• Animal cells and systems
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• v.2 no.4
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• pp.501-506
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• 1998

In the goby Micropercops swinhonis, the development of its egg's enveloping layers could be divided into 4 stages. In the earliest developmental period, stage I, there is a simple oocyte surrounded by a layer of squamous follicular cells. Stage II corresponds to the yolk vesicle stage of vitellogenesis. Here the initial follicular layer has become bilaminar with the retention of its outer squamous cell layer and the acquisition of an inner cuboidal cell layer just over the zona radiata. The number and size of the cuboidal cells increases throughout this stage. Stage III corresponds to the yolk granule stage of true vitellogenesis. Here the cuboidal cells begin to be replaced by columnar cells. As the oocyte grows, the columnar cells increase in size. The columnar cells produce cytoplasmic neutral mucins and by the end of this stage their cytoplasm has been filled with this mucin. In stage IV a single layer of squamous cells still remained as the outer follicular layer of the oocyte. The secretory activity of the inner follicular layers' columnar cells has ceased and they had lost their cell wall integrity and ended as a series of bullet-shaped, neutral mucin deposits.

• Journal of Magnetics
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• v.19 no.3
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• pp.241-247
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• 2014

The objective of this study was to study the effect of magnetized water on porcine cumulus cell-oocyte complexes (COCs). Oocytes obtained from female pig were cultured in a medium magnetized at 0, 2000, 4000, and 6000 Gauss (G) for 5 minutes using the neodymium magnet. Subsequently, intracellular hydrogen peroxide ($H_2O_2$) concentration, glutathione (GSH) activity, oocyte membrane integrity, anti-apoptosis factor Bcl-xL expression, and nuclear maturation were analyzed. The intracellular $H_2O_2$ levels in COCs cultured for 44 hours were not significantly different among the variously magnetized samples. However, GSH activity were significantly higher in the magnetized samples compared to the 0 G sample. The Bcl-xL mRNA expression in COCs cultured for 44 hours was higher in the 4000 G sample than other treatment groups. Membrane damage in COCs cultured for 22 and 44 hours was significantly lower in 4000 G group than control group. On the other hand, nuclear stages as maturation indicator significantly increased in 2000, 4000, and 6000 G groups compared to 0 G group. These results indicate that incubation of porcine oocytes and cumulus cells in magnetized medium improves intracellular GSH levels, membrane integrity and nuclear maturation, and inhibits apoptosis in vitro.

• Korean Journal of Agricultural Science
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• v.44 no.3
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• pp.309-317
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• 2017

Melatonin (N-acetyl-5-methoxytryptamine) is an indole synthesized from tryptophan by the pineal gland in animal. The major function of melatonin is to modulate circadian and circannual rhythms in photoperiodic mammals. Importantly, however, melatonin is also a free radical scavenger, anti-oxidant, and anti-apoptotic agent. Recently, the beneficial effects of melatonin on oocyte maturation and embryonic development in vitro have been reported in many species such as pig, cattle, sheep, mouse, and human. In this review, we will discuss recent studies about the role of melatonin in the production of porcine and bovine oocytes and embryos in vitro in order to provide useful information of melatonin in oocyte maturation and embryo culture in vitro.

• Journal of Embryo Transfer
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• v.31 no.1
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• pp.9-12
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• 2016

Growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) are oocyte-specific growth factors that regulate many critical processes involved in early folliculogenesis and oocyte maturation. In this study, effects of GDF9 and BMP15 treatment during in vitro maturation of porcine oocytes upon development after parthenogenetic activation were investigated. Neither GDF, BMP15 alone nor in combination affects the number and viability of cumulus cells or the rates of oocyte maturation and blastocyst development. However, the treatment of GDF9 on porcine oocytes increased the number of trophectodermal (TE) cells of blastocysts derived from activated oocytes (P<0.05). The treatment of BMP15 increased the cell numbers of both inner cell mass (ICM) and TE cells (P<0.05). The treatment with the combination of GDF9 and BMP15 further increased the numbers of ICM and TE cells, compared with GDF9 or BMP15 treatment alone (P<0.05). In conclusion, the treatment of GDF9 or BMP15 (or both) enhanced the quality of blastocysts via the increased number of ICM and/or TE cells.

