Publications

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    ABSTRACT: The aim of our study was to assess whether the cryotolerance of in vitro-produced embryos could be influenced by the length of in vitro culture and size of blastocoel cavity before vitrification, using the pig as a model. For this purpose we analysed the cryoresistance and apoptosis rate of blastocysts at different stages of development as derived on Day 5 and 6 of in vitro culture. Blastocysts were subsequently vitrified, warmed and cultured for 24h. Re-expansion rates were recorded at 3 and 24h and total cell number and apoptotic cells were determined at 24h. Day-6 blastocysts showed the highest rates of survival after warming, which indicates higher quality compared with Day-5 blastocysts. Higher re-expansion rates were observed for expanded blastocysts and those in the process of hatching when compared with early blastocysts. Total cell number and apoptotic cells were affected by blastocyst stage, vitrification-warming procedures and length of in vitro culture, as expanding and hatching-hatched blastocysts from Day 6 presented higher percentages of apoptotic cells than fresh blastocysts and blastocysts vitrified at Day 5. Our findings suggest that the cryotop vitrification method is useful for the cryopreservation of porcine blastocysts presenting a high degree of expansion, particularly when vitrification is performed after 6 days of in vitro culture. Furthermore, these results show that faster embryo development underlies higher blastocyst cryotolerance and provide evidence that blastocoel cavity expansion before vitrification is a reliable index of in vitro-produced embryo quality and developmental potential.
    Reproduction Fertility and Development 12/2014; · 2.58 Impact Factor
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    ABSTRACT: It has been previously described that a simple treatment with medium containing elevated NaCl or sucrose concentrations increases the cryotolerance and developmental competence of in vitro-matured porcine oocytes after vitrification and parthenogenetic activation (Lin et al. 2009 Reprod. Fertil. Dev. 21, 338-344). This work was designed to study whether the exposure to increased concentrations of NaCl or sucrose before vitrification improves cryotolerance of in vitro-matured bovine oocytes. In Experiment 1, in vitro-matured oocytes were exposed to different NaCl and sucrose concentrations (from 375 to 808 mOsm) for 1h. In Experiment 2, and according to the results obtained in the first experiment, oocytes were exposed to 375 mOsm NaCl or sucrose solution, vitrified, and warmed. Nontreated oocytes were used as controls. In both experiments, oocytes were fixed after treatment and microtubule, and chromosome distribution was analysed by immunocitochemistry. All statistical analyses were conducted with the IBM SPSS 19 for Windows (IBM corp., Chicago, IL). ANOVA was performed to analyse differences in meiotic spindle. Statistical significance was set at P<0.05. After exposure to 375 mOsm of NaCl or sucrose, similar percentages of oocytes showing normal chromosome distribution were obtained compared to the control group (83.4, 71.8, and 85.0%, respectively). Groups treated with higher concentrations (443 to 808 mOsm) triggered significantly lower proportions of normal spindles. After vitrification/warming, no significant differences were observed between nonvitrified oocytes (71.3%) and those treated with NaCl before vitrification/warming procedure (41.9%) when normal chromosome organisation was analysed. Significantly higher percentages of normal chromosome configuration were observed when oocytes were exposed to sucrose before vitrification (34.2%) compared with control-vitrified oocytes (23.3%). However, pretreatment with NaCl or sucrose before vitrification did not trigger significant differences in terms of percentages of normal microtubule configuration (41.9 and 32.9%, respectively) compared with control-vitrified oocytes (40.2 and 24.4%, respectively), although both treatments differed significantly from control (79.1 and 81.7%, respectively). In conclusion, this study showed that a 375-mOsm NaCl or sucrose pretreatment of bovine oocytes before vitrification did not have a deleterious effect on the organisation of the meiotic spindle of vitrified/warmed bovine oocytes. Further experiments are required to investigate whether in vitro-matured oocytes subjected to this osmotic treatment could improve their development competence after being vitrified/warmed.
