• Journal of Animal Reproduction and Biotechnology
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• v.34 no.4
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• pp.300-304
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• 2019

This study was conducted to examine the oocyte recovery efficiency through having an OPU session once and twice a week. Also, the oocyte recovery efficiency was examined by using OPU after two and three months of rest period. Six cows were used for oocytes collection and were randomly divided into two groups. In experiment 1, OPU sessions were conducted once and twice a week to collect oocytes. The collected oocytes between once and twice OPU groups were classified into four groups (grade 1, 2, 3 and 4) according to the quality of cumulus cells and ooplasm. Based on the result, the percentage of collected oocytes per aspirated follicle number was similar between once and twice OPU session groups (65.5 ± 1.9 and 68.7 ± 1.4 vs.). However, the percentage of grade 1 oocytes from the twice OPU session group was significantly high compared with that of the once a week OPU session group (25.3 ± 0.9 and 32.5 ± 1.2% vs. once and twice session group, respectively, p < 0.05). In experiment 2, the group with three months of rest period tended to have a high percentage of collected oocyte compared with the group with two months of rest period (64.6 and 70.9% vs. 2 and 3 months rest group, respectively, p = 0.62). The percentage of grade 4 in the group with three months of rest period was significantly low compared with the group with two months of rest period group (27.3 and 36.5% vs. two and three months rest group, respectively, p = 0.05). In conclusion, twice a week OPU session is suitable for collection of high quality oocytes by using OPU, and three months of rest period is needed for the recovery of oocyte quality of a donor cow.

• Journal of Embryo Transfer
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• v.4 no.1
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• pp.46-55
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• 1989

The effects of an antiprogesterone (RU 486) and an antiestrogen (tamoxifen) on ovulatory response and oocyte morphology were examined in pregnant mare serum gonadotropin (PMSG)-primed immatare female rats (28 days of age): a comparison has been made on two different regirnens primed with a "control" dose (4 IU) and a "superovulatory" dose (40 IU) of PMSG. Females for control control regimen received three consecutive injections of lmg RU486, lmg tamoxifen, or vehicle at 24, 36 and 48hr, and were killed at 72l'r after PMSG. Animals for superovalatory regimen received lmg RU486, 2.5mg tamoxifen, or vehicle fouowlag the injection schedule comparable to control regimen, and were killed at 60 and 72hr after PMSG. Compared to vehicle group, there was a significant reduction in ovulatory response as judged by the proportion of rats ovulating andi or by the mean number of oocytes per rat for each treatment of RU486 and tamoxifen in both regimens. The activity of tamoxifen in inhibiting the ovulatory response was greater in control, but less in superovulatory regimen than that of RU486 based on the dose employed for each antisteroid. In both regimens, RU 486 did not have any effect 6n the changes in the proportion of degenerate oocytes as well as ovarian weight, well tamoxifen treatment resulted in a marked promotion of oocyte degeneration as well as a great reduction in ovarian weight, compared to each parameter of vehicle group. RU486 treatment in each regimen did not alter the serum levels of any steroid hormones observed. Howerver, tamoxifen treatment was associated with significant increases in serum 17$\beta$-estradiol and decreases in progesterone in both regimens; also significant increases in androgens in superovulatory regimen. The results illustrate the relative inhibitory activity of RU486 and tamoxifen indicating major steroid hormone involved in PMSG-induced ovulation: 17$\beta$-estradiol for control and progesterone for superovulatory regimen. It also appears that tamoxifen-associated elevation of circulating 17$\beta$-estradiol andi or androgens could be in part, a contributing factor to the promotion of oocyte degeneration presumably by producing a hostile oviductal environment after ovulation.ent after ovulation.

• Journal of Embryo Transfer
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• v.11 no.1
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• pp.41-50
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• 1996

This experiment was carried out to investigate the ovarian responses of the ovulation point, ovarian weight and size, the number of ovarian follicles and collected embryos, and to study the effects of the developmental stages (oocytes, 2-4 cell. 8-16 cell and morulae), additional levels of Ficoll (0, 15, 30%) on the survival rate (FDA-test) of rat embryos frozen in vitrification solution (20% glycerol + 10% ethylene glycol + 10% sucrose). Sunanarized results was as follows; 1. The mean ovulation point per head was 7, and the weight of ovaries was 0.03g. The size of ovary was 5.9 mm(L) and 4.6 mm(W), and the number of ovarian follicles over and below 2 mm was 4.7 and 8.7, respectively. The number of the collected embryos per head was 5.5 (79%). 2. 2. The FDA score of embryos frozen in 20 G 10 E 10 S without Ficoll was 2.8 (oocyte), 2.6 (2-4 cell), 3.9 (8-16 cell) and 3.6 (morula), respectively. However, there were no significant differences among treatments. 3. The FDA score of embryos frozen in 20 G 10 E 10 S with 15% Ficoll was 3.4 (oocyte), 4.0 (2-4 cell), 4.7 (8-16 cell) and 4.8 (morulae), respectively (P>0.05). 4. The FDA score of embryos frozen in 20 G 10 E 10 S with 30 % Ficoll was 3.7 (oocyte), 3.2 (2-4 cell), 4.4 (8-16 cell) and 4.4 (morulae), respectively (P>0.05). 5. As shown in the above results, the higher survival rate was obtained in the treatment of 15% Ficoll than that of 30%. And the survival rate (FDA-test)of the oocytes and 2-4 cell stages of the rat embryos was lower than that of 8~16 cell and morulae stages. It was considered that 8-16 cell and morulae could be available for the successful freezing by vitrification of rat embryos with 15% Ficoll except for oocytes.

