• Clinical and Experimental Reproductive Medicine
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• v.25 no.2
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• pp.179-187
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• 1998

In mammal, lots of follicles start simultaneously their growth but only a few oocytes are ovulated in every sexual cycles. Most of matured and grown oocytes are destined to degenerate by atresia. However, the molecular and physiological mechanisms are not elucidated yet. The present study was designed to establish an induction method of follicular atresia with ketamine or pentobarbitone and evaluate the effect of these anesthetics on oocyte maturation and granulosa cell apoptosis of the mouse ovarian follicle. The percentages of degenerated oocyte and apoptotic granulosa cell in ketamine treated groups were significantly higher than that in controls (58.9% vs 33.5%, p<0.01, degeneration; 44.9% vs 26.6%, p<0.01, apotosis). Futhermore, it was revealed that the concentrations of progesterone in both groups were markedly higher than that in control. In cunclusion, it is considered that ketamine induce an atresia as pentobarbitone, and may be useful for inducing follicular atresia.

• Clinical and Experimental Reproductive Medicine
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• v.23 no.3
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• pp.293-301
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• 1996

In the present study, mouse follicular oocytes and 2-cell embryos(late -zygote stage embryos included) were cultured on the electric pad for electric stimulation in the culture incubator. In addition, follicular oocytes and embryos were tested for maturation and development under higher temperature condition($39^{\circ}C$).Mouse follicular oocyte maturation were not affected by anion electric stimulation and there is no significant difference in GBVD and MI between the control and experiment group after 4hr culture. In the embryo culture, it was found that more morula and blastocyst were found in the electric stimulation group rather than the control(96hr). This may seem to be caused with cytoplasmic $Ca^{2+}$ transient rise by electric stimulation(anion pad). On the other hand higher temperature incubation ($39^{\circ}C$) on the anion pad caused all the embryos degenerated within $12h{\sim}24hr$ culture. This was quite different from large animal embryos(bovine, pig, sheep), in which beneficial effect of high temperature incubation for oocyte maturation and embryo development were found.

• Clinical and Experimental Reproductive Medicine
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• v.48 no.4
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• pp.347-351
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• 2021

Objective: We investigated the impact of vitamin D₃ (VD3) supplementation during mouse preantral follicle culture in vitro and the mRNA expression of 25-hydroxylase (CYP2R1), 1-alpha-hydroxylase (CYP27B1), and vitamin D receptor (VDR) in mouse ovarian follicles at different stages. Methods: Preantral follicles were retrieved from 39 BDF1 mice (7-8 weeks old) and then cultured in vitro for 12 days under VD3 supplementation (0, 25, and 50 pg/mL). Follicular development and the final oocyte acquisition were assessed. Preantral follicles were retrieved from 15 other BDF1 mice (7-8 weeks old) and cultured without VD3 supplementation. Three stages of mouse ovarian follicles were obtained (preantral, antral, and ruptured follicles). Total RNA was extracted from the pooled cells (from 20 follicles at each stage), and then reverse transcriptase-polymerase chain reaction was performed to identify mRNA for CYP2R1, CYP27B1, and VDR. Results: The survival of preantral follicles, rates of antrum formation and ruptured follicles (per initiated follicle) and the number of total or mature oocytes were all comparable among the three groups. Both CYP2R1 and CYP27B1 were expressed in antral and ruptured follicles, but not in preantral follicles. VDR was expressed in all three follicular stages. Conclusion: VD3 supplementation in vitro (25 or 50 pg/mL) did not enhance mouse follicular development or final oocyte acquisition. Follicular stage-specific expression of CYP2R1, CYP27B1, and VDR was observed.

• Reproductive and Developmental Biology
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• v.28 no.4
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• pp.267-273
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• 2004

Maturation of oocytes is maintained by complex procedures along with follicular genesis and is a critical step for embryonic development. Purine known as an oocyte maturation regulator is present in follicular fluid. In this study, the roles of guanosine as a strong inhibitor of GVBD and a modulator of cyclic GMP concentration in ooyctes were revealed. Denuded immature oocytes were treated with guanosine, and the maturation rates and cGMP concentration of oocytes were measured. GVBD was blocked in a concentration dependent manner by guanosine, but this effect was reversible. However, GVBD was lagged yet not significant by adenosine. Both guanosine and adenosine modified cGMP concentration in oocytes. The characteristic of the guanosine-treated oocyte was significantly higher cGMP compared with the adenosine-treated oocyes at initial time of the maturation. Based these results, guanosine may be a strong and reversible GVBD inhibitor. Although the precise mechanism of guanosine presently is unclear, the results suggest that guanosine may lead the accumulation of cGMP in oocyte cytoplasm, which in turn suppresses GVBD.