    Reproduction Fertility and Development 12/2014; 27(1):116. · 2.58 Impact Factor
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    ABSTRACT: After cryopreservation, oocytes may suffer morphological and functional damage, due to the high cytoplasm lipid content and to the reactive oxygen species formation. The aim of this work was to evaluate the spindle configuration and the DNA fragmentation of vitrified/warmed oocytes after in vitro maturation (IVM) in a media supplemented with l-carnitine and/or resveratrol, a lipolytic and antioxidant agent, respectively. The IVM viable COC with at least 3 cumulus cell layers and homogenous cytoplasm were randomly distributed into 4 groups: (1) control: conventional IVM media with TCM-199, epidermal growth factor, and 10% FCS; (2) L-CAR: control media supplemented with 0.6mgmL(-1) of l-carnitine; (3) RES: control media supplemented with 1μMmL(-1) of resveratrol; and 4) L+R: control media supplemented with 0.6mgmL(-1) of l-carnitine and 1μMmL(-1) of resveratrol. After 22h of IVM, half of the COC from each group were vitrified and warmed, using the cryotop methodology. After warming, the oocytes were allowed to recover in their respective media for 2 additional hours. After 24h of IVM, oocytes from all treatments were completely denuded and fixed and stained using specific fluorescent probes. The microtubule/chromosome configuration and the DNA fragmentation were analysed by immunocytochemistry under a fluorescent microscope (A.40FL, Carl Zeiss, Oberkochen, Germany). All statistical analyses were conducted with IBM SPSS 19 (IBM; Chicago, IL, USA). ANOVA was performed to analyse differences in meiotic spindle configuration, and the Chi-squared test was used for DNA fragmentation. The significance level was 5%. Although vitrification may cause severe oocyte damage, IVM with l-carnitine alone or in association with resveratrol was able to reduce the percentage of abnormal spindle configurations (Table 1), whereas the addition of resveratrol alone or its association with l-carnitine reduced DNA fragmentation of IVM oocytes after a vitrification/warming process. These results indicate the IVM supplementation with RES and/or L-CAR could modify oocyte composition, increasing its cryotolerance. However further studies are required to confirm the beneficial effect of these molecular interactions.
    Reproduction Fertility and Development 12/2014; 27(1):115-6. · 2.58 Impact Factor
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    ABSTRACT: Aquaporins (AQPs) are integral membrane water channels that allow transport of water and small solutes across cell membranes. Although water permeability is known to play a critical role in mammalian cells, including spermatozoa, little is known about their localisation in boar spermatozoa. Two aquaporins, AQP7 and AQP11, in boar spermatozoa were identified by western blotting and localised through immunocytochemistry analyses. Western blot results showed that boar spermatozoa expressed AQP7 (25kDa) and AQP11 (50kDa). Immunocytochemistry analyses demonstrated that AQP7 was localised in the connecting piece of boar spermatozoa, while AQP11 was found in the head and mid-piece and diffuse labelling was also seen along the tail. Despite differences in AQP7 and AQP11 content between boar ejaculates, these differences were not found to be correlated with sperm quality in the case of AQP7. Conversely, AQP11 content showed a significant correlation (P<0.05) with sperm membrane integrity and fluidity and sperm motility. In conclusion, boar spermatozoa express AQP7 and AQP11, and the amounts of AQP11 but not those of AQP7 are correlated with sperm motility and membrane integrity.
    Reproduction Fertility and Development 10/2014; · 2.58 Impact Factor
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    ABSTRACT: The low number of oocytes collected from unstimulated donors by ovum pick-up means that embryos produced from each individual female have to be cultured individually or in very small groups. However, it has been demonstrated that single-embryo culture is less efficient than embryo culture in groups. To overcome this limitation, we developed a direct embryo-tagging system, which allows the collective culture of embryos from different origins whilst preserving their pedigree. Presumptive bovine zygotes were tagged with eight wheat-germ agglutinin biofunctionalised polysilicon barcodes attached to the outer surface of the zona pellucida (ZP). Four different barcodes were used to encode groups of 20-25 embryos, which were then cultured in the same drop. Cleavage, Day-7 and Day-8 blastocysts and barcode retention rates were assessed. In addition, Day-7 blastocysts were vitrified and warmed. Barcode attachment to the ZP of bovine embryos affected neither in vitro embryo development nor post-warming survival of the tagged embryos. All the embryos maintained barcodes attached until Day 8 of culture (3.63±0.37 barcodes per embryo) and could be identified. In conclusion, identification of embryos by barcodes attached to the ZP is feasible and will allow the culture of embryos from different donors in the same drop.
