44 THE EFFECT OF SUCROSE CONCENTRATION FOR SINGLE-STEP DILUTION ON THE VIABILITY OF CRYOTOP-VITRIFIED IN VITRO-PRODUCED BOVINE EMBRYOS

2015 ◽  
Vol 27 (1) ◽  
pp. 115
Author(s):  
S. Kondo ◽  
K. Imai ◽  
O. Dochi
Keyword(s):  
Ethylene Glycol ◽  
Dimethyl Sulfoxide ◽  
Liquid Nitrogen ◽  
Sucrose Concentration ◽  
Calf Serum ◽  
Single Step ◽  
Bovine Embryos ◽  
Vitrification Solution ◽  
Phosphate Buffered Saline

The aim of this study was to test sucrose concentrations for single-step dilution on the viability of vitrified in vitro-produced bovine embryos. Blastocysts (n = 173, 7 to 8 days after fertilization) were vitrified using the Cryotop (Kitazato, Tokyo, Japan) method placement by incubating the blastocysts in Dulbecco's phosphate buffered saline supplemented with 20% calf serum, 7.5% ethylene glycol, and 7.5% dimethyl sulfoxide for 3 min and then transferring into vitrification solution (Dulbecco's phosphate buffered saline supplemented with 20% calf serum, 16.5% ethylene glycol, 16.5% dimethyl sulfoxide, and 0.5 M sucrose). Each embryo was placed on a Cryotop with minimum volume of vitrification solution, and then the Cryotop was plunged into liquid nitrogen. Total time from placement in vitrification solution to plunging into liquid nitrogen was 1 min. The blastocysts were warmed by incubation in the single-step dilution medium for 5 min [0 M sucrose (n = 42), 0.25 M sucrose (n = 44), 0.5 M sucrose (n = 43), and 1.0 M sucrose (n = 44)] at 38.0°C. After dilution, the embryos were washed in TCM-199 supplemented with 20% calf serum and 0.1 mM β-mercaptoethanol and were cultured for 72 h in the same medium at 38.5°C in an atmosphere of 5% CO2. The rates of re-expanded blastocysts and hatched blastocysts were determined at 24 and 72 h after warming, respectively. Data were analysed using the chi-squared test. The percent of re-expanded blastocysts at 24 h after warming in dilution medium supplemented with any level of sucrose was significantly higher (P < 0.05) than in blastocysts warmed without sucrose (Table 1). The hatched blastocyst rate of embryos at 72 h after warming in dilution medium with 0.5 M sucrose was significant higher than that with no sucrose. There were no differences in hatched blastocyst rates between the sucrose concentrations supplemented to the dilution medium. These results suggest that embryos vitrified by the Cryotop method can be diluted in single-step dilution using 0.25, 0.5, or 1.0 M sucrose supplemented to the medium. Table 1.The effect of sucrose concentration for single-step dilution on the viability of Cryotop vitrified in vitro-produced bovine embryos

28 Short equilibration improves vitrification of invitro-produced bovine embryos using VitTrans device

2020 ◽  
Vol 32 (2) ◽  
pp. 140
Author(s):  
I. Martínez-Rodero ◽  
T. García-Martínez ◽  
M. López-Béjar ◽  
T. Mogas
Keyword(s):  
Ethylene Glycol ◽  
Dimethyl Sulfoxide ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Calf Serum ◽  
Field Conditions ◽  
Bovine Embryos ◽  
Fluid Medium ◽  
Apoptosis Index ◽  
Vitrification Solution

