29 Cryopreservation by slow freezing of bovine in vitro embryos in different stages of development

2022 ◽  
Vol 34 (2) ◽  
pp. 249
Author(s):  
L. R. Peixoto ◽  
B. L. Cardoso ◽  
N. J. Lopes ◽  
B. A. P. Maiollo ◽  
M. F. A. Borges ◽  
...  
Keyword(s):  
Slow Freezing ◽  
Stages Of Development

50 SURVIVAL OF SEXED IVF-DERIVED BOVINE EMBRYOS FROZEN AT DIFFERENT PREIMPLANTATION STAGES OF DEVELOPMENT

2017 ◽  
Vol 29 (1) ◽  
pp. 132
Author(s):  
L. Ferré ◽  
C. Fresno ◽  
M. Kjelland ◽  
P. Ross
Keyword(s):  
Cytochalasin B ◽  
Cell Monolayer ◽  
Cumulus Cell ◽  
Slow Freezing ◽  
Treatment Level ◽  
Bovine Embryos ◽  
Low Oxygen ◽  
Stages Of Development ◽  
Cell Layers

The ability to freeze in vitro-produced bovine embryos with a high post-thaw viability is still problematic and hampers logistics of on-farm embryo transfer. The objectives of this experiment were to compare different stages of development, freezing methods, and addition of cytoskeletal stabilisers (cytochalasin-B) before freezing. Ovaries were collected from an abattoir and oocytes aspirated from 2- to 6-mm follicles. Cumulus-oocyte complexes containing compact and complete cumulus cell layers were selected and matured in groups of 50 in 400 µL of M199 medium supplemented with ALA-glutamine (0.1 mM), Na pyruvate (0.2 mM), gentamicin (5 µg mL−1), EGF (50 ng mL−1), ovine FSH (50 ng mL−1), bLH (3 µg mL−1), cysteamine (0.1 mM), and 10% fetal bovine serum (FBS) for 22 to 24 h. Fertilization (Day 0) was done using female sex-sorted semen selected with a discontinuous density gradient and diluted to a final concentration of 1 × 106 sperm/mL. Synthetic oviductal fluid (SOF)-FERT medium was supplemented with fructose (90 µg mL−1), penicillamine (3 µg mL−1), hypotaurine (11 µg mL−1), and heparin (20 µg mL−1). After 18 h, presumptive zygotes were denuded and cultured in groups of 15 to 20 in 50-µL drops of SOF-BSA for 7 days. On Day 3.5 post-fertilization, 3% FBS was added. Low oxygen tension (5% O2) was used for culture. Morulae were selected at Day 5.5–6, blastocysts at Day 6–6.5, and expanded blastocysts at Day 6.5–7. Embryo harvesting for each stage was performed from a dedicated drop/dish and discarded in order to avoid further embryo stage collections. Grade 1 morulae, blastocysts, and expanded blastocysts were selected for freezing and placed randomly into 2 groups: slow-freezing and vitrification. Before freezing, half of the embryos from each stage were exposed to cytochalasin-B for 45 min. The slow freezing protocol consisted of 1.5 M ethylene glycol (EG) + 20% FBS + 0.4% BSA, and the cooling rate was 0.5°C/min. Slow-frozen embryo thawing was performed by exposing the 0.25-mL straws to air (23°C) for 10 s and then underwater at 35°C for 1 min. The vitrification (Cryo-Top) medium was 15% (vol/vol) EG + propylene glycol. Vitrified embryos were thawed in a solution of H199 + 20% FBS and 0.25 M sucrose at 39°C. Thawed embryos from both groups were cultured in SOF-BSA + 10% FBS under cumulus/granulosa cell monolayer co-culture. Embryo assessment involved post-thaw survival (0 h), re-expansion, and hatching of the zona pellucida (72 h). Three replicates were performed for each treatment level. Fisher’s l.s.d. test with Bonferroni correction was used to determine treatment differences (P < 0.05). The post-thaw survival, re-expansion, and hatching results showed that either expanded blastocysts (84.7 ± 3.2%, 74.1 ± 3.9%, and 60.9 ± 4.4%) or blastocysts (81.7 ± 3.5%, 69.6 ± 4.2%, and 55 ± 4.6%) were preferred (P < 0.05) embryo stages for cryopreservation compared with morulae (67.6 ± 4.4%, 52.5 ± 4.6%, and 33.2 ± 4.3%). Vitrification and cytochalasin-B pre-freezing exposure (61.3 ± 3.6% and 56.6 ± 3.8%) provided better (P < 0.05) hatching results compared with slow-freezing and without cytochalasin-B (37.8 ± 3.6% and 42.5 ± 3.7%).

