scholarly journals Comparison of two vitrification methods for cryopreservation of porcine embryos

2011 ◽  
Vol 49 (No. 5) ◽  
pp. 183-189
Author(s):  
J. Říha ◽  
J. Vejnar
Keyword(s):  
Ethylene Glycol ◽  
Liquid Nitrogen ◽  
Artificial Insemination ◽  
Culture Medium ◽  
Calf Serum ◽  
Foetal Calf Serum ◽  
Post Mortem ◽  
Donor Insemination ◽  
Viable Embryo ◽  
Fresh Embryos

The aim of this study was to compare two vitrification methods of porcine perihatching blastocysts with regard to the success of transfer of these embryos to the recipients. Expanded, hatching, or hatched blastocysts were recovered post mortem from superovulated donors in 5.5 to 6.0 days after artificial insemination of donor gilts with homospermic doses. In protocol VS I, the embryos in perihatching developmental stage were equilibrated in a culture medium H-MEMD with 10% v/v of glycerol (1.37M solution of glycerol in medium) for 10 min and placed in a vitrification medium for 1.5 min max. (vitrification medium contained 50% v/v 2M sucrose in tridistilled water, 30% v/v of glycerol, and 20% v/v of foetal calf serum – FCS). Then they were dropped with micropipette and stored in liquid nitrogen vapour. For protocol VS II, we used H-MEMD culture medium supplemented with 20% v/v of FCS, 25% v/v ethylene glycol, and 25% v/v dimethyl sulphoxide (DMSO). Embryos were equilibrated for 10 min in a mixture of the vitrification medium and culture medium (1 : 1), and were kept in the vitrification medium for 1.5 minutes. Then they were dropped with micropipette and stored in liquid nitrogen vapour. Embryos were thawed by immersing the drop with the embryo in H-MEMD culture medium with 0.8M sucrose for 10 minutes. After thawing and washing in the medium with sucrose, all embryos were washed three times in a fresh medium and prepared for transfer. Recipients were synchronized either using Regumate-feeding followed by treatment with PMSG and HCG (gilts) or using piglet weaning (sows – 1st and 2nd parity). Recipients showing standing heat at the time of donor insemination were used for laparoscopic and non-surgical ET on day 5.5–6.0 of the cycle. The fraction of viable embryo vitrified under VS I or VS II protocol was 85% and 80%, compared to 95% in control fresh embryos (P > 0.05). Pregnancy of recipients was 57.3% (5/7), 67.0% (4/6) for VS I or VS II group and 42.7% (10/23) for control (P < 0.001). We can conclude on the basis of our data that both protocols for vitrification yielded similar results and can be used for cryopreservation of porcine embryos.  

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.

42 Vitrification of invitro-produced feline embryos

2020 ◽  
Vol 32 (2) ◽  
pp. 146
Author(s):  
D. Fuller ◽  
J. Herrick ◽  
J. Graham ◽  
J. Barfield
Keyword(s):  
Dimethyl Sulfoxide ◽  
Liquid Nitrogen ◽  
Room Temperature ◽  
Culture Medium ◽  
Fetal Calf Serum ◽  
Calf Serum ◽  
Epididymal Sperm ◽  
Quality Grade ◽  
Developmental Rates ◽  
Species Specific