For the successful application of vitrification technology to field conditions, the procedures for the warming and transfer of the cryopreserved bovine embryos should be as simple as possible. The device VitTrans, designed by our group, enables warming/dilution of embryos and their transfer directly to recipient females in field conditions (Morato and Mogas 2014 Cryobiology 68, 288). VitTrans vitrification protocol consists of an incubation in equilibration solution during 12min followed by an exposure of 40s to vitrification solution. However, there are other reports using similar vitrification devices where equilibration length is shorter than ours. This study aimed to improve VitTrans methodology by comparing two vitrification protocols: short equilibration (SE) and long equilibration (LE). A total of 63 invitro-produced Day 7 blastocysts (IETS stage code 7) were randomly placed in an equilibration solution with 7.5% ethylene glycol + 7.5% dimethyl sulfoxide in holding medium (tissue culture medium-199 HEPES + 20% fetal calf serum) for either 3min (SE) or 12min (LE). Then, blastocysts were transferred to vitrification solution (15% ethylene glycol + 15% dimethyl sulfoxide + 0.5M sucrose in holding medium) for 40s, loaded onto the VitTrans device, plunged into liquid nitrogen, and covered with a 0.5mL straw. Fresh nonvitrified blastocysts (n=30) were set as control. For warming, the VitTrans was quickly submerged into a water bath at 45°C, while a syringe containing 0.3mL of diluting solution (0.5M sucrose in holding medium) at 45°C was injected through the hollow of the device. Blastocysts were then transferred to synthetic oviductal fluid medium and cultured for 24h at 38.5% in a 5% CO2 and 5% O2 environment in a humidified atmosphere. Re-expansion rates were recorded 3 and 24h after warming. Blastocysts were fixed and stained with SOX2 (Invitrogen) for inner cell mass (ICM) count, TUNEL (Roche) for apoptosis index assessment, and DAPI (Vector Laboratories) for total cell count (TCC). Images were captured using a Leica TCS SP5 confocal microscope (Leica Microsystems) and examined with Imaris 9.2 software (Oxford Instruments). Blastocyst survival rates were compared between groups using chi-squared test. Blastocyst TCC, ICM count, and apoptosis indices were analysed using analysis of variance. Significance was set at P ≤ 0.05. No differences were observed in re-expansion rate at 3h postwarming (61.3 and 59.4% for SE and LE, respectively). However, significantly higher re-expansion rates were found after 24h of culture for the blastocysts of the SE group (74.2%) when compared with the blastocysts of the LE group (65.7%). Blastocysts vitrified using the LE protocol produced the lowest TCC (115±5.9; P ≤ 0.05), whereas TCC of the SE (152±9.7) and fresh control (138±8.6) treatments were similar. No differences were found in ICM count among groups. Nevertheless, apoptosis index was higher (P ≤ 0.05) in both vitrification groups when compared with fresh control. These results indicate that short equilibration vitrification not only improves VitTrans outcomes but adds efficiency by taking less time to perform. Supported by MCIU, Spain (Project AGL2016-79802-P and Grant BES-2017-081962).

71 VITRIFICATION OF BOVINE OOCYTES IN MEDIA WITH GLYCEROL + ETHYLENE GLYCOL BEFORE AND AFTER IN VITRO MATURATION

2008 ◽  
Vol 20 (1) ◽  
pp. 116
Author(s):  
L. G. Devito ◽  
C. B. Fernandes ◽  
H. N. Ferreira ◽  
F. C. Landim-Alvarenga
Keyword(s):  
Ethylene Glycol ◽  
Liquid Nitrogen ◽  
In Vitro Maturation ◽  
Calf Serum ◽  
Quiescent State ◽  
Developmental Potential ◽  
Immature Oocytes ◽  
Nitrogen Vapor ◽  
Bovine Oocytes

The cryopreservation process aims to keep the cellular metabolism in a quiescent state for an indeterminate length of time. In mammals, oocyte cryopreservation success is important for the establishment of genetic banks. The objective of the present experiment was to evaluate the effect of vitrification on oocyte meiotic ability and the integrity of the metaphase plate in immature and in vitro-matured bovine oocytes. Bovine cumulus–oocytes complexes (COCs) were harvested from slaughterhouse ovaries and randomly divided into 3 groups: (G1) non-vitrified oocytes subjected to in vitro maturation, (G2) immature oocytes vitrified and then subjected to in vitro maturation after warming, and (G3) in vitro-matured oocytes subjected to vitrification. For in vitro maturation, oocytes were incubated for 22 h in 5% CO2 in air in TCM-199 with fetal calf serum, estradiol, LH, FSH, pyruvate, and gentamicin. For vitrification, the oocytes were exposed to the cryoprotectors in three steps: solution 1 containing 1.4 m glycerol in PBS for five min, and then solution 2 containing 1.4 m glycerol and 3.6 m ethylene glycol in PBS for another five min. After exposure to the second solution, the oocytes were transferred to 30-µL drops of solution 3 containing 3.4 m glycerol and 4.6 m ethylene glycol, loaded (5 oocytes per straw) in less than 1 min into 0.25-mL straws between two columns of 0.5 m galactose in PBS separated by two air bubbles, and immediately set in liquid nitrogen vapor. After 1 min of equilibration in liquid nitrogen vapor, the straws were immersed in liquid nitrogen. Warming was performed by holding the straws for 10 s in air, followed by 10 more s in a water bath at 20–22�C. The straws were then shaken 5 to 8 times to mix the bubbles (movement similar to that for a thermometer) and left horizontally for 6 to 8 min at room temperature. The rates of metaphase II and degeneration were analyzed by ANOVA followed by the Student t-test. The oocytes were stained with 100 µg mL–1 Hoechst 33342 and examined in an inverted microscope equipped with fluorescent light (UV filters 535 and 617 mm). Three different routines were realized with a total of 90 oocytes per group. The metaphase II rates in G1 (48/90, 53.3%) and G3 (42/90, 46.6%) were statistically the same (P e 0.05), but were higher (P d 0.05) than in G2 (0/90, 0%). The degeneration rates were: G1 (18/90, 20%), G2 (77/90, 85.6%), and G3 (7/90, 7.8%). The vitrification procedure damaged mainly the immature oocytes, since in the G2 the degeneration rate was higher and the oocytes were not able to resume meiosis. Meanwhile, when oocytes were vitrified after in vitro maturation, the metaphase II rate was similar to the one observed in IVM oocytes not subjected to vitrification. This indicates that the vitrification procedure performed in this experiment did not damage the structure of the metaphase II plate. However, more studies are necessary to predict the developmental potential of these in vitro-matured oocytes.

