In vitro cytotoxic effects of 5-Fluorouracil on isolated murine ovarian preantral follicles.

5 fluorouracil (5FU), an antineoplastic drug, is often utilized in the therapeutic regimen for several types of cancer, including the hepatoblastoma in children. The effects of 5FU on the population of ovarian preantral follicles, which is the largest oocyte reservoir, is still poorly understood. The integrity of the ovarian preantral follicle pool is important for lifelong fertility. The better understanding of such effects may favor intervention strategies to protect fertility in 5FU-treated children and women coping with cancer. To analyze the effects of 5FU on isolated murine secondary follicles in vitro, ovaries were collected from young mice (28-30 days old), and secondary follicles were isolated and cultured for 12 days in basic culture medium, with or without 5FU at concentrations of 0.3 mM, 1 mM, 3 mM, 10 mM, and 30 mM. In the in vitro study, we analyzed the percentage of morphologically normal follicles, antrum formation, follicular diameter, and hormone production. On day 12, oocytes were recovered for in vitro maturation. 5FU treatment did not alter the percentage of morphologically normal follicles. On day 12, only 1, 10, and 30 mM 5FU significantly reduced the percentage of antrum. From day 4 onwards, 5FU treatments significantly reduced follicle diameter. The meiosis resumption rate was significantly lower in all 5FU treatments. 5FU concentrations ≥3 mM reduced estradiol levels. In conclusion, 5FU does not affect follicular morphology. However, 5FU deleteriously affects follicular growth, estradiol production, and oocyte maturation in isolated ovarian follicles.

The cytokine platelet factor 4 successfully replaces bovine serum albumin for the in vitro culture of porcine embryos.

The cytokine platelet factor 4 (PF4) enhances differentiation and cell viability of different stem cells lines in vitro. This study investigated whether PF4 addition to customary pig embryo semi-defined culture media can improve their developmental outcome (Experiment 1) and ultimately replace the need for bovine serum albumin (BSA, Experiment 2). Experiment 1 added PF4 (100-1000 ng/mL, 0 = control) to NCSU-23 with 0.4 mg/mL BSA culturing 3430 presumptive zygotes. Experiment 2 added PF4 (100-1000 ng/mL, 0 = Control-PVA) to a BSA-free medium (NCSU-23 with 0.3 mg/mL PVA) culturing 3820 presumptive zygotes. Zygote culture in NCSU-23 with 0.4 mg/mL BSA was used as overall control. All groups of Experiment 1 displayed similar rates of day 2-cleavage (range: 65.0 ±â€¯10.9 to 70.0 ±â€¯5.8%); of day 7-blastocyst rates (range: 46.6 ±â€¯10.0 to 56.4 ±â€¯8.2%) and of total day 7-blastocyst efficiency (range: 32.3 ±â€¯8.3 to 37.2 ±â€¯7.3%). Addition of PF4 did not affect total cell numbers of day 7 blastocysts (range: 44.1 ±â€¯23.2 to 50.5 ±â€¯26.4). In Experiment 2, PF4 accelerated embryo development, increasing (P < 0.01) blastocyst yield compared to 0-PF4, and blastocyst formation by day 5 adding PF4 100-500 ng/mL (range: 29.9 ±â€¯7.8 to 31.8 ±â€¯5.5%; P < 0.05) compared with BSA-control (17.2 ±â€¯8.2%) and PF4 1000 ng/mL (15.5 ±â€¯7.9%); showing similar blastocyst rates (range: 42.0 ±â€¯11.5 to 49.3 ±â€¯10.0%), total efficiency (28.0 ±â€¯8.2 to 32.3 ±â€¯7.1%) total cell numbers (range: 42.6 ±â€¯19.3 to 45.7 ±â€¯23.9) as BSA-controls. In conclusion, although PF4 did not show additive improvement under usual semi-defined, BSA-supplemented embryo media, it successfully replaced BSA sustaining porcine blastocyst production in chemically defined conditions.

High pre-freezing sperm dilution improves monospermy without affecting the penetration rate in porcine IVF.