31 Evaluation of in vitro-produced bovine embryos with conventional and SexedULTRA-4M X and Y chromosome-bearing semen: survival after slow freezing for direct transfer

2022 ◽  
Vol 34 (2) ◽  
pp. 250
Author(s):  
H. Álvarez-Gallardo ◽  
M. Kjelland ◽  
M. Pérez-Martínez ◽  
A. Velázquez-Roque ◽  
F. Villaseñor-González ◽  
...  
Keyword(s):  
Y Chromosome ◽  
Slow Freezing ◽  
Direct Transfer ◽  
Bovine Embryos

P-444 Presence of pharmacological inhibitors of the PI3K/PTEN/Akt and mTOR signalling pathways during cryopreservation and organotypic cultures of murine ovaries limits early primordial follicle depletion

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
C Terren ◽  
M Nisolle ◽  
C Munaut
Keyword(s):  
In Vitro Culture ◽  
Organotypic Culture ◽  
Primordial Follicle ◽  
Slow Freezing ◽  
Signalling Pathways ◽  
Primordial Follicle Activation ◽  
Mtor Signalling ◽  
Follicle Activation

Abstract Study question Which signalling pathways are implicated in primordial follicle activation induced by cryopreservation and/or organotypic culture? Is it possible to limit this activation through pharmacological inhibitors? Summary answer Our findings provide support for the hypothesis that mTOR and PI3K inhibitors might represent an attractive tool to delay cryopreservation- and culture-induced primordial follicle activation. What is known already Cryopreservation of ovarian tissue containing immature primordial follicles followed by auto-transplantation (OTCTP) is the only option available to preserve the fertility of prepubertal patients or patients requiring urgent therapy for aggressive malignancies. However, a major obstacle in this process is follicular loss immediately after grafting, possibly due to slow neovascularization, apoptosis and/or massive follicular recruitment. In vitro and in vivo studies indicate that the PI3K/PTEN/Akt and mTOR signalling pathways are involved in follicle activation. The transplantation process seems to be the major cause of primordial follicle activation after OTCTP but information about how cryopreservation itself impacts follicle activation is sparse. Study design, size, duration Whole murine ovaries (4-8-weeks old) were cryopreserved by slow freezing and exposed to LY294002 (a powerful PI3K inhibitor) or rapamycin (a specific mTOR inhibitor) during cryopreservation and/or organotypic in vitro culture for a 24 h or 2 days. Participants/materials, setting, methods Western Blot and immunofluorescence analyses were used to determine the activation of PI3K/PTEN/Akt and mTOR signalling pathways in murine ovaries cryopreserved and/or organotypically cultured with/without inhibitors.Follicles were quantified according to their maturation degree on H&E stained histological sections.  Main results and the role of chance Ratio of phosphorylated Akt or rps6 to total proteins (p-Akt/Akt and p-rps6/rps6) was increased in slow-frozen murine ovaries compared to control fresh ovaries, indicating an activation of the PI3K/PTEN/Akt and mTOR signalling pathways. The use of pharmacological inhibitors of follicle signalling pathways (LY294002 (25µM) and rapamycin (1µM)) during the cryopreservation process decreased p-Akt/Akt and p-rps6/rps6 ratios. In vitro organotypic culture for 24 h increased only the activation of the PI3K/PTEN/Akt pathway, as shown by increased p-Akt/Akt ratio in fresh ovaries cultured for 24 h compared to fresh non-cultured ovaries. This activation can be counteracted by cryopreservation of murine ovaries with rapamycin followed by in vitro culture for 24 h in the presence of LY294002. Follicle density quantifications indicated that when cryopreserved ovaries were maintained in culture for 2 days, a decrease of primordial follicle density concomitant with an increase of secondary and more mature follicles were found in comparison to slow-frozen/thawed ovaries without culture. Supplementation of the culture medium with LY294002 and rapamycin for 24 h or 2 days preserved primordial follicle densities compared to ovaries cultured without inhibitors. Limitations, reasons for caution This study is an in vitro study using murine ovaries. To analyze the efficiency of LY294002 and rapamycin to limit cryopreservation and transplantation induced follicle recruitment, these inhibitors should be tested in an in vivo model. Furthermore, these findings will need to be confirmed with human samples. Wider implications of the findings We showed for the first-time that the sequential use of pharmacological inhibitors, rapamycin during the slow freezing process followed by organotypic culture supplemented with LY294002, is effective to limit early primordial follicle depletion. Trial registration number /