• Development and Reproduction
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• v.27 no.3
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• pp.127-135
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• 2023

Effects of changes in photoperiod on the reproductive events in fish are suggested to be mediated mainly via the action of melatonin (MEL). Changing levels of plasma MEL throughout the day and year are suggested to influence the hypothalamus-pituitary-gonadal axis in fish. Therefore, in this study, we aimed to investigate the effects of MEL on oocyte maturation and germinal vesicle breakdown (GVBD) in the marine fish, Chaenogobius annularis, in vitro. Oocytes at three different stages (pre-, mid-, and late-vitellogenesis) were incubated with (a) only MEL (5, 10, 50, 100, 500, and 1,000 pg/mL) and (b) 50 pg/mL of 17α,20β-dihydroxy-4-pregnen-3-one (17α20βP), maturation-inducing hormone (MIH) of this species, and MEL (4-h incubation before addition of MIH). Any single MEL treatment did not significantly induce GVBD. However, treatment with 50 pg/mL MEL or MIH significantly induced GVBD. These results suggest that preincubation with MEL accelerates the effect of MIH on longchin goby oocyte maturation.

• Animal cells and systems
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• v.5 no.1
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• pp.51-57
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• 2001

We have previously shown that oocyte maturation is induced by an immobilized progesterone, progesterone-3-carboxymethyloxime - bovine serum albumin conjugate (P-BSA) in Rana dybowskii. In this study, we confirmed the maturation inducing activity of P-BSA on Xenopus oocyte and examined the binding character of the immobilized progesterone on the surface of Xenopus oocytes after removal of the vitelline layer. P-BSA induced maturation of Xenopus oocytes but E-BSA failed to do so as observed in Rana. Binding of the immobilized progesterone, fluorescein isothiocyanate-labeled progesterone-3-0-carboxymethyloxime-BSA (P-BSA-FITC) on the devitellined oocytes surface was examined by fluorescence confocal microscopy. The binding affinity of P-BSA-FITC to the devitellined oocyte was higher than that of estrogen-BSA-FITC (E-BSA-FITC) or testosterone-BSA-FITC (T-BSA-FITC). The binding disappeared in the presence of excess free progesterone but not in the presence of free estrogen. Maximum binding occurred after two-hours of incubation with P-BSA-FITC at pH 7.5. Stronger binding occurred in oocytes at stage Vl than stage IV, and in vitro treatment of hCG enhanced the binding. Taken together, these results suggest that a specific receptor for progesterone exists on the plasma membrane of Xenopus oocytes and that progesterone acts initially on this putative receptors and triggers generation of membrane-mediated second messengers during the early stage of oocyte maturation In amphibians.

• Korean Journal of Environment and Ecology
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• v.17 no.1
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• pp.18-25
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• 2003

In order to know the effects of PCB(Arochlor 1248) on the oocyte maturation and proges-terone(P$_4$) production by FPH(Frog pituitary homogenate: 0.01 p.e/$m\ell$) of frog in vitro, the oocytes were cultured for 20 hours in presence of the PCB at various concentrations and exam-ined their maturation(germinal vesicle breakdown: GVBD) rates and P$_4$ levels secreted by the oocyte in the culture medium. The results show that PCB concentration of 10 ppb suppressed the maturation of the oocytes and secretion of P$_4$. To examine the reversibility of the inhibitory effects, the oocytes were exposed to the PCB only for 3 hours, and then transferred to plain medium and cultured further for 17 hours. The oocytes were recovered from the toxic effect of the PCB when they were exposed to 2.5 ppb, but not to 5 ppb of the PCB. These results indi-cate that PCB suppress the maturation of oocytes and secretion of p, at low concentration, sug-gesting that the frog oocyte culture system can be used as a useful tool to evaluate the toxicity of the pollutants in the environment.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.7
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• pp.972-979
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• 2008