The high incidence of polyspermy is still an unresolved problem for the production of in vitro-produced porcine embryos. In this work, we modified the usual sperm processing sequence for in vitro fertilization (IVF), and the spermatozoa from four boars were frozen directly at a low sperm concentration of 20 × 106 sperm/mL (high pre-freezing sperm dilution group; F20), thawed and processed for IVF in three replicates. Spermatozoa from the same boars frozen at a conventional concentration (1000 × 106 sperm/mL) were used as the control group. The post-thaw sperm quality evaluation demonstrated that despite there being no differences in the percentage of motile spermatozoa between groups, the proportion of live spermatozoa with intact acrosomes was significantly higher in the F20 group than in the control. The in vitro penetration rate was also similar between groups; however, the co-incubation of oocytes with F20 sperm increased monospermy, IVF efficiency, cleavage rate and the efficiency of blastocyst formation compared with the results for oocytes co-incubated with control spermatozoa. These results indicate, for the first time, that a high pre-freezing sperm dilution increases monospermy without affecting penetration rates, thereby increasing blastocyst formation.

Dose-dependent effects of frutalin on in vitro maturation and fertilization of pig oocytes.

The aim of the present study was to evaluate the effect of frutalin (FTL) on in vitro maturation (IVM), and fertilization (IVF) of pig oocytes. In the Experiment 1, cumulus-oocyte complexes (COCs) were submitted to IVM in maturation medium alone or supplemented with different FTL concentration (0.6, 6 and 60 µg/mL), or 0.3 µg/mL doxorubicin (DXR). After IVM, some oocytes were evaluated for chromatin configuration, and the remaining oocytes were submitted to in vitro fertilization. In Experiment 2, matured oocytes were fertilized in IVF medium alone (control) or in presence of different FTL concentration (0.6, 6 and 60 µg/mL), or 0.3 µg/mL DXR. After 18 h post fertilization, the endpoints penetration rate, monospermy, spermatozoa per oocyte, and the IVF efficiency were evaluated in both experiments. In Experiment 1, 6 and 60 µg/mL FTL, as well as DXR increased (P < 0.05) the rate of oocytes with abnormal chromatin configuration when compared to oocyte matured in control medium alone or supplemented with 0.6 µg/mL FTL. The percentage of meiotic resumption in oocytes cultured with 60 µg/mL FTL or DXR was less (P < 0.05) than in the other treatments. Moreover, oocytes matured with 6 or 60 µg/mL FTL and DXR had a lesser IVM efficiency when compared to those matured with 0.6 µg/mL FTL or in control medium. Additionally, there was a greater (P < 0.05) with culture in a medium containing 6 µg/mL FTL for the rate of partenogenetically activated oocytes when compared with the other treatments. Culturing of COCs during IVM in a medium containing 6 or 60 FTL resulted in a lesser (P < 0.05) sperm penetration and spermatozoa/oocyte rates when compared to other treatments, and IVF efficiency was less (P < 0.05) than that in control medium alone or with a medium containing 0.6 µg/mL FTL. In Experiment 2, culturing in a medium containing 0.6 µg/mL FTL resulted in greater (P < 0.05) monospermy and IVF efficiency rates when compared to culturing in the control medium. In addition, culturing in a medium with 6 and 60 µg/mL FTL resulted in a lesser (P < 0.05) spermatozoa penetration, sperm/oocyte rates and IVF efficiency, although there were greater (P < 0.05) monospermy rates. In conclusion, culturing in a medium containing 0.6 µg/mL FTL resulted in lesser spermatozoa penetration rates and number of spermatozoa/oocyte increasing the IVF efficiency without harmful effects. Use of a greater concentration of FTL in the medium has toxic effects during oocyte maturation and results in a reduced IVF efficiency.

Cryopreservation of domestic cat (Felis catus) ovarian tissue: Comparison of two vitrification methods.

We aimed to evaluate the effect of two vitrification methods on the morphology and functionality of vitrified feline preantral follicles. Feline ovarian tissue was vitrified with EG + trehalose combined or not with dimethyl sulphoxide (DMSO), using two different techniques (open or closed systems). Morphology, developmental capacity and mRNA expression of markers for follicle survival and quality were assessed before and after in vitro culture (IVC). Both vitrification and culture media were serum-free. Vitrification of feline ovarian tissue from five adult domestic cats was performed with EG + trehalose combined or not with DMSO. Two systems were used: the open system solid-surface vitrification (SSV) and the closed system ovarian tissue cryosystem (OTC). Histological analysis of follicle integrity showed that the percentages of normal follicles in previously vitrified ovarian fragments decreased after 7 days of in vitro culture (IVC), independently of the protocol used. Although follicular activation was observed by Ki-67 labelling, this was accompanied by extensive follicular degeneration as detected by a 3-4-fold decrease in follicular density. Remarkable follicle activation was observed in the ovarian tissue vitrified using OTC and subjected to IVC, probably due to a higher rate of degeneration of developing follicles. Even with such follicular loss, the results are promising for the combination of EG + DMSO + trehalose in a serum-free medium when applying the SSV method, with this approach resulting in the highest rates of normal developing follicles (19%) after 7 days IVC, together with granulosa cells proliferating at the same rate observed in fresh tissue.