Preservation of feline embryos is useful in propagating endangered species, preserving valuable genetics, and supporting biomedical research. Although a wide variety of cryoprotectants (CP) and protocols are successfully used for vitrification of invitro-produced (IVP) embryos, there are often species-specific differences in viability of embryos post-warming. The purpose of this study was to evaluate the viability of IVP feline embryos after vitrification using two common CPs, propanediol (PrOH) or ethylene glycol (EG). Embryos were produced with oocytes and frozen-thawed epididymal sperm collected from local spay-neuter clinics using a published IVP protocol developed for producing domestic feline embryos. Day 7 early blastocysts (stage 5), blastocysts (stage 6), and expanded blastocysts (stage 7) were evaluated for quality (grade 1 or 2) and randomly assigned to one of three treatments: vitrification with PrOH (n=32), vitrification with EG (n=31), or control (n=47), which was allowed to continue in culture until Day 8. The vitrification protocol was as follows. The base medium for all vitrification media was a HEPES-buffered feline optimized culture medium (FOCMH). Embryos were placed in 0.5mL of equilibration medium (7.5% dimethyl sulfoxide, 7.5% PrOH or EG, 0.5M sucrose, 10% Ficoll, and 20% fetal calf serum (FCS)) for 5min at room temperature. Individual embryos were then moved to 20-μL drops of vitrification medium (15% dimethyl sulfoxide, 15% PrOH or EG, 0.5M sucrose, 10% Ficoll, and 20% FCS) at room temperature for 30s before being loaded onto Cryolock devices and plunged into liquid nitrogen. Warming was done using a 3-step process for all vitrified embryos. First, embryos were moved from liquid nitrogen directly to 0.5mL of 1M sucrose, 10% Ficoll, and 20% FCS at 37°C for 1min. Next, embryos were moved to 0.5mL of 0.5M sucrose, 10% Ficoll, and 20% FCS at 20°C for 3min. Finally, embryos were transferred to 0.5mL of FOCMH for 5min at 37°C. All warmed embryos were cultured in medium, optimized for feline embryos, with 5% FCS and evaluated for re-expansion of the blastocoele and progression in development at 24 and 48h. Results are from five replicates. Embryos vitrified in EG exhibited higher percentages of viable embryos 24h after warming (84%) than embryos vitrified in PrOH (59%; P<0.05). The continued embryonic growth of viable embryos after culture for 48h showed equivalent developmental rates, at 87, 96, and 100% for control, EG-treated, and PrOH-treated embryos, respectively (P>0.05). Results indicate EG is a more successful CP treatment for vitrification of feline embryos when evaluating viability 24h post-warming. We report a higher viability of embryos post-thaw than previous studies using the same CPs (Pope et al. 2012 Reprod. Domest. Anim. 47, 125). This may be due to the shorter exposure time to the CPs we used during the vitrification process. We conclude that EG and PrOH are effective CPs for Day 7 feline IVP embryos using this protocol. Further research is needed to increase treatment numbers and evaluate pregnancy rates from embryos transferred post-warming.

scholarly journals Immunoreactive insulin from mouse brain cells in culture and whole rat brain

1984 ◽  
Vol 218 (1) ◽  
pp. 19-27 ◽  
Author(s):  
N P Birch ◽  
D L Christie ◽  
A G C Renwick
Keyword(s):  
Rat Brain ◽  
Mouse Brain ◽  
Culture Medium ◽  
Calf Serum ◽  
Brain Cells ◽  
Immunoreactive Insulin ◽  
Foetal Calf Serum ◽  
Cells In Culture ◽  
Pancreatic Insulin ◽  
Contrast Microscopy

Foetal mouse brain cells were cultured as described previously [Sotelo, Gibbs, Gajdusek, Toh & Wurth (1980) Proc. Natl. Acad. Sci. U.S.A. 77, 653-657] without added insulin and without foetal calf serum after 12 days in culture. Examination by phase-contrast microscopy showed that these modifications did not appear to affect growth and development of the cells adversely. Silver impregnation of the cultures and indirect immunofluorescence following reaction with tetanus toxin showed that a high proportion of the cells resembled neurones. Analysis of concentrated culture medium by radioimmunoassay and high-pressure liquid chromatography (h.p.l.c.) revealed that the cells produced two main forms of immunoreactive insulin which differed from authentic pancreatic insulin in retention time. Immunoreactive somatostatin was also produced in culture and this was resolved into at least three forms by h.p.l.c. Immunoreactive insulin was also extracted from whole rat brain by using two published procedures. The method of Havrankova, Schmechel, Roth & Brownstein [Proc. Natl. Acad. Sci. U.S.A. (1978) 75, 5737-5741] consistently gave greater yields of insulin than did that of Eng & Yalow [Diabetes (1980) 29, 105-109] and the concentration was about three times that of plasma. The extracted insulin was further characterized by h.p.l.c. in each case and was found to behave like authentic pancreatic insulin. The production of insulin and somatostatin by foetal mouse brain cells in culture suggests that they may be a useful model system for studies of neuropeptide biosynthesis.