38 Vitrification of prepubertal lamb spermatogonia using a novel vitrification system

2019 ◽  
Vol 31 (1) ◽  
pp. 145 ◽  
Author(s):  
S. Ledda ◽  
S. Pinna ◽  
S. Nieddu ◽  
D. Natan ◽  
A. Arav ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
In Vitro Culture ◽  
Dimethyl Sulfoxide ◽  
Fertility Preservation ◽  
Testicular Tissue ◽  
Gonadal Tissue ◽  
New Device ◽  
Vitrification Solution ◽  
Tissue Cryopreservation

Vitrification is a method extensively used for preserving oocytes and embryos and is also gaining acceptance for preserving gonadal tissue. Cryopreservation of spermatogonial stem cells is an applicable method for young males seeking fertility preservation before starting a treatment or can be a tool for genetic preservation of rare or high-value animals. The aim of this work was to evaluate the cryopreservation of testicular tissue from young lambs by vitrification using a new device named E.Vit (FertileSafe, Ness Ziona, Israel) that permits all cryopreservation procedures to be performed in straw. The new device consists of a 0.3-mL straw (Cryo Bio System, IMV, L’Aigle, France) with a capsule containing 50-µm pores inserted at one end. Testicular tissue extracts were prepared from testes of slaughtered lambs (n=10, 40 days old), opened by sagittal sectioning with a microblade and collecting small pieces of testicular tissue (1mm3) from the middle part of the rete testis. Three pieces of gonadal tissue were inserted into each E.Vit device. Each straw was sequentially loaded vertically in two 1.5-mL microtubes, which contained the following solutions: first, the equilibrating solution (7.5% dimethyl sulfoxide+7.5% ethylene glycol+20% FCS in TCM-199) for 6min, followed by 90min in the vitrification solution (18% dimethyl sulfoxide+18% ethylene glycol+0.5M Trehalose+BSA in TCM-199). After exposure to the equilibrating solution and vitrification solution, the solutions were removed and the straws were directly loaded into LN2. The warming procedure consisted of placing the straws directly into 5-mL tubes containing 100, 50, and 25% warming solution (1M sucrose in TCM-199+20% FCS) at 38.6°C for 5min each before arrival into the holding medium. Samples were recovered from the straws incubated at 38.6°C in 5% CO2 in air in TCM 199+5% FCS and evaluated at 0 and 2h post-warming for viability using trypan blue staining. Expression of a panel of specific genes (SOD2, HSP90b, BAX, POUF5/OCT4, TERT, CIRBP, KIF11, AR, FSHR) was analysed by real-time PCR in cryopreserved tissue in vitro cultured for 2h post-warming (2hV), in fresh controls immediately after tissue dissection (0hF), and after 2h of in vitro culture (2hF). The majority of cells survived after vitrification, although viability immediately after warming (0hV: 56%±1.45) or after 2h of in vitro culture (IVC) (2hV: 54±7%) was significantly lower compared with non-cryopreserved fresh controls (0hF: 89%±1.45; ANOVA P&lt;0.05). Expression analysis showed specific patterns for the different genes. Notably, BAX transcript abundance was not affected by vitrification or IVC, indicating an acceptable level of stress for the cells. The genes HSP90b and CIRBP were down-regulated in 2hF but increased in 2hV, as expected. Expression of SOD1 and OCT4 was altered by vitrification but not by IVC. Conversely, expression of TERT, KIF11, and AR was affected by both IVC and cryopreservation (ANOVA P&lt;0.05). This novel protocol for testicular tissue cryopreservation of prepubertal animals may be a promising strategy for fertility preservation and can contribute as a new approach in the development of large-scale biodiversity programs.