Relationship between follicular dynamics and oocyte maturation during in vitro culture as a non-invasive sign of caprine oocyte meiotic competence.

The search for non-invasive signs of oocyte meiotic competence is very important for the development of in vitro follicle culture (IVFC) systems. The aims of the present study were: (1) to investigate the effect of in vitro maturation (IVM) of in vivo grown goat COCs, in group or individually, on oocyte chromatin configuration (Experiment 1), and (2) the influence of IVFC period (12 vs. 18 days) on the ability of the oocyte to resume meiosis immediately after IVFC (before in vitro maturation; IVM), or after IVM (Experiment 2). In experiment 1, in vivo grown cumulus-oocyte complexes (COCs) were submitted to IVM in groups (10 COCs/100 µL-drop) or individually (1 COC/10 µL-drop), and chromatin configuration was assessed. In experiment 2, isolated follicles were individually cultured for 12 or 18 days, and submitted to individual IVM afterwards. The following end points were evaluated: follicular growth and morphology, oocyte diameter, viability and chromatin configuration, as well as individual follicular estradiol production. Similar maturation rates were obtained between in vivo grown COCs matured individually and in groups (66.7% vs. 63.6%, respectively) (Experiment 1). Only after 18 days of IVFC, oocytes were able to grow during IVM, reaching a mean oocyte diameter of 119 µm. Also, this treatment produced the highest rate of metaphase II oocytes (46.2% out of the total number of cultured follicles). Finally, it was observed that follicles with a daily growth rate >7.1 µm/day (fast-growing) and that reached at least 600 µm in diameter, were more likely (P < 0.05) to produce oocytes capable of attaining MII. In conclusion, caprine oocytes can be individually matured in vitro, as efficiently as in groups. This result was essential to pair in vitro follicle development and in vitro oocyte maturation with specific individual follicles. Using this approach, it was possible to establish non-invasive signs for the efficiency of IVFC based on follicle daily growth rate and diameter, and oocyte diameter: follicle daily growth >7 µm, follicle diameter of at least 600 µm, and oocyte diameter ≥120 µm. In addition, 18 days seems to be the most suitable culture time for caprine early antral follicles.

Effects of meiotic inhibitors and gonadotrophins on porcine oocytes in vitro maturation, fertilization and development.

This study evaluated the effect of three reversible meiotic inhibitors (MINs) and their interaction with gonadotrophins (Gns) on the meiotic maturation and developmental competence of porcine oocytes. In experiment 1, the oocytes were matured for 22 hr in the presence or absence of dbcAMP (1 mM), cycloheximide (7 µM) or cilostamide (20 µM) with or without Gns, and for an additional 22 hr in the absence of MINs and Gns. At 22 hr of maturation, regardless of the presence of Gns, a higher proportion (p < .001) of oocytes cultured in the presence of MINs were effectively arrested at the germinal vesicle stage compared with the oocytes cultured without MINs. At 44 hr of maturation, the proportion of oocytes that reached MII was higher (p < .05) in groups with Gns compared with groups without Gns. In experiment 2, oocytes that were matured as in experiment 1 were inseminated and cultured for 7 days to evaluate fertilization parameters and blastocyst formation. Only oocytes from the dbcAMP + Gns group had higher (p < .05) efficiency of fertilization compared with the other treatment groups. The presence of dbcAMP during maturation also increased (p < .05) blastocyst formation and efficiency of blastocyst formation in both the presence and absence of Gns. These results indicate that the interaction of Gns with the tested MINs improved meiotic progression. In addition, regardless of supplementation with Gns, the presence of dbcAMP during the first maturation period increased and even doubled the capacity of oocytes to develop to the blastocyst stage.

Caprine ovarian follicle requirements differ between preantral and early antral stages after IVC in medium supplemented with GH and VEGF alone or in combination.