    Reproduction Fertility and Development 06/2014; 26(5):645-52. · 2.58 Impact Factor
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    ABSTRACT: The aim of the present study was to determine the effect of l-ascorbic acid on embryo quality and gene expression of porcine blastocysts after supplementations of in vitro culture medium and/or vitrification–warming media. Embryo quality, in terms of total cell number (TCN), DNA fragmentation and peroxide levels, together with the relative transcript abundance of BCL-2 associated X protein (BAX), BCL2-like 1 (BCL2L1), POU class 5 homeobox 1 (POU5F1) and heat shock protein 70 (HSPA1A), was analysed. In Experiment 1, gene expression and embryo quality of fresh blastocysts were evaluated after culture with or without l-ascorbic acid; no significant differences were observed between the groups. In Experiment 2, blastocysts cultured with or without l-ascorbic acid were vitrified using two different vitrification solutions, supplemented or not with l-ascorbic acid. Supplementation of culture and vitrification media significantly enhanced survival rates and reduced peroxide levels. No significant differences i
    Reproduction Fertility and Development 04/2014; · 2.58 Impact Factor
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    ABSTRACT: The aims of the present study were to: (1) evaluate the effect of vitrification and warming on quality parameters and expression levels of pluripotency, apoptotic and stress genes in in vitro-produced (IVP) porcine blastocysts; and (ii) determine the correlation between these parameters. To this end, total cell number, DNA fragmentation, peroxide levels and the relative transcript abundance of BCL-2 associated X protein (BAX), BCL2-like 1 (BCL2L1), heat shock protein 70 (HSPA1A), POU class 5 homeobox 1 (POU5F1), superoxide dismutase 1 (SOD1) and superoxide dismutase 2 (SOD2) were analysed in fresh and vitrified IVP blastocysts. The results suggest that vitrification procedures have no effect on total cell number and gene expression of BAX, BCL2L1, SOD1 and SOD2 or the BAX : BCL2L1 ratio. Nevertheless, a significant increase in DNA fragmentation (2.9 ± 0.4% vs 11.9 ± 2.0%) and peroxide levels (80.4 ± 2.6 vs 97.2 ± 3.1) were seen in vitrified compared with Day 7 fresh blastocysts. In addition,
    Reproduction Fertility and Development 04/2014; · 2.58 Impact Factor
  • Roser Morató, Teresa Mogas
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    ABSTRACT: Two experiments were designed to test the use of a new device designed to vitrify and in-straw warm in vitro produced (IVP) embryos, which can potentially be used for their direct transfer to recipient females in field conditions. In experiment 1, IVP embryos from both prepubertal and adult animals were vitrified on cryotops and warmed in steps (1 M, 0.5 M and 0 M sucrose; protocol W3) or directly in 0.5 M (protocol W1/0.5) or 0 M sucrose (protocol W1/0). Similar survival rates were recorded 24h after warming for calf embryos irrespective of the warming procedure (W3: 79.2%, W1/0.5: 62.5%, W1/0: 66.7%). For cow embryos, survival rates at 24h post-warming were significantly higher when embryos were warmed using the W3 (85.7%) or W1/0.5 (89.1%) protocols compared to the W1/0 protocol (70.5%). In experiment 2, IVP embryos were vitrified on the new designed device followed by their in-straw cryoprotectant (0.5 M sucrose) dilution/warming and different warming temperatures (45°C, 50°C, 60°C and 70°C) were tested. When warming solution passed through the new vitrification/warming device at 45°C, 61.5% of blastocysts were fully re-expanded or hatched at 24h post-warming, being not significantly different to the control (65%). Other warming temperatures triggered significantly lower survival rates at 24h post-warming. No significant differences were detected in total cell numbers and blastocyst apoptosis indices in response to vitrification followed by warming at 45°C respect to the control. Our findings indicate that the new device allows vitrification and in-straw warming of IVP bovine embryos, being a useful option for their direct transfer in field conditions.
