Effects of Melatonin on the Meiotic Maturation of Mouse Oocytes in vitro / 대한불임학회지

OBJECTIVE: Melatonin, which is secreted by pineal gland play an important role in the regulation of ovarian function via seasonal rhythm and sleep in most mammals. It also has a role in the protection of cells by removing toxic oxygen free radicals brought about by metabolism. In the present study, effects of melatonin on the mouse oocyte maturation were examined using two different culture conditions provided with 5% or 21% oxygen concentration. MATERIAL AND METHOD: Immature mouse oocytes were obtained from the ovarian follicles of 3~4 weeks old ICR strain mice intraperitoneally injected with 5 I.U. PMSG 44 hour before. Under stereomicroscope, morphologically healthy oocytes with distinct germinal vesicle (GV) were liberated from the graafian follicles and collected using mouth-controlled micropipette. They were then cultured for 17 hour at 37degrees C, 5% CO2 and 21% O2 (95% air) or 5% CO2, 5% O2 and 90% N2. New modified Hank's balanced salt solution (New MHBS) was used as a culture medium throughout the experiments. Effects of melatonin were examined at a concentration of 0.0001 micrometer, 0.01 micrometer or 1.0 micrometer. For the prevention of spontaneous maturation of immature oocytes during culture, dibutyryl cyclic AMP (dbcAMP) and/or hypoxanthine were included in the medium. RESULTS: Under 21% oxygen condition, oocytes cultured in the presence of 0.01 micrometer melatonin showed a significantly higher maturation rates, in terms of germinal vesicle breakdown (95.0% vs 89.0%) and polar body formation (88.1% vs 75.4%), compared to those cultured with 0.0001 micrometer or 1.0 micrometer melatonin. However, no difference was observed in oocytes cultured under 5% oxygen whether they were treated with melatonin or not. In the presence of 0.01 micrometer melatonin, oocytes either cultured under 21% or 5% oxygen exhibited no difference in the polar body formation (85.6% vs 86.7%). However, in the absence of melatonin, oocytes cultured under 21% oxygen exhibited lower polar body formation (74.7%). When oocytes were cultured in the presence of dbcAMP alone or with varying concentrations of melatonin, those treated with both compounds always showed better maturation, i.e., germinal vesicle breakdown and polar body formation, compared to those cultured with dbcAMP alone. At the same concentration of melatonin, however, oocytes exposed to 21% oxygen showed poor maturation than those to 5% oxygen. Similar results were obtained from the experiments using hypoxanthine instead of dbcAMP. CONCLUSION: Based upon these results, it is suggested that melatonin could enhance the meiotic maturation of mouse oocytes under 21% oxygen concentration, and release oocytes from the meiotic arrest by dbcAMP or hypoxanthine regardless of the concentration of oxygen, probably via the removal of oxygen free radicals.

The effect of Ni2+ on the intracellular Ca2+ increase of the mouse early 2-cell embryos / 대한불임학회지

OBJECTIVE: We reported the overcoming effect of Ni2+ on the in vitro 2-cell block of mouse embryos. In this study, we aim to investigate whether Ni2+ should induce intracellular Ca2+ transient in the mouse embryos. MATERIALS AND METHODS: Embryos were collected at post hCG 32hr from the oviduct of the ICR mouse and cultured in M2 medium omitted phenol red. Intracellular Ca2+ was checked by using a confocal laser scanning microscope and fluo-3AM by using various intracellular Ca2+ antagonists. RESULTS: In 1mM Ni2+ treated medium which contained Ca2+(1.71mM), 75.7% of the embryos showed [Ca2+]i transient about 200 sec later. In the Ca2+-free medium, 69.8% of the embryos showed [Ca2+]i transient. In U73122, phospholipaseC(PLC) inhibitor (5uM, 10min) pretreated group, 33.3% of the embryos showed [Ca2+]i transient. Heparine, inositol 1,4,5-triphosphate receptor(IP3R) antagonist preinjected embryos showed no response with 1mM Ni2+. In danthrolene treatment, ryanodine receptor(RyR)-antagonist, 43% embryos showed [Ca2+]i transient but they showed delayed response about 340sec in the presence of Ca2+. CONCLUSIONS: Summing up the above results, Ni2+ seems to induce Ca2+-release from the Ca2+-store even in the Ca2+-free medium. IP3 receptors of the mouse 2-cell embryos might have an essential role for the intracellular Ca2+ increase by Ni2+.

