scholarly journals 107TOXICITY OF ETHYLENE GLYCOL ON FROZEN AND THAWED IVP EMBRYOS IN DIRECT TRANSFER METHOD

2004 ◽  
Vol 16 (2) ◽  
pp. 175 ◽  
Author(s):  
S. Matoba ◽  
K. Imai ◽  
Y. Mimaki ◽  
M. Narita ◽  
M. Tagawa ◽  
...  
Keyword(s):  
Survival Rate ◽  
Ethylene Glycol ◽  
Calf Serum ◽  
Holding Time ◽  
Morphological Development ◽  
Direct Transfer ◽  
Holding Period ◽  
Development Data ◽  
Transfer Method

Ethylene glycol (EG) is a cryoprotectant which is highly permeable to mammalian embryos. But the toxicity of this cryoprotectant for embryos after thawing has not been investigated. The aim of this study was to determine the toxicity of EG to embryos frozen and thawed by a direct transfer method. In vitro-produced Day 7 blastocysts (n=529) of grade 1 quality were used in this study. Embryos were frozen in 1.5MEG in Dulbecco’s PBS (DPBS) supplemented with 0.1M sucrose, 4mgmL−1 BSA and 20% fetal calf serum (FCS). Embryos were transferred into freezing medium, loaded into 0.25-mL straws and kept for more than 15min for equilibration; then the straws were plunged into a −7°C methanol bath of a programmable freezer for 1min, seeded at −7°C, held at −7°C for 14min, cooled to −30°C at the rate of −0.3°Cmin−1 and then plunged into liquid nitrogen. The straws were thawed by holding in air for 6sec, and then placed in water at 30°C for 15s. After thawing, the straws were held for 0, 10, 20, 30 and 60min (holding time) at either 38.5 or 26.0°C. Ethylene glycol was removed from the embryos by placing them into DPBS supplemented with 20% CS at 38.5°C more than 20min. The embryos were cultured in TCM-199 supplemented with 20% FCS and 0.1mM β-mercaptoethanol under a gas phase of 5% CO2 in air at 38.5°C for 72h. Viability of embryos was evaluated at 0-, 24-, 48- and 72-h incubation by their morphological development. Data were analyzed by ANOVA. There was no significantly difference in the survival rate of thawed embryos held at 38.5°C or 26.0°C for the same holding periods. The survival rate of the thawed embryos held at 38.5°C decreased significantly when the holding period exceeded 30min compared with no holding period after 24- and 72-h culture (P<0.05, respectively). On the other hand, the survival rate of the thawed embryos held at 26.0°C decreased significantly when the holding time was 60min compared with less than 20min of holding after 24-h culture, and less than 10min after 72-h culture (P<0.05, respectively). Therefore, toxicity of EG was observed when thawed embryos were held for 30 and 60min at 38.5°C and 60min at 26.0°C. These results suggest the toxicity of EG in direct transfer methods can be avoided by transferring the embryos within 20min after thawing. Table 1

149 IN VITRO BOVINE EMBRYOS FROZEN BY DIRECT TRANSFER METHOD WITH ETHYLENE GLYCOL

2015 ◽  
Vol 27 (1) ◽  
pp. 166
Author(s):  
S. H. Kizil ◽  
M. Satilmis ◽  
N. Akyol ◽  
T. Karasahin
Keyword(s):  
Ethylene Glycol ◽  
Survival Rates ◽  
Hatching Rate ◽  
Direct Transfer ◽  
Embryo Freezing ◽  
Frozen Embryos ◽  
Transfer Method ◽  
Phosphate Buffered Saline ◽  
In Vitro Survival

