• Asian-Australasian Journal of Animal Sciences
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• v.22 no.1
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• pp.35-41
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• 2009

This study was undertaken to evaluate how ${\beta}$-mercaptoethanol (bME), an exogenous antioxidant, interacts with preantral follicles cultured in vitro. Mouse primary or secondary follicles were cultured in glutathione (GSH)-free or GSH-containing medium supplemented with bME of various concentrations, and the growth of preantral follicles, the maturation of intrafollicular oocytes and preimplantation development after parthenogenesis were monitored. In experiment 1, 0, 25, 50 or 100 ${\mu}M$ bME was added to culture medium supplemented with 100 ${\mu}M$ GSH or not. When secondary follicles were cultured in GSH-free medium, no significant change in follicle growth was detected after bME addition. However, exposure to bME in the presence of GSH significantly inhibited both follicle growth and oocyte maturation. Such detrimental effect became prominent in primary follicles and bME strongly inhibited follicle growth in the absence of GSH. In conclusion, there are stage-dependent effects of bME on follicle growth and oocyte maturation, and selective use of antioxidants contributes to establishing an efficient follicle culture system.

• Journal of Animal Reproduction and Biotechnology
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• v.34 no.1
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• pp.35-39
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• 2019

This study aimed to recover the ovarian function through in vitro culture of preantral follicles from aged mice. First, we isolated the preantral follicles from ovaries of sixty-seven-week old B6D2F1 mice with decreased fecundity to know how many follicles were present in them, which was 6 preantral follicles including 2 primary, 2 early secondary and late secondary follicles from 8 aged mice. It was confirmed that a few follicles (~2) were present in aged mice through histological analysis compared to adult mice as control. The 9 days of in vitro culture of preantal follicles showed in vitro growth and induced maturation after treatment with hCG (2.5 IU/mL) and EGF (5 ng/mL). Cumulus cells in the cumulus-oocyte complexes (COCs) were removed using hyaluronidase and oocytes at the germinal vesicle (GV) and GV breakdown (GVBD) were obtained from preantral follicle culture of aged mice in vitro. In conclusion, these observations demonstrated that there still were a few preantral follicles in the ovaries of 67 week-old mice, which we were able to culture in vitro and oocytes were obtained from them. This study proposed an in vitro culture system using preantral follicle as a therapeutic strategy for fertility preservation in humans for assisted reproductive medicine.

• Journal of Animal Reproduction and Biotechnology
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• v.34 no.2
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• pp.117-122
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• 2019

The objective of this study was to establish an in vitro culture system for ovarian preantral follicles of B6D2F1. First, we optimized the in vitro preantral-follicle culture by culture duration, follicle stimulating hormone (FSH) type, and activin A concentration. Duration of in vitro culture for 9, 11, and 13 days was sufficient for the normal development of preantral follicles to antral follicles. Formation of cumulus cell-oocyte complex (COC) was induced by treatment with human chorionic gonadotropin (hCG; 2.5 IU/mL) and epidermal growth factor (EGF; 5 ng/mL). In addition, metaphase II (MII) oocytes formed during this in vitro culture of preantral follicles. In vitro preantralfollicle culture for 9 days showed higher rates of growth and maturation, thus yielding a greater number of antral follicles, and there were significant differences (p < 0.05) in the number of MII oocytes (that formed from these preantral follicles via differentiation) between the 9-day culture and 11-day or 13-day culture. The follicles cultured for 9 days contained a tightly packed well-defined COC, whereas in follicles cultured for 11 days, the COC was not well defined (spreading was observed in the culture dish); the follicles cultured for 13 days disintegrated and released the oocyte. Second, we compared the growth of the preantral follicles in vitro in the presence of various FSH types. There were no significant differences in the growth and maturation rates and in differentiation into MII oocytes during in vitro culture between preantral follicles supplemented with FSH from Merck and those supplemented with FSH from Sigma. To increase the efficiency of MII oocyte formation, the preantral follicles were cultured at different activin A concentrations (0 to 200 ng/mL). The control follicles, which were not treated with activin A, showed the highest rate of differentiation into antral follicles and into MII oocytes among all the groups (0 to 200 ng/mL). Therefore, activin A (50 to 200 ng/mL) had a negative effect on oocyte maturation. Thus, in this study, we propose an in vitro system of preantral-follicle culture that can serve as a therapeutic strategy for fertility preservation of human oocytes for assisted reproductive medicine, for conservation of endangered species, and for creation of superior breeds.

