• Journal of Animal Reproduction and Biotechnology
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• v.36 no.4
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• pp.183-188
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• 2021

In vitro maturation (IVM) of oocytes is the procedure where the immature oocytes are cultivated in a laboratory until they are mature. Since IVM oocytes generally have low developmental competence as compared to those matured in vivo, development of an optimal IVM culture system by fine-tuning culture conditions is crucial to maintain high quality. In-depth knowledge and a deep understanding of the in vivo physiology of oocyte maturation are pre-requisites to accomplish this. Within ovarian follicles, various signaling pathways that drive oocyte development and maturation regulate interaction between oocytes and surrounding somatic cells. This review discusses the sonic hedgehog (SHH) signaling pathway, which has been demonstrated to be intimately involved in folliculogenesis and oocyte maturation. Advances in elucidating the role of the SHH signaling pathway in oocyte maturation will aid attempts to improve the current inferior in vitro oocyte maturation system.

• Journal of Animal Reproduction and Biotechnology
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• v.36 no.3
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• pp.162-167
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• 2021

Camel (camelus dromedarius) is a unique large mammalian species that can survive harsh environmental conditions and produce milk, meat, and wool. Camel reproduction is inferior when compared to other farm animal species such as cattle and sheep. Several trials have been reported to increase camel reproduction and production through assisted reproductive techniques (ARTs) such as in vitro fertilization and cloning. For these reasons, obtaining enough mature oocytes is a cornerstone for ARTs. This demand would be improved by the oocyte in vitro maturation (IVM) systems. In this review, the current approaches and views from different laboratories using ARTs and the IVM to produce embryos in vitro in camel species. For the last two decades, conventional IVM system was the common approach, however, recently the bi-phasic IVM system has been introduced and showed promising improvement in IVM of camel oocytes. Detailed studies are needed to understand camel meiosis and IVM to efficiently increase the production of this species.

• Korean Journal of Animal Reproduction
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• v.27 no.1
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• pp.35-44
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• 2003

The present study was performed to investigate the first polar body(PB) extrusion during in-vitro maturation(IVM) and to examine the effect of different maturation time on the embryo development of Korean Native Cows(KNC) with regard to blastocyst(BL) cell numbers and pregnancy rates. PB extrusion did not take place for the first 12 hours(hr) of IVM, and most of KNC oocytes extruded PB from 14 to 20 hr after the onset of maturation. There was no significant difference in cleavage and 8-cell stage rates among the treatment groups, but BL and BL/8-cell rates were significantly higher(P<0.05) in 18 hr maturation group(31.0$\pm$5.7 and 82.0$\pm$5.1%) than 22 and 24 hr maturation group. The proportion of BL formed on day 7 and 8 was significantly higher(P<0.05) in 18 hr maturation group(85%) than in 24 hr maturation group(55%). There was a significant difference(P<0.05) in inner cell mass, trophectoderm and total cell number between day 7 BL produced by in-vivo and IVM 18 hr and day 8 BL produced by IVM 18 hr and 24 hr. Pregnancy rates are also significantly higher(P<0.05) in in-vivo(56.3%) and IVM 18 hr day 7(50.0%) group than day 8 treatment groups(18 hr: 16.7%, 24 hr: 10.5%). These results suggest that KNC oocytes achieve developmental competency within 20 hr of IVM, and "short" IVM (18 hr) is more effective than "long" IVM(24 hr) in embryo development rates, BL cell numbers and pregnancy rates.

• Reproductive and Developmental Biology
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• v.28 no.4
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• pp.221-226
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• 2004

The present study was performed to investigate the effects of in vitro maturation (IVM) and in vitro fertilization (IVF) duration on the development of Korean Native Cattle embryos. The time of blastocyst formation and the quality of blastocysts based on cell numbers were examined. The cleavage rate increased with the length of IVF duration in the groups of 18-hr IVM, but was constant in the groups of 24-hr IVM. The development rate to the 8-cell stage was significantly higher in the IVM 18: IVF 20 group than in the IVM 24: IVF 24 group. The development rate to the blastocyst stage was highest in the IVM 18: IVF 20 group, significantly different from that of the IVM 18: IVF 16, IVM 24: IVF 20 and IVM 24: IVF 24 group. The time of blastocysts formation tended to be shorter when IVM and IVF duration were decreased. The number of inner cell mass, trophoblast and the total cells were significantly higher in the IVM 18: IVF 16 group than in the IVM 24: IVF 24 group (P<0.05). These results demonstrated that the IVM and IVF duration should be adequate for the efficient production of bovine embryos, and it might particularly be essential to determine the proper combination of IVM and IVF duration.