The objective of this study was to search for capability of freezing by ethylene glycol direct transfer method of in vitro-produced cattle embryos. Fifty-six in vitro-produced good-quality cow embryos were frozen by direct transfer method with ethylene glycol in this study. Cattle ovaries were collected from a slaughterhouse and oocytes were aspirated from follicles with 2 to 8 mm diameters. Then oocytes were let for maturation of 20 to 22 h in 100-μL microdroplets of TCM-199 with 0.1 mM β-mercaptoethanol and 20% FCS. After 5 to 6 h of fertilization in Bracket Oliphant (BO), they were cultured for 7 days in 100 µL of CR1aa medium with 5% FCS under 5% CO2, 98% relative humidity, and 38.5°C in a CO2 incubator. Embryos were equilibrated for 15 min in room temperature in 1.8 M ethylene glycol + 0.1 M sucrose in Dulbecco's phosphate buffered saline (D-PBS) supplemented with 20% FCS. Embryos were then loaded individually into a 0.25-mL straw and placed directly into a cooling chamber of a programmable freezer with methyl alcohol precooled to –7°C. After 2 min, the straw was seeded and maintained at –7°C for 8 min more. Then it was cooled to –30°C at 0.3°C min–1 before plunging into liquid nitrogen. The frozen embryos were thawed by allowing the straw to stand in air for 5 to 6 s and then immersing them in a 30°C water bath for 10 s. After thawing, embryos were transferred into TCM-199 + 0.1 mM β-mercaptoethanol + 20% FCS medium to check in vitro survival rates at 48 h post-thawing. The re-expansion and hatching rate of blastocysts was 64.28% (36 blastocysts). This result indicated that ethylene glycol can be used effectively for cow embryo freezing as a suitable cryoprotectant for direct transfer method.

83 VITRIFICATION OF IMMATURE AND IN VITRO-MATURED HORSE OOCYTES

2006 ◽  
Vol 18 (2) ◽  
pp. 149 ◽  
Author(s):  
L. Bogliolo ◽  
F. Ariu ◽  
I. Rosati ◽  
M. T. Zedda ◽  
S. Pau ◽  
...  
Keyword(s):  
Survival Rate ◽  
Ethylene Glycol ◽  
Survival Rates ◽  
Germinal Vesicle ◽  
Cumulus Cells ◽  
Hoechst 33342 ◽  
Nuclear Maturation ◽  
And Control ◽  
Cryopreservation Protocol

Few attempts have been carried out to cryopreserve equine oocytes, and an effective cryopreservation protocol is not defined yet. Studies were conducted to compare the viability of immature and in vitro-matured horse oocytes vitrified by the minimal volume cooling (MVC) cryotop vitrification method (Kuwayama et al. 2005 Reprod. BioMed. Online 11, 300–308). Oocytes were recovered from slaughterhouse ovaries and divided, on the basis of the morphology of cumulus cells, into cumulus-expanded (CE) and cumulus-compacted (CC) oocytes. Groups of CC and CE oocytes were vitrified immediately after recovery [germinal vesicle (GV) stage] or matured in vitro (IVM) and cryopreserved at the MII stage as follows: oocytes were incubated 30 min in TCM-199 + 20% FCS + 10% ethylene glycol (EG) + 10% DMSO, followed by 20 min in TCM-199 + 20% FCS + 20% EG + 20% DMSO + 0.25 M sucrose, loaded in cryotops (2 µL), and plunged into liquid nitrogen. Warming was performed at 38.5°C by washing the oocytes in TCM-199 + 20% FCS with decreasing sucrose concentrations (1.25 M, 0.62 M, 0.31 M). After warming oocytes cryopreserved at the GV stage were matured in vitro for 24 h (CE) or 36 h (CC) in TCM-199 + 10% FCS + FSH, LH each at (0.1 UI/mL) + cysteamine, fixed, and stained with glycerol-Hoechst 33342 to assess nuclear maturation. Oocytes vitrified at the MII stage were in vitro cultured for 2 h to evaluate their morphological survival on the basis of the presence of an intact zona pellucida and membrane. Nonvitrified oocytes undergoing the same maturation protocol were used as controls. Results (Table 1) indicated that the survival rate of oocytes vitrified at the GV stage, after IVM, was similar between CE and CC oocytes (43.6% vs 42.6%). Significantly (P < 0.01) higher numbers of vitrified CE MII oocytes (52.9%) survived, compared to CC (34.8%), after 2-h culture. The percentages of viable MII oocytes from CE and CC GV vitrified oocytes were 43.6% and 40.9% respectively and were comparable to those from vitrified MII oocytes (CE, 52.9%; CC, 34.8%) and control oocytes (CE, 56.4%; CC, 53.3%). In conclusion, the results of this study showed that vitrification by the MCV Cryotop method of horse oocytes at either the GV or the MII stage allows a similar number of viable mature oocytes to be recovered. Table 1. Maturation and survival rates of immature and mature equine oocytes vitrified by the MCV Cryotop method