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

113 EVALUATION OF DIFFERENT CRYOPROTECTANT AND FORSKOLIN IN THE CULTURE MEDIUM FOR IMPROVING THE EFFICACY OF VITRIFICATION OF BOS INDICUS IN VITRO-DERIVED EMBRYOS

2010 ◽  
Vol 22 (1) ◽  
pp. 215 ◽  
Author(s):  
B. V. Sanches ◽  
B. D. O. Filho ◽  
J. H. F. Pontes ◽  
A. C. Basso ◽  
M. L. G. Meirinhos ◽  
...  
Keyword(s):  
Liquid Nitrogen ◽  
Lipid Droplets ◽  
Culture Medium ◽  
Bos Taurus ◽  
Bos Indicus ◽  
Calf Serum ◽  
Genetic Material ◽  
Embryo Cryopreservation ◽  
Hatching Rate

Embryo cryopreservation is an essential method for the biotechnology of reproduction. This is the safest option for interchange of genetic material for research and commercial purposes. For cattle, Brazil has become the leading country in the world for the number of in vitro-produced embryos, using mostly Bos indicus animals. However, considering the in vitro method of embryo production, field results have shown a lower resistance to cryopreservation for B. indicus when compared with Bos taurus embryos. A possible explanation for this is a great concentration of lipid droplets in the cytoplasm of cells fromB. indicus embryos. The objective of this study was to compare 2 cryoprotectants (Propanediol and DMSO) to vitrification and evaluate the effect of adding 10 μM forskolin to the SOF medium for embryo culture before cryopreservation. For all the experiments, ovaries from slaughtered Nelore Bos indicus donors were recovered and maintained at 30 to 35°C in NaCl solution until recovery of the COC. Embryos submmited to vitrification were expanded blastocysts at Day 7 of in vitro culture. In the first experiment embryos were first incubated in 10% ethylene glycol (EG) plus 10% DMSO dissolved in holding medium (TCM-HEPES with 20% calf serum) for 1 min and then transferred to droplet of 20% EG plus 20% DMSO in holding medium and 0.5 M sucrose for 20 s before immersing in liquid nitrogen (n = 107; group EG + DMSO). For the group EG + Propanediol (EG + PRO; n = 96), blastocysts were placed in 10% EG plus 10% PRO in holding medium for 1 min and then transferred to a droplet of 20% EG plus 20% PRO in holding medium and 0.5 M sucrose for 20 s before immersing in liquid nitrogen. Both treatments were performed using the Cryotop system. Results were compared with embryos (n = 118) not submitted to cryopreservation. The evaluation was done by the hatching rate of blastocysts at Day 9, being higher (86.4%) for embryos not cryopreserved, when comparing with 77.1% for group EG + PRO and 72.9% for group EG + DMSO (P < 0.05). In the second experiment, Day 5 embryos obtained in vitro from Nelore donors were cultured using SOF medium with 10 μM forskolin (n = 112) or not (control; n = 101), being all submitted to cryopreservation using Cryotop and the same vitrification method for group EG + DMSO. Results were compared with embryos cultured with SOF medium and not submitted to cryopreservation (n = 96). The evaluation was performed by considering hatching rate at Day 9, being higher (85.4%) for not cryopreserved, when compared with 63.3% for control and 70.5% for forskolin group (P < 0.05). Considering embryos submitted to cryopreservation, the hatching rate was higher (P < 0.05) for the forskolin group.