    Cryobiology 04/2014; · 2.14 Impact Factor
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    ABSTRACT: The present study sought to determine the effect of adding L-ascorbic acid (AC) to (1) in vitro culture medium and (2) vitrification and warming solutions on redox status and developmental ability and quality of IVP porcine embryos. In both experiments, embryo quality was analysed in terms of total cell number (TCN), DNA fragmentation, intracellular peroxide levels and expression of three oxidative stress-related genes: glutathione peroxidase 1 (GPX1), superoxide dismutase 1 (SOD1) and 2 (SOD2). In the first experiment, fresh blastocysts were found to upregulate SOD1 expression when cultured with medium supplemented 100 μM AC. No differences were found between culture groups in the other analysed parameters, In the second experiment, blastocysts cultured with or without AC were divided into two groups: vitrified and warmed with solutions containing 0 or 100 μM AC. Addition of AC during culture and vitrification-warming upregulated the expression of GPX1 and SOD1 genes, enhanced survival rates and decreased peroxide levels at 24 h post-warming. In addition, peroxide levels were negatively correlated with relative GPX1- and SOD1-transcript abundances, whereas GPX1 was positively correlated with embryo survival at 24h post-warming. No effects of AC-supplementation were seen for TCN, DNA fragmentation or relative SOD2-transcript abundance in vitrified blastocysts. In conclusion, the addition of AC to culture and vitrification-warming media increases gene expression of antioxidant enzymes SOD1 and GPX1. This appears to improve redox balance and is suggested to ultimately enhance embryo cryosurvival.
    Cryobiology 03/2014; · 2.14 Impact Factor
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    ABSTRACT: One of the major obstacles for the vitrification of mature porcine oocytes with ethylene glycol is their low permeability to this cryoprotectant, which results in osmotic stress-induced cell damage and low survival. Pig blastocysts, on the other hand, show enhanced water and cryoprotectant permeability, which has been related to the transcriptional activation of aquaporin-3 (AQP3) channels at this stage of development. In this study, we asked if expression of cRNAs encoding two aquaglyceroporins, human AQP3 (hAQP3) or the zebrafish Aqp3b-T85A mutant, in porcine oocytes can increase their permeability. Microinjection of germinal-vesicle-stage oocytes with enhanced green fluorescent protein (EGFP) or AQP3 cRNAs resulted in the expression of the corresponding proteins in ∼26% of the metaphase-II stage oocytes at 40-44 h of in vitro culture; co-injection of EGFP cRNA appeared to be a suitable marker for oocyte selection since all EGFP-positive oocytes also expressed the corresponding aquaporin. Using this method, we found that mature oocytes co-expressing EGFP and hAQP3 or EGFP and Aqp3b-T85A showed approximately a twofold increase of the hydraulic conductivity (Lp ) with respect non-injected or EGFP alone-injected oocytes in a 0.43 M sucrose or 1.3 M ethylene glycol solution, whereas the ethylene-glycol permeability (PEG ) of EGFP + hAQP3 and EGFP + Aqp3b-T85A oocytes was 6.7- and 12-fold higher, respectively, than control oocytes. These data demonstrate that the artificial expression of aquaglyceroporins in porcine metaphase-II oocytes improves their permeability, and that the zebrafish Aqp3b-T85A mutant is more efficient than the human channel at increasing the oocyte permeability to ethylene glycol. Mol. Reprod. Dev. © 2014 Wiley Periodicals, Inc.