• Journal of Animal Reproduction and Biotechnology
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• v.35 no.4
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• pp.357-365
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• 2020

The aim of present study was to investigate regulatory mechanism of alpha-linolenic acid (ALA) during in vitro maturation (IVM) on nuclear and cytoplasmic maturation of porcine oocytes. Basically, immature cumulus-oocyte complexes (COCs) were incubated for 22 h in IVM-I to which hormone was added, and then further incubated for 22 h in IVM-II without hormone. As a result, relative cumulus expansion was increased at 22 h after IVM and it was enhanced by treatment of ALA compared with control group (p < 0.05). During IVM process within 22 h, cAMP level in oocytes was decreased at 6 h (p < 0.05) and it was recovered at 12 h in ALA-treated group, while oocytes in control group recovered cAMP level at 22 h. In cumulus cells, it was reduced in all time point (p < 0.05) and ALA did not affect. Treatment of ALA enhanced metaphase-I (MI) and MII population of oocytes compared with oocytes in control group at 22 and 44 h, respectively (p < 0.05). Intracellular GSH levels in ALA group was increased at 22 and 44 h after IVM (p < 0.05), whereas it was increased in control group at 44 h after IVM (p < 0.05). In particular, the GSH in ALA-treated oocytes during 22 h of IVM was higher than control group at 22 h (p < 0.05). Lipid amount in oocytes from ALA group was higher than control group (p < 0.05). Treatment of ALA did not influence to absorption of glucose from medium. Cleavage and blastocyst formation of ALA-treated oocytes were enhanced compared with control group (p < 0.05). These findings suggest that supplementation of ALA could improve oocyte maturation and development competence through increasing GSH synthesis, lipid storage, and regulation of cAMP accumulation during early 22 h of IVM, and these might be mediated by cumulus expansion.

• Clinical and Experimental Reproductive Medicine
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• v.40 no.4
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• pp.143-147
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• 2013

Oocyte in vitro maturation (IVM) is an assisted reproductive technology in which oocytes are retrieved from the antral follicles of unstimulated or minimally stimulated ovaries. IVM of human oocytes has emerged as a promising procedure. This new technology has advantages over controlled ovarian stimulation such as reduction of costs, simplicity, and elimination of ovarian hyperstimulation syndrome. By elimination or reduction of gonadotropin stimulation, IVM offers eligible infertile couples a safe and convenient form of treatment, and IVM outcomes are currently comparable in safety and efficacy to those of conventional in vitro fertilization. IVM has been applied mainly in patients with polycystic ovary syndrome or ultrasound-only polycystic ovaries, but with time, the indications for IVM have expanded to other uncommon situations such as fertility preservation, as well as to normal responders. In this review, the current clinical experiences with IVM will be described.

• Journal of Animal Reproduction and Biotechnology
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• v.34 no.3
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• pp.205-211
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• 2019

In this study, we investigated the possibility of using mouse embryonic stem cell conditioned medium (ESCM) and embryonic stem cell medium (ESM) for in vitro maturation in the efficient in vitro production of blastocysts from porcine follicular oocyte. Depending on the concentration of supplement of ESCM added to the NCSU-23 solution did not affect 2-cell development rates and blastocysts development. However, in particular, the survival rate (10 days of culture) of blastocyst was significantly higher than that of the control group as the additive concentration (30%) increased (p < 0.05). The survival rate of blastocysts showed a similar tendency even with addition of ESM (30%) alone. On the other hand, the duration of the addition of these additives during IVM (0-44 h) was that the IVM I period (0-22 h) were more effective than the IVM II period (22-44 h). Thus, the effect of these additives is probably due to the combination of the various physiologically active substances of ESCM or the appropriate amino acids and vitamins of ESM. In particular, these additives were more effective during the first half (IVM I) of in vitro maturation. In summary, optimization of ESCM or ESM supplementation may improve in vitro maturation of porcine oocyte and affect developmental competency. Therefore, if more efficient methods of adding ESCM or ESM to basal culture medium can be developed during in vitro maturation of porcine follicle oocytes, high quality blastocysts will be developed from low porcine follicular oocyte compared to other domestic animals.