The Study on Apoptosis and Expression of Fas, Fas-ligand, Bax, and Bcl-2 in Human Fragmented Embryos / 대한불임학회지

OBJECTIVE: The present study was performed to investigate whether apoptosis occur in human embryos by annexin staining and detect the expression of Fas, Fas-ligand (FasL), Bax, and Bcl-2 in human fragmented embryos derived from IVF-ET by immunofluorescence and Western blot analysis. MATERIALS AND METHODS: Using annexin staining, immunofluorescence and Western blot analysis on normal and fragmented embryos, we were able to detect apoptotsis and apoptotic gene products in fragmented embryos. RESULTS: Phosphatidylserine (PS) translocation, the marker for apoptosis, were detected frequently in fragmented embryos. Bcl-2 and Bax protein were detected in both fragmented and non-fragmented embryos. When fragmented embryos compared to normal embryos, immunofluorescent intensity of Bcl-2 tended to be lower in fragmented embryos. Bax gene expression increased in the fragmented embryos compared to the normal embryos. This result supports a model in which the molar ratio of Bcl-2 to Bax determines whether apoptosis induced or inhibited in human embryo. Fas was highly expressed in human preimplantation embryos but not FasL. It suggests that embryo may undergo apoptosis by binding with FasL produced by follicular or immune cells. CONCLUSION: The over expression of Bax and Fas will trigger apoptosis to lead embryo fragmentation and change embryo to be nonviable.

Effect of Cryopreservation on the Heat Shock Protein 90 Expression in Mouse Ovarian Tissue / 대한불임학회지

OBJECTIVE: Heat shock protein family is related to protective mechanism of cells by environmental changes. This study was performed to evaluate the effect of cryopreservation on the heat shock protein 90 (Hsp90) expression in mouse ovarian tissue. METHODS: Cryopreservation of mouse ovarian tissue was carried out by slow freezing method. The mRNA level of Hsp90 expression in both fresh and cryopreserved mouse ovarian tissue was analyzed by RT-PCR. The protein expression of Hsp90 was evaluated by Western blot analysis and immunohistochemistry. RESULTS: The mRNA and protein of Hsp90 were expressed in both fresh and cryopreserved mouse ovarian tissue. The amount of Hsp90 mRNA was increased in cryopreserved ovarian tissue after 60 and 90 minutes after thawing and incubation. The amount of Hsp90 protein was increased in the cryopreserved ovarian tissue after 6 hours of the incubation in Western blot analysis. In immunohistochemical study, Hsp90 protein was localized in cytoplasm of oocytes and granulosa cells. Significant level of immunoreactive Hsp90 protein was detected in theca cells contrast to the weak expression in ovarian epithelial cells. CONCLUSION: This results showed the increase of Hsp90 expression in both mRNA and protein level in the cryopreserved mouse ovarian tissue. It can be suggested that Hsp90 may play a role in the protective or recovery mechanism against the cell damage during cryopreservaion.

