• Reproductive and Developmental Biology
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• v.32 no.2
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• pp.111-115
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• 2008

The aim of this study was to examine more effective cryoprotectant for the cryopreservation of mouse preantral follicles. Enzymetically isolated preantral follicles from 12-day-old mice were cryopreserved by a slow freezing protocol with 1.5 M propanediol (PROH), dimethyl sulphoxide (DMSO) or glycerol (GLY) and then grown and matured in vitro for 11 days after thawing. The survival of preantral follicles immediately after freezing and thawing was not different among the PROH (68.2%), DMSO (72.4%) and GLY (72.1%). After grown and matured in vitro, the rates of survival and metaphase II oocytes were 54.9% and 36.6% for PROH which was significantly higher rates (p<0.05) compared with the rates obtained from DMSO (16.9% and 9.0%) and GLY (16.3% and 7.5%). The diameter of metaphase II oocytes from pre antral follicles frozen in PROH ($67.4{\pm}1.8\;{\mu}m$) was significantly (p<0.05) smaller than that of the fresh preantral follicles ($69.1{\pm}2.3\;{\mu}m$). The results from the present study revealed that PROH is more suitable cryoprotectant for the cryopreservation of mouse preantral follicles.

• Nuclear Engineering and Technology
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• v.31 no.4
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• pp.385-390
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• 1999

Ovarian follicles are faced with one of two fates, atresia or development. Up to 99% of follicles become degenerated rather than ovulated in female life span. Thus, atresia occurs at all stages of follicle development in mammalian ovaries. In the present experiment, the effect of ${\gamma}$-radiation on primordial follicles was morphologically analyzed in a mouse ovary. Thirty-seven percent of the primordial follicles in the non-irradiated control mice ovaries were abnormal. At day 8 post irradiation, most of primordial follicles became atretic. They lost their integrity of architecture in the follicular shape. Then, all the oocytes disappeared from the follicles. And only 3 to 4 granulosa cells lay down onto the basement membrane. Disappearance of granulosa cells or oocytes resulted from the radiation-induced apoptotic process. It is definitely clear that ${\gamma}$-radiation induces rapid apoptotic degeneration of the primordial follicles. The morphological degeneration induced by radiation in the primordial follicles can be used as an experimental model to draw out a deeper insight for radioprotectant researches.

• Clinical and Experimental Reproductive Medicine
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• v.13 no.1
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• pp.29-38
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• 1986

In order to study the mechanism of follicular atresia, follicles were classified into the normal groups and the atretic ones, according to the criteria with or without corpus luteum, size of follicles, vascularization, status of granulose cells and the hypertrophy of theca layers in the porcine ovary. To estimate the binding capacity of human chorionic gonadotropin (hCG) receptor on the granulosa cells during atresia, hCG were iodinated by the chloramine-T method and then purified through the column chromatography. The concentration" of hCG receptor in each group were measured by the hCG receptor binding assay. Binding capacity in large normal follicles were 1.16%, but atretic ones were 0.45%. But in medium and small follicles (below 6mm in diameter), the binding capacity in normal follicles were 0.09%, but atretic ones were 0.05%, which was lower than those of large follicles. The present ( ) that the concentrations of hCG receptors on granulosa cells is decreased when the follicles become atretic and be used as a sort of creteria for the identification of follicles atresia.

• 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.

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.8-8
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• 2001

Mouse follicles require the addition of gonadotropins (Gns) to complete maturation and ovulation of oocyte and antrum formation of follicles in vitro. However, we tried examination of in vitro growth of mouse pre-antral follicles in medium without Gns and physiological 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. Pre-antral follicles (91-120${\mu}{\textrm}{m}$) were isolated mechanically by fine 30G needles not using enzymes from ovary of 3-6 weeks old female ICR mice. Isolated pre-antral follicles were cultured in 20 ${mu}ell$ droplets of TCM (n=17; follicles: 107.8 $\pm$ 1.58 ${\mu}{\textrm}{m}$; oocytes: 59.9$\pm$1.2 ${\mu}{\textrm}{m}$) or MEM (n=12; follicles: 109.3$\pm$2.53 ${\mu}{\textrm}{m}$; oocytes: 55.4 $\pm$1.6${\mu}{\textrm}{m}$) under mineral oil on the 60mm culture dish. All experimental media was supplemented with 10% FBS but without Gns and/or physiological factors. Pre-antral follicles were individually cultured in drops for 8 days. Antrum formation and growth of pre-antral follicles and intra-follicular oocytes were evaluated using a precalibrated ocular micrometer at $\times$200 magnifications during in vitro culture. Results between different groups were analyzed using combination of Student's t-test and Chi-square, and considered statistically significant when P<0.05. Antrum formation of pre-antral follicles had started in two culture media on day-2. On day-8, antrum formation had occurred in 58.3%(7/12) of pre-antral follicles cultured in MEM, but only in 23.5% (4/17) of those cultured in TCM (P=0.0364). Growth of pre-antral follicles and intra-follicular oocytes were observed on day-4 and -8. On day-4, follicular diameters was similar (P=0.1338) in TCM (119.4$\pm$2.58 ${\mu}{\textrm}{m}$) and MEM (125.4$\pm$4.52 ${\mu}{\textrm}{m}$). However, on day-8, diameters of pre-antral follicles cultured in MEM (168.9$\pm$17.29 ${\mu}{\textrm}{m}$) was significantly (P=0.0248) bigger than that in TCM (126.7$\pm$4.28 ${\mu}{\textrm}{m}$). On day-4 and -8, diameters of intra-follicular oocytes were similar TCM (67.1$\pm$1.3 and 72.4$\pm$0.9${\mu}{\textrm}{m}$) and MEM (65.2$\pm$1.7 and 73.3$\pm$1.5 ${\mu}{\textrm}{m}$), respectively. We can conform that medium not supplemented with Gns and/or physiological factors can be used for in vitro antrum formation and growth of mouse pre-antral follicles and intra-follicular oocytes. In conclusion, MEM supplemented with FBS can be used for growth in vitro of mouse pre-antral follicles isolated mechanically.