    Molecular Reproduction and Development 02/2014; · 2.81 Impact Factor
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    ABSTRACT: The present study examined the relationship between the relative amount of high motile sperm and sperm-oocyte interactions obtained from Holstein bull ejaculates. Post-thaw sperm motility was analyzed using a computer-assisted sperm analyzer system and evaluated to determine the sperm motility subpopulations. Adhesion and penetration of zona pellucida (ZP) and pronucleus formation using post-thawed samples (15 ejaculates form 5 different bulls) with different percentages of sperm in the subpopulation with the fastest and most progressive subpopulation (subpopulation 4 [SP4]) were analyzed. The correlation between the proportion of sperm in SP4 and the number of spermatozoa bound to the zona pellucida (ZBA), the penetration rate, and the rate of pronucleus formation were calculated. A significant (P < 0.05) and positive correlation was found between the number of spermatozoa bound to the zona pellucida, the penetration rate, and the rate of pronucleus formation with the proportion of sperm in SP4 (r = 0.79, r = 0.66, and r = 0.63, respectively). Our results suggest that this specific high motile and progressive subpopulation is positively and significantly correlated with the ability of a thawed bull semen sample to interact properly with the oocyte and its extracellular vestments. These findings emphasize the relevance of analyzing semen subpopulation composition to predict bull sperm fertilizing ability and to select Holstein bulls for breeding purposes.
    Theriogenology 01/2014; · 2.08 Impact Factor
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    ABSTRACT: The present study was designed to evaluate the effect of activin-A during the in vitro oocyte maturation (IVM) and in vitro embryo culture (IVC) on nuclear maturation, blastocyst yield and blastocyst quality of prepubertal goat oocytes. In Experiment 1, three groups of oocytes were used during the IVM of prepubertal goat oocytes to determine the optimal concentration of recombinant human activin-A added to the maturation medium. Cumulus-oocyte complexes were matured in an IVM medium containing 0, 10 and 100 ng/ml (groups A0, A10 and A100), fertilized and in vitro cultured using standard procedures. In Experiment 2, the addition of 10 ng/ml activin-A at IVM (A10A0), IVC (A0A10) or IVM+IVC (A10A10) was studied and compared with the control group (A0A0). Results of the first experiment demonstrated that the addition of activin-A yielded similar percentages of maturation (⩽71.0%) and blastocyst formation rates (⩽24.9%) than the control group (A0). Experiment 2 showed that exposure of prepubertal goat oocytes to an IVC medium containing 10 ng/ml activin-A (A0A10) significantly increased the rates of development to the blastocyst stage, as compared with the control group (A0A0) (19.5±2.21% v. 13.1±2.37%, respectively; P<0.05). With regard to the blastocyst quality, total number of cells, inner cell mass (ICM) and trophectoderm of prepubertal goat embryos produced in the presence of activin-A did not differ significantly among experimental groups. In summary, these results indicate that supplementation of the IVC medium with activin-A enhances embryo development of prepubertal goat oocytes.
    animal 10/2013; · 1.65 Impact Factor
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    ABSTRACT: Our aim was to determine the effect of ejaculates with different motile sperm subpopulations structure on sperm-oocyte binding ability. Fifteen ejaculates from five separate bulls were collected and cryopreserved through a standard protocol. Post-thaw sperm motility was analyzed by using a CASA system and evaluated to identify sperm subpopulations as described by Mui~no et al. (Ani Repr Sci 109; 27–39, 2008). Adhesion to zona pellucida of post-thawed samples with low, medium and high percentages of sperm included in the subpopulation with the fastest and most progressive spermatozoa (T4) were tested through a zona binding assay (ZBA). For this purpose, in vitro maturated cow oocytes were denuded and transferred in groups of 10 to a 45 ll drop of fertilization medium. A 5 ll aliquot of sperm suspension (10 9 106 spz/ml) was added to each drop. After 19– 20 hpi, the oocytes were fixed and stained with DAPI. Statistical differences between means were analyzed by Tukey’s test and correlations by Spearman rank correlation. We found a significant difference (p < 0.05) in the number of spermatozoa bound to zona pellucida among the ejaculates for the same bull and between different bulls. A significant correlation (r = 0.79, p < 0.01) was found between the ZBA and the precise percentage of sperm pertaining to the T4 subpopulation. Our results suggest that the precise motile sperm subpopulations structure is closely related with the ability of a thawed bull semen sample in binding to the ZP.