Forskolin effect on the cryosurvival of in vitro-produced bovine embryos in the presence or absence of fetal calf serum

Zygote ◽  
2012 ◽  
Vol 22 (2) ◽  
pp. 146-157 ◽  
Author(s):  
Daniela Martins Paschoal ◽  
Mateus José Sudano ◽  
Midyan Daroz Guastali ◽  
Rosiára Rosária Dias Maziero ◽  
Letícia Ferrari Crocomo ◽  
...  
Keyword(s):  
Culture Medium ◽  
Fetal Calf Serum ◽  
Calf Serum ◽  
Similar Rate ◽  
Bovine Embryos ◽  
Embryo Survival ◽  
Vitrification Solution ◽  
Oviductal Fluid

SummaryThe objective of this study was to assess the viability and cryotolerance of zebu embryos produced in vitro with or without the addition of fetal calf serum (FCS) and forskolin (F). Embryos produced in vivo were used as a control. Presumptive zygotes were cultured in modified synthetic oviductal fluid supplemented with amino acids (SOFaa), bovine serum albumin (BSA) and with (2.5%) or without (0%) FCS. On day 6 of growth, the embryos from each group were divided into treatments with or without 10 μM F to induce embryonic lipolysis, comprising a total of four experimental groups: 2.5% FCS, 0% FCS, 2.5% + F and 0% + F. For vitrification, embryos were exposed to vitrification solution 1 (5 M EG (ethylene glycol)) for 3 min and then transferred to vitrification solution 2 (7 M EG, 0.5 M galactose solution and 18% (w/v) Ficoll 70) before being introduced to liquid nitrogen. The presence of FCS in the culture medium resulted in the production of embryos with a similar rate of damaged cells compared with in vivo-produced embryos. After vitrification, the 2.5% FCS group had a significantly higher rate of damaged cells when compared with the other groups (P < 0.05). The results of this experiment indicated that the omission of FCS and the addition of forskolin do not have deleterious effect on embryo production rates. In addition, embryos produced in the presence of FCS had greater sensitivity to cryopreservation, but this effect was reversed when forskolin was added to the medium, which improved embryo survival without affecting embryo development and quality after vitrification.

scholarly journals 86COMPARISON OF TWO VITRIFICATION PROTOCOLS FOR CROSSBRED BOS INDICUS×BOS TAURUS IN VITRO-PRODUCED EMBRYOS

2004 ◽  
Vol 16 (2) ◽  
pp. 164 ◽  
Author(s):  
L.S.A. Camargo ◽  
R.S. Oliveira ◽  
J.H.M. Viana ◽  
W.F. Sá ◽  
A.M. Ferreira ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Liquid Nitrogen ◽  
Bos Indicus ◽  
Cumulus Cells ◽  
Dairy Herds ◽  
Hatching Rate ◽  
Humid Atmosphere ◽  
Significant Difference ◽  
Vitrification Solution