• Journal of Embryo Transfer
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• v.10 no.3
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• pp.183-191
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• 1995

This experiment was carried out to study the determination of survival of vitrified and thawed mammal follicular oocytes by FDA-test. Oocytes were divided into 3 groups according to attachment of cumulus cell. Group A oocytes were tightly surrounded by cumulus cell, group B oocytes were partially surrounded by cumulus cell, and group C oocytes were poorly surrounded by cumulus cell. Vitrification solution developed by our previous study (Kim et al, 1992) which consisted of permeable agent (20 % glycerol + 10 % ethylene glycol) and nonpermeable agent (30 % Ficoll + 10 % sucrose). Oocytes (7~10) loaded into 0.25 ml straw after 10 min equilibration were plunged into liquid nitrogen (- 196$^{\circ}C$) directly. The FDA-score of vitrified and thawed group A oocytes was higher in rat (4.2) than in rabbit (3.9), cow (3.8), mouse (3.4) and porcine (2.4), however that of cumulus cell was higher in rabbit (4.7) than in rat (4.1), cow (2.9), porcine (2.6) and mouse (1.4). The FDA-score of vitrified and thawed group B oocytes were 3.1 (cow), 2.9 (rabbit), 2.9 (mouse), 2.6 (rat) and 2.5 (porcine), respectively. However that of cumulus cell was higher in rabbit (3.7) than in porcine (2.6), rat (2.3), cow (1.7) and mouse (0.3). The FDA-score of vitrified and thawed group C oocytes was higher in mouse (4.1) than in cow (2.9), rabbit (2.6), rat (1.3) and porcine (1.1). As shown in the above results, The survival rates of oocytes were higher in group A than in group B and C except in mouse and cow. These results suggest that the survival of cumulus cell as well as follicular oocytes can be reliably judged by their fluorescence with FDA-test.

• Proceedings of the Zoological Society Korea Conference
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• 2000.10a
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• pp.190.1-190
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• 2000

No Abstract, See Full Text

• The Korean Journal of Zoology
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• v.33 no.1
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• pp.45-52
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• 1990

In order to determine whether maturation inhibiting activity(MIA) in the cytoplasm of growing follicular oocytes would suppress the cleavage of the embryonal cells, the growing oocytes were fused with the 2 or 4 cell blastomeres and then examined for the nuclear phase of the fused giant cells 24 hr after culture. A significant number of the giant cells(60%) composed of growing mouse oocyte and 2 cell mouse blastomere(1/2) in interphase has contained 2 nuclei 24 hr after culture and most of the giant cells (90%) composed of the growing oocyte and 4 cell blastomere(1/4) also contained 2 nuclei after culture. The unfused blastomeres or the isolated blastomeres cultured without fusion treatment cleaved one cell cycle under the same culture condition. In contrast, the nucleus of the growing oocytes was disintegrated and the chromosome condensed when fused with 2 cell blastomere in mitosis. The growing rat oocytes also suppressed the nuclear disintegration of the mouse embryonal cells during culture. The data presented here showed that MIA in the growing mammalian oocyte inhibited the cleavage of the embryonal cells in interphase stage, but not in milosis stage.

• Clinical and Experimental Reproductive Medicine
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• v.28 no.2
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• pp.79-86
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• 2001