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.

Developmental competence in vitro and in vivo of cryopreserved, hatched blastocysts from the dromedary camel (Camelus dromedarius)

2004 ◽  
Vol 16 (6) ◽  
pp. 605 ◽  
Author(s):  
J. A. Skidmore ◽  
M. Billah ◽  
N. M. Loskutoff
Keyword(s):  
Survival Rate ◽  
Fetal Calf Serum ◽  
Calf Serum ◽  
Sodium Lactate ◽  
Developmental Competence ◽  
Penicillin G ◽  
Dromedary Camel ◽  
Dromedary Camels

The present paper describes experiments designed to investigate methods for cryopreserving embryos from dromedary camels. Because preliminary studies had shown ethanediol to be the best cryoprotectant to use for camel embryos, the current experiments were performed to determine the minimum exposure time to 1.5 m ethanediol required to achieve cryoprotection. The uteri of 30 donor camels were flushed non-surgically 8 days after mating. Embryos were recovered and 158 were assigned to one of three groups, which were exposed to 1.5 m ethanediol for either 10 min (n = 67), 5 min (n = 51) or 1 min (n = 40). Embryos were subsequently thawed and rehydrated by expelling either directly into holding medium (HM; HEPES-buffered Tyrode's medium containing sodium lactate and 3 mg mL−1 bovine serum albumin, 10% fetal calf serum, 100 IU mL−1 penicillin G, 100 μg mL−1 streptomycin and 25 μg mL−1 amphotercin B) or initially into HM containing 0.2 m sucrose for 5 or 10 min. The survival rate of all embryos immediately post-thawing, as judged by the morphological appearance of the embryos, was high (91%), but was greatly reduced after 2 h culture (59%). Ninety-two embryos were transferred to recipient camels resulting in 18 viable fetuses (1 min ethanediol exposure, n = 1/15; 5 min ethanediol exposure, n = 3/34; 10 min ethanediol exposure, n = 14/43). Of the embryos rehydrated directly in HM, six of 65 resulted in viable fetuses and those rehydrated initially in 0.2 m sucrose for 5 or 10 min resulted in nine of 47 and three of 46 fetuses respectively. From these experiments, we conclude that camel embryos can be cryopreserved using ethanediol as a cryoprotectant when the embryos are cooled slowly (to 33°C) before being plunged into liquid nitrogen for storage.

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

68 EFFECT OF CO-CULTURE DURING FERTILIZATION OF BUFFALO (BUBALUS BUBALIS) IN VITRO-MATURED DENUDED OOCYTES VITRIFIED BY CRYOTOP

2008 ◽  
Vol 20 (1) ◽  
pp. 115
Author(s):  
L. Attanasio ◽  
A. De Rosa ◽  
L. Boccia ◽  
R. Di Palo ◽  
G. Campanile ◽  
...  
Keyword(s):  
Survival Rate ◽  
In Vitro Fertilization ◽  
Survival Rates ◽  
Calf Serum ◽  
Cumulus Cells ◽  
Control Group ◽  
Cleavage Rate ◽  
Vitro Fertilization ◽  
Group B