    Reproduction in Domestic Animals 09/2013; 48(1):77. · 1.39 Impact Factor
  • Arcarons N, Morató R, Ferraz M, Mogas T
    AETE, Istambul, Turkey; 09/2013
  • Reproduction Fertility and Development 07/2013; · 2.58 Impact Factor
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    ABSTRACT: The aim of this study was to test the effect of insulin–transferrin–selenium (ITS), l-ascorbic acid (AA) and different hormone concentrations at IVM on blastocyst development, MPF activity and ATP content in lamb oocytes. In this study we used three maturation media: conventional IVM medium (CM), growth medium (GM: CM + ITS + AA and low level of hormones) and modified CM (MM: CM + ITS + AA and conventional hormone concentration). Cumulus–oocyte complexes (COCs) were classified into two categories according to results from BCB staining: fully grown oocytes or BCB+ and growing oocytes or BCB−. A group of control oocytes (not BCB stained), BCB+ and BCB− were matured (IVM) for 24 h in CM (Treatments A, B and C, respectively). Also, BCB− oocytes were matured in four treatment groups: Treatment D: 12 h in GM plus 12 h in CM; Treatment E: 24 h in GM; Treatment F: 12 h in GM plus 12 h in MM; Treatment G: 24 h in MM. After IVM, oocytes were fertilized and cultured for 8 days and blastocyst development was assessed. Before and after IVM, a sample of each oocyte group was taken to evaluate MPF and ATP content. The BCB+ oocytes produced the highest blastocyst (13.3%) yield. BCB− oocytes did not show any statistically significant differences in blastocysts between treatments, D (5.9%), E (7.2%), F (2.9%) and G (3.9%) compared to Treatment C (4%). Results of MPF activity and ATP content assessed before and after IVM showed an increase in all oocytes (P < 0.001) after 24 h of IVM compared to immature oocytes (0 h). No differences were observed among treatment groups. In conclusion, BCB− oocytes were unable to improve embryo development in any of the treatments tested in this study. Embryo development of BCB+ oocytes was significantly higher than BCB− oocytes.
    Small Ruminant Research 05/2013; 112(s 1–3):103–107. · 1.12 Impact Factor
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    ABSTRACT: The effect of combining double layer density gradient centrifugation (DL-DGC) with different capacitation treatments on the fertilising capacity of frozen-thawed stallion sperm was examined via a heterologous assay involving in vitro-matured, zona pellucida-free bovine oocytes. In a first experiment, aliquots of frozen-thawed stallion sperm were subjected to one of five capacitation treatments without DL-DGC - ionomycin at 1.0μM, 0.1μM, 0.05μM or 0.01μM, or caffeine at 200μg/mL. The fertilising capacity of the semen was then assessed at 18h by staining the above oocytes with 4,6-diamidino-2-phenylindole (DAPI) and examining for sperm penetration, the number of penetrated spermatozoa per oocyte, and male pronucleus formation. In a second experiment, aliquots of frozen-thawed stallion sperm were subjected to DL-DGC selection - or not - and then further subjected to the two best capacitation treatments (0.1μM and 0.05μM ionomycin). The fertilising capacity of the semen was then determined as above. The DL-DGC/capacitated sperm samples showed the highest mean penetration rates: 24.16% following capacitation with 0.1μM ionomycin, and 12.21% following capacitation with 0.05μM ionomycin. The capacitated but non-DL-DGC-selected sperm returned significantly lower values: 6.26% and 7.02% for the same ionomycin treatments respectively. These findings suggest that combining DL-DGC selection with ionomycin capacitation improves the fertilising capacity of frozen-thawed stallion sperm.