The aim of the present study was to evaluate the effect of growth hormone (GH) and vascular endothelial growth factor (VEGF) added alone, sequentially or in combination, in the presence of insulin at physiological concentration (10 ng/mL) on the IVC of two different follicular categories: preantral (experiment 1; Exp.1) and early antral (experiment 2; Exp.2). Isolated follicles were individually cultured for 24 (Exp.1) and 18 days (Exp.2) in the following treatments: αMEM+ (Control), or Control medium supplemented with 50 ng/mL GH (GH), 100 ng/mL VEGF (VEGF), the combination of both (GH + VEGF), GH during the first 12 days and VEGF from Day 12 until the end of the culture (GH/VEGF) and vice versa (VEGF/GH). At the end of the culture, cumulus-oocyte complexes from in vitro-grown follicles were recovered and subjected to IVM. The following end points were evaluated: Follicle morphology, growth rates and antrum formation, production of estradiol, progesterone and testosterone, oocyte viability and meiotic stage, as well as relative expression of LHR, Amh, HAS2, PTGS2, CYP17, CYP19A1, and 3ßHSD. A considerable amount of viable fully grown oocytes were recovered after the IVC of early antral follicles in all treatments. Nevertheless, the GH treatment presented the highest percentage of fully grown oocytes (60%), mean oocyte diameter (117.74 ± 2.61 µm), and meiotic resumption (50%). Furthermore, GH treatment produced higher (P < 0.05) rates of metaphase II oocytes than all the other treatments, and similar LHR, Amh, and PTGS2 transcript levels to in vivo. Contrary to early antral follicles, preantral follicles were not affected by medium supplementation. In conclusion, the addition of GH to a culture medium containing physiological concentrations of insulin improves oocyte growth and maturation after the IVC of goat early antral follicles.

Balance of insulin and FSH concentrations improves the in vitro development of isolated goat preantral follicles in medium containing GH.

The aim of this study was to evaluate the effect of different combinations of insulin and FSH concentrations in culture media containing GH on the in vitro follicle morphology, antrum formation, growth rates, estradiol (E2) production, oocyte viability and maturation as well as gene expression for FSHR, GHR, INSR, CYP19A1, CYP17, 3ßHSD. Secondary follicles were individually cultured for 18 days in a basic medium containing 50ng/mL GH supplemented with low insulin concentration (INS-LW: 10ng/mL) or high insulin concentration (INS-HG: 10µg/mL) alone or with a fixed FSH concentration (FSH100: 100ng/mL) or with increasing FSH concentrations (FSH-SEQ: 100ng/mL, days 0-6; 500ng/mL, days 6-12; 1000ng/mL days 12-18). In the INS-LW treatment was observed a higher (P<0.05) incidence of normal follicles at day 18 of culture. However, overall higher (P<0.05) follicular growth, oocyte diameter and meiotic resumption rates were obtained using INS-HG+FSH 100. The INS-HG and INS-HG+FSH100 treatments showed higher E2 production and mRNA levels for CYP19A1, CYP17, 3ßHSD when compared to INS-LW and INS-LW+FSH100. However, the addition of increasing FSH concentration, regardless of insulin concentration, did not improve the follicular growth, meotic resumption, E2 production or gene expression of steroidogenic enzymes when compared with INS-HG+FSH100. In conclusion, in presence of GH, a basic medium supplemented with 10µg/mL insulin and 100µg/mL FSH throughout the culture period, improves follicular and oocyte growth, oocyte meiotic resumption and E2 production from isolated preantral caprine follicles cultured in vitro.

Handling of boar spermatozoa during and after flow cytometric sex-sorting process to improve their in vitro fertilizing ability.

The objective of this study was to develop an adequate sperm handling protocol in order to obtain a sex-sorted sperm population with an optimal fertilizing ability. For this purpose, different aspects of the sorting procedure were examined. The effects of the high dilution rates (experiment 1), type of collection medium used (experiment 2), and sheath fluid composition (experiment 3) on sorted boar sperm quality and function were evaluated. Sperm quality was assessed by motility and viability tests, whereas sperm function was evaluated by an in vitro fertilization assay which determined the penetration and polyspermy rates as well as the mean number of sperm penetrating each oocyte. In experiment 1, the results obtained indicated that the high dilution rates did not cause a decrease either in the sperm quality parameters evaluated or the in vitro fertilization ability of spermatozoa. In experiment 2, although sperm quality was not affected, fertilizing ability was compromised after sorting, regardless of the collection medium that was used. In the experiment 3, all groups displayed adequate sperm quality values, but higher in vitro fertility parameters were obtained for spermatozoa sorted in presence of EDTA in the sheath fluid and egg yolk (EY) in the collection media when compared with those sorted in absence of these protective agents. No differences in penetration rates between unsorted highly diluted (control) and sorted sperm in the presence of EDTA and EY were observed. In conclusion, fertilizing ability was compromised in sex-sorted sperm. The addition of EDTA to sheath fluid and EY to collection medium improved boar sperm fertilizing ability, and both agents should be included as essential media components in future studies.