Megakaryocytic Progenitors in Long Term Cultures from MDS Patients.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4924-4924
Author(s):  
Maria Juliana Majado ◽  
María I. Macizo ◽  
Consuelo González-García ◽  
Eduardo Salido ◽  
José A. Molina ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Culture Medium ◽  
Horse Serum ◽  
Calf Serum ◽  
Methyl Cellulose ◽  
Refractory Anemia ◽  
Foetal Calf Serum ◽  
Cell Counts ◽  
Control Bone

Abstract Introduction: bone marrow long-term cultures (LTC) have been reported to produce very poor adherent stromal layer in MDS, but there are not many studies about the behaviour of the progenitor cells in supernatant culture medium. In this study we report the results of megakaryocytic progenitors (CFU-MK) in the supernatant of LTC of patients with refractory anemia (RA). Material and method: LTCs were performed to 11 RA patients and to 13 normal multiorgan donors as control. Bone marrow red cells were sedimented with 1% methyl-cellulose and seeded for LTC in 10ml flasks (Nalge Nunc International), with Iscover medium supplemented with horse serum, foetal calf serum, hydrocortisone and carbonic air, at a final concentration of 1x106 per ml. Flasks were placed in an incubator for 8 weeks. Half culture medium volume was renovated weekly, cell counts and assays of CFU-MK (Megacult C, Stem Cell Technologies), were performed. CFU-MK colonies were separated in three groups, containing 3–20 cells, 21–50 cells and more than 50 cells. Student t-test was used for statistical comparisons. Results: Are in the following table, expressed as mean + standard desviation. After the third week no colony growth was observed in normal such as in MDS. Growth of CFU-MK colonies containing more than 50 cells was higher in basal control bone marrow, no statistical differences were found in the rest of the cultures. Results CFU-MK(3–30 Cells) CFU-MK(20–50 Cells) CFU-MK (&gt;50 Cells) CFU-MK total w: week Control basal 15.75±15.79 3.33±5.42 4.88±7.44 22.42±26.43 RA basal 7.85±8.66 0.80±1.01 0.70±0.98 9.45±9.46 t-St ns ns 0.047 ns Control w 1 3.54±4.42 0.7±1.44 0.74±1.48 4.98±6.62 RA w 1 3.29±4.52 0.29±0.93 0.25±0.67 3.82±5.65 t-St ns ns ns ns Control w 2 0.55±1.14 0.07±0.24 0.05±0.25 0.67±1.43 RA w 2 0.18±0.32 0.00±0.00 0.04±0.13 0.21±0.38 t-St ns ns ns ns Control w 3 0.18±0.53 0.00±0.00 0.00±0.00 0.18±0.53 RA w 3 0.00±0.21 0.00±0.00 0.00±0.00 0.00±0.21 t-St ns ns Discussion: No important difference was found in LTC supernatant CFU-MK in our RA patients, and this supports the idea that the stromal damage is more important, in the pathophysyology of MDS, than that of the stem cells.

scholarly journals Freezing goat embryos at different developmental stages and quality using ethylene glycol and a slow cooling rate

2018 ◽  
Vol 70 (5) ◽  
pp. 1489-1496 ◽  
Author(s):  
J.F. Fonseca ◽  
R.I.T.P. Batista ◽  
J.M.G. Souza-Fabjan ◽  
M.E.F. Oliveira ◽  
F.Z. Brandão ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Cooling Rate ◽  
Liquid Nitrogen ◽  
Developmental Stages ◽  
Slow Cooling ◽  
Air Bubble ◽  
Frozen Embryos ◽  
Glycol Solution ◽  
Fresh Embryos ◽  
Fresh Transfer