Although removal of cumulus cells improves the efficiency of vitrification of buffalo (Bubalus bubalus) in vitro-matured (IVM) oocytes (Gasparrini et al. 2007 Anim. Reprod. Sci. 98, 335–342), the lack of cells impairs the fertilization process. Therefore, the aim of the present work was to evaluate the influence of a somatic support during in vitro fertilization (IVF) of buffalo vitrified denuded matured oocytes. Since IVF on a cumulus cells monolayer was inefficient, we verified the effects of co-culture with cumulus-enclosed oocytes (COCs). IVM buffalo oocytes (n = 316) were vitrified by the Cryotop� method (Kuwayama and Kato 2000, J. Assist. Reprod. Genet. 17, 477 abst) that was recently proven suitable for buffalo oocyte cryopreservation (Attanasio et al. 2006 Reprod. Domest. Anim. 41, 302–310). Denuded buffalo oocytes were equilibrated in 10% ethylene glycol (EG) and 10% dimethyl sulfoxide (DMSO) for 3 min, transferred into 20% EG and 20% of DMSO in TCM199 with 20% fetal calf serum (FCS) + 0.5 m sucrose, loaded on Cryotops, and plunged into liquid nitrogen within 25 s. For warming, oocytes were exposed for 1 min to 1.2 m sucrose and then to decreasing concentrations of the sugar (0.6, 0.4, 0.3 m for 30 s) in TCM199 + 20% FCS. Oocytes were rinsed and allocated to IVM drops for 1.5 h. Survival rate was evaluated at this point and the oocytes that had survived (292/316 = 92.4%) were split into 2 fertilization groups: (A) approximately 5 buffalo oocytes per 50-µL drop of IVF medium, and (B) approximately 3 buffalo oocytes + 3 bovine fresh COCs per 50-µL drop of IVF medium. Since buffalo COCs easily lose their cells following IVF, for better identification we used bovine COCs that have a brighter and more compact cumulus mass. In vitro fertilization and culture were carried out as previously described (Gasparrini et al. 2007). As control, buffalo oocytes (n = 104) were in vitro-matured, fertilized, and cultured up to the blastocyst stage. On Day 1, survival rate was evaluated in the two vitrification groups; cleavage and blastocyst rates were recorded on Days 5 and 7, respectively, in all groups. The experiment was repeated 4 times. Differences in the percentages of survival, cleavage, and blastocyst formation among treatments were analyzed by chi-square test. Within vitrification groups, despite similar survival rates on Day 1 (90.6% v. 93.3%, respectively, in Groups A and B), cleavage rate was significantly improved in Group B compared to Group A (59.2% v. 45.4%, respectively; P < 0.01). Interestingly, the cleavage rate in Group B was not significantly different from that recorded in the control group (71.0%). Although blastocysts were produced in both vitrification groups (3.6% v. 4.1%, respectively, in Groups A and B), the yield was significantly lower than that of the control group (29.0%, P < 0.01). In conclusion, co-culture with bovine COC during fertilization improves the capability of buffalo denuded vitrified oocytes to cleave.

88 EFFECT OF VITRIFICATION PROCEDURE ON SURVIVAL RATE OF BOVINE EMBRYOS PRODUCED IN VITRO

2011 ◽  
Vol 23 (1) ◽  
pp. 149
Author(s):  
E. Y. Herrera ◽  
C. de Frutos ◽  
R. Laguna-Barraza ◽  
A. Gutierrez-Adan ◽  
D. Rizos
Keyword(s):  
Survival Rate ◽  
Survival Rates ◽  
Calf Serum ◽  
Basal Medium ◽  
Bovine Embryos ◽  
Oviduct Fluid ◽  
Bovine Oocytes ◽  
Cryopreservation Method ◽  
Hatching Rates