    Animal reproduction science 04/2013; · 1.56 Impact Factor
  • R Morató, T Mogas
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    ABSTRACT: Although slow freezing continues to be the most widely used technique of cryopreservation for bovine in vivo- and in vitro-produced embryos, vitrification has been tested in different species with good results, especially when dealing with in vitro-produced embryos. Vitrification represents a minor expense in time and equipment associated with cryopreservation compared with conventional slow freezing. However, vitrification, which is the most common method for human embryo cryopreservation, has not been widely adopted by embryo-transfer practitioners for commercial use in cattle. In general, vitrification requires gradual cryoprotectant dilution in a laboratory setting, and it is difficult to perform in the field. The objective of this study was to develop a one-step dilution method suitable for one-step bovine embryo transfer using the cryotop vitrification method. Embryos produced in vitro by standard procedures were vitrified at the blastocyst stage at Day 7 post-insemination in a mixture of 15% ethylene glycol+15% dimethyl sulfoxide+0.5M sucrose using cryotop devices. Embryos were randomly assigned to 1 of 3 warming methods: (1) W3: warming was carried out following the cryotop method (1M sucrose for 1min, 0.5M sucrose for 3min, and 0M sucrose for 6min); (2) W1/0.5: embryos were warmed directly in 0.5M sucrose for 3 min; and (3) W1/0: embryos were warmed directly in 0M sucrose for 5min. Survival rates were assessed in terms of blastocyst re-expansion, hatching, and hatched status at 3 and 24h after warming. Data were analyzed using the statistical analysis systems package (SAS, v9.1). Data from at least 3 replicates were collected. Comparisons of vitrified-warmed blastocyst survival rates between groups were performed using the chi-squared test. The level of statistical significance was set at P<0.05. When embryo survival was evaluated at 3h postwarming, embryos warmed using the 3-step dilution protocol and those warmed directly in 0.5M sucrose showed higher percentages of survival (W3: 89.8%, n=98; W1/0.5: 87.5%, n=64; P<0.05) than those blastocysts that were warmed directly in 0M sucrose (W1/0: 66.4%, n=146). However, similar rates irrespective of the warming procedure were observed at 24h postwarming (W3: 85.7%, W1/0.5: 88.2%, W1/0: 70.5%). Warmed in vitro-produced embryos exposed to W3 (47.6%) and W1/0.5 (35.6%) achieved higher percentages of embryos developing to the hatched blastocyst stage after 24h of culture than those embryos warmed in W1/0 (20.4%; P<0.05). Our results indicate that direct warming and dilution of cyotop-vitrified embryos in 0.5M sucrose for 3min may enable one-step bovine embryo transfer without requirement of a microscope or other laboratory equipment, simplifying the embryo-transfer procedure of vitrified embryos on farm at the same level of complexity as carrying out AI.
    Reproduction Fertility and Development 12/2012; 25(1):182. · 2.58 Impact Factor
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    ABSTRACT: The low number of oocytes collected from unstimulated donors by ovum pick-up means that embryos produced from each female have to be cultured in very small groups. Because embryo quality and development rates are reduced in individual and small group culture, several methods to culture embryos individually but sharing the same medium have been designed. However, these systems prevent embryo movements, interfering with paracrine factors transmission and gradient changes. Here, we present an alternative in vitro culture method to allow the co-culture of embryos from different origins, without movement restriction and preserving their pedigree, by labelling the zygotes with polysilicon barcodes attached to the outer surface of the zona pellucida (ZP). Barcodes (10×6×1µm) with 8 rectangular bits of binary codification (256 possible combinations), which can be read under a standard inverted microscope, were fabricated using silicon microtechnologies. To provide the barcodes with a ZP-binding capacity, they were biofunctionalized by self-assembled monolayers with the wheat germ agglutinin (WGA) lectin, which recognizes specific saccharides highly abundant in the ZP of most mammalian species. As a proof of concept, the culture method was tested on bovine zygotes produced from slaughterhouse-derived cow oocytes matured and fertilized in vitro. Using a mouth-controlled