Studies of Changes of Ca2+-channels Distribution in the Activated Mouse Ova / 대한불임학회지

OBJECTIVE: In muscle and neuronal cells, calcium channels have been classified by electrophysiological and pharmacological properties into (1) voltage-dependent Ca2+-channel(1) P/Q-type Ca2+-channel (2) N-type Ca2+-channel R(3) L-type Ca2+-channel (4) T-type Ca2+-channel (5)R-type Ca2+-channel. The present study was done in order to investigate whether there is any difference in Ca2+-channel distribution between activated and normally fertilized embryos. METHODS: The immunocytochemical method was used to identify the existence of voltage-dependent Ca2+-channels in parthenogenetically activated 2-cell embryos by ethanol and SrCl2 treatment. These 2-cell embryos were obtained by exposure to 6% ethanol for 6 min and to 10 mM SrCl2 for 2h. RESULTS: P/Q-type Ca2+ channels and L-type Ca2+-channels have been identified. Whereas, three type of Ca2+-channel P/Q-type, N-type, L-type have been identified in 2-cell embryos fertilized in vivo. CONCLUSION: Activation by ethanol was faster than those by SrCl2. However, there was difference in DAB staining of the embryos between ethanol and SrCl2 treatment (87.7% and 54.1%). Intensity of staining was also different between ethanol- and SrCl2-treated group. However, it has not been known why there was some difference in DAB staining and staining intensity in the present study.

Influence of Transforming Growth Factor-alpha on Expression of Matrix Metalloproteinase-2, 9 and Epidermal Growth Factor Receptor Gene in the Mouse Blastocysts / 대한불임학회지

No abstract available.

Effect of Magnesium Ion in the Culture Medium on the Development of Preimplantation Mouse Embryos In Vitro / 대한불임학회지

OBJECTIVE: The present study was undertaken to examine the effects of magnesium ion in the culture medium on the development of mouse fertilized oocytes either before or after pronuclear formation, and to investigate whether the effect of magnesium ion is related with the redistributional change of mitochondria. METHODS: Fertilized oocytes obtained from the oviducts of mice at 15 hr after hCG injection before pronuclear formation (pre-PN) or 21 hr after hCG injection after pronuclear formation (post-PN) were used. The embryos were cultured for 3 days with basic T6 medium-magnesium free and various concentrations of magnesium ion, 0.0, 0.5, 1.0, 2.0, 4.0 or 8.0 mM, respectively. After culture, the developmental stages of embryos and the number of nuclei were evaluated. To observe the effects of magnesium ion on the mitochondrial distribution, fertilized oocytes were collected at 21 hr after hCG injection and cultured for 6 hr with various concentration of magnesium ion. As a control, fertilized oocytes with pronuclei at 27 hr after hCG injection were used. RESULTS: The concentration of magnesium ion to accelerate the in vitro development of mouse fertilized oocytes appeared to be at 2.0 mM for the pre-PN and the post-PN stage embryos. In the mitochondrial redistribution patterns, the embryos cultured in 2.0 mM concentration of magnesium ion showed the highest percentage (22.6%) of distinct perinuclear clustering pattern comparing to other experimental group. CONCLUSION: The effect of magnesium ion may be related to the cytoplasmic redistribution of mitochondria. This relationship seems to connect the developmental competence of preimplantation mouse embryos in vitro. These results can suggest that higher concentration of magnesium ion (2.0 mM) than those of conventional culture medium (0.2~1.2 mM) is more suitable for in vitro culture of preimplantation mouse embryos.

The Development of Early Mouse Embryos Depend on Ca2+ Concentration / 대한불임학회지

OBJECTIVE: This study was to determine the effect of different concentration of calcium in medium on the preimplantational development of zygotes and early 2-cell embryos. METHODS: Female mice of ICR strain (5~8 weeks old) were superovulated and mated with fertile males. Zygotes or early 2-cell embryos were collected by flushing the oviducts 31~32 hours after hCG injection. The embryos were cultured in various concentrations of Ca2+ in medium or with EDTA, EGTA and Ni2+. RESULT AND CONCLUSION: Treatment of high concentration of Ca2+ (3.42 mM (2X)~17.1 mM (10X) in medium didn't develop well compared to the control Low concentrations of Ca2+ (0.214 mM (1/8X)~0.855 mM (1/2X)) were deterimental to development beyond 2-cell stage. EDTA, Ca2+ chelating agent was treated with ranged concentrations of eDTA (0.014 mM~0.107 mM) to medium contaning 1.71 mM Ca2+ showed beneficial effect to development to blastocyst compared to the control. EGTA, extracellular Ca2+ chelator, was treated with ranged concentrations of EGTA (0.014~0.107 mM) to the medium contaning 1.71 mM Ca2+. There is no significant difference with the control. Ni2+ (50 micrometer), T-type Ca2+-channel blocker was treated to medium contaning low concentration of Ca2+. It overcame 2-cell block significantly. Rate of degenerated embryos decreased and developmental rate to morula and blastocyst increased more than low Ca2+ concentration alone. Further studies are needed for the overcoming effect of 2-cell block by Ni2+.