Effect of MEM vitamins and forskolin on embryo development and vitrification tolerance of in vitro-produced pig embryos.

The aims of this study were (1) to determine the effect of in vitro maturation (IVM) medium supplementation with MEM vitamins on in vitro embryo development and sensitivity to vitrification of Day 6 blastocysts and (2) to evaluate whether the addition of forskolin to in vitro culture (IVC) medium enhances blastocyst survival following Super Open Pulled Straw (SOPS) vitrification. Cumulus-oocyte complexes (COCs; n=4000) were matured with 0.0% or 0.05% (v/v) MEM vitamins. After 44h of IVM, the oocytes were in vitro fertilized, and presumptive zygotes were cultured. At Day 5 of IVC, embryos from both experimental groups were cultured for 24h with 0 or 10µM forskolin, achieving a 2×2 factorial design. The blastocyst formation rate was assessed on Day 6, and subsets of samples from the four experimental groups were vitrified (n=469) or kept fresh (n=546). Fresh and vitrified-warmed blastocysts were cultured for 24h prior to embryo survival and total blastocyst cell number assessment. The MEM vitamins increased (P<0.001) the blastocyst formation rate at Day 6, but they did not affect embryo survival after vitrification. In contrast, the addition of forskolin to the culture medium enhanced (P<0.05) the blastocyst vitrification tolerance. The total blastocyst cell number was similar among the groups. In conclusion, supplementation with 0.05% MEM vitamins improved the blastocyst formation rate, and the addition of 10µM forskolin to the culture medium increased survival in Day 6 in vitro-produced blastocysts after SOPS vitrification.

The in vitro and in vivo developmental capacity of selected porcine monospermic zygotes.

In this study, we evaluated the in vitro and in vivo developmental capacity of selected monospermic zygotes produced in vitro. Cumulus-oocyte complexes were matured in vitro and inseminated with frozen-thawed spermatozoa. Thirteen hours after insemination, presumptive zygotes were centrifuged at 15,000 ×g for 20 minutes to polarize the lipids in the cytoplasm and permit the visualization of pronuclei. Then, the oocytes were individually classified as bipronuclear (2PN) or polypronuclear (three or more pronuclei, PPN). To examine embryo development, 102 selected zygotes were cultured for 7 days. There were no differences in cleavage rate (93.0% and 88.9% for 2PN and PPN zygotes, respectively). However, the blastocyst formation rate was higher (P < 0.003) in 2PN (80.7%) zygotes than in PPN (53.3%) zygotes. The control (noncentrifuged, nonselected zygotes) group showed lower (P < 0.003) cleavage rate and blastocyst formation than the 2PN and PPN zygotes. In a second experiment, 2PN zygotes and control zygotes were transferred (30 zygotes per transfer) by laparoscopy into the oviducts of recipient gilts (10 recipients per group) on the first day of standing estrus. The farrowing rates were 70% and 40% for transfers made with 2PN and control zygotes, respectively. The average number of piglets born per recipient farrowed did not differ between groups (4.9 ± 0.6 and 4.5 ± 1.2, respectively), but the efficiency (number of live piglets per total transferred embryos) was higher (P < 0.01) for 2PN zygotes than for the control group (9.3% and 4.0%, respectively). These results demonstrate the effectiveness of centrifugation for the selection of monospermic zygotes as a procedure to improve in vitro embryo production in pigs. In addition, the results indicate that the laparoscopic technique described here is a simple and effective procedure for transferring embryos into one oviduct.

Non-surgical deep intrauterine transfer of superfine open pulled straw (SOPS)-vitrified porcine embryos: evaluation of critical steps of the procedure.