• 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.

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.31-31
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• 2001

This study was to establish in uitro culture system of mouse preantral follicles and to obtain higher in vitro development rates and production of live young. Preantral follicles were obtained from 12-day-old FI mouse (C57BL $\times$ CBA) by enzymatical methods. Oocyte-granulosa cell complexes (OGCs) of preantral follicles were loaded on Transwell-COL insert and cultured in $\alpha$MEM supplemented with 5% FBS, 100 mIU/$m\ell$ FSH and 100 mIU/$m\ell$ hMG for IVG. IVM was performed in $\alpha$MEM supplemented 1.5 IU/$m\ell$ hCG for 18 hrs and IVF was carried out in Ml6 medium. Embryos were cultured in modified Ml6 medium supplemented 10% FBS for 4 days. The effect of the OGCs size on the nuclear/cytoplasmic maturation was significantly higher in 120-150 ${\mu}{\textrm}{m}$ (MII: 33.0%, $\geq$2-cell: 36.7%, $\geq$morula: 20.9%) than in 70-110 ${\mu}{\textrm}{m}$ (MII: 12.2%, $\geq$2-cell: 10.2%, $\geq$morula: 4.8%) (p<0.001). In period of the IVG days, the rate of $\geq$2-cell was significantly higher in 10 days(38.2%) than in 12 days (20.0%) (p<0.01). In period of IVF time, 9 hrs ($\geq$2-cell: 31.5%, $\geq$ morula: 14.3%) indicated significantly higher cytoplasmic maturation rate than 4 hrs ($\geq$2-cell: 17.5%, This study was to establish in vitro culture system of mouse preantral follicles and to obtain higher in vitro development rates and production of live young. Preantral follicles were obtained from 12-day-old FI mouse (C57BL $\times$ CBA) by enzymatical methods. Oocyte-granulosa cell complexes (OGCs) of preantral follicles were loaded on Transwell-COL insert and cultured in $\alpha$MEM supplemented with 5% FBS, 100 mIU/$m\ell$ FSH and 100 mIU/$m\ell$ hMG for IVG. IVM was performed in $\alpha$MEM supplemented 1.5 IU/$m\ell$ hCG for 18 hrs and IVF was carried out in Ml6 medium. Embryos were cultured in modified Ml6 medium supplemented 10% FBS for 4 days. The effect of the OGCs size on the nuclear/cytoplasmic maturation was significantly higher in 120-150 ${\mu}{\textrm}{m}$ (MII: 33.0%, $\geq$2-cell: 36.7%, $\geq$morula: 20.9%) than in 70-110 ${\mu}{\textrm}{m}$ (MII: 12.2%, $\geq$2-cell: 10.2%, $\geq$morula: 4.8%) (p<0.001). In period of the IVG days, the rate of $\geq$2-cell was significantly higher in 10 days(38.2%) than in 12 days (20.0%) (p<0.01). In period of IVF time, 9 hrs ($\geq$2-cell: 31.5%, $\geq$ morula: 14.3%) indicated significantly higher cytoplasmic maturation rate than 4 hrs ($\geq$2-cell: 17.5%, $\geq$morula: 4.8%) and 7 hrs ($\geq$2-cell: 20.4%, $\geq$morula: 6.1%) (p<0.01). However, there was no difference in cytoplasmic maturation between co-cultured preantral follicle ( $\geq$morula: 17.4%) and preantral follicle cultured in Ml6 ( $\geq$morula: 17.4%). 22 morula and blastocysts produced in above optimal condition were transferred to uterus of 2 pseudopregnant recipients, 1 recipient was pregnant and then born 1 live young. This result demonstrates that in vitro culture system of preantral follicles can be used efficiently as another method to supply mouse oocyte.morula: 4.8%) and 7 hrs (2-cell: 20.4%, $\geq$morula: 6.1%) (p<0.01). However, there was no difference in cytoplasmic maturation between co-cultured preantral follicle ( $\geq$morula: 17.4%) and preantral follicle cultured in Ml6 ( $\geq$morula: 17.4%). 22 morula and blastocysts produced in above optimal condition were transferred to uterus of 2 pseudopregnant recipients, 1 recipient was pregnant and then born 1 live young. This result demonstrates that in vitro culture system of preantral follicles can be used efficiently as another method to supply mouse oocyte.