• Clinical and Experimental Reproductive Medicine
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• v.39 no.4
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• pp.127-131
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• 2012

Primordial follicles are formed prenatally in mammalian ovaries, and at birth they are fated to be activated to primary follicles, to be dormant, or to die. During the early stage of folliclulogenesis, the oocyte undergoes dynamic alterations in expression of numerous genes, which are regulated by transcription factors. Several germ-cell specific transcriptional regulators are critical for formation and maintenance of follicles. These transcriptional regulators include: Figla, Lhx8, Nobox, Sohlh1, and Sohlh2. A subset of these transcriptional regulators is mutated in women with ovarian insufficiency and infertility. Establishment of this oocyte pool is essential for fertility. This review focuses on these transcriptional regulators of female primordial follicles.

• Journal of Veterinary Clinics
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• v.5 no.2
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• pp.83-86
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• 1988

Morphometric observation on the ovarian follicles of ICR strain-female mice has been conducted to investigate the effect of induced inflammation on the follicular populations. Inflammation was induced by administering 25${\mu}\ell$ of turpentine oil intraperitoneally 2 times at the interval of 3 days. Mice showing 5-day estrous cycle about 20 days after induction of inflammation are placed in experimental group. Normal follicles of 100～399$\mu\textrm{m}$ in diameter increased at estrus but those of over 400$\mu\textrm{m}$ decreased. super-ovulation increased the number of normal follicles of over 400$\mu\textrm{m}$. The number of normal follicles of over 400$\mu\textrm{m}$ 48 hours after superovulation was not significantly different between experimental and control groups. Present results indicated that the number of preovulatory follicles 48 hours after PMSG injection did not decrease in the mice which showed regular estrous cycle even after the induction of inflammation.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.3
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• pp.353-357
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• 2008

A series of studies has been conducted to establish a base infrastructure for an ovarian follicle culture system in the porcine and this study was designed to develop an effective retrieval protocol of preantral follicles. Five different methods using collagenase type I (A) or IV (B, C1, C2 and C3), which employed different treatment durations and/or conditions, were employed and sliced ovarian tissue of prepubertal gilts was provided for the retrieval. A significant increase in total number of follicles retrieved was detected when collagenase IV (methods B or C) was used. In total, more ovarian follicles were retrieved by method B undertaking agitation and method C2 without the agitation than method C1 and C3, while the number of preantral follicles collected was the largest in method B. Neither incubation in 5% $CO_2$ in air atmosphere instead of the agitation nor increased duration of enzymatic treatment up to 120 minutes improved the efficiency of follicle retrieval. There were no differences in the number of follicles retrieved from intact ovaries and from used ovaries for oocyte collection. These results demonstrate the collagenase IV treatment with agitation is effective for retrieving porcine preantral follicles from the ovaries.

• Proceedings of the KSAR Conference
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• 2000.10a
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• pp.9-9
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• 2000

The mammalian ovary has a large number of primordial and preantral follicles, which are a potential source of oocytes for the in vitro mass production of embryos. Several in vitro culture systems have been developed to support the growth and development of oocytes from mouse preantral follicles. Under the appropriate condition, meiotically incompetent oocytes from preantral follicles can grow to final size and complete nuclear maturation in vitro. Furthermore, the successful production of live young from in vitro grown and matured oocytes demonstrates that oocytes from preantral follicles are able to acquire full developmental capacity in vitro. However, the efficiency of in vitro production of embryos from mouse preantral follicles is still low. In farm animals as well as human, the growth of oocyte from preantral follicle to the meiotic competence stage has yet to be demonstrate. Therefore, further studies to improve the culture condition or to develope new culture system should be needed in the future. In addition, the visible progress in the establishment of the in vitro culture system for preantral follicles of farm animals and human could help to enlarge the populations of valuable agricultural, phamaceutical product-producing, and endangered animals, and to rescue the oocytes of women about to undergo clinical procedures that jeopardize oocytes.

• Korean Journal of Veterinary Research
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• v.17 no.2
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• pp.41-49
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• 1977

The present study was underve the histochemical nature of various follicles and interstitial tissues in the ovaries of Korean native goats and cattle as well as the histochemical changes of those in the ovaries of Korean native goats treated with dexamethasone. Much more lipid granules appeared in the granulosa and theca cells of atretic follicles compared with normal follicles in these ruminant ovaries. In the ovaries of Korean native goats the interstitial tissue derived from the theca interna of atretic follicles appeared the form of patches of cells and the interstitial tissue derived from stromal cells appeared the form of diffuse, obscure bounds. In the ovaries of Korean native cattle the interstitial tissue derived from theca interna of atretic follicles showed sparsely scattered form of pathes of cells. The histochemical components were described on the basis of lipids in the granulosa and theca cells of normal follicles, atretic follicles and interstitial tissue. In the ovaries of Korean natve goats treated with dexamethasone, the granulosa and theca cells of atretic foillicle contained plenty lipid granules that were increased in size and number, however, lipid granules were markedly decreased in the interstitial tissue.