Dairy herds in tropical countries are often maintained as crossbred B. indicus×B. taurus hybrids to take advantage of heterosis, such as resistance to heat stress. Creating crossbred B. indicus×B. taurus embryos by in vitro methods may offer a means of rapidly improving tropical dairy herds, especially if the embryos can be cryopreserved. The aim of this study was to compare the viability of in vitro-produced crossbred B. indicus×B. taurus embryos (1/2, 3/4) using two vitrification solutions and equilibration/dilution temperatures. Cumulus-oocyte complexes were aspirated from purebred B. indicus and crossbred (B. indicus×B. taurus hybrid) ovaries, matured in vitro, and fertilized with spermatozoa collected from a Holstein bull. Presumptive zygotes were co-cultured in CR2aa medium with cumulus cells, in a humid atmosphere of 5% CO2-air at 38.8°C. On day 7 of co-culture, embryos were assessed and classified as good or excellent, and those at the appropriate developmental stage were vitrified using one of two vitrification solutions, a mixture of either glycerol/ethylene glycol (GE) or dimethylsulphoxide/ethylene glycol (DE). Embryos (n=34) assigned to GE vitrification were equilibrated in a medium of PBS+20% FCS (HM1) containing 10% v/v G for 5min, followed by 10% v/v G+20% v/v E for 5min., and then transferred to a vitrification solution of 25% v/v G+25% v/v E in HM1 for 30s. The embryos were immediately aspirated into an Open Pulled Straw (OPS) and plunged into liquid nitrogen. Embryos vitrified in GE were warmed by immersing the OPS in HM1 containing 1M sucrose for 1min (37°C), then stepwise diluted in fresh HM1 containing 1M, 0.5M, and 0.25M sucrose for 5min; and finally washed in HM1. Stepwise equilibration and dilution of GE embryos was at 20°C. Embryos (n=43) assigned to DE vitrification were equilibrated in a medium of PBS+5% FCS (HM2) containing 10% v/v D+10% v/v E for 1min, and then transferred to a vitrification solution of 20% v/v D+20% v/v E in HM2 for 30s. The embryos were immediately aspirated into an Open Pulled Straw (OPS) and plunged into liquid nitrogen. Embryos vitrified in DE were warmed by immersing the OPS in HM2 containing 0.25M sucrose for 1min (39°C), then stepwise diluted in fresh HM2 containing 0.25M and 0.15M sucrose for 5min, and finally washed in HM2. Stepwise equilibration and dilution of DE embryos was at 39°C. Diluted embryos from both groups and untreated control embryos (n=49) were cultured in TCM-199 with monolayer granulosa cells for 72h in conditions described above. Blastocyst re-expansion and hatching was assessed and analyzed by chi-square test. Overall, 67% of the thawed embryos were expanded blastocysts (remainder were blastocysts) and 56% were excellent quality (remainder were good). No significant difference (P&gt;0.05) was found between the rates of blastocyst re-expansion and hatching for the GE and DE vitrification procedures (respectively, 59 and 79%, and 41 and 58%). However the hatching rate of control embryos (77%) was significantly higher than that of vitrified embryos (P&lt;0.05). These results indicate that both vitrification procedures are promising for the cryopreservation of crossbred B. indicus×B. taurus in vitro-produced embryos. Supported by CNPq.

scholarly journals 113COMPARISON OF TWO ETHYLENE GLYCOL EQUILIBRATION TREATMENTS FOR THE QUICK FREEZING OF IN VITRO-PRODUCED BOVINE EMBRYOS

2004 ◽  
Vol 16 (2) ◽  
pp. 178
Author(s):  
A.C. Nicácio ◽  
R. Simões ◽  
C. Yamada ◽  
H.V.A. Caetano ◽  
M.R.B. Mello ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Liquid Nitrogen ◽  
Granulosa Cell ◽  
Cell Monolayer ◽  
Slow Freezing ◽  
Bovine Embryos ◽  
Treatment Groups ◽  
Quick Freezing ◽  
Hatching Rates

The aim of this study was to compare two ethylene glycol (EG) equilibration procedures for the quick freezing of in vitro-produced bovine embryos. Cumulus-oocyte complexes (COCs) were collected from slaughterhouse ovaries. COCs were matured in TCM199 containing 10% of bovine fetal serum, LH, FSH and E2, and fertilized. Presumptive zygotes were co-cultured in TCM199 with a granulosa cell monolayer, at 39°C in humidified atmosphere of 5% CO2 in air. Grade 1, expanded blastocysts (n=761) were selected 7 and 9 days after insemination and randomly distributed to one of eight treatment groups. In Equilibration Procedure 1, embryos were exposed to 10% EG for 5 min, and then to 17%, 22% or 28% EG for 60s (respectively referred to as EG 17, EG 22 and EG 28). In Equilibration Procedure 2, embryos were exposed to the same EG solutions as in Equilibration Procedure 1, but the period of exposure was 10min to 10% EG and 30 s to EG 17, EG 22 and EG 28. In Equilibration Procedure 3 (slow-freezing controls), embryos were exposed to 10% EG for either 5 or 10min and then cryopreserved by slow-freezing method at 1.2°C/min. In all treatment groups, EG solutions were prepared in PBS+0.2% BSA, and embryos were exposed to EG solutions at 22°C. Embryos were loaded into 0.25mL straws and heat-sealed. Straws were cooled in liquid nitrogen vapor for 2min, and then plunged into and stored in liquid nitrogen. Straws were thawed in room temperature air for 10s, and then in 25°C water for 20s. Thawed embryos were diluted by transferring them into 0.5ml of PBS+0.2% BSA+0.3M sucrose for 3min, and then 0.5mL of PBS+0.2% BSA for 3min. Embryos were co-cultured on granulosa cell monolayer in TCM199 and evaluated after 24h for blastocyst re-expansion (EXP), and again at 48, 72 and 96h for hatching (HAT). A total of 724 in vitro-produced bovine blastocysts were used as controls to determine hatching rates. The results are presented in the table. Embryos exposed to 10% EG for 10min (Equilibration Procedure 1) yielded significantly higher rates of blastocyst re-expansion and hatching when compared to embryos exposed for 5min (Equilibration Procedure 2, P&lt;0.05). These results suggest that quick freezing of in vitro-derived bovine embryos may be an alternative to vitrification; however, additional studies are needed to optimize cryopreservation protocols and increase post-thaw survival. This project was supported by FAPESP (01/11266-4) Table 1 Effect of equilibration procedure on in vitro re-expansion and hatching rates of embryos cryopreserved by slow and quick freezing methods