• Korean Journal of Animal Reproduction
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• v.23 no.1
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• pp.53-61
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• 1999

The present study was designed to investigate the effects of gonadotrophins on in vitro growth and maturation in mouse preantral follicles. Ovaries were removed from 12-day-old ICR mice. Follicles were dissociated enzymetically in Leibovitz L-15 medium containing 1 mg/$m\ell$ collagenase and 0.2 mg/$m\ell$ DNase I. The follicles were cultured on Transwell-COL membrane inserts in six well cluster dishes for 10 days. The culture medium was $\alpha$MEM medium supplemented with 5% fetal bovine serum and FSH or HMG. After 10 days of growth in vitro, follicles were allowed to mature for 18~20 hr in medium supplemented with 1.5 IU/$m\ell$ hCG. The oocytes were then denuded of their cumulus cells and assessed maturation status. Concentrations of oestradiol and progesterone were measured with a radioimmunoassay. Oocyte diameter was determined with an ocular micrometer. The survival and Metaphase II rates of oocytes were significantly higher in FSH treatment groups than in control group (P＜0.001), but there were no differences among the groups of treated FSH concentration. The survival and Metaphase II rates of oocytes in HMG treatment group (60.9 and 40.6%) were higher than in FSH treatment group (76.6 and 48.2%) and control group (49.2 and 7.1%). The survival and Metaphase II rates of oocytes on both FSH and LH treatment groups were no differences among the ratios of FSH and LH. Diameter of oocyte was no differences among the treatment groups, but smaller than compared to in vivo grown oocyte. Through the entire culture period, secretions of oestradiol and progesterone were significantly less in control group than in HMG and FSH treatment groups. These results suggest that gonadotrophins playa key role in in vitro culture of mouse preantral follicles. Especially, addition of FSH and LH should be more effective than FSH alone.

• Korean Journal of Animal Reproduction
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• v.25 no.2
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• pp.101-111
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• 2001

The present study was conducted to develop an in vitro culture system that would support bovine follicle growth from preantral to antral stage, oocyte maturation, fertilization, and embryonic development. Bovine preantral follicles (150$\pm$1.2 ${\mu}{\textrm}{m}$) surrounded by theca cell were isolated ezymatically and mechanically from ovarian cortical slides in Leibovitz L-l5 medium containing 1 mg/$m\ell$ collagenase and 0.2 mg/$m\ell$ DNase I and cultured for 25 days in the presence of different concentrations of bovine FSH and LH in $\alpha$MEM medium. The survival and growth rates of follicles cultured in the presence of FSH (10~150 ng/$m\ell$) were significantly higher than those of control group (P ＜ 0.001), but no significant differences were observed in survival and growth rates of follicles between the LH treatment groups (1~125 ng/$m\ell$) and the control. The survival (40%) and growth (244 $\pm$ 0.5 $\mu\textrm{g}$) of follicles cultured with FSH (90 ng/$m\ell$) and LH (25 ng/$m\ell$) were higher than those of control (25%, 160 $\pm$1.0 $\mu\textrm{g}$). Finally, 50% percent of healthy antral follicles were obtained, and almost 60% of them has complete meiotic division with 1st polar body (18.1%) and 10.0% have developed to the cleaved embryo and blastocyst stage. These results suggest that bovine preantral follicle with intact theca cell can grow to the antral stage using these culture conditions, and that oocytes from in vitro-matured bovine preantral follicle may acquire meiotic competence and can undergo fertilization and development.

