OBJECTIVE: We aimed to evaluate the effects of different oxygen conditions (20% [high O₂], 5% [low O₂] and 5% decreased to 2% [dynamic O₂]) on mouse pre- and peri-implantation development using a novel double-channel gas supply (DCGS) incubator (CNC Biotech Inc.) to alter the oxygen concentration during in vitro culture.METHODS: The high-O₂ and low-O₂ groups were cultured from the one-cell to the blastocyst stage under 20% and 5% oxygen concentrations, respectively. In the dynamic-O₂ group, mouse embryos were cultured from the one-cell to the morula stage under 5% O₂ for 3 days, followed by culture under 2% O₂ to the blastocyst stage. To evaluate peri-implantation development, the blastocysts from the three groups were individually transferred to a fibronectin-coated dish and cultured to the outgrowth stage in droplets.RESULTS: The blastocyst formation rate was significantly higher in the low-O₂ and dynamic-O₂ groups than in the high-O₂ group. The total cell number was significantly higher in the dynamic-O₂ group than in the low-O₂ and high-O₂ groups. Additionally, the apoptotic index was significantly lower in the low-O₂ and dynamic-O₂ groups than in the high-O₂ group. The trophoblast outgrowth rate and spread area were significantly higher in the low-O₂ and dynamic-O₂ groups than in the high-O₂ group.CONCLUSION: Our results showed that a dynamic oxygen concentration (decreasing from 5% to 2%) had beneficial effects on mouse pre- and peri-implantation development. Optimized, dynamic changing of oxygen concentrations using the novel DCGS incubator could improve the developmental competence of in vitro cultured embryos in a human in vitro fertilization and embryo transfer program.
Animals ; Apoptosis ; Blastocyst ; Cell Count ; Embryo Transfer ; Embryonic Structures ; Fertilization in Vitro ; Humans ; In Vitro Techniques ; Incubators ; Mental Competency ; Mice ; Morula ; Oxygen ; Trophoblasts

OBJECTIVE: This study aimed to examine the effect of laser-assisted zona thinning (LAZT) at one or four-points on the blastocyst formation and hatching process in mice with respect to female age. METHODS: Eight-cell or morula embryos collected from superovulated C57BL female mice with different ages (6-11 and 28-31 weeks) were treated with LAZT at one-point (LAZT1) or four-points (LAZT4). The zona pellucida was thinned to more than 70% of its initial thickness by making two holes of 15-20 microm. RESULTS: In the young mice, LAZT resulted in a significant increase in early hatching and hatching rates compared to the control group (p<0.05). However, in the old mice, LAZT significantly increased blastocyst formation as well as early hatching and hatching compared to the controls (p<0.05). These effects were more remarkable in LAZT4 than in LAZT1 and in aged mice than in young ones. CONCLUSION: These results show that multi-point LAZT leads to a significant improvement of blastocyst formation and hatching in mice compared to controls.
Animals ; Blastocyst ; Embryonic Structures* ; Female ; Herpes Zoster* ; Humans ; Mice* ; Morula ; Zona Pellucida

OBJECTIVE: We intended to know how the cryoprotectant ethylene glycol (EG) would affect the outcome of the embryo development when used in slow freezing method. And to know if there is any difference in the outcome of frozen-thawed embryos according to freezing methods and the timing. METHODS: We used 5-6 weeks old ICR female mice and T6 containing 0.4% BSA for basic culture media. The embryos at the developmental stages of 1-cell, 8-cell and blastocyst were cryopreserved respectively by slow freezing method using EG, propylene glycol (PROH), and glycerol as a cryoprotectant. We also compared the results of slow freezing and vitrification methods with the same cryoprotectant, EG. And finally, we evaluated the quality of blastocysts by counting the cell numbers in each group. RESULTS: The post-thaw embryo development were better in EG group when they were frozen at 1-cell and blastocyst stage (P<0.05). Although there were no differences in the recovery rate, the survival rate in vitrification group was significantly higher (P<0.05). Post-thaw embryo development to morula and blastocyst were better in vitrification group when frozen at 1-cell embryo (P<0.05), not at 8-cell and blastocyst group. The cell counts of blastocyst derived from 1-cell stage frozen EG group were significantly increased than that of PROH-glycerol groups (P<0.05), however, there was no difference between the two freezing methods. CONCLUSION: These results suggest that EG may be advantageous comparing with the conventional cryoprotectants, PROH and glycerol in slow freezing method for mouse embryo cryopreservation. In terms of freezing method, vitrification is better than slow freezing.
Animals ; Blastocyst ; Cell Count ; Cryopreservation ; Culture Media ; Embryonic Development ; Embryonic Structures* ; Ethylene Glycol* ; Female ; Freezing* ; Glycerol ; Humans ; Mice* ; Morula ; Pregnancy ; Propylene Glycol ; Survival Rate ; Vitrification