Vitrification and Ultrarapid Freezing of Day 2 Mouse Embryos / 대한불임학회지

OBJECTIVE: The study was performed to compare the survival rate and the development of day 2 mouse embryos which had freezing procedures done. METHODS: We used three different vitrification solutions (EFS, VS14, DPS) and a ultrarapid freezing solution (UFS) for cryopreservation of day 2 mouse embryo. RESULTS: We tested toxicity by exposing embryos to vitrification solutions and a ultrarapid freezing solution. The survival rates are 100%, 97.8%, 95.6% and 100% (EFS, VS14, DPS and UFS). After cultured for 96 hours, hatching rates of each group are 93.5% (no freezing), 95.6% (EFS), 86.4% (VS14), 93.0% (DPS), and 93.0% (UFS). There is no significant differences among groups. The survival rates after thawing cryopreserved embryos are 80.2%, 91.7%, 69.5%, 0% and 91.8% (slow freezing, EFS, VS14, DPS and UFS). Also cultured for 96 hours, the hatching rates are 93.5% (no freezing), 84.1% (slow freezing), 93.9%) (EFS), 48.5% (VS14) and 70.1% (UFS). CONCLUSION:The survival rates of vitrification in EFS solution and ultrarapid freezing are higher than slow freezing (p<0.05). The hatching rate of vitrification in EFS solution cultured for 96 hours is highest, so vitrification of day 2 mouse embryos in EFS solution considered as more effective for cryopreservation.

Effects of Follicle Cells on the Chymotrypsin Resistance of Mouse Oocytes / 대한불임학회지

OBJECTIVE: Mammalian follicle cells are the most important somatic cells which help oocytes grow, mature and ovulate and thus are believed to provide oocytes with various functional and structural components. In the present study we have examined whether cumulus or granulosa cells might play a role in establishing the plasma membrane structure of mouse oocytes during meiotic maturation. DESIGN: In particular the differential resistances of mouse oocytes against chymotrypsin treatment were examined following culture with or without cumulus or granulosa cells, or in these cell-conditioned media. RESULTS: When mouse denuded oocytes, freed from their surrounding cumulus cells, were cultured in vitro for 17~18 hr and then treated with 1% chymotrypsin, half of the oocytes underwent degeneration within 37.5 min (t50=37.5+/-7.5 min) after the treatment. In contrast cumulus-enclosed oocytes showed t50=207.0. Similarly, when oocytes were co-cultured with cumulus cells which were not associated with the oocytes but present in the same medium, the t50 of co-cultured oocytes was 177.5+/-13.1 min. Furthermore, when oocytes were cultured in the cumulus cell-conditioned medium, t50 of these oocytes was 190.0+/-10.8 min whereas t50 of the oocytes cultured in M16 alone was 25.5+/-2.9 min. Granulosa cell-conditioned medium also increased the resistance of oocytes against chymotrypsin treatment such that t50 of oocytes cultured in granulosa cell-conditioned medium was 152.5+/-19.0 min while that of oocytes cultured in M16 alone was 70.0+/-8.2 min. To see what molecular components of follicle cell-conditioned medium are involved in the above effects, the granulosa cell-conditioned medium was separated into two factions by using Microcon-10 membrane filter having a 10 kDa cut-off range. When denuded oocytes were cultured in medium containing the retentate, t50 of the oocytes was 70.0+/-10.5 min. In contrast, t50 of the denuded oocytes cultured in medium containing the filtrate was 142.0+/-26.5 min. T50 of denuded oocytes cultured in medium containing both retentate and filtrate was 188.0+/- 13.6 min. However, t50 of denuded oocytes cultured in M16 alone was 70.0 +/-11.0 min and that of oocytes cultured in whole granulosa cell-conditioned medium was 156.0+/-27.9 min. When surface membrane proteins of oocytes were electrophoretically analyzed, no difference was found between the protein profiles of oocytes cultured in M16 alone and of those cultured in the filtrate. CONCLUSIONS: Based upon these results, it is concluded that mouse follicle cells secrete a factor(s) which enhance the resistance of mouse oocytes against a proteolytic enzyme treatment. The factor appears to be a small molecules having a molecular weight less than 10 kDa.