Special Problems of Experimenting in ovo on the Early Chick Embryo, and a Solution

Development ◽  
1960 ◽  
Vol 8 (4) ◽  
pp. 369-375
Author(s):  
P. H. S. Silver
Keyword(s):  
Chick Embryo ◽  
Short Term ◽  
Stages Of Development ◽  
In Ovo ◽  
Technical Problems ◽  
Early Chick Embryo ◽  
In Vitro Methods ◽  
Early Stages

It seems to be generally accepted that experimenting in ovo on the chick during the early stages of development (up to about 48 hours) is fraught with the greatest difficulty. After about this time no serious technical problems arise and a high proportion of successful results can be expected. It is natural to ask why there should be this change-over from extreme difficulty to reasonable simplicity. New (1955) attributed to this ‘inaccessibility of the chick embryo in the egg’ the invention of his own and many other in vitro methods during the last 30 years. There is no doubt that, when short-term experiments only are required, in vitro methods will probably always be preferred. But all in vitro methods suffer from the disadvantage that the embryo cannot be expected to survive for more than 48 hours or so after explantation.

scholarly journals In vitro survival of follicles in prepubertal ewe ovarian cortex cryopreserved by slow freezing or non-equilibrium vitrification

2019 ◽  
Vol 36 (9) ◽  
pp. 1823-1835 ◽  
Author(s):  
Yann Locatelli ◽  
L. Calais ◽  
N. Duffard ◽  
L. Lardic ◽  
D. Monniaux ◽  
...  
Keyword(s):  
Slow Freezing ◽  
Ovarian Cortex ◽  
In Vitro Survival ◽  
Non Equilibrium

111 SLOW FREEZING AND VITRIFICATION OF IN VITRO-MATURED DOMESTIC CAT OOCYTES

2007 ◽  
Vol 19 (1) ◽  
pp. 173 ◽  
Author(s):  
J. Braun ◽  
C. Otzdorff ◽  
T. Tsujioka ◽  
S. Hochi
Keyword(s):  
Polar Body ◽  
Blastocyst Stage ◽  
Domestic Cat ◽  
Slow Freezing ◽  
Developmental Potential ◽  
Freezing Medium ◽  
First Polar Body ◽  
Blastocyst Rate ◽  
Chi Square Analysis

The effects of slow freezing or vitrification as well as exposure to the cryoprotective media without cooling and warming of in vitro-matured domestic cat oocytes on the in vitro development to the blastocyst stage was investigated. Cumulus–oocyte complexes were matured for 24 h in TCM-199 supplemented with 3 mg mL−1 BSA, 1 µg mL−1 estradiol, 0.1 IU mL−1 FSH, and 0.0063 IU mL−1 LH. Denuded oocytes with a detectable first polar body were inseminated with 2 × 106 cells mL−1 cauda epididymal spermatozoa for 22 h in TALP solution. Presumptive zygotes were cultured in modified SOF medium at 38.5°C in 5% CO2 in air. For slow freezing, oocytes were equilibrated for 20 min at ambient temperatures in PBS with 20% FCS containing either 1.5 M ethylene glycol (EG) + 0.2 M sucrose or 1.5 M EG + 0.2 M trehalose. Oocytes were loaded into 0.25-mL straws, cooled to −7°C at 2°C min, held for 5 min, seeded, cooled down to −30°C at 0.3°C min, and finally plunged into liquid nitrogen. The straws were thawed for 5 s at room temperature and for 30 s in a waterbath at 30°C. Oocytes were washed 3 times before insemination. In vitro-matured oocytes were exposed to the cryoprotective media for 30 min before they were inseminated and then they were cultured for 7 days. For vitrification (Hochi et al. 2004 Theriogenology 61, 267–275), a minimum-volume cooling procedure using Cryotop (Kitazato Supply Co., Tokyo, Japan) as a cryodevice was applied. No blastocysts could be obtained after slow freezing with a cryoprotective medium containing 0.2 M sucrose. Simple exposure to the same freezing medium after in vitro maturation without cryopreservation resulted in a blastocyst rate of 7.9% (control oocytes, 10.7%; not significant (NS); chi-square analysis). Use of trehalose as an extracellular cryoprotectant resulted in the harvest of one blastocyst (0.6%) after slow freezing. Exposure to the same cryoprotective medium resulted in a blastocyst rate of 10.0% (fresh control, 10.9%; NS). After exposure of in vitro-matured oocytes to the vitrification solution, a blastocyst rate of 16.0% was observed (8/50), which was not statistically different from the blastocyst rate in fresh control oocytes (16.3%; 15/92). No blastocysts could be obtained after vitrification (0/64). The results (Table 1) demonstrate that there is no obvious toxic effect of the cryoprotectants employed here for slow freezing or vitrification on the in vitro-matured oocytes, but the developmental potential of cryopreserved oocytes to the blastocyst stage is severely impaired. Table 1. Effect of slow freezing or exposure to freezing medium of matured cat oocytes on the development to the blastocyst stage in vitro