Vitrification as a cryopreservation method has many advantages compared with slow freezing. Many variables in the vitrification process exists that influence the survival rates of vitrified oocytes and embryos. These include the cryoprotectants (type, concentration, and duration of exposure), the temperature of the vitrification solution at exposure, the device used for vitrification, and the quality and developmental stage of embryos. It is worthwhile to mention that vitrification protocols successfully used in bovine oocytes and embryos have been used also with human oocytes and embryos. Vitrification is relatively simple, requires no freezing equipment, and relies on the placement of the embryos in a very small volume of vitrification medium that must be cooled at extreme rates not obtainable in regular enclosed straws. The aim of the present study was to evaluate the efficiency of 4 different vitrification protocols on the survival rate of in vitro produced (IVP) bovine embryos. Blastocysts were produced by a standard IVP procedure following in vitro maturation, fertilization, and culture in synthetic oviduct fluid supplemented with 5% fetal calf serum (FCS). On Day 7 (Day of IVF = Day 0), a total of 297 blastocysts were vitrified using (i) the open pulled straw (OPS) in 20% DMSO and 20% ethylene glycol (EG) in a basal medium of TCM-199 with HEPES supplemented with 20% FCS; (ii) the modified OPS, in 20% DMSO, 20% EG, and 0.5 M sucrose in a basal medium of phosphate buffer saline (PBS) supplemented with 20% FCS; (iii) the cryoloop, in 15% DMSO, 15% EG, 10 mg mL–1 Ficoll 70, and 0.65 M sucrose in a basal medium of PBS supplemented with 20% FCS; and (iv) in 0.25 straws in 20% glycerol, 20% EG, 0.3 M sucrose, 3% polyethylene glycol, and 0.3 M xylose in a basal medium of PBS. After warming, embryos were placed in culture for additional 24 h. Re-expansion and hatching rates were measured at 2 and 24 h after warming. Data were analysed by 1-way ANOVA. At 2 h post-warming, the re-expansion of blastocysts vitrified with cryoloop was significantly higher compared with OPS, modified OPS, and the 0.25 straw methods (54.08 ± 15.53 v. 10.40 ± 3.00, 22.67 ± 9.20, and 8.82 ± 2.15, respectively; P ≤ 0.028). At 24 h post-warming, only embryos from cryoloop and modified OPS were still alive with a survival rate of embryos vitrified with cryoloop significantly higher than that of those vitrified with modified OPS (48.45 ± 17.56 v. 3.75 ± 3.75, respectively; P ≤ 0.007). Hatching rates at 24 h post-warming were not different between cryoloop and modified OPS groups (5.63 ± 4.40 and 1.25 ± 1.25, respectively). These results clearly demonstrate that embryo cryotolerance is affected by the method used for cryopreservation. Moreover, cryoloop vitrification was found to be more effective than OPS and 0.25 straw methods for the cryopreservation of bovine embryos.

85 VITRIFICATION OF IN VITRO-MATURED PORCINE OOCYTES AT THE METAPHASE-II STAGE

2008 ◽  
Vol 20 (1) ◽  
pp. 123
Author(s):  
B. Ogawa ◽  
S. Ueno ◽  
N. Nakayama ◽  
H. Matsunari ◽  
Y. Ikeda ◽  
...  
Keyword(s):  
Survival Rate ◽  
Mitotic Spindle ◽  
Early Stage ◽  
Formation Rate ◽  
Calf Serum ◽  
Slight Modification ◽  
Combination Group ◽  
Chi Square ◽  
The Difference