OBJECTIVE: This study was conducted to find an optimal condition for the vitrification of mouse morulae and expanded blastocysts. MATERIALS AND METHODS: Mouse embryos were obtained at 2-cell stage and cultured to morula and expanded blastocyst stage in Human Tubal Fluid (HTF) medium supplemented with 10% Serum Substitute Supplement (SSS). The vitrification solutions used were EFS30, EFS35 and EFS40 that contains 30%, 35% and 40% ethylene glycol, respectively, with 18% ficoll and 0.5 M sucrose diluted in Dulbecco's phosphate-buffered saline (DPBS) medium supplemented with 10% SSS. The vitrification procedure was performed in EFS solution with three steps, followed by thawing in 6 steps with 0.5 M sucrose, and then survival and hatching-hatched rate per embryos recovered were compared among six groups. RESULTS: After 24 h culture in different vitrification and thawing solution, the survival rate of morula embryos was 94.1%, 85.4% and 59.7% for EFS30, EFS35 and EFS40 group, respectively. Hatching rate of morula embryos after 72 h culture was 30.6%, 25% and 11.3% for EFS30, EFS35 and EFS40 group, respectively. The survival rate of expanded blastocyst embryos after 24 h culture was 90.4%, 98.5% and 100% for EFS30, EFS35 and EFS40 group, respectively. Hatching rate of expanded blastocyst embryos after 48 h culture was 46.2%, 57.6% and 64.3% for EFS30, EFS35 and EFS40 group, respectively. CONCLUSION: The EFS30 solution was the best for vitrification of mouse morulae. The EFS40 solution was the best for vitrification of mouse expanded blastocysts. The mouse expanded blastocyst was better than mouse morula for vitrification of mouse embryos.
Animals ; Blastocyst ; Embryonic Structures* ; Ethylene Glycol ; Ficoll ; Humans ; Mice* ; Morula ; Sucrose ; Survival Rate ; Vitrification*

Although ethylene glycol (EG) has been widely used for embryo cryopreservation in domestic animals, few attempts were made to use this molecule to freeze mouse and human embryos. In the few studies that used EG for slow-freezing of mouse and human embryos, complicated protocols for human embryos were used, and the protocols need to be simplified. Besides, freezing mouse morula with EG as a cryoprotectant has not been reported. In this paper, we studied the effects of embryo stages, EG concentration, duration and procedure of equilibration, sucrose supplementation and EG removal after thawing on the development of thawed mouse embryos, using the simple freezing and thawing procedures for bovine embryos. The blastulation and hatching rates (81.92% +/- 2.24% and 68.56% +/- 2.43%, respectively) of the thawed late compact morulae were significantly (P < 0.05) higher than those of embryos frozen-thawed at other stages. When mouse late compact morulae were frozen with different concentrations of EG, the highest rates of blastocyst formation and hatching were obtained with 1.8mol/L EG. The blastulation rate was significantly higher when late morulae were equilibrated in 1.8 mol/L EG for 10 min prior to freezing than when they were equilibrated for 30 min, and the hatching rate of embryos exposed to EG for 10 min was significantly higher than that of embryos exposed for 20 and 30 min. Both rates of blastocyst formation and hatching obtained with two-step equilibration were higher (P < 0.05) than with one-step equilibration in 1.8 mol/L EG. Addition of sucrose to the EG-based solution had no beneficial effects. On the contrary, an increased sucrose level (0.4 mol/L) in the solution impaired the development of the frozen-thawed embryos. In contrast, addition of 0.1 mol/L sucrose to the propylene glycol (PG)-based solution significantly improved the development of the frozen-thawed embryos. Elimination of the cryoprotectant after thawing did not improve the development of the thawed embryos. The cell numbers were less (P < 0.05) in blastocysts developed from the thawed morulae than in the in vivo derived ones. In summary, embryo stage, EG concentration, duration and procedure of equilibration and sucrose supplementation had marked effects on development of the thawed mouse embryos, and a protocol for cryopreservation of mouse embryos is recommended in which the late morulae are frozen in 1.8 mol/L EG using the simple freezing and thawing procedures of bovine embryos after a two-step equilibration and the embryos can be cultured or transferred without EG removal after thawing.
Animals ; Cryopreservation ; methods ; Cryoprotective Agents ; pharmacology ; Dose-Response Relationship, Drug ; Embryo, Mammalian ; drug effects ; physiology ; Embryonic Development ; physiology ; Ethylene Glycol ; pharmacology ; Female ; Mice ; Morula ; physiology ; Pregnancy ; Sucrose ; pharmacology