Vitrication of in vitro produced bovine embryos at different ages using one- and three-step addition of cryoprotective additives

1997 ◽  
Vol 9 (7) ◽  
pp. 741 ◽  
Author(s):  
S. Saha ◽  
T. Suzuki
Keyword(s):  
Survival Rate ◽  
Ethylene Glycol ◽  
Hatching Rate ◽  
Bovine Embryos ◽  
Different Ages ◽  
One Step ◽  
Vitrification Solution ◽  
Hatching Rates

The effect of embryo age on development and ratio of live : dead cells after vitrication and warming was examined. One-step and three-step addition of cryoprotectants in vitrification solution (40% ethylene glycol, 0·3 M trehalose and 12% polyvinylpyrrolidone) were compared usingin vitro produced (IVP) bovine blastocysts and expanded blastocysts. Rates of development and hatching were 74 ·2% and 41· 9% for Day 7, 57·8% and 23· 8% for Day 8, 33· 7% and 6·1% for Day 9 embryos with one-step addition. In three-step addition, those rates were 86·2% and 77·3% for Day 7, 72·3% and 39·0% for Day 8, 47·3% and 10·5% for Day 9 embryos. Day 7 embryos showed highest (P < 0·01) development and hatching rates with one exception. Hatching rate of Day 7 embryos with three-step addition was higher (P < 0·01) than with one-step addition. The ratio of live : dead cells differed between one-step (94%) and three-step (97%) additions for Day 7 embryos (P < 0· 05). The results indicate the higher resistance of younger IVP bovine embryos against vitrication and the potential for three-step addition of cryoprotectants to yield a higher survival rate after warming than with one-step addition.

80 EFFECT OF PRE-EQUILIBRATION TIME ON THE SURVIVAL RATE OF IN VITRO-FERTILIZED BOVINE EMBRYOS AFTER VITRIFICATION

2008 ◽  
Vol 20 (1) ◽  
pp. 120 ◽  
Author(s):  
H. Koyama ◽  
A. H. Sugulle ◽  
O. Dochi
Keyword(s):  
Calf Serum ◽  
Equilibration Time ◽  
Bovine Embryos ◽  
Chi Square ◽  
Chi Square Test ◽  
Vitrification Solution ◽  
Short Time ◽  
Further Development ◽  
Hatching Rates