Studies on the Participation of Prostaglandin in the Process of Hatchin gin the Mouse / 대한산부인과학회잡지

Most mammalian embryos implant on the uterine endometrium after hatching fromzona pellucida of the expanded blastocyst and pregnancy takes place. The blastocysts produceand control a variety of prostaglandins which activate a few proteolytic enzymes thatdissolve the zona pellucida of the embryos. In the present study, the goal was to investigatethe indomethacin and aspirin(inhibitors of cyclooxygenase pathway which regulates thepathway from arachidonic acid to prostaglandins), which can affect the hatching and implantationof the mouse embryos by the treatment of the different dose level of indomethacinand aspirin in the culture of mouse embryos.The female and male ICR mice, 6~8 weeks and were used for superovulation andmating and M16 was used as a basic culture medium.The above results can be summarized as following:1. Indomethacin seemed to inhibit the development of the mouse embryos and hatchingprocess because of inhibiting or blocking the activation of hatching related enzymes andhigh dose of indomethacin inhibited implantation.2. Aspirin had no effect on the hatching of the embryos at the dose of 0.16 mg/ml.3. FBS seemed to contain a factor which induced outgrowth of the embryo whereasBSA did not and outgrowth did not take place in the BSA contained medium.4. Blastocysts produced enough prostaglandins F2alpha which was needed for thehatching whereas they needed a factor for implantation which might be produced in theendometrium or exuded from the blood.In conclusion the concentration of indomethacin used in the present study inhibithatching of the blastocysts. This seems to be caused by inhibiting the synthesis of theproteins need for hatching. The factor that induce the outgrowth of the blastocysts doesnot seem to be produced in the blastocysts themselves but seem to be present in the FBS.

Cryopreservation of Day 3 Mouse Embryos by Vitrification / 대한불임학회지

The use of hormonal stimulation in human in vitro fertilization and embryo transfer (IVF-ET) leads to increased production of embryos for ET. So to avoid high pregnancies and to allow conception in future, unstimulated cycles, cryopreservation of spare embryos is desirable. One of the improvement of cryopreservation methods is vitrification. We cryopreserved mouse day 3 embryos by vitrification using the three different vitrification solution (EFS40, VSll and VS3a). EFS40 solution is consisted of 40% (v/v) ethylene glycol, Ficol170 30% (w/v) and 0.5M sucrose and VSll is 6.0M ethylene glycol and 1.8M glycerol. And VS3a is 6.5M glycerol and 6% (w/v) BSA (bovine serum albumin). First we tested the toxicity of three vitrification solution by exposure to these solution during 3 min. After washing by thawing solution, the survival rates of each groups are 95.5%, 90.9% and 84.4% (EFS40, VS11 and VS3a). High percentages of them developed to expanded blastocyst and hatching embryos in culture 48hrs 94.2%, 97.7%, 100% and 97.4% (no treatment group, EFS40, VS11 and VS3a). So there is no significant differences among the each group. Second, after thawing of vitirfied embryos, the survival rates of each groups are 96.8% (slow freeze), 94.1% (EFS40), 85.5% (VS11) and 80.0% (VS3a, P vs. no freeze or EFS40 is 0.01). Vitrified embryos exhibited a high rate of development in vitro after 48hrs culture. The percentages of each group to blastocyst and hatching embryos are 88.7% (no freeze), 91.8% (slow freeze), 93.4% (EFS40), 87.7% (VS11) and 73.0% (VS3a, P vs. other group is 0.01). The results suggest that there is no significant differences in exposure of various vitrification solution and day 3 mouse embryos can be vitrified in solution EFS40 and VS11 by simple procedure.