• Clinical and Experimental Reproductive Medicine
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• v.49 no.3
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• pp.175-184
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• 2022

Objective: The aim of this study was to evaluate the impacts of platelet-rich plasma (PRP) and conditioned medium (CM) derived from endometrial stromal cells on mouse preantral follicle culture in a two-dimensional system to produce competent mature oocytes for fertilization. Methods: In total, 240 preantral follicles were isolated from female mouse ovarian tissue and divided into four groups. The preantral follicles were isolated three times for each group and then cultured, respectively, in the presence of alpha minimum essential medium (control), PRP, CM, and PRP+CM. The in vitro growth, in vitro maturation, and cleavage percentage of the preantral follicles were investigated. Immunocytochemistry (IHC) was also conducted to monitor the meiotic progression of the oocytes. Additionally, the mRNA expression levels of the two folliculogenesis-related genes (Gdf9 and Bmp15) and two apoptosis-related genes (Bcl2 and Bax) were investigated using real-time polymerase chain reaction. Results: In the PRP, CM, and PRP+CM groups, the preantral follicle maturation (evaluated by identifying polar bodies) were greater than the control group. The cleavage rate in the CM, and PRP+CM groups were also greater than the control group. IHC analysis demonstrated that in each treatment group, meiotic spindle was normal. In the PRP+CM group, the gene expression levels of Bmp15, Gdf9, and Bcl2 were greater than in the other groups. The Bax gene was more strongly expressed in the PRP and control groups than in the other groups. Conclusion: Overall, the present study suggests that the combination of CM and PRP can effectively increase the growth and cleavage rate of mouse preantral follicles in vitro.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.8
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• pp.1190-1195
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• 2007

This study was conducted to improve efficiency of a follicle culture system without reducing developmental competence of intrafollicular oocytes. Preantral follicles (100 to $125{\mu}m$ in diameter) of F1 hybrid (B6CBAF1) mice were cultured singly for 216 h in modified ${\alpha}$-MEM-glutamax medium, to which 2.5 IU/ml hCG and epidermal growth factor was added 16 h prior to the end of culture. Medium change was either performed three times (54 h interval), twice (72 h interval), once (108 h interval), or not at all (216 h interval). Maturation (progression to the metaphase II stage) of intrafollicular oocytes was detected from 4 days after culture in the three-times change treatment, while all treatments yielded mature oocytes from day 5 of culture. Compared with the three-times change, decreasing the change frequency to once did not reduce the capacity to begin maturation (germinal vesicle breakdown of 82 to 86%), to mature (78 to 79%) and to develop into blastocysts after parthenogenetic activation (29 to 32%). Morphological parameters were similar among these treatments. Except for the no medium change treatment, similar colony-forming activity of inner cell mass cells after culturing of blastocysts in leukemia inhibitory factor-containing medium was detected, while the morphology of the colony-forming cells deteriorated in the change-once treatment compared with the change twice or three-times. In conclusion, the efficiency of the preantral follicle culture system could be improved by reducing frequency of medium change up to a 72 h interval (three times in total 216 h culture) without decreasing developmental competence of oocytes.

• Clinical and Experimental Reproductive Medicine
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• v.46 no.4
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• pp.152-165
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• 2019

Objective: This study aimed to examine the effect of vitrification on apoptosis and survival in human preantral follicles after thawing. Methods: This experimental study was conducted at an acute tertiary care hospital from March 2012 to April 2013. Ovaries were sliced into 5 × 5 × 1-mm pieces and divided into the following three groups: preantral follicle isolation, ovarian tissue vitrification-warming followed by follicle isolation, and immunohistochemistry of fresh ovarian tissue. For statistical analyses, the Student t-test, chi-square test, Kruskal-Wallis test, and Kaplan-Meier survival analysis were used. Results: A total of 161 preantral follicles (70% secondary) were collected from ovarian cortex tissue of six women between 30 and 37 years of age who underwent oophorectomy due to cervical cancer or breast cancer. There were no significant differences in the follicular morphology of fresh preantral follicles and vitrified follicles after thawing. The mean Fas ligand (FasL) mRNA expression level was 0.43 ± 0.20 (relative to β-actin) in fresh preantral follicles versus 0.51 ± 0.20 in vitrified follicles (p= 0.22). The mean caspase-3 mRNA expression level in fresh preantral follicles was 0.56 ± 0.49 vs. 0.27 ± 0.21 in vitrified follicles (p= 0.233). One vitrified-thawed secondary follicle grew and developed to an antral follicle within 6 days of culture. Conclusion: Vitrification did not affect preantral follicle morphology or mRNA expression of the apoptosis markers FasL and caspase-3. Further studies are required to establish whether vitrification affects the outcomes of in vitro culture and the maturation of preantral follicles.