ABSTRACT The efficiency of an alternative freezing protocol for goat embryos of different morphology and quality was tested. Fifty-eight embryos on Day 6-7 stage were transferred as fresh or after freeze-thawing (n=29/group). For freezing, embryos were placed into 1.5M ethylene-glycol solution for 10min. During this time, they were loaded in the central part of 0.25mL straw, separated by air bubble from columns containing PBS/BSA 0.4% plus 20% BFS. Straws were then frozen using a freezing machine from 20ºC to -6ºC at a cooling rate of 3ºC/min, stabilization for 15min (seeding after 5min), from -6 C to -32ºC at 0.6 C/min,and plunged into liquid nitrogen. Frozen embryos were thawed for 30s at 37ºC in a water bath. Embryos subjected to fresh transfer were maintained in holding medium (37ºC). Fresh and frozen-thawed embryos were transferred at day 7 post-estrus to 30 recipients. Kidding and kid born rates were similar (P> 0.05), respectively, for recipients receiving fresh (66.7% or 10/15; 55.2% or 16/29) or frozen-thawed (60% or 9/15; 51.7% or 15/29) embryos. The cryopreservation of goat embryos using slow-freezing protocol and 1.5MEG resulted in similar efficiency rates of fresh embryos.

82 VIABILITY OF SHEEP-SKIN FIBROBLASTS AFTER SLOW FREEZING

2013 ◽  
Vol 25 (1) ◽  
pp. 188
Author(s):  
Y. Toishibekov ◽  
N. Belyaev ◽  
H. Blackburn ◽  
R. Tleulieva ◽  
B. Katubayeva ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Liquid Nitrogen ◽  
Culture Medium ◽  
Blue Staining ◽  
Wide Range ◽  
Significant Difference ◽  
Fetal Bovine ◽  
Breeding Pool ◽  
Phosphate Buffered Saline ◽  
Skin Samples

Both tissue and cell cryopreservation can be applied for biodiversity conservation. The proper preservation of tissues and cells from a wide range of animals of different species is of paramount importance, because these cell samples could be used to reintroduce lost genes back into the breeding pool by somatic cell cloning. The aim of this work was to investigate the effect of different cooling rates on viability of frozen–thawed sheep fibroblasts for conservation of biodiversity so that it might be used in the future to provide nuclear donors (Table 1). Skin samples collected from 10 adult sheep were cut on small pieces (1 × 1 mm), placed into culture Petri dishes containing DMEM supplemented with 20% (v/v) fetal bovine serum (FBS), and covered with coverslips followed by incubation at 5% CO2, 95% relative humidity, and 37°C. During culture, fibroblasts left skin samples and proliferated. Culture medium was changed every 4 days. After 21 to 22 days of incubation, a fibroblast monolayer was observed, culture medium was removed, and cells were incubated for 7 to 10 min in presence of Dulbecco’s phosphate buffered saline + 0.25% trypsin. Dissociated fibroblasts were washed with DMEM by centrifugation at 300g for 10 min. For cryoconservation, fibroblast samples were then diluted at a concentration of 2 × 106 cells mL–1 in DMEM + 20% FBS and 10% dimethyl sulfoxide or 10% ethylene glycol and placed into 0.25-mL plastic straws or 2-mL cryovials. Straws were sealed with modeling clay and maintained at +5°C for 120 min before freezing. Cryopreservation of fibroblasts was carried out by 2 procedures: (1) straws were frozen in programmable freezer Kryo Planer 360-3,5 using the following freezing regimen: +5°C to –40°C at –1°C min–1, –40°C to –85°C at –4°C min–1, and then plunged into liquid nitrogen; (2) cryovials were placed in a Styrofoam box and loaded into a freezer at –70°C for 24 h, and then samples were plunged into liquid nitrogen for storage. Samples were thawed for 1 min in a 37°C water bath. Frozen–thawed samples were diluted with DMEM (1 : 5) and centrifuged at 300g for 7 to 10 min. Supernatants were removed, and cells were diluted with DMEM at a concentration of 2 × 106 cells mL–1. Viability of frozen–thawed fibroblast samples was detected using the Trypan Blue staining method. The values obtained (Table 1) are expressed as mean standard error of the mean (SEM). Statistical analysis was done using Student’s test. Results indicated that there was a significant difference in viability between fresh and cryopreserved fibroblasts. However, there were no differences between the cooling procedures. Importantly, our data suggest that the use of 1.5-M ethylene glycol reduced the toxic elements contained in the cryopreservation solution while maintaining a similar ability to produce viable fibroblasts after cryoconservation. Table 1.Effect of 2 cryoprotectant agent (CPA) on the viability of frozen–thawed ovine fibroblasts