Expression of exogenous gene(SV40 early/LacZ) during preimplantation development after microinjection into mouse fertilized eggs / 대한불임학회지

No abstract available.

Effect of Ca++ ionophore and Ca++: channel on the mouse oocyte maturation / 대한불임학회지

No abstract available.

Studies on the in vitro 2-cell block of mouse embryos / 대한산부인과학회잡지

No abstract available.

Effect of calcium inhibitors on mouse oocyte maturation / 대한불임학회지

No abstract available.

Effect of gonadotropin on Ca++ uptake in follicle-enclosed mouse oocytes cultured in vitro / 대한불임학회지

No abstract available.

The in Vitro Maturation of the Mouse Oocyte

Mouse follicular oocytes, denuded and intact, were cultured in pyruvate salt sol and glutamine salt sol supplemented bovine serum albumin to compare the maturation rate. Glutamine has no effect on maturation of the denuded mouse oocyte but has an effect on maturation of the intact oocyte by increasing the maturation rate, depending on the increased concentration of glutamine (0.4 mM to 2 mM). Changes in osmolarity of the operation medium from 280 mOsm to 310 mOsm has no discernible effect on the oocyte maturation. A high frequency of abnormal 1st polar bodies was observed in pyruvate salt sol. and this may be due to the increased energy source in the cytoplasm of the 1st polar body when the po1ar body was extruded into the perivitelline space after the 1st meiosis.

The in Vitro Maturation of the Mouse Oocyte

Mouse follicular oocytes, denuded and intact, were cultured in pyruvate salt sol and glutamine salt sol supplemented bovine serum albumin to compare the maturation rate. Glutamine has no effect on maturation of the denuded mouse oocyte but has an effect on maturation of the intact oocyte by increasing the maturation rate, depending on the increased concentration of glutamine (0.4 mM to 2 mM). Changes in osmolarity of the operation medium from 280 mOsm to 310 mOsm has no discernible effect on the oocyte maturation. A high frequency of abnormal 1st polar bodies was observed in pyruvate salt sol. and this may be due to the increased energy source in the cytoplasm of the 1st polar body when the po1ar body was extruded into the perivitelline space after the 1st meiosis.

The Maturation in Vitro of The Rabbit Oocytes I. Amino Acids Support the Maturation In Vitro of the Rabbit Oocytes

Rabbit follicular oocytes were cultured in a medium supplemented with various elements such as bovine serum(RS), bovine serum albumin(BSA), amino acids and chorionic gonadotrophic hormone(HCG) in order to find which factors among them were most effective for oocyte maturation. The presence of BSA in the basic medium (modified Krebs-Ringer bicarbonate) did not elevate the proportion of oocyte maturation. When BS alone was added to the medium, only a few oocytes could reach to metaphase I and most of them were in degeneration. This implies that BS may act as an inhibitory or a toxic agent to the rabbit oocytes. It was found that the medium supplemented with 0.4% BSA and amino acids together raised the proportion of the oocyte maturation (54-62%). Especially the presence of proline, or of both proline and glutamine, gave a more favourable condition for the initiation of meiotic division than other amino acids. Addition of HCG to the medium did not promote the proportion of the oocyte maturation. As a consequence, it is apparent that amino acids in the medium are the most essential factors in inducing oocyte meiotic division.