pipette, presumptive zygotes were individually rolled over WGA-biofunctionalized barcodes (8 barcodes/embryo) previously placed at the bottom of a drop of manipulation media. Four different barcodes, each one with a different codification, were used to encode 25 embryos (6-7 embryos/barcode codification), which were then cultured together in the same drop of medium. Day 7 (D7) and Day 8 (D8) blastocyst, and barcode retention rates were assessed. In addition, D7 expanded blastocysts were vitrified by the cryotop method and post-warming survival was determined as re-expansion rate at 24h in culture. Finally, the quality of D8 blastocysts was assessed by differential staining and counting of inner cell mass (ICM) and trophectoderm (TE) cells. In all the experiments, a control group without barcodes was cultured and vitrified-warmed. Data were analyzed by chi-square and Mann-Whitney tests. The presence of barcodes attached to the ZP did not affect in vitro embryo development (D8 blastocysts: 29.7% control n=309, 36.2% encoded n=315), post-warming survival (86.4% control n=66, 80.5% encoded n=82), or blastocyst quality (IMC/TE: 22.1±1.4/64.5±5.7 control n=18, 22.2±1.7/64.1±6.1 encoded n=23). The labelling system was effective until D8 of culture, as all the embryos maintained barcodes attached (4±1.8 barcodes/embryo) and could be identified, even after undergoing vitrification and warming. In conclusion, identification of co-cultured embryos by biofunctionalized barcodes attached to the ZP is feasible and will allow to culture embryos from different donors in the same drop, keeping the benefits of collective culture.
    Reproduction Fertility and Development 12/2012; 25(1):218-9. · 2.58 Impact Factor
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    ABSTRACT: The benefits of adding L-ascorbic acid during the cryopreservation procedure have been reported before in mouse and bovine. In this study, the effects of L-ascorbic acid (AC) supplementation during culture, cryopreservation, or both procedures on the developmental ability and embryo quality of in vitro produced porcine blastocysts were examined. Embryo quality criteria consisted of total cell number, percentage of apoptosis, and cryotolerance. After in vitro fertilisation, presumptive zygotes were randomly assigned to 2 culture treatments in which the culture medium NCSU23 was supplemented with 100µM AC (n=1162) or nonsupplemented (n=1163) for a 144-h period. On Day 6, blastocyst formation was assessed by stereomicroscopy, and a representative fraction of Grade I- and II-blastocysts of each culture treatment was evaluated using 4',6-diamidino-2-phenylindole-TUNEL co-staining and considered as fresh-control. The remaining fraction of Grade I- and II-blastocysts was vitrified/warmed following the Cryotop(®) method. To determine the effect of AC supplementation during cryopreservation procedures, each culture treatment was divided into 2 groups: (1) embryos exposed to 100µM AC, and (2) nonexposed embryos (vitrified-control). Survival was determined according to reexpansion rates after 24h of recovery in NCSU23 medium. After 24h, reexpanded blastocysts were co-stained using the 4',6-diamidino-2-phenylindole-TUNEL technique, and total number of cells and apoptosis indexes were determined. Experiment was replicated 9 times for each group. Data were analyzed by t-test for independent variables and a 2-way ANOVA. Results are expressed as means ± SE, and the significant level was set at 5% (Table 1). After culture, supplementing NCSU23 medium with AC showed no significant differences in blastocyst formation (fresh-control 11.6±7.8 v. AC 11.6±7.7), in number of cells (fresh-control 36.7±15.8 v. AC 36.1±15.9), or in apoptosis index (fresh-control 2.9±5.7 v. AC 3.5±4.7). On the other hand, only when both culture and vitrified media were supplemented with AC was there a significant increase of blastocyst survival. In contrast, no significant differences in embryo survival were observed when only 1 of these 2 media (culture or vitrification) was supplemented. Supplementing culture media or cryopreservation solutions with AC did not affect the total cell number or apoptosis index in vitrified blastocysts. In conclusion, the addition of 100µM L-ascorbic acid to the culture and cryopreservation solutions improves the cryotolerance of in vitro-produced porcine blastocysts.
    Reproduction Fertility and Development 12/2012; 25(1):177. · 2.58 Impact Factor

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