Previous trials achieved extremely poor results when using the one-step warming method in a syringe in combination with non-surgical deep intrauterine transfer (NET) of superfine open pulled straw (SOPS)-vitrified embryos. This study aimed to assess the effect of the warming procedure on the in vitro and in vivo development of SOPS-vitrified embryos. The effect of the passage of the vitrified-warmed (VW) embryos through the NET catheter was also evaluated. Groups of 4 to 6 morulae and blastocysts, collected from weaned sows, were SOPS-vitrified in 1 µL of vitrification medium, warmed by the one-step warming method in a dish or in a 1-mL syringe and cultured in vitro for 48 h to evaluate the embryo survival (ES) and hatching rates (HR). Warming in syringe had a deleterious effect (P < 0.05) on the in vitro ES (60.5 ± 10.4%) and HR (39.6 ± 9.5%) of VW embryos in comparison with embryos warmed in a dish (85.4 ± 10.6% and 69.0 ± 8.4%, respectively). This decreased embryonic development was due to the increased time required between the removal of the straws from the liquid nitrogen and the contact of the embryos with the warming medium when the warming was performed in a syringe in comparison with that for the warming in a dish. After verifying that the passage of VW embryos through the NET catheter does not have a damaging effect on their further in vitro development, the negative effect of warming in a syringe was also confirmed after NET. Fifteen fresh and SOPS-vitrified embryos warmed in a syringe or in a dish were transferred to each recipient (n = 28) and recovered 24 h later to assess their developmental progression. All embryos from the syringe group were found to have degenerated at recovery. The in vivo ES and HR from the dish group (80.4 ± 3.4% and 14.2 ± 7.2%, respectively) were lower (P < 0.05) than those from the fresh group (94.0 ± 4.1% and 36.8 ± 7.8%, respectively). Combining the warming in a dish and the NET procedure, 35 VW embryos were transferred to each of 10 gilts. Five recipients farrowed an average of 10.4 ± 0.9 piglets. In conclusion, the method of one-step warming in a syringe has a negative effect on the in vitro and in vivo viability of SOPS-vitrified porcine embryos. In addition, NET of SOPS-vitrified embryos warmed by the one-step method in a dish showed promising reproductive performance of recipients. However, despite the great potential of this technology, further developments are required for large-scale commercial applications.

Exposure of in vitro-matured porcine oocytes to SYBR-14 and fluorescence impairs their developmental capacity.

Staining with Hoechst 33342 followed by ultraviolet irradiation is frequently used to aid or confirm the enucleation of recipient oocytes in porcine somatic cell nuclear transfer programs. However, the procedure has a clearly deleterious effect on the developmental ability of oocytes. This study evaluated the effectiveness of a longer-wavelength fluorochrome (SYBR-14) for visualizing maternal chromosomes in in vitro-matured porcine oocytes and the effects of this dye in combination with fluorescence excitation on the subsequent in vitro fertilization and embryo development of the oocytes. In the first experiment, the oocytes were exposed to different concentrations (1, 3, 5 and 7 µg/mL) of SYBR-14 at different incubation times (5, 10 and 30 min) in a 4 × 3 factorial design. The optimal condition for proper metaphase-II plate and first polar body visualization was a 10-min incubation with 5 µg/mL of SYBR-14. In the second experiment, the degeneration rate of the oocytes 18 h after exposure to SYBR-14 (5 µg/mL for 10 min) and fluorescence excitation for 5 or 30s was significantly higher (p<0.002) than that obtained for non-exposed oocytes. The fertilization parameters were not influenced by the treatments. The cleavage and blastocyst rates during culture were lower (p<0.001) for the oocytes exposed to SYBR-14 and fluorescence than for those in the non-exposed group. These results indicate that the exposure of mature oocytes to SYBR-14 and fluorescence for periods as short as 5s increased the rate of oocyte degeneration and limited their subsequent developmental competence.

Effects of Hoechst 33342 staining and ultraviolet irradiation on the developmental competence of in vitro-matured porcine oocytes.