OBJECTIVE: To find out the optimal freezing time in terms of developmental stage of mouse embryo and the effectiveness of vitrification method for freezing them. METHODS: Superovulation induction was performed using PMSG and hCG. Total 1,437 mouse embryos (vitrification group: 743, slow-freezing group: 694) were obtained and cultured with the T6 containing 0.4% BSA medium. Each developmental stage of embryos (1-, 2-, 4-, 8-cell, morula and blastocyst) were cryopreserved by vitrification and also by slow freezing method for comparison of the results. After thawing, the recovery rate, the survival rate and the blastocyst developmental rate were analysed and compared in two different settings. Student's t-test was used for statistical analysis. RESULTS: The survival and developmental rates at all subgroups of vitrification method are significantly higher than those of slow-freezing groups, but not in the recovery rates. In vitrification group, the survival rate and the blastocyst developmental rate are highest when frozen at morula stage, 98.4% and 86.4%, respectively. In slow-freezing group, the survival rate is also highest when frozen at morula stage, 87.2%, and the blastocyst developmental rate is highest when frozen at 8-cell stage, 78.1%. CONCLUSION: The vitrification method is more efficient for mouse embryo freezing compared with slow freezing one. Among various developmental stages of mouse embryos, morula stage seems to be the optimal stage for cryopreservation, whatever the freezing method applied. Therefore, we recommend embryo freezing at morula stage by vitrification method.
Animals ; Blastocyst ; Cryopreservation ; Embryonic Structures* ; Freezing ; Mice* ; Morula ; Superovulation ; Survival Rate ; Vitrification*

OBJECTIVES: The aim of this study was to evaluate the influence of three different media on preimplatation embryo development and the expression of Bcl-2, Mcl-1, Bax, and Bok in mouse. MATERiALS AND METHODS: Two-cell embryos were retrieved from iCR female mice (4 weeks old) at 48 hr after hCG injection and cultured in Ham's F-10, HTF, and G1.2 media. The developmental rate of 2-cell embryos was evaluated from 24 hr to 72 hr after culture. RT-PCR was performed for the detection of Bcl-2, Mcl-1, Bax, and Bok gene expression. RESULTS: The rates of morula and blastocyst in HTF and G1.2 media (88%, 98.1%) were significantly higher than those in Ham's F-10 media (39.6%) at 48 hr. Likewise, the rates of hatching and hatched blastocyst in HTF and G1.2 media (21.9%, 52.9%) were higher than those in Ham's F-10 media (3.5%) at 72 hr. Bcl-2 and Bax mRNAs were highly detected in embryos cultured in Ham's F-10 when compared in embryos cultured in HTF and G1.2. in contrast, the expression of Mcl-1 and Bok was not significantly different. CONCLUSION: These results show that HTF and G1.2 culture media increase the rate of blastocyst formation and stimulate Bcl-2 and Bax gene expression in mouse preimplantation embryos.
Animals ; Blastocyst* ; Culture Media ; Embryonic Development* ; Embryonic Structures ; Female ; Gene Expression ; Humans ; Mice* ; Morula ; Pregnancy ; RNA, Messenger

OBJECTIVE: To evaluate mouse embryos development in conventional medium IVF-20 versus vero cell coculture. METHODS: Female ICR mice aged 6 to 8 weeks, were stimulated with 5IU PMSG and 48 hours later were injected 5IU of hCG, then female and male mice were mated. At 48 hour post-hCG injection, oviducts were dissected out and 2-cell embryos were flushed. The 2-cell embryos were cultured in IVF-20 media or media containing vero cell (African green monkey kidney epithelial cell lines) for 120 hours. Coculture techniques have been applied in mouse 2-cell embryos culture used vero cell lines. RESULTS: 1. After 48 hours culture, 60.7% and 55.7% of 2 cell embryos developed to 4 cell and morulae stage, respectively, in IVF-20 culture medium, but significantly less embryos developed to 4 cell (47.6%, p<0.05) and momlae (42.9%, p<0.05) in vero cell coculture. 2. After 72 hours culture, 51.6% of 2 cell embryos developed to blastocyst and expanded blastocyst in IVF-20 culture medium, but significantly less embryos developed to blastocyst and expanded blastocyst (25.9%, p<0.01) in vero cell coculture. 3. After 96 hours culture, 37.7% and 32.6% of 2 cell embryos similar developed to expanded blastocyst and hatching in IVF-20 culture medium and vero cell coculture, respectively. 4. After 120 hours culture, 36.9% and 37.4% of 2 cell embryos similar developed to expanded blastocyst and hatching in IVF-20 culture medium and vero cell coculture, respectively. CONCLUSION: There was no difference of embryo development rates between the two culture groups. IVF-20 medium alone gives a benefit to the viability of an embryo compared with a vero cell coculture.
Animals ; Blastocyst ; Cercopithecus aethiops ; Coculture Techniques* ; Embryonic Development ; Embryonic Structures* ; Epithelial Cells ; Female ; Humans ; Kidney ; Male ; Mice* ; Mice, Inbred ICR ; Morula ; Oviducts ; Pregnancy ; Vero Cells*