• Clinical and Experimental Reproductive Medicine
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• v.44 no.2
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• pp.79-84
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• 2017

Objective: Optimizing in vitro maturation (IVM) media to achieve better outcomes has been a matter of interest in recent years. The aim of this prospective clinical trial was to investigate the effects of different media on the IVM outcomes of immature oocytes at the germinal vesicle (GV) stage. Methods: A total of 400 immature oocytes at the GV stage with normal morphology were retrieved from 320 infertile women aged $31{\pm}4.63years$ during stimulated intracytoplasmic sperm injection (ICSI) cycles. They were divided into groups of homemade IVM medium (I, n = 100), cleavage medium (II, n = 100), blastocyst medium (III, n = 100), and Sage IVM medium (IV, n = 100) and cultured for 24 to 48 hours at $37^{\circ}C$. ICSI was performed, and the rates of fertilization and embryo formation were compared across the four groups. Results: In the 400 retrieved GV oocytes, the total maturation rates showed significant differences in groups I to IV (55%, 53%, 78%, and 68%, respectively, p<0.001). However, there were no significant differences in the fertilization, embryo formation, or arrest rates of metaphase II oocytes across these groups. In all groups, GV maturation was mostly completed after 24 hours, with fewer oocytes requiring 48 hours to mature (p<0.01). Moreover, the rate of high-quality embryos was higher in group IV than in the other groups (p=0.01). Conclusion: The quality of the IVM medium was found to affect clinical IVM outcomes. Additionally, blastocyst medium may be a good choice in IVM/ICSI cycles as an alternative IVM medium.

• Journal of Embryo Transfer
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• v.23 no.2
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• pp.93-100
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• 2008

This study was conducted to establish an in vitro maturation (IVM) system by selection of efficient macromolecule in the porcine in vitro production (IVP) technology. To choose the efficient macromolecules in the development of porcine embryos, the effects of 3 kinds of macromolecules (porcine serum; PS, porcine follicular fluid; pFF, and polyvinyl alcohol; PVA) supplemented in IVM media on the maturation, cleavage, and development rates to blastocyst of parthenogenetic activation (PA) and in vitro fertilization (IVF) embryos were examined. The maturation rates of porcine oocytes in media supplemented with PS were significantly higher than those with pFF and PVA (92.4% vs. 85.4%, 77.1%; p<0.05). In the cleavage and development to blastocyst rates, supplement with PS or pFF in the IVM media was more effective than PA. However, there were no significant differences in cleavage and development to blastocyst between PS and pFF group. From the results of this study, it was demonstrated that PS was optimal macromolecule in the porcine IVM media.

• Journal of Embryo Transfer
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• v.31 no.3
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• pp.153-159
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• 2016

(-)-Epicatechin gallate (ECG) is a polyphenol compound of green tea exhibiting biological activities, such as antioxidant and anticancer effects. To examine the effect of ECG on porcine oocytes during in vitro maturation (IVM), oocytes were treated with 0-, 5-, 15-, and $25{\mu}M$ ECG. After maturation, we investigated nuclear maturation, intracellular glutathione (GSH) and reactive oxygen species (ROS) levels and subsequent embryonic development after parthenogenetic activation (PA) and in vitro fertilization (IVF). After 42 hours of IVM, the $5{\mu}M$ group exhibited significantly increased (p< 0.05) nuclear maturation (89.8%) compared with the control group (86.1%). However, the $25{\mu}M$ group observed significantly decreased (p< 0.05) nuclear maturation (83.5%). In intracellular maturation assessment the 5-, 15-, and $25{\mu}M$ groups had significantly increased (p< 0.05) GSH levels and decreased ROS levels compared with the controls. The 5- and $15{\mu}M$ group showed significantly increased (p< 0.05) embryo formation rates and total cell number of blastocysts after PA (18% and 68.9, 15% and 85.1 vs. 12% and 59.5, respectively) compared with controls. Although the $25{\mu}M$ group observed significantly lower blastocyst formation rates after PA (27.6% vs. 23.2%) than control group, the $5{\mu}M$ group showed significantly increased blastocyst formation rates after PA (37.2% vs. 23.2%) compared to the control group. Furthermore, the $5{\mu}M$ group measured significantly increased blastocyst formation rates (20.7% vs. 8.6%) and total cell number after IVF ($88.3{\pm}1.5$ vs. $58.0{\pm}3.6$) compared to the control group. The treatment of $5{\mu}M$ ECG during IVM affectively improved the porcine embryonic developmental competence by regulating intracellular oxidative stress during IVM.