Cryopreservation of mammalian metaphase-II (M-II) oocytes is still impractical compared to that of early stage embryos. In this study we examined the effects of delipation and mitotic spindle stabilization in order to improve the post-vitrification survival rate of in vitro-matured (IVM) porcine oocytes at the M-II stage. Cumulus–oocyte complexes that had been collected from slaughterhouse ovaries were matured in vitro in NCSU23 supplemented with 0.6 mm cysteine, 10 ng mL–1 epidermal growth factor (EGF), 10% porcine follcular fluid (PFF), and 10 IU mL–1 eCG and hCG. The denuded M-II oocytes were vitrified in the presence of 30% ethylene glycol and 0.5 m sucrose using the minimum volume cooling (MVC) method with a MVC plate (Cryotop�; Kitazato Supply, Tokyo, Japan). Vitrified embryos were rewarmed by immersing the MVC plate directly into rewarming solution containing 1 m sucrose and 20% calf serum at 39�C for 1 min, followed by stepwise dilution of the cryoprotectants. We compared the effects of previtrification treatments, namely, (1) delipation, (2) mitotic spindle stabilization, (3) delipation + mitotic spindle stabilization, and (4) no treatment. For delipation, we used a noninvasive method (Esaki et al. 2004 Biol. Reprod. 71, 432–437) that we had published previously with slight modification. The embryos were treated with 4% trypsin at 38�C for approximately two min to expand the zona pellucida, and then centrifuged (12 000g, 38�C 23 min) with 7.5 µg mL–1 cytochalasin B to polarize cytoplasmic lipid droplets within the perivitelline space. For mitotic spindle stabilization, M-II oocytes were vitrified in the presence of 1 µm paclitaxel. After the oocytes were rewarmed, electrical activation of the oocytes (150 V mm–1, 100 µs, one time) was carried out to induce parthenogenesis. These parthenogenetic embryos were cultured in PZM-5 for 7 days, and the number of vitrified embryos that developed into blastocysts with respect to each treatment was determined. The blastcyst formation rate and mean cell numbers of the blastcysts were compared among the treatment groups (chi-square test, Tukey's test). Of the 50 M-II oocytes that had been vitrified without pretreatment, only one oocyte (2.0%) developed into a blastocyst with 20 cells. By contrast, the number of vitrified embryos that developed into blastocysts was significantly high when they were delipated prior to vitrification (37.8%, 14/37, 64.0 � 9.6; P < 0.01). Mitotic spindle stabilization also improved the survival rate of vitrified oocytes (18.6%, 21/113, 56.7 � 9.6; P < 0.01). The combination of delipation and mitotic spindle stabilization produced the highest number of vitrified oocytes that developed into blastocysts (43.8%, 35/80, 69.4 � 6.4), although the difference between the combination group and the delipation group was not significant. These results indicate that blastocysts can be produced very efficiently from IVM porcine oocytes that have been vitrified at the M-II stage using both noninvasive delipation and mitotic spindle stabilization procedures.

137 EFFECT OF THE ADDITION OF FOLIC ACID TO MATURATION AND CULTURE MEDIA ON DEVELOPMENT OF THE BOVINE BLASTOCYST AND ITS SURVIVAL RATE AFTER FREEZE-THAWING

2017 ◽  
Vol 29 (1) ◽  
pp. 177
Author(s):  
S. Sato ◽  
O. Dochi ◽  
K. Imai
Keyword(s):  
Folic Acid ◽  
Survival Rate ◽  
Culture Media ◽  
Cell Damage ◽  
Calf Serum ◽  
Cleavage Rate ◽  
Chi Square ◽  
Exact Test ◽  
Chi Square Test