135 IN VITRO DEVELOPMENT OF IN VIVO PRODUCED EMBRYOS FROZEN AT MORULA OR BLASTOCYST STAGES

2008 ◽  
Vol 20 (1) ◽  
pp. 148
Author(s):  
R. Sartori ◽  
G. M. Machado ◽  
M. M. Guardieiro ◽  
M. R. Bastos ◽  
L. Leme ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Liquid Nitrogen ◽  
Zebu Cattle ◽  
Hatching Rate ◽  
Chi Square ◽  
Fluid Medium ◽  
Chi Square Test ◽  
Fresh Embryos

This study was designed to compare cryotolerance between morulae and blastocysts collected from superovulated heifers. Twenty pubertal beef heifers (10 Nelore and 10 crossbred Nelore � Simmental) were superovulated with 100 mg of FSHp (Folltropin-V, Bioniche, Ontario, Canada), and embryos were collected and evaluated 7 days after estrus. Grades 1 and 2 embryos (IETS) were divided into four groups: morulae cryopreserved (MC) in liquid nitrogen (n = 24); blastocysts cryopreserved (BC; n = 19); morulae fresh (MF; n = 23); and blastocysts fresh (BF; n = 18). For freezing, embryos were immersed in ethylene glycol (Ethylene Glycol Freeze Plus with 0.1 m sucrose, Bioniche, Pullman, WA, USA), and a standard protocol (cooling rate of –0.5�C/min) was used. Prior to in vitro culture, embryos were removed from nitrogen, kept at room temperature for 5 s, and put in a water bath at 30�C for 20 s. Within 5 h after recovery, thawed and fresh embryos were washed five times in holding solution (Holding Plus, Bioniche), transferred to synthetic oviduct fluid medium (SOF, Nutricell, Campinas, SP, Brazil), and cultured for 72 h. Embryos were evaluated at 48 and 72 h of culture. After the last evaluation, degenerate and non-hatched embryos were removed from culture, and the remaining embryos were measured by a graduated ocular coupled to the Motic Images Plus 2.0 program. Hatched blastocysts were kept in culture for an additional 48 h for post-hatching development assessment. For post-hatching culture PHD medium (Brand�o DO et al. 2005 Biol. Reprod. 71, 2048–2055) was added into each well, to have a final composition of 50% SOF and 50% SOF PHD. At 120 h of culture (48 h of PHD culture) only morphologically normal blastocysts were measured. Comparison among groups was performed by ANOVA or chi-square test. Data are presented as mean � SEM. After 48 h of culture, hatching rate (%) was significantly lower in cryopreserved (MC = 8.3 and BC = 21.5) than in fresh (MF = 56.5 and BF = 77.8) embryos (P < 0.05). However at 72 h, hatching rate was similar among BC (75.9), MF (78.3), and BF (88.9), being MC (41.7) still lower (P < 0.05). The diameter (µm) of hatched embryos after 72 h of culture was 272.8 � 27.1a (n = 8), 320.6 � 18.6ab (n = 14), 385.3 � 14.2c (n = 17), and 378.0 � 22.0bc (n = 16) for MC, BC, MF, and BF, respectively (a–cP < 0.05). After 120 h of culture, the diameter of MC (379.0 � 39.9; n = 8), although similar to BC (495.4 � 59.6; n = 10), was smaller than MF (509.1 � 36.5; n = 11) and BF (511.8 � 41.2; n = 14). The results of this study with zebu cattle suggest that morulae are less resistant to cryopreservation in liquid nitrogen than blastocysts. Moreover, frozen/thawed embryos, when put in culture, present a slower development compared with fresh embryos. Financial support from CNPq and FAPESP from Brazil.

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