• Journal of Embryo Transfer
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• v.33 no.3
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• pp.99-105
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• 2018

To determine the differences in the in-vitro ovum maturation process of bovine, we compared the expression of MMPs in these oocytes and cumulus cell throughout oocytes maturated. In an attempt to investigate the effect of MMP activation and inhibitors in total protein of cumulus cell and, oocytes during oocytes maturation, we examined and monitored the localization and expression of MMPs (MMP-2 and MMP-9), TIMPs (TIMP-2 and TIMP-3), as well as their expression profiles (Real-time PCR, Gelatin Zymography and ELISA). Our results that the bovine oocytes MMP-2 and MMP-9 level was significantly associated with the rate of maturity of oocytes (P<0.05). In cumulus cell, MMP-2 was highly expressed in all stages of the oocyte's maturation. The final oocytes maturation exhibited strong gelatinase activity. There was no significant correlation between cumulus cell MMP-9 and the maturation rate of oocytes. However, for the oocyte cytoplasm MMP-9 expression was significant correlation to the maturation oocytes. There was no significant correlation between cumulonimbus cells MMP-9 and oocyte maturation rates; however, for oocyte cytoplasm, MMP-9 expression was significantly correlated with mature oocyte. However, the TIMP-1 and TIMP-2 protein expression patterns are not correlated with the maturation rate of the oocyte. Our results suggest that MMP different expression pattern may regulate the morphological remodeling of oocyte's in the cumulus cell. Further, the MMP-2 expression has a strong relation with a higher maturation rate of the oocyte.

• Clinical and Experimental Reproductive Medicine
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• v.47 no.4
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• pp.306-311
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• 2020

Objective: The aim of this study was to determine whether co-administration of a gonadotropin-releasing hormone (GnRH) agonist and human chorionic gonadotropin (hCG) for final oocyte maturation improved mature oocyte cryopreservation outcomes in young women with decreased ovarian reserve (DOR) compared with hCG alone. Methods: Between January 2016 and August 2019, controlled ovarian stimulation (COS) cycles in women (aged ≤35 years, anti-Müllerian hormone [AMH] <1.2 ng/mL) who underwent elective oocyte cryopreservation for fertility preservation were retrospectively analyzed. Results: A total of 76 COS cycles were triggered with a GnRH agonist and hCG (the dual group) or hCG alone (the hCG group). The mean age and serum AMH levels were comparable between the two groups. The duration of stimulation, total dose of follicle-stimulating hormone used, and total number of oocytes retrieved were similar. However, the number of mature oocytes retrieved and the oocyte maturation rate were significantly higher in the dual group than in the hCG group (p=0.010 and p<0.001). After controlling for confounders, the dual-trigger method remained a significant factor related to the number of mature oocytes retrieved (p=0.016). Conclusion: We showed improved mature oocyte collection and maturation rate with the dual triggering of oocyte maturation in young women with DOR. A dual trigger appears to be more beneficial than hCG alone in terms of mature oocyte cryopreservation for young women with DOR.

• Development and Reproduction
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• v.25 no.3
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• pp.157-171
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• 2021

To determine whether the reproductive processes of sea bass, Lateolabrax japonicus, proceed normally after transportation from an outdoor net-cage into indoor tanks, we examined changes in the gonadosomatic index (GSI), histological gonadal tissue, and plasma levels of sex hormones (testosterone and estradiol-17ß) during their annual reproductive cycle. We also measured maturation and spawning across two sea water salinity levels (full and low salinity). Fecundity was estimated by the relationship between egg number and body size in female sea bass. Monthly changes in the GSI, histological gonadal tissues, and oocyte size showed both male and female sea bass reach final maturation in January and February, respectively, indicating that the spermiation of males occurs earlier than the spawning of females. The histological results indicated that the sea bass is a multiple spawner, similar to many marine teleosts, exhibiting group-synchronous oocyte development. Female maturation and spawning were enhanced in lower salinity seawater (29.6-31.0 psu) compared to that of normal salinity (34.5-35.1 psu). These results confirm that sea bass reproduction can occur successfully in captivity and imply that fertilized eggs can be collected from February to March. Additionally, our results show that lower salinity enhances oocyte maturation and spawning of female sea bass.