Successful cryopreservation of embryos depends on the pre-equilibration time. This study was designed to compare 2 pre-equilibration times – short (1 min) and long (5 min) – and to evaluate the re-expansion and hatching rates of different stages of embryos using the short pre-equilibration method. Cumulus–oocyte complexes (COCs) from ovaries obtained from a slaughterhouse were matured, fertilized, and cultured in vitro. In Experiment 1, expanded blastocysts between 7 and 9 days of culture were pre-equilibrated for the short time (1 min) in 100 μL of vitrification solution 1 (VS1: containing 7.5% ethylene glycol (EG), 7.5% dimethyl sulfoxide (DMSO), and 20% calf serum (CS) in TCM-199), followed by incubation in 100 μL of vitrification solution 2 (VS2: containing 15% EG, 15% DMSO, 20% CS, and 1 m sucrose (Suc) in TCM-199) for 30 s. Another group of blastocysts was subjected to the long pre-equilibration (5 min) in 100 μL VS1, followed by incubation in 100 μL of VS2 for 30 s. The embryos were placed into Cryotops® (Kitasato Supply Co., Tokyo, Japan) and immediately submerged in liquid nitrogen and kept there for 1 week. Blastocysts were warmed by plunging the Cryotops into 1 m Suc in TCM-199 for 1 min, placed in 0.5 m Suc in TCM-199 for 3 min, and finally placed in CR1aa alone for 5 min before being cultured. In Experiment 2, 8-cell embryos, morulae, and expanded blastocysts were vitrified by the previously described short equilibration method. The re-expansion and hatching rates of embryos were determined as the percentage of vitrified–warmed embryos undergoing further development in the in vitro culture. The data were analyzed by the chi-square test. Results are presented in Table 1. There was no difference between the short and long pre-equilibration times in terms of survival (94.0% v. 94.1%, respectively) and morphological appearance immediately after warming. However, re-expansion of blastocysts (ability to develop further) was slightly higher with the short pre-equilibration than with the long pre-equilibration (90.0% v. 85.9%, respectively). In Experiment 2, there were no differences in embryo re-expansion, but the hatching rates of 8-cell embryos were lower than those of morulae, blastocysts, and controls. In conclusion, the results of this study indicate that the length of pre-equilibration time prior to vitrification does not influence embryo re-expansion, and that bovine morulae and blastocysts can be vitrified with equal success. We also conclude that insufficient permeation of cryoprotectants may occur in 8-cell embryos. Table 1. Survival and hatching rates of vitrified bovine embryos after warming

43 MASS VITRIFICATION OF GERMINAL-VESICLE STAGE EQUINE OOCYTES

2016 ◽  
Vol 28 (2) ◽  
pp. 151
Author(s):  
H. S. Canesin ◽  
I. Ortiz ◽  
J. G. Brom-de-Luna ◽  
Y. H. Choi ◽  
K. Hinrichs
Keyword(s):  
Ethylene Glycol ◽  
Dimethyl Sulfoxide ◽  
Bovine Serum ◽  
In Vitro Maturation ◽  
Fetal Bovine Serum ◽  
Control Group ◽  
Cleavage Rate ◽  
Fetal Bovine ◽  
Vitrification Solution

Oocyte cryopreservation has the potential to preserve female genetics. In addition, equine oocytes are not readily available in some areas, and vitrification could be used to accumulate oocytes at remote locations to provide material for research. To preserve large numbers of oocytes, a method for rapid vitrification of multiple oocytes is needed. First, we determined whether immature equine oocytes could be held overnight before vitrification, and we tested the use of a mesh+capillary-action media-removal vitrification platform. Oocytes were collected via ultrasound-guided transvaginal follicle aspiration and randomly allotted to either immediate vitrification or overnight holding (24 to 27 h in 40% M199-Earle’s salts, 40% M199-Hanks’ salts, 20% fetal bovine serum, and 0.3 mM pyruvate) then vitrification. Oocytes were vitrified using different times (1 or 4 min) in vitrification solution and first warming solution: 1v1w, 1v4w, 4v1w, and 4v4w. The base solution was MH (80% M199-Hanks’ salts and 20% fetal bovine serum). Cryoprotectant concentration (vol/vol) was increased in 3 steps until reaching 7.5% dimethyl sulfoxide and 7.5% ethylene glycol. The oocytes were then held in vitrification solution (MH with 15% dimethyl sulfoxide, 15% ethylene glycol, and 0.5 M sucrose) for either 1 or 4 min, according to treatment, and 3 to 10 oocytes were transferred to a 75-μm sterile stainless steel mesh. The mesh was placed on sterile paper to absorb excess medium, then plunged in LN. The oocytes were warmed in MH solution with 1.25 M sucrose for either 1 or 4 min, then placed in 0.62 M and 0.31 M sucrose solutions for 5 min each and undetermined time in MH. After warming, oocytes were cultured for maturation (in vitro maturation) in M199-Earle’s salts, 5 mU mL–1 FSH, and 10% fetal bovine serum. After 30 to 36 h, the oocytes were denuded and stained with Hoechst 33258. Data were analysed by Fisher’s exact test. There were no significant differences (P > 0.05) in rates of meiotic resumption among timing treatments (35, 24, 26, and 39% for 1v1w, 1v4w, 4v1w, and 4v4w, respectively), nor between immediately vitrified (17/55, 31%) and overnight held-vitrified groups (18/56, 32%). In the second experiment, all oocytes were held overnight. They were vitrified and warmed using only the 1v1w and 4v4w schedules, then subjected to in vitro maturation, intracytoplasmic sperm injection, and embryo culture. The MII rate of the control group (27/37, 73%) was higher (P < 0.05) than that for 1v1w (12/33, 36%) or 4v4w treatments (10/35, 29%). The cleavage rate for control (25/27, 93%) was higher than that for 1v1w (5/9, 56%) but not than that for 4v4w (6/9, 67%). Blastocyst rates were 19% (5/27), 11% (1/9), and 0% (0/9) for control, 1v1w, and 4v4w, respectively (P > 0.05). These results indicate that blastocysts may be produced from equine immature oocytes vitrified en masse; however, both the maturation and blastocyst production rates were relatively low. Additional studies are required to improve the efficiency of this technique. This work was supported by the Clinical Equine ICSI Program, Texas A&M University.