Hoechst 33342 (H342) in combination with ultraviolet (UV) irradiation is frequently used to assist the enucleation of porcine oocytes in somatic cell nuclear transfer programs. This work evaluated the effects of H342 (5 µg/mL for 12 min) staining and/or exposure to UV irradiation on fertilisability and developmental capacity of porcine oocytes matured in vitro. In Experiment 1, a total of 1388 mature oocytes were distributed in the following groups: Group 1: oocytes without treatment (Control), Group 2: oocytes stained with H342, Group 3: oocytes stained with H342 and UV irradiated for 30 sec, and Group 4: oocytes UV irradiated for 30 sec. Oocytes from each group were exposed to thawed spermatozoa and cultured for 18 h to assess fertilization parameters or for 7 d to evaluate embryo development. Sperm penetration (P < 0.001) and monospermy (P < 0.04) were lower in oocytes exposed to H342/UV (80.7 ± 4.5% and 30.7 ± 5.4%, respectively) than in oocytes from the control group (94.9 ± 4.3 and 50.0 ± 4.9, respectively). The oocytes exposed to H342/UV showed lower (P < 0.001) cleavage (49.8 ± 2.9%) and blastocyst (7.7 ± 2.9%) rates than oocytes from the other groups (range: 73.8 ± 2.9% to 77.7 ± 2.9% and 22.3 ± 2.9% to 30.9 ± 3.0%, respectively). Experiment 2 was designed to evaluate the effect of shorter UV irradiation (5 sec). A total of 1835 mature oocytes were separated into the same groups as those of Experiment 1. The fertilization parameters and the cleavage rates were not influenced by the different treatments. However, the oocytes exposed to H342 and UV irradiation for 5 sec showed a lower (P < 0.02) rate of blastocyst formation (15.2 ± 4.5%) than the oocytes from other groups (range: 26.1 ± 4.5% to 30.7 ± 4.5%). In conclusion, our results demonstrate that the combination of H342 staining with UV irradiation has a clear deleterious effect on the developmental ability of oocytes, with the effects being more intense with increased exposure to UV irradiation.

Use of polarized light microscopy in porcine reproductive technologies.

The meiotic spindle in the oocyte is composed of microtubules and plays an important role during chromosome alignment and separation at meiosis. Polarized light microscopy (PLM) could be useful for a non-invasive evaluation of the meiotic spindle and may allow removal of nuclear structures without fluorochrome staining and ultraviolet exposure. In this study, PLM was used to assess its potential application in porcine reproductive technologies. The objectives of the present study were to assess the efficiency of PLM to detect microtubule-polymerized protein in in vitro-matured porcine oocytes; to examine its effects on the oocyte developmental competence; to select oocytes based on the presence of the meiotic spindle detected by PLM; and to assess the efficiency oocyte enucleation assisted with PLM. In the first experiment, the presence of microtubule-polymerized protein was assessed and confirmed in oocytes (n = 117) by immunostaining and chromatin detection. In the second experiment, oocytes (n = 160) were exposed or not (controls) to PLM for 10 minutes, and then parthenogenetically activated and cultured in vitro. In the third experiment, development competence of oocytes with a positive or negative signal to PLM was analyzed after in vitro fertilization. Finally, oocytes (n = 54) were enucleated using PLM as a tool to remove the meiotic spindle. A positive PLM signal was detected in 98.2 % of the oocytes, which strongly correlated (r = 1; p < 0.0001) with the presence of microtubule-polymerized protein as confirmed by immunostaining. Oocytes exposed to PLM did not differ significantly from controls on cleavage, total blastocyst, expanded blastocyst rates and total cell numbers. The percentage of oocytes at the MII stage and blastocyst formation rate in the negative PLM group significantly differed from control and PLM positive groups. Overall efficiency of spindle removal using the PLM-Oosight system was 92.6%. These results suggest that polarized light microscopy is an efficient system to detect microtubule-polymerized protein in in vitro-matured porcine oocytes and does not exert detrimental effects on porcine oocyte developmental competence. Selecting oocytes by the presence of a PLM signal provides limited improvement on IVF results. Finally, PLM appears as an efficient method to enucleate porcine oocytes.

Vitrification and warming of in vivo-derived porcine embryos in a chemically defined medium.