Objective: Mouse pre-antral follicles require the addition of gonadotropins (Gns) to complete maturation and ovulation of oocyte and antrum formation in vitro. However, we tried examination of in vitro growth of mouse pre-antral follicles in medium without Gns and/or phygiological factors. And also, pre-antral follicles were isolated from ovaries by mechanical method. Our present studies were conducted to evaluate on the growth of follicles and intra-follicular oocytes and antrum formation in vitro of mouse pre-antral follicles in two different media. Methods: Pre-antral follicles ($91{\sim}120{\mu}m$) were isolated mechanically by fine 30G needles not using enzymes from ovaries of 3-6 week-old female ICR mice. Isolated pre-antral follicles were cultured in $20{\mu}l$ droplets of TCM (n=17; follicles: $107.8{\pm}1.58{\mu}m$; oocytes: $57.9{\pm}1.2{\mu}m$) or MEM (n=12; follicles: $109.3{\pm}2.53{\mu}m$; oocytes: $55.4{\pm}1.6{\mu}m$) under mineral oil on the 60 mm culture dish. All experimental media was supplemented with 10% FBS without Gns and/or physiological factors. Pre antral follicles were individually cultured for 8 days. Antram formation and growth of pre-antral follicles and intra-follicular oocytes were evaluated using precalibrated ocular micrometer at X200 magnifications during in vitro culture. Results were analyzed using combination of Student's t-test and Chi-square, and considered statistically significant when p<0.05. Results: Antrum formation had started in two culture media on day 2. On day 8, antrum formation had occurred in 58.3% of pre-antral follicles cultured in DMEM, but only in 23.5% of those cultured in TCM (p=0.0364). Growth of pre-antral follicles and intra-follicular oocytes were observed on day 4 and 8. On day 4, follicular diameter was similar (p=0.1338) in TCM ($119.4{\pm}2.58{\mu}m$) and MEM ($125.4{\pm}4.52{\mu}m$). However, on day 8, diameters of pre-antral follicles cultured in MEM ($168.9{\pm}17.29{\mu}m$) were significantly bigger (p=0.0248) than that in TCM ($126.7{\pm}4.28{\mu}m$). On day 4 and 8, diameters of intra-follicular oocytes were similar in TCM ($67.1{\pm}1.3$ and $72.4{\pm}0.9{\mu}m$) and MEM ($65.2{\pm}1.7$ and $73.3{\pm}1.5{\mu}m$), respectively. Conclusion: We can conform that medium without Gns and/or physiological factors can be used for in vitro antrum formation and growth of pre-antral follicles and intra-follicular oocytes in mouse. In conclusion, MEM supplemented with FBS can be used for growth in vitro of mouse pre-antral follicles isolated mechanically.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.3
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• pp.319-327
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• 2009

Follicular fluid meiosis-activating sterol (FF-MAS) has been suggested as a positive factor which could improve the oocyte quality and subsequent embryo development after in vitro fertilization. However, FF-MAS is a highly lipophilic substance and is hard to detect in studying the relationship between MAS and quality of oocyte maturation. The present study focused on the expression of lanosterol 14${\alpha}$-demethylase (LDM), a key enzyme that converts lanosterol to FF-MAS, on mouse oocyte maturation and its potency on development. LDM expression was strong in gonadotropin-primed germinal vesicle stage oocytes, weak after germinal vesicle breakdown (GVBD), and then strong in MII stage oocytes. The LDM-specific inhibitor azalanstat significantly inhibited oocyte fertilization (from 79.4% to 68.3%, p<0.05). Also, azalanstat (5 to 50 ${\mu}M$) decreased the percentage of blastocyst development dosedependently (from 78.7% to 23.4%, p<0.05). The specific inhibition of sterol ${\Delta}14$-reductase and ${\Delta}7$-reductase by AY9944 accumulates FF-MAS and could increase blastocyst development rates. Additionally, in the AY9944 group, the rate of inner cell mass (ICM)/ total cells was similar to that of in vivo development, but the rate was significantly decreased in azalanstat treatment. In conclusion, LDM, the key enzyme of FF-MAS production, may play an important role in fertilization and early development of the mouse embryo, especially in vitro.

• Clinical and Experimental Reproductive Medicine
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• v.27 no.4
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• pp.387-392
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• 2000

Objectives: 1) To compare the efficacy of urofollitropin (Follimon) to that of recombinant human FSH (rhFSH) on the growth and maturation of mouse early preantral follicles in vitro, and 2) effect of vitrification on the growth and maturation of preantral follicles and oocytes . Methods: Isolated early preantra1 follicles (100-130 ${\mu}m$ diameter) were cultured for 12 days in 20 ${\mu}l$ ${\alpha}$-MEM media drop under the mineral oil. Follimon or rhFSH was added to the culture medium at various concentrations (0, 10, 100, and 1000 mIU/ml). Results: With Follimon, the dose of 10 mIU/ml showed the best follicle survival, growth, and MIl rate of oocyte than the other concentrations. Whereas the optimal dose of rhFSH was 100 mIU/ml. Despite the different optimal doses, the efficacy of two different FSHs on the follicle growth and maturation was similar. Isolated mouse preantral follicles were cryopreserved by vitrification and cultured in vitro for 12 days with 100 mIU/ml rhFSH. Despite the decreased follicular survival rate after thawing, the follicular growth and maturation rate of its oocyte were comparable to those of the fresh follicle. Conclusion: Results from the present study revealed that 1) the optimal doses of Follimon and rhFSH for in-vitro culture of mouse follicles are different, and 2) the frozen-thawed follicles develop normally after vitrification.