or donor sperm, or for the various assisted reproductive technology procedures. It is the opinion of the authors that the information generated in this study is of importance for those scientists and clinicians involved in the handling and manipulation of cryopreserved spermatozoa.

Fertilization potential and qualitative characteristics of human spermatozoa after short-term cryostorage at 5 degrees C in two different TEST-yolk buffer preparations

Use of the media TEST-yolk buffer (TYB) in semenology today enables the short-term incubation and cryostorage of spermatozoa and its subsequent use in the various assisted reproductive technologies (ART). Preparation of TYB media involves the addition of egg yolk (20% v/v) to a physiological solution of the zwitterion buffers TES and Tris. The TYB is usually thermoprecipitated to remove the majority of the egg yolk globules and other macromolecules from the medium. However, removal of these egg yolk constituents could possibly eliminate or reduce essential factors that could enhance the sperm viability and fertilization potential after short-term dilution and storage. Improvements in the quality of the TYB could add greater benefits to those techniques employed in the various forms of ART. The objectives of the investigation were 1) to study the sperm qualitative characteristics following short-term cryostorage at 5 degrees C in either thermoprecipitated (T-TYB) or non-thermoprecipitated (NT-TYB), and 2) to compare the fertilizing potential of spermatozoa stored for 24 hours at 5 degrees C in the two TYB preparations. In Experiment 1, semen specimens from 15 patients were collected, assessed and split into two aliquots. Sperm specimens were processed by diluting 1:1 (v/v) with the T-TYB or NT-TYB, followed by centrifugation and reconstitution of the specimen to its initial volume with the corresponding TYB medium. Sperm specimens were cryostored for 1, 2, 24, 48 and 72 hours. Samples were taken at each interval and placed in a 37 degrees C water bath and allowed to warm for 15 minutes after each cryostorage interval. Semen specimens were assessed for percentage and grade of motility. The results of this study indicated that, although the NT-TYB yielded better results than the T-TYB, overall those differences were not statistically significant. In Experiment 2, the fertilization potential of spermatozoa recovered after 24 hours of cryostorage in the two TYB preparations and further prepared via filtration, was assessed by the sperm penetration assay (SPA) using zona-free hamster oocytes. The average penetration rate (PR) and penetration index (PI) were significantly better for the NT-TYB than for the T-TYB. The PR was 54% vs. 25%, and the PI 0.78 and 0.27 for spermatozoa incubated in the NT-TYB vs. T-TYB. The range of penetration was also much lower for the T-TYB (6 to 100%) preparation when compared to the NT-TYB (22 to 100%). The highest penetrator showed 100% for both preparations. However, the lowest penetrator showed 6% for the T-TYB and 22% for the NT-TYB. The data obtained in this study suggest that both TYB preparations can be employed in short-term cryostorage (5 degrees C) of human spermatozoa and can adequately maintain the qualitative characteristics of those spermatozoa. The data also showed that the NT-TYB preparation yielded sperm samples of higher fertilization potential, thus possibly establishing the superior usefulness of the NT-TYB in an ART program.