The aim of this study was to design a protocol for vitrification and warming of porcine embryos in a chemically defined medium. A total of 663 morulae and blastocysts were collected from weaned crossbred sows (Large White-Landrace) 5 to 6 d after estrus and vitrified with the Superfine Open Pulled Straw method. In Experiment 1, embryos were vitrified using as a basic medium TCM-199-HEPES supplemented with 20% newborn calf serum (NBCS) or with 0, 0.1%, 0.5%, or 1% polyvinyl alcohol (PVA). Nonvitrified embryos were used as a fresh control group. Survival and hatching rates were evaluated after 72 h of in vitro culture to assess embryo viability. In addition, some hatched blastocysts derived from morulae and blastocysts were processed to determine the total cell number and the cell proliferating index as measures of their quality. Within each stage of embryo development, the different vitrification groups and the fresh control group showed similar high embryo survival (range, 70.5+/-7.1% to 84.9+/-8.1% and 85.3+/-8.1% to 98.4+/-8.2% for morulae and blastocysts, respectively) and hatching rate (range, 46.3+/-10.1% to 66.7+/-11.2% and 73.7+/-11.3% to 89.4+/-11.2% for morulae and blastocysts, respectively) and quality after in vitro culture. In Experiment 2, embryos were vitrified using 0.1% PVA and warmed with TCM-199-HEPES-0.13 M sucrose supplemented with 20% NBCS or either 0 or 0.1% PVA. Nonvitrified embryos were used as a fresh control group. As in Experiment 1, no significant differences were detected in embryo survival (range, 67.9+/-6.6% to 74.5+/-6.6% and 91.9+/-7.0% to 99.5+/-6.3% for morulae and blastocysts, respectively) and hatching rate (range, 47.0+/-7.2% to 64.8+/-9.9% and 89.4+/-7.4% to 98.2+/-6.9% for morulae and blastocysts, respectively) and quality among the warming groups or among vitrified and fresh control embryos. In both experiments, the developmental embryo stage influenced the survival and hatching rates, as well as the number of cells (P<0.01), with the blastocyst stage yielding the best results. In conclusion, PVA can be used as a substitute for serum in vitrification and warming solutions without detrimental effects on the in vitro development of in vivo-derived porcine morulae and blastocysts.

Multicentre evaluation of the Boehringer Mannheim Hitachi 911 system for homogeneous immunoassays.

A multicentre evaluation of the new analyser, Hitachi 911, is reported for three different classes of homogeneous immunoassays (latex assays, immunoprecipitation assays, and CEDIA assays). The evaluation protocol follows ECCLS, IFCC and NCCLS guidelines. Using patient samples and commercial controls, within run and between run coefficients of variation were less than 3% in most cases, but as high as 9.7% for some CEDIA and latex assays. All the assays were linear, either in the reference or the therapeutic range of the analytes. No interference by haemolysis, lipaemia or icterus was observed. The methods were compared with other commercial methods. Coefficients of correlation were higher than 0.94 for all the methods. However, there were differences of slope and intercept for rheumatoid factor, apolipoprotein A-I and apolipoprotein B. On the Hitachi 911, all of the eight methods give precise and accurate results, and compare well with other established methods on immunoassay dedicated analysers. The discrepancies observed could be ascribed to current problems of immunoassay standardization.

Automated determination of apolipoproteins A-I and B with an improved immunoturbidimetric assay using Boehringer Mannheim and Hitachi analyzer systems.

Results from an evaluation of immunoturbidimetric methods (Tina-quant) for apolipoprotein A-I (apo AI) and apolipoprotein B (apo B), are presented and compared with results from six other commercial immunoassays. These apo AI and B procedures are fully automated on the Boehringer Mannheim (BM) and Hitachi 704 and 717 analyzers and use undiluted serum. The methods provide an analytical range from 0.002 to 2.3 g/L for apo AI and from 0.003 to 2.2 g/L for apo B and are precise with maximal CVs of 4%. Neither hemoglobin nor intralipid interfered with the assays. Bilirubin concentrations higher than 376 mumol/L for apo AI and 444 mumol/L for apo B, produce a negative interference. In the apo AI method a positive interference caused by rheumatoid factor was found for concentrations higher than 440 x 10(3) IU/L. All comparisons showed an excellent correlation (r > 0.93) with all methods, and slopes ranged from 1.01 to 1.25 for apo AI, and from 0.62 to 1.15 for apo B.

Automated turbidimetry of serum lipoprotein(a).

We describe a simple immunoturbidimetric method for quantifying lipoprotein(a) in serum based on latex-enhanced particle agglutination technology. Carboxylated latex particles (diameter 240 nm) covalently coated with F(ab')2 fragments of anti-lipoprotein(a) antibodies are incubated with the sample for 5 min at 37 degrees C, and the resulting agglutination is quantified by measuring the change of turbidity produced at 700 nm. The assay is rapid, precise and fully automated on the Hitachi 911 analyser. The assay range is about 0.03-0.9 g/l. Average analytical recovery was 97.8%. Precision (CV) ranged from 1.9 to 3.1% at different lipoprotein(a) values. There was no interference from bilirubin, Intralipid, haemoglobin, plasminogen or apolipoprotein B. Comparisons with a latex nephelometric assay carried out on the Behring nephelometer analyser, and with three commercially available methods, a radioimmunoassay and two ELISA assays, gave good correlations (r > 0.95), although a large among-method variation in lipoprotein(a) values was found. We conclude that the proposed latex turbidimetric immunoassay method is suitable for routine use in clinical laboratories.