• Development and Reproduction
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• v.25 no.2
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• pp.75-82
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• 2021

We studied steroid metabolites produced from red-spotted grouper ovarian follicles during maturation. Oocytes with 350-500 ㎛ diameter were in vitro incubated in the presence of [³H] 17α-hydroxyprogesterone as a precursor. Steroid metabolites were extracted from incubated media and oocytes. The extracts were separated and identified using thin layer chromatography, high performance liquid chromatography and gas chromatography-mass spectrometry. The identified metabolites were androstenedione (A₄), testosterone (T) and estrone (E₁). The metabolites of A₄ was dominant in all size of oocytes and it was the highest in 480 ㎛ diameter oocytes. The metabolites of two progestins, 17α,20β-dihydroxy-4-pregnen-3-one and 17α,20α-dihydroxy-4-pregnen-3-one were detected in the oocytes less than 480 ㎛ diameter although they were not identified definitely. In the oocytes of 480 ㎛ diameter, metabolite of progestin was the highest, and germinal vesicle (GV) was still in the middle of cytoplasm. In the oocytes of 500 ㎛ diameter, GV was began to migrate and the major metabolites were A₄ and E₁. The metabolite of E₁ was detected in all size of oocytes and it was higher than that of E₂. These results suggest that oocytes of 480 ㎛ diameter are the transitional stage involving steroidogenic shift to final oocyte maturation and potential function of E₁ during maturation process.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.2
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• pp.174-183
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• 2001

During the rapid phase of gonadal development of the freshwater teleost, the catfish (Silurus asotus), the influence of hCG upon the inducement of final oocyte maturation and spawning was investigated electrophoretically and ultrastructurally. The electrophoretic patterns obtained were different in the presence and absence of some of the major or minor zones, because of the hormone level in catfish. The vitellogenin of hormone-treated fish was stained more intensively than that of sham-treated fish. These proteins showed some minor or main bands of egg extracts which migrated at positions corresponding to molecular weights of approximately 90,000. However, the thickness of electrophoretic band in molecular weight for hCG-treated fish was slightly lower than that for saline control. It seemed the plasma protein with molecular weight of approximately 45,000 in hCG-treated fish disappeared. In contrast to the control fish, the ovaries in the catfish treated with hCG shows a marked ultrastructural change under the electron microscope. No dilated profiles were seen in the granulosa cells of the mature oocyte before ovulation. After germinal vesicle breakdown (GVBD), the zona radiata interna (ZRI) becomes more compact, and there is a loss of all the processes from the pore canals. There is a wide space between the vitelline membrane and zona radiata. Also, during final maturation, the microvillar processes from the oocyte are seen no longer to penetrate deeply into the extracellular spaces of the overlying granulosa cells, and the reticulate patterns of the zona radiata interna becomes occluded, giving the zona radiata a more solid appearance. It has been possible to initiate 100% oocyte maturation in yolk granules and follicles in vivo by treatment with hCG and a high water temperature ($27^{\circ}C$). In hCG-treated fish, the percentages of successful artificial fertilization and hatching were maximal at 15 h after a single injection. It seems clear that a long acting preparation containing hCG can be successfully used in prespawning fish to advance the final events of gonadal maturation and initiate spawning. Further studies are necessary to evaluate the potential of hCG to either stimulate or inhibit the reproductive development of fish at other stages of the seasonal reproductive cycle.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.1
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• pp.41-47
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• 2017

Perhaps the most common type of reproductive dysfunction in captive fish is failure of females to undergo final oocyte maturation and thus to ovulate and spawn. The success of aquaculture could therefore be improved by developing techniques to enhance natural spawning, artificial maturation, and/or to induce ovulation in farmed fish. This study aimed to investigate the effects of prostaglandin $E_2$ ($PGE_2$) and prostaglandin $F_{2{\alpha}}$ ($PGF_{2{\alpha}}$) on in vitro oocyte maturation (germinal vesicle breakdown, GVBD) and ovulation in the marine fish Chasmichthys dolichognathus. Post-vitellogenic follicles (0.80-0.94 mm diameter oocytes) were incubated with $PGE_2$ or $PGF_{2{\alpha}}$ at concentrations of 5, 50, or 500 ng/mL for 24 hours. A significant increase in GVBD was seen in 0.84 mm and 0.94 mm oocytes incubated with 50 ng/mL $PGE_2$ compared with the control. There was no significant increase in GVBD in any of the other experimental conditions (5 or 500 ng/mL $PGE_2$ or 5, 50, or 500 ng/mL $PGF_{2{\alpha}}$). Neither of the prostaglandins induced ovulation at the concentrations tested.These results suggest that GVBD was induced by incubation with 50 ng/mL $PGE_2$.

