• Korean Journal of Ichthyology
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• v.24 no.3
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• pp.220-226
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• 2012

The aim of this study is to observe the reproductive behavior of the marine medaka, Oryzias dancena, and determine the factors of reproductive behavior to provide useful information for improving their artificial reproduction techniques. The reproductive behavior of the marine medaka was observed in laboratory aquaria. Once the experiment began, all of the males chased the females. The males attempted to stimulate the urogenital openings of the females. While chasing a female, a large male would bite a relatively small male's anus. Larger males expelled smaller males with biting, and the defeated males were barred from the female. After the other males were expelled, the remaining male approached and drew alongside the female. The male's dorsal and anal fins covered the female's body. Spawning began after complete covering took place. Spawning of males and females occurred simultaneously. The loadings for 2 factors were calculated. The calculation was restricted to 2 factors because these 2 factors explained about 81% of the total common variance (P<0.05) and the following factors possessed no practical significance. Two movements (biting, expelling) had high positive values for factor one. This factor related a male's defensive behavior to courtship behavior and spawning, and explained 23.1% of the total common variance (P<0.05). The second factor had high positive values for chasing, rejection, covering, and parallel swimming. This factor related a male's courtship behavior and female's defensive behavior to spawning, and explained 59.7% of the total common variance (P<0.05). This research provided basic biological data for the conservation of this species and useful information for improving their artificial reproduction techniques.

• Clinical and Experimental Reproductive Medicine
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• v.38 no.3
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• pp.135-141
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• 2011

Objective: Ovarian angiogenesis plays an important role in folliculogenesis. However, little is known about the expression of angiogenic factors during follicular development according to female age. Stromal cell derived factor-$1{\alpha}$ (SDF-$1{\alpha}$) plays a role in granulosa cell survival and embryo quality as an angiogenic chemokine. Leptin is also involved in folliculogenesis and angiogenesis. This study examined expression of SDF-$1{\alpha}$ and leptin, and their effects on the expression of angiogenic factors in the ovary during follicular development according to female age. Methods: Ovaries were collected from C57BL mice of two age groups (6-9 weeks and 24-26 weeks) at 6, 12, 24, and 48 hours after 5 IU pregnant mare's serum gonadotropin (PMSG) injection. The expression of ovarian SDF-$1{\alpha}$ and leptin mRNA was evaluated by RT-PCR. In the organ culture experiment, the ovaries were cultured in transwell permeable supports with Waymouth's medium treated with various doses of SDF-$1{\alpha}$(50-200 ng/mL) or leptin (0.01-1 ${\mu}g$/mL) for 7 days. Then, mRNA expression of vascular endothelial growth factor (VEGF), endothelial nitric oxide synthase (eNOS), and visfatin were examined in the cultured ovaries. Results: Expression of SDF-$1{\alpha}$ and leptin in the ovary was significantly lower in the aged mouse group compared to the young mouse group ($p$ <0.05). Expression of these two factors increased with follicular development after PMSG administration. SDF-$1{\alpha}$ treatment stimulated visfatin expression in a dose-dependent manner, while leptin treatment significantly increased eNOS expression. Conclusion: These results suggest that decrease of ovarian SDF-$1{\alpha}$ and leptin expression may be associated with aging-related reduction of ovarian function. SDF-$1{\alpha}$ and leptin may play a role in follicular development by regulating the expression of angiogenic factors in mouse ovaries.

• Clinical and Experimental Reproductive Medicine
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• v.30 no.1
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• pp.105-109
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• 2003

Objective s: To assess the fertilizing capacity using sperm penetration assay (SPA) to predict the outcome of the in vitro fertilization-embryo transfer (IVF-ET) outcome. Materials and Methods: Semen samples were provided by 129 patients undergoing IVF. We attempted to correlate the extent of sperm penetration under enhanced SPA protocol with the results of fertilization, cleavage, preimplantation embryo development, and pregnancy. Results: Univariate analysis demonstrated a statistically significant correlation between fertilizing capacity and motility, kinetics, fertilization, cleavage and embryo development, and pregnancy rate. By logistic regression analysis, fertilizing capacity was found to be the only variable that was statistically significant with respect to pregnancy rate. Fertilizing capacity, cleavage rate and pregnant rate were significantly higher in pregnant group. However, the fertilization rates was comparable with both group. Conclusions: Lower fertilizing capacity could denote a poorer prognosis for establishing a pregnancy, even after satisfactory fertilization rate is achieved.