OBJECTIVE: The objective of this study was to examine the effect on development of mouse preimplantation embryos in culture media with different composition of energy sources in vitro culture. METHODS: Two hundred and seventy one two-cell embryos were cultured in four different culture system for 96 hours. Group I (n=61) was cultured in DMEM-G (DMEM with glutamine) only, groupII (n=64) was cultured in DMEM-GGP (DMEM with glutamine, glucose and pyruvate) only, group III (n=72) was cultured for 48 hours in DMEM-G and then transferred to DMEM-GGP and group IV (n=74) was cultured for 48 hours in DMEM-GGP and then transferred to DMEM-G. Development of embryos in each group was observed every 24 hours. RESULTS: After 24 hours, the rate of development > or = 3-cell was significantly higher in groupII (87.5%) and IV (86.5%) compared with group I (59.0%) and III (62.5%). After 48 hours, the rate of development into > or = morula stage was significantly higher in GroupII (79.7%) and IV (86.5%) compared with group I (34.4%) and III (37.5%). After 72 hours, the rate of development into blastocyst was significantly higher in group IV (74.3%) compared with group I (49.2%) and III (45.8%). After 96 hours, the rate of development into > or = expanded blastocyst was significantly higher in group IV (70.3%) compared with group I (32.8%),II (53.1%), and group III (40.3%). CONCLUSION: Mouse preimplantation embryos development was the most effective in culture system with DMEM-GGP for 48 hours and then transferred to DMEM-G.
Animals ; Blastocyst* ; Culture Media* ; Embryonic Structures ; Glucose ; Glutamine ; Mice* ; Morula ; Pyruvic Acid

OBJECTIVES: Chromosome aneuploidy is associated with recurrent abortion and congenital anomaly and genetic diseases occur repeatedly in the specific families. Preimplantation genetic diagnosis (PGD) can prevent aneuploidy or genetic disease by selecting normal embryos before implantation and is an alternative to prenatal diagnosis. The aim of this study is to assess the outcome of PGD cycles by using FISH or PCR, and to determine the clinical usefulness and values in patients with risk of chromosomal aneuploidy or genetic disease. MATERIALS AND METHODS: From 1995 to Apr. 2001, a total of 108 PGD cycles in 65 patients with poor reproductive outcome were analyzed. The indications of PGD were translocation (n=49), inversion (n=2), aneuploidy screening (n=7), Duchenne muscular dystrophy (n=5) and spinal muscular atrophy (n=2). PGD was applied due to the history of recurrent abortion, previous birth of affected child or risk of aneuploidy related to sex chromosome aneuploidy or old age. Blastomere biopsy was performed in 6~10 cell stage embryo after IVF with ICSI. In the single blastomere, chromosome aneuploidy was diagnosed by using FISH and PCR was performed for the diagnosis of exon deletion in DMD or SMA. RESULTS: The FISH or PCR amplification was successful in 94.3% of biopsied blastomeres. The rate of transferable balanced embryos was 24.0% in the chromosome translocation and inversion, 57.1% for the DMD and SMA, and 28.8% for the aneuploidy screening. Overall hCG positive rate per transfer was 17.8% (18/101) and clinical pregnancy rate was 13.9% (14/101) (11 term pregnancy, 3 abortion, and 4 biochemical pregnancy). The clinical pregnancy rate of translocation and inversion was 12.9% (11/85) and abortion rate was 27.3% (3/11). In the DMD and SMA, the clinical pregnancy rate was 33.3% (3/9) and all delivered at term. The PGD results were confirmed by amniocentesis and were correct. When the embryos developed to compaction or morula, the pregnancy rate was higher (32%) than that of the cases without compaction (7.2%, p<0.01). CONCLUSIONS: PGD by using FISH or PCR is useful to get normal pregnancy by reducing spontaneous abortion associated with chromosome aneuploidy in the patients with structural chromosome aberration or risk of aneuploidy and can prevent genetic disease prior to implantation.
Abortion, Habitual ; Abortion, Induced ; Abortion, Spontaneous ; Amniocentesis ; Aneuploidy* ; Biopsy ; Blastomeres ; Child ; Chromosome Aberrations ; Diagnosis ; Embryonic Structures ; Exons ; Female ; Humans ; Mass Screening ; Morula ; Muscular Atrophy, Spinal ; Muscular Dystrophy, Duchenne ; Parturition ; Polymerase Chain Reaction ; Pregnancy ; Pregnancy Rate ; Preimplantation Diagnosis* ; Prenatal Diagnosis ; Prostaglandins D ; Sex Chromosomes ; Sperm Injections, Intracytoplasmic