• Clinical and Experimental Reproductive Medicine
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• v.44 no.1
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• pp.15-21
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• 2017

Objective: The aims of this study were to investigate whether fertilization could induce the resumption of meiosis in mouse oocytes arrested at metaphase I (MI) after in vitro maturation (IVM), and to investigate the effect of $Ca^{2+}$ chelator treatment at the time of fertilization on the transition from MI to metaphase II (MII). Methods: MII-stage and arrested MI-stage mouse oocytes after IVM were fertilized, and then embryonic development was monitored. Blastocysts from each group were transferred into 2.5 days post-coitum pseudo-pregnant ICR mice. MI oocytes after IVM were treated with a $Ca^{2+}$ chelator to investigate the effect of $Ca^{2+}$ oscillations on their maturation. Results: As insemination time increased, the number of oocytes in the MI group that reached the MII stage also increased. The blastocyst rates and total cell numbers in the MII group were significantly higher than in the MI group. No pregnancy occurred in the MI group, but 10 pregnancies were achieved (10 of 12) in the MII group. The proportion of MI oocytes that matured to MII oocytes after fertilization was significantly higher in the non-treated group than in the $Ca^{2+}$ chelator-treated group. Conclusion: The findings that a higher proportion of MI-arrested oocytes progressed to MII after fertilization and that the MI-to-MII transition was blocked by $Ca^{2+}$ chelator treatments before fertilization indicate that the maturation of MI oocytes to MII oocytes is associated with intracellular $Ca^{2+}$ oscillations driven by fertilization.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2000.05a
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• pp.282-283
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• 2000

The egg development of various fishes is studied by various methods including electron microscopy(Matsuyama et al, 1991) and hormone treatment(Schoonbee et al. 1980). In addition to attempt to induce final maturation and spawning, the present experiments were conducted to investigate the influence of hCG upon reproductive cycles in catfish(Silurus asotus) with developing gonads and to stimulate the reproductive system during the rapid phase of gonadal development. (omitted)

• Development and Reproduction
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• v.12 no.3
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• pp.275-281
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• 2008

Endocrine disrupting chemiclas (EDCs) such as bisphenol A (BPA) and nonylphenol (NP) have estrogenic activity and can alter reproduction in fish. In the present study, the effects of BPA and NP on in vitro steroid production from oocytes of maturation stage (oocyte diameter$\fallingdotseq$1.88 mm) from the greenling (Hexagrammos agrammus) were evaluated. Oocytes were incubated with different concentrations of BPA and NP (0.1, 1, 10, 100 and 1,000 ng/$m{\ell}$) in the presence or absence of 50 IU human chorionic gonadotropin (HCG) for 48 hours. After incubation, levels of $17{\alpha},\;20{\beta}$-dihydroxy-4-pregnen-3-one ($17{\alpha}20{\beta}OHP$), estradiol-$17{\beta}(E_2)$ and testosterone (T) from incubated media were quantified by radioimmunoassay (RIA). In BPA treatment, 100 ng/$m{\ell}$ of BPA stimulated $E_2$ production regardless HCG supplement. Every concentration of BPA inhibited T production without HCG although 0.1 ng/$m{\ell}$ of BPA stimulated T production with HCG. In NP treatment, 10 ng/$m{\ell}$ of NP stimulated $17{\alpha}20{\beta}OHP$ and T production without HCG. 1 ng/$m{\ell}$ of NP inhibited $E_2$ production. Taken toghther, these results suggest that BPA might have weak estrogen-agonistic effect and NP has estrogenantagonistic effect at final oocyte maturation stage of H. agrammus.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.123-123
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• 2003

This study was conducted to determine the ability of nuclear development of canine oocytes depend on the kind of maturation media and addition of serum sources. Ovaries were collected from a bitches at various stages of estrus cycle by an ovariohysterectomy. Oocytes were collected of cumulus oocytes complexes after slicing of ovaries with blade. The maturation medium was containing 0.6 mM/ml cysteine, 0.2 mM pyruvic acid, 20 ng/ml $E_2$ and 1 $\mu g/ml$ rbST Exp. 1, the oocytes were matured in four different maturation medium as follows: 1) TCM-199, 2) DMEM, 3) NCSU37 and 4) modified-NCSU37 with 10% FBS. Exp. 2: the oocytes were matured in mNCSU37 supplemented with different protein sources (10% FBS, 10% EDS, 0.3% BSA and 0.1% PVA) to select the optimal one. Oocytes were matured in a humidified atmosphere containing 5% $CO_2$ at $39{\circ}C$ for 72 hrs. The maturation rate were analyzed by Duncan's multiple range test using General Linear Models procedure in SAS. The rates of meiotic resumption to MI-MII depend on different culture media were achieved with TCM-199 (5.2%), DMEM (5.0%), NCSU37 (7.2%) and m-NCSU37 (5.9%), respectively. The rates of meiotic resumption to MI-MII according to addition of protein source were 10% FBS (13.3%), 10% EDS (25.0%), 0.3% BSA (25.0%) and 0.1% PVA (15.4%), respectively. In conclusion, the results obtained showed that in vitro maturation media and protein supplement to m-NCSU37 culture medium tested did not promote the final steps of IVM in canine oocytes.