Reactive oxygen species (ROS) are the main causes of cell damage in bovine embryos in vitro. Folic acid (FA) is an antioxidant that protects cells from ROS. We studied the effect of the addition of FA to maturation and culture media on development of bovine blastocysts and their survival rate after freeze-thawing. Cell-oocyte complexes (COC) were allowed to mature in HEPES (25 mM)-buffered TCM199 (TCM199) supplemented with 5% calf serum (CS), 0.02 AU mL−1 of FSH, and FA (0, 2.5, 25, and 50 µM) for 20 hours (20–25 COC/100-µL droplet of the medium). After 6 hours of gamete co-culture (5 × 106 sperm/mL), presumptive zygotes were cultured in CR1aa medium supplemented with 5% CS and FA (0, 2.5, 25, and 50 μM) for 9 days (day of fertilization = Day 0). Expanded blastocysts that developed from Day 7 to 9 were frozen for further study. Each embryo was frozen in Dulbecco’s PBS (D-PBS) supplemented with 20% CS, 1.5 M ethylene glycol (EG), and 0.1 M sucrose (SUC). Embryos were equilibrated with their freezing medium for 15 min and loaded individually into a 0.25-mL straw. These straws were put into the cooling chamber of a programmable freezer precooled at −7°C. After 2 min, straws were seeded and held for 13 min at −7°C. Next, straws were cooled to −30°C at −0.3°C/min before being plunged into liquid nitrogen. Frozen embryos were thawed by allowing straws to stand in air for 7 s and warming them in a 30°C water bath for 20 s. Thawed embryos were washed twice with D-PBS supplemented with 20% fetal calf serum (FCS), which was warmed to 38°C. They were immersed into the same medium at 38°C for 10 min, and each embryo was cultured in a 20-μL droplet of TCM199 supplemented with 10% FCS and 0.1 mM β-mercaptoethanol (TCM-199-βME) for 72 h. Embryo cleavage rate was observed at 55 h post-insemination. Blastocyst rates were analysed at 9 days post-insemination. Rates of embryos developing into reexpanded, hatching, and hatched blastocyst stages were determined after 72 h of thawing. All data were analysed by the chi-square test and Fisher’s exact test. Cleavage and blastocyst rates after insemination at 55 hours and 9 days, respectively, were not significantly different among media containing 0 μM (n = 278; 74.1% and 39.9%), 2.5 μM (n = 260; 74.2% and 45.8%), 25 μM (n = 258; 75.6% and 45.7%), and 50 μM (n = 253; 76.3% and 42.7%) FA. Survival and hatching rates of frozen and thawed expanded blastocysts after 72 h in culture were 62.5% and 56.3%, respectively, in 0 μM FA (n = 16); 85.2% and 74.1% in 2.5 μM FA (n = 27); 66.7% and 62.5% in 25 μM FA (n = 24); and 68.0% and 64.0% in 50 μM FA (n = 25). Blastocysts cultured in media containing 2.5 μM FA tended to have a higher survival rate than those cultured in media containing 0 μM FA, although this difference was not significant (P = 0.09). Inclusion of FA did not appear to influence development or post-thaw survival of bovine blastocysts produced in vitro.

A staging scheme for assessing development in vitro of organogenesis stage embryos of the stripe-faced dunnart, Sminthopsis macroura (Marsupialia: dasyuridae)

Reproduction ◽  
2000 ◽  
pp. 99-108 ◽  
Author(s):  
YP Cruz ◽  
D Hickford ◽  
L Selwood
Keyword(s):  
Fetal Calf Serum ◽  
Calf Serum ◽  
Microscopic Analysis ◽  
Culture Conditions ◽  
Didelphis Virginiana ◽  
Morphological Development ◽  
Rat Serum ◽  
Sminthopsis Macroura ◽  
Development In Vitro

The inaccessibility of mammalian organogenesis stage embryos has precluded their widespread use in embryological and teratological studies. As organogenesis occurs during the last 1.5 days of the 10. 7 days of gestation in the stripe-faced dunnart (Sminthopsis macroura), the aim of the present study was to investigate whether day 9 and day 10 embryos and fetuses could be grown to term in vitro. High glucose Dulbecco's modified Eagle's medium with 10% fetal calf serum (FCS) supported embryonic growth for various periods of time, some to within 5 h of the predicted time of parturition. A roller culture system maintained at 35 degrees C was used to incubate organogenesis stage embryos (n = 43). Nine unincubated (control) embryos were either fixed for microscopic analysis or frozen for microprotein determination. The results of the present study indicate that with some optimization of the culture conditions (increasing oxygen in the gas phase in the culture tubes, replacing FCS with rat serum), it might be possible for organogenesis stage S. macroura embryos to be grown to term. A scoring scheme for assessing morphological development was devised for use as a standard in staging organogenesis stage embryos. This scheme reflects the highly compressed schedule of developmental events that occurs mainly during day 9 of gestation in S. macroura embryos. In comparison, during embryogenesis in Didelphis virginiana these developmental events occur from day 8 to day 10.5 of gestation, and birth occurs on day 13.

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