193 IMPROVED POST-THAW SURVIVAL OF BOVINE EMBRYOS PRODUCED IN SERUM-FREE IN VITRO PRODUCTION SYSTEM

2016 ◽  
Vol 28 (2) ◽  
pp. 227
Author(s):  
M. Nõmm ◽  
E. Mark ◽  
O. Sarv ◽  
S. Kõks ◽  
Ü. Jaakma
Keyword(s):  
Survival Rates ◽  
Slow Freezing ◽  
In Vitro Fertilisation ◽  
Ministry Of Education ◽  
In Vitro Production ◽  
Freezing And Thawing ◽  
Embryo Survival ◽  
Serum Free

Over a few decades the bovine in vitro embryo production (IVP) systems have been improving rapidly. Still, the goal to produce the same quality embryos in vitro as in vivo has not yet been reached. The FCS is usually added to media during IVP to provide growth factors and energy sources. Currently, serum-free culture systems are often preferred due to the lower risk of contamination and prevention of the development of large offspring syndrome. The aim of this study was to establish whether complete elimination of FCS from the bovine IVP system has an effect on blastocyst rates, embryo quality, and embryo survival rates after slow freezing. We replaced our conventional in vitro maturation (IVM) medium [tissue culture medium-199, 10% (v/v) FCS, 10 µg mL–1 epidermal growth factor (EGF), 1500 U mL–1 serum gonadotropin and chorionic gonadotropin (PG600), Na-pyruvate 0.5 mM, gentamycin sulfate 50 µg mL–1 and l-glutamine 1 mM] with SOF (SOFaaci) supplemented with 0.4% fatty acid-free BSA fraction V, 10 µg mL–1 EGF, and 1500 U mL–1 PG600. Matured cumulus-oocyte complexes (COC) from both experimental groups (total of 1145 from serum-free IVP and 687 from our conventional IVP system) were used for in vitro fertilisation and culture. Blastocyst rates were similar in the serum-free and our usual IVP protocol, 18 and 22%, respectively. Seventy-seven Grade 1 (according to IETS) Day 7 blastocysts from the serum-free IVP system and 80 Grade 1 Day 7 blastocysts from our conventional IVP system were frozen in 1.5 M ethylene glycol and 0.1 M sucrose containing cryopreservation medium. The post-thaw survival rates after 24 h of culture and evaluated as percentages of re-expanded embryos were 63.6% for the serum-free IVP and 46.3% for the conventional IVP system (P < 0.05, Z Test for 2 population proportions). These results indicate that it is possible to have a completely serum-free bovine IVP system and based on the slow freezing and thawing results the quality of serum-free IVP embryos might be better than of the embryos matured in our conventional maturation media. However, more experiments and increased sample sizes are needed to confirm the results. This study was supported by Project 3.2.0701.12–0036 of Archimedes Foundation, AP 2.4 of CCRMB, and institutional research funding (IUT 08–01) of the Estonian Ministry of Education and Research.

Developmental Potential of Human Oocytes After Slow Freezing or Vitrification: A Randomized In Vitro Study Based on Parthenogenesis

2008 ◽  
Vol 15 (10) ◽  
pp. 1027-1033 ◽  
Author(s):  
Alessio Paffoni ◽  
Federica Alagna ◽  
Edgardo Somigliana ◽  
Liliana Restelli ◽  
Tiziana A. L. Brevini ◽  
...  
Keyword(s):  
In Vitro Study ◽  
Vitro Study ◽  
Slow Freezing ◽  
Developmental Potential ◽  
Human Oocytes
Sign in / Sign up

Export Citation Format

Share Document