• Clinical and Experimental Reproductive Medicine
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• v.42 no.2
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• pp.33-44
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• 2015

The generation of artificial gametes is a real challenge for the scientific community today. In vitro development of human eggs and sperm will pave the way for the understanding of the complex process of human gametogenesis and will provide with human gametes for the study of infertility and the onset of some inherited disorders. However, the great promise of artificial gametes resides in their future application on reproductive treatments for all these people wishing to have genetically related children and for which gamete donation is now their unique option of parenthood. This is the case of infertile patients devoid of suitable gametes, same sex couples, singles and those fertile couples in a high risk of transmitting serious diseases to their progeny. In the search of the best method to obtain artificial gametes, many researchers have successfully obtained human germ cell-like cells from stem cells at different stages of differentiation. In the near future, this field will evolve to new methods providing not only viable but also functional and safe artificial germ cells. These artificial sperm and eggs should be able to recapitulate all the genetic and epigenetic processes needed for the correct gametogenesis, fertilization and embryogenesis leading to the birth of a healthy and fertile newborn.

• The Korean Journal of Malacology
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• v.4 no.1
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• pp.30-41
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• 1988

The gonadal development, the annual reproductive cycle and the first sexual maturity of surf clam, Mactra veneriformis Reeve were studied histologically. Speciemens were monthly collected at the intertidal zone of Naechodo, Chollabuk-do, Korea, for one year from March 1986 to February 1987. Sexuality of the clam is dioecious. The gonads were located between the subregion of mid-intestinal gland in the visceral cavity and the reticular connetive tissues of the foot, The ovary is composed of a number of ovarian sacs, and the testis comprise several testiculat lobules. The undifferentiated mesenchymal tissues and eosinophilic granular cells function as nutritive cells in the early stage. The ripe eggs were about 50-60${\mu}{\textrm}{m}$ in diameter, and they were wurroundedby the gelatinous membranes. The spawing period was from early June to September the main spawning occurred beetween July and August when the water temperature reached above 24$^{\circ}C$. The annual reproductive cycle of this species could be classified into five successive stages: multiplicative(January to March), growing(March to May), mature(April to August), spent(June to September), degenerative and resting(September to February). The monthly changes of fatness coefficient closely correlated with the annual reproductive cycle. Percentages of the first sexual maturity of female and male clams were over 50% among those individals ranging from 2.1 To 2.5cm, and 100% in those over 2.6cm in shell length.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.296.2-296.2
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• 2002

Our previous study demonstrated that 2.3', 4.4'. 5- Pentachlorobiphenyl (PCB 118) showed an antiestrogenic activity in vitro and in vivo. In the present study. we examined the effect of PCB 118 on postnatal reproductive development in female rats. PCB 118 (0.001. 0.01 or 0.1 mg/kg/day) was administered to pregnant female SD rats from gestation day (GO) 6 to 18 via subcutaneous injection. and developmental parameters such as vaginal opening were determined. PCB 118 significantly delayed vaginal opening of female offsprings at dose of 0.1 ${\mu}g$/kg/day. whereas had no effects on body weights. In addition. in utero treatment of PCB 118 caused significant decreases in serum levels of E2, T3 and T4 in female oftsprings at certain doses on postnatal day (PND) 22. Our data of results indicate that in utero exposure to PCB 118 may postnatal reproductive development in female rat through its antiestrogenic activity.

• Clinical and Experimental Reproductive Medicine
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• v.43 no.1
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• pp.31-37
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• 2016

Objective: The aim of this study was to investigate associations between the morphology score of blastocysts and blastocoele re-expansion speed after warming with clinical outcomes, which could assist in making correct and cost-effective decisions regarding the appropriate time to vitrify blastocysts and to transfer vitrified-warmed blastocysts. Methods: A total of 327 vitrified-warmed two-blastocyst transfer cycles in women 38 years old and younger were included in this retrospective study. Results: The clinical pregnancy rate (CPR) and implantation rate (IR) of transfers of two good-morphology grade 4 blastocysts vitrified on day 5 (64.1% and 46.8%, respectively) were significantly higher than the CPR and IR associated with the transfers of two good-morphology grade 3 blastocysts vitrified on day 5 (46.7% and 32.2%, respectively). No significant differences were found in the CPR and IR among the transfers of two good-morphology grade 4 blastocysts regardless of the day of cryopreservation. Logistic regression analysis showed that blastocoele reexpansion speed after warming was associated with the CPR. Conclusion: The selection of a good-morphology grade 4 blastocyst to be vitrified could be superior to the choice of a grade 3 blastocyst. Extending the culture of grade 3 blastocysts and freezing grade 4 or higher blastocysts on day 6 could lead to a greater likelihood of pregnancy. Since re-expansion was shown to be a morphological marker of superior blastocyst viability, blastocysts that quickly re-expand after warming should be prioritized for transfer.

