• Journal of Embryo Transfer
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• v.16 no.3
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• pp.193-201
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• 2001

This study was designed to examine the factors affecting in fertilization and development of embryos in vitro, and to examine whether zone drilling by laser irradiation can improve the hatching rate of IVF embryos from DNA marker-proved Hanwoo. DNA markers related to marbling score were identified using DNA fingerprinting with Ml3 probe and restriction enzyme Hae III. Oocytes were aspirated from immature ovarian follicles using a combined method of rectal ovarian-palpation and transvaginal ultrasound-guidance(6.5MHz) under local anesthesia. The aspirated oocytes were washed twice with fresh D-PBS containing 5% FBS and were rewashed 4 to 5 times with TCM-199 containing 5% FBS. A morphological grade of I to IV was assigned to each oocyte. Data were analyzed using the GLM procedure of SAS. Sperm separation methods did not have any significant effect on cleavage or developmental abilities of IVF embryos. Significantly(P<0.05) higher cleavage rate was observed in embryos from GI(60.0%, 3/5), GII(69.2%, 18/26) and GIII(62.1%, 59/95) compared to embryos from GIV oocytes(36.2%, 25/69). And the developmental rate to blastocyst stage was higher(P<0.05) in embryos from GI(33.3%, 1/3) and GII oocytes(38.9%, 7/18) than those from GIII(16.9%,10/59) and GIV oocytes(4.0%, 1/25). There was no significant difference in development of IVF embryos to blastocyst by media for in vitro culture. Proportion of hatched blastocyst was significantly(P<0.05) higher in embryos received zona drilling by laser than those of non-drilled.

• Journal of Embryo Transfer
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• v.29 no.3
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• pp.241-248
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• 2014

This study was carried out to evaluate the effects of embryonic stage, cryoprotectant, and freezing-thawing method on the rates of survival and development of the cryopreserved mouse early embryo and finally to establish the cryopreservation method of surplus embryos obtained during assisted reproductive technology (ART). Two to eight cell embryos were obtained from oviducts of mated $F_1$ hybrid female mice superovulated by PMSG and hCG. Two-step EG, DMSO and 4-step EG, DMSO were used as cryoprotectant and dehydration and rehydration method of embryos, and slow-cooling or rapid-cooling method was used as frozen program. The survival rates of embryos were measured after thawing and rehydration, and the developmental rates of embryos were compared and observed during culturing embryos for 24, 48, 72, 96 hrs. As for the survival and development rates of embryos according to embryonic stage, the survival rate of 2 cell stage in EG and DMSO was significantly higher than 4~8 cell (65.4% versus 61.2%, 81.1% versus 72.5%) (p<0.01, p<0.01), but the development rates of 4~8 cell embryos in EG and DMSO were significantly higher than 2 cell embryos for whole culture period (p<0.01) and the development rates of 4~8 cell embryos in EG were significantly higher than 2 cell embryos in DMSO (p<0.01). As for the survival and development rates of embryos according to cryoprotectant, the survival rate of 2 cell embryo in DMSO was significantly higher than that in EG(77.0% versus 64.4%) (p<0.01), whereas the development rate of embryos was not differ till 24 hrs. The development rate from morular to hatching blastocyst, however, was sinificantly higher in EG than in DMSO during 48 hr (p<0.01). The survival rate of 4~8 cell embryo was 62.5% in EG and 73.3% in DMSO. The development rates of embryo in EG were significantly higher for whole culture periods (p<0.01, 0.05). In respect to the effect of freezing and thawing program on the survival and development rates of embryos, method of slow cooling and rapid thawing was more effective than that of rapid cooling and rapid thawing. The survival rate of embryo in 2 cell stage was higher than in 4~8 cell stage, and EG appears more effective cryoprotectant than DMSO because EG showed better development rates of embryos in 2 and 4~8 cell stage. Moreover, slow cooling and rapid thawing method was considered as the best cryopreservation program.

• Clinical and Experimental Reproductive Medicine
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• v.24 no.2
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• pp.211-216
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• 1997

The present study was carried out to evaluate whether the coculture system of human embryos with Vero cells can improve the quality of embryo or overcome the repetitive implantation failures in order to obtain pregnancy. From January to December 1996, a total 202 cases which patients with the problems of repetitive implantation failures (group I) or those with the poor embryonic quality in their previous cycles (group II) was analysed. The quality of cocultured embryo, pregnancy, on-going and implantation rates between coculture and control groups were compared. Of 93 cases in group I, coculture was performed in 34 cases and conventional IVF for the rest. Of 109 cases in group II, 36 for coculture and 73 for conventional IVF. In group I, pregnancy, on-going and implantation rates in coculture group (14/34 (41.2%), 9/34 (26.5%), 16/81 (19.8%), respectively) were higher than those of control (11/59 (18.6%), 8/59 (13.6%), 12/152 (7.9%), respectively). There is significance in the pregnancy and implantation rates (p=0.028 and p=0.015). In group II, pregnancy, on-going and implantation rates in coculture group (8/36 (22.2%), 5/36 (13.9%), 8/87 (9.2%), respectively) were higher than those of control (5/73 (6.8%), 3/73 (4.1%), 3/158 (1.9%), respectively). Like the result of group I, there is significance in the pregnancy and implantation rates (p=0.028 and p=0.022). Coculture system with Vero cells works well in the groups of the two indications. Although the case of 3 day-coculture was small as 15 cases in group II, 3 day-coculture improved pregnancy rate (4/15 (26.7%)). Therefore, 3 day-coculture with assisted hatching is recommended to the patients with poor embryonic quality. In conclusion, coculture system with Vero cells can be suggested as an effective method which improves pregnancy rate in those who have repetitive implantation failures or whose embryonic quality was poor in their previous cycles.