It has been recently shown that expression of the LH receptor (LHR) in cumulus cells is related with FSH-induced meiotic resumption of mouse cumulus enclosed oocytes (CEOs). However, to date, it is still unclear whether LHR expression in cumulus cells plays a key role during FSH-induced oocyte maturation. The purpose of this study was to characterize the functional role of LHRs in cumulus cells. CEOs were isolated from eCG-primed preovulatory follicles and cultured in hypoxanthine (HX) arrested medium. LHR protein expression in cumulus cells was time-dependent increasing during the process of FSH-induced oocyte maturation. While the sense oligodeoxynucleotide (ODN) had no effect, antisense ODN inhibited FSH-induced LHR expression and meiotic resumption. Moreover, this antisense ODN against LHR could inhibit FSH-induced mitogen-activated protein kinase (MAPK) phosphorylation. This study suggested that LHR expression in cumulus cells is involved in FSH-induced oocyte meiotic resumption, which process is possibly regulated by MAPK cascade.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.1
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• pp.17-24
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• 2010

In the antral follicle phase, several layers of cumulus cells surround the oocyte and play an important support and regulation role in oocyte development and maturation via intercellular communications and interactions between oocytes and cumulus cells. However, information on stage specific gene expression in swine during the phase is not well understood. To investigate the function of cumulus cells during in vitro maturation of porcine oocytes and gene expression, suppression subtractive hybridization (SSH) was performed to screen genes that were differentially expressed between cumulus-oocyte complexes (COCs) and naked oocytes (NOs). Utilizing mRNAs from in vitro maturation oocytes, a SSH cDNA library from COCs as the tester and NOs as the driver was constructed. The SSH cDNA library was then screened using dot blot analysis. Results showed that a total of 70 clones randomly selected from the library were differentially expressed. Among these, 41 exhibited high homology to known genes and 11 were novel expressed sequences tags (ESTs). Four differentially expressed genes, including bfgf, sprouty 2, egr and btc, were further studied by real time quantitative PCR; results confirmed an increased expression of respective mRNA in COCs compared with NOs, which suggests that these factors may play an important role in oocyte development and maturation.

• Journal of Animal Reproduction and Biotechnology
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• v.34 no.3
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• pp.212-221
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• 2019

Sestrin-2 (SESN2) as a stress-metabolic protein is known for its anti-oxidative effects as a downstream factor of PERK pathways in mammalian cells. However, the expression patterns of SESN2 in conjunction with the UPR signaling against to ER stress on porcine oocyte maturation in vitro, have not been reported. Therefore, we confirmed the expression pattern of SESN2 protein, for which to examine the relationship between PERK signaling and SESN2 in porcine oocyte during IVM. We investigated the SESN2 expression patterns using Western blot analysis in denuded oocytes (DOs), cumulus cells (CCs), and cumulus-oocyte complexes (COCs) at 22 and 44 h of IVM. As expected, the SESN2 protein level significantly increased (p < 0.01) in porcine COCs during 44 h of IVM. We investigated the meiotic maturation after applying ER stress inhibitor in various concentration (50, 100 and 200 μM) of tauroursodeoxycholic acid (TUDCA). We confirmed significant increase (p < 0.05) of meiotic maturation rate in TUDCA 200 μM treated COCs for 44 h of IVM. Finally, we confirmed the protein level of SESN2 and meiotic maturation via regulating ER-stress by only tunicamycin (Tm), only TUDCA, and Tm + TUDCA treatment in porcine COCs. As a result, treatment of the TUDCA following Tm pre-treatment reduced SESN2 protein level in porcine COCs. In addition, SESN2 protein level significantly reduced in only TUDCA treated porcine COCs. Our results suggest that the SESN2 expression is related to the stress mediator response to ER stress through the PERK signaling pathways in porcine oocyte maturation.