• Clinical and Experimental Reproductive Medicine
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• v.31 no.1
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• pp.75-81
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• 2004

Objective: The purpose of this study was to evaluate the efficacy and effect of various cryopreservation method on the survival and the cytoskeletal stability of metaphase II mouse oocyte. Methods: Mouse ovulated oocytes were collected and cryopreserved by a modified slow-freezing method with 1.5 M 1, 2-propanediol (PrOH)+0.1 M sucrose or by vitrification using cryo loop and EM grid with 40% ethylene glycol+0.6 M sucrose. Four hours after thawing, intact oocytes were fixed and stained with fluorescein isothiocyanate (FITC)-conjugated monoclonal anti-$\beta$-tubulin antibody to visualize spindle and propidium iodide (PI) to visualize chromosome. Spindle morphology was classified as follows: normal (barrel-shaped), slightly and absolute abnormal (multipolar or absent). Results: Survival rate of the frozen-thawed oocytes in vitrification group was significantly higher than that of slow-freezing group (62.7% vs. 24.4%, p<0.01). Vitrification with cryo loop showed significantly higher survival rate than that with EM grid (67.7% vs. 53.5%, p<0.05). On the other hand, proportion of normal spindle and chromosome configurations of the frozen-thawed oocytes between two vitrification group was not significantly different. Conclusion: For mouse ovulated oocytes, vitrification with cryo loop may be a preferable procedure compared to slow-freezing method. Further study should be needed to investigate developmental competency of frozen-thawed mouse oocytes.

• Clinical and Experimental Reproductive Medicine
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• v.27 no.1
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• pp.1-7
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• 2000

Objective: Mammalian embryos undergo changes of energy environment for transfer from oviduct to uterus. Also, the human reproductive organ (oviduct, uterus) contains energy sources of different concentration (oviduct - glucose: 0.5 mM, pyruvate: 0.32 mM, lactate: 10.5 mM; uterus - goucose: 3.15 mM, pyruvate: 0.1mM, lactate: 5.87 mM, respectively). This study was conducted to examine the effect of these energy sources added in DMEM with glutamine on the mouse embryo development. Methods: There was used ICR female mouse. Two cell embryos of mouse are collected by method of 'flushing'. Flushing fluid was used Ham's F-10 added to 20% FBS. The collected 2 cell embryos were cultured in media such as Control (only DMEM), group A and B (DMEM supplemented with 0.5 mM and 3.15 mM glucose), and group C and D (DMEM supplemented with 0.1 mM and 0.32 mM pyruvate), and group E and F (DMEM supplemented with 5.87 mM and 10.5 mM lactate). All experimental media supplemented with 20% hFF, respectively. Pattern of embryo development was observed to interval at 24hr during 96hr. Results : The media with glutamine added glucose (group A: 51.0%; group B: 48.4%) was significantly (p<0.05) higher than other experimental group in development into the morula stage after 24 hr in culture, but not significantly different compared with control and the rate of development into the blastocyst was significantly (p<0.05) low in the both of pyruvate (group C: 7.9% group D: 6.8%) and lactate (group E: 7.1%, group F: 7.1%) treatment group after 48 hr in culture. Development into the blastocyst and hatched balstocyst after 72 hr in culture revealed similarly in control (81.9%) and glucose treatment group (group A: 83.3%, group B: 82.8%). However, development into the hatched and attached blastocyst after 96hr in culture revealed significantly (p<0.05) development in the glucose treatment group (group A: 82.3%, group B: 78.5%) than control (63.2%), and its of pyruvate (group C: 34.1%, group D: 34.1%) and lactate (group E: 25.9%, group F: 33.3%) treatment group were significantly (p<0.05) lower than control similar to previous observations. Conclusion : The glucose added to the DMEM with only glutamine, as energy source, was highly to the rate of development compared with control, but the other energy sources were not, synthetically. Above refer to, the human reproductive organ (oviduct, uterus) contains energy sources of different concentration. Thus, further studies are will examine continuously to effects by interaction of different energy sources in the mouse embryo development, and these results will provide to foundation on the human embryo culture.

• Environmental Analysis Health and Toxicology
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• v.16 no.2
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• pp.51-56
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• 2001

To evaluate the arsenic effect of fish endocrine disruption, crucian carp (Carassius auratus) were treated with 0.5 mg/L and 3.0 mg/L of As$_2$O$_3$ for 14 days and gonadal development was examined by histological analysis. In ovaries from female crucial carps exposed to 3.0 mg/L, immature follicles and atretic follicles were appeared while various normal developmental stages of oocytes were shown in control group. Body weight and Gonadosomatic Index (GSI) of treated carp were also decreased compared to control group. However, no other significant histological changes in liver or kidney were shown in this exposure scheme. This means that reproductive organs are more sensitive than other organs and arsenic may exert endocrine disrupting effect through inhibiting the development of reproductive organ in fish.