49 SUCCESSFUL CRYOPRESERVATION USING LOW ETHYLENE GLYCOL CONCENTRATION FOR IN VITRO-PRODUCED BOVINE EMBRYOS

2017 ◽  
Vol 29 (1) ◽  
pp. 132
Author(s):  
M. Takayama ◽  
S. Sato ◽  
Y. Nishimura ◽  
K. Imai ◽  
O. Dochi
Keyword(s):  
Ethylene Glycol ◽  
Calf Serum ◽  
Bovine Embryos ◽  
Embryo Survival ◽  
Lower Survival Rate ◽  
Treatment Groups ◽  
Chi Squared ◽  
Hatching Rates

In vitro-produced (IVP) bovine embryos tend to have a lower survival rate after cryopreservation than in vivo embryos do. Therefore, the freezing medium (FM) and concentration of cryoprotectant are very important factors. This study was to investigate the effect of 1.2 M ethylene glycol (EG) with 0.1 M sucrose (SUC) on survival of IVP embryos after freezing. The COC were matured in 25 mM HEPES-buffered TCM199 (TCM199) supplemented with 5% calf serum (CS) and 0.02 AU mL−1 FSH. Oocytes (20 to 25) were cultured in 100-μL droplets of maturation medium for 20 h. After 6 h of gamete co-culture (5 × 106 sperm/mL), the presumptive zygotes were cultured in CR1aa medium supplemented with 5% CS for 9 days (fertilization = Day 0). Only the expanded blastocysts from Days 7 to 9 were used in this experiment and separated into 3 treatment groups. The first and second groups were frozen in Dulbecco’s phosphate-buffered saline (D-PBS) supplemented with 20% CS, 0.1 M SUC, and 1.2 or 1.5 M EG (groups 1.2 or 1.5 M EG), respectively. The third group was D-PBS supplemented with 20% fetal calf serum (FCS), 0.25 M SUC, and 1.4 M glycerol (group GLY). In each group, embryos were equilibrated with their FM for 10 min and loaded into 0.25-mL straws individually. These straws were placed into the cooling chamber of a programmable freezer precooled to −7°C. After 2 min, the straws were seeded and then held for a further 13 min at −7°C. Then, the straws were cooled to −30°C at −0.3°C/min before being plunged into liquid nitrogen. The cryopreserved embryos were thawed by allowing the straws to stand in air for 7 s and then warming them in a 30°C water bath for 20 s. The thawed embryos were washed twice using 38°C D-PBS supplemented with 20% FCS. Subsequently, they were immersed in the same medium, held at 38°C for 10 min, and then each embryo was cultured in 20-μL droplets of TCM199 supplemented with 20% FCS and 0.1 mM β-mercaptoethanol for 72 h. The rates of embryos developing to the re-expanded and hatching blastocyst stages were determined 72 h after thawing. All data were analysed by the chi-squared test with Yates’ correction. The re-expanded and hatching rates of frozen-thawed embryos after 72 h in culture were not significantly different between 1.2 M EG (n = 39: 71.8% and 69.2%), 1.5 M EG (n = 38: 76.3% and 63.2%), and 1.4 M GLY (n = 37: 75.7% and 64.9%) groups (P > 0.05). Survival and hatching rates according to embryo quality were also not significantly different between 1.2 M EG (good n = 18: 88.9% and 88.9%; fair n = 21: 57.1% and 52.4%), 1.5 M EG (good n = 19: 89.5% and 84.2%; fair n = 19: 63.2% and 42.1%), and 1.4 M GLY (good n = 18: 77.8% and 66.7%; fair n = 19: 73.7% and 63.2%) (P > 0.05). In conclusion, cryoprotectant type and concentration did not affect embryo survival or development after cryopreservation in this study. Therefore, the ethylene glycol concentration used for the cryopreservation of IVP embryos can be reduced.

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