• Clinical and Experimental Reproductive Medicine
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• v.29 no.4
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• pp.229-236
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• 2002

Objective : The purpose of this study was to evaluate the effect of Cytochalasin B (CCB) on the cytoskeletal stability of mouse oocyte frozen by vitrification. Methods : Mouse oocytes retrieved from cycle stimulated by PMSG and hCG were treated by CCB and then vitrified in EFS-30. These oocytes were placed onto an EM grid and submerged immediately in liquid nitrogen. Thawing of the oocytes was carried out at room temperature for 5 seconds, then the EM grid was placed into 0.75 M, 0.5 M and 0.25 M sucrose at $37^{circ}C$ for 3 minutes, each. These oocytes were fixed in 4% formaldehyde for an hour and then washed in PPB for 15 minutes 3 times, then incubated in PPB containing anti-tubulin monoclonal antibody at $4^{circ}C$ overnight. And then, the oocytes were incubated with FITC-conjugated anti-mouse IgG and propidium iodide (PI) for 45 minutes. Pattern of microtubules and microfilaments of oocytes were evaluated with a confocal microscope. Results: The rate of oocytes containing normal microtubules and microfilaments was significantly decreased after vitrification. The rate of oocyte containing normal microtubules in CCB treated group was higher than those in non-treated group (53.7% vs. 48.9%), but the difference was not significant. The rate of oocyte containing normal microfilaments in CCB treated group was significantly higher than those in non-treated group (64.5% vs. 38.3%, p<0.05). Conclusion: Microfilaments stability could be improved by CCB treatment prior to vitrification. It is suggested that CCB treatment prior to vitrification improve stability of cytoskeleton and then increase success rate in IVF-ET program using vitrification and thawing oocyte.

• The Korean Journal of Zoology
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• v.34 no.2
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• pp.188-195
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• 1991

The effect of lanthanum ion (La3 +), which is associated with the mobilization of internal calcium, on the regulation of oocyte maturation was investigated with Rana dybowskii follicles. Follicular oocytes matured (germinal vesicle breakdown, GVBD) dose dependently when they were exposed to La3+ (O.O1-1.O mM) and the maturation occurred in 9-12 hours after the la3+(0.33 mM) stimulation. lanthanum also accelerated the onset of maturation of the lollicular oocytes exhibiting spontaneous maturation. Three hours of exposure to La3+ was enough to induce the maturation. The La3 + -induced maturation was not associated with progesterone production by follicle cells, and the maturation was inhibited by forskolin (9 $\mu$ M), and cyclobeximide (0.01 - 1.0 - $\mu$g/2 ml) in the medium. The La3+ and hormone stimulated maturation showed the same patterns of protein phosphorylation and dephosphorylation during the maturation. The data suggest that the oocyte maturation by La3+ stimulation is very similar to that by progesterone. Thus, it seems that internal mobilization of Ca2+ plays a key role in the initiation of oocyte maturation in amphibia.

• The Korean Journal of Zoology
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• v.33 no.1
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• pp.53-62
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• 1990

Fully grown amphibian oocytes undergo their maturation (germinal vesicle breakdown, GVBD) during in vitro follicle culture when they are stimulated with frog pituitary homogenate (FPH) or progesterone. Present experiments were designed to determine whether proteolytic enzymes are involved in the regulation of the matunation process. Treatment of a $\alpha$ -chymoiyypsin inhibitor, N a -tosyl-L-phenylalanine-chloromethyl-ketone(TP) to the oocytes exhibited a biphasic phenomenon, the induction of the maturation without added hormone at relatively low doses (0.001-1 $\mu$M) and inhibition of the hormone induced oocyte maturation at a high dose (100 $\mu$M). Treatment of a trypsin inhibitor, N a -tosyl-L-lysine-chloromethyl ketone(TLCK) to the oocytes did not induce the maturation, but rather suppressed the hormone induced oocyte maturation in a high dose(100 $\mu$ M). Treatment of exogenous iyypsin to the oocyte induced their maturation without added hormone in a dose dependent manner (0.001-1 $\mu$ M). The data presented here indicate that some proteolytic enzymes play a role in the regulation of the maturation(meiotic arrest or reinitiation) in amphibians.

• Journal of Aquaculture
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• v.2 no.1
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• pp.21-32
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• 1989

This study was undertaken to understand development stage of ovary and changes of hormone concentrations in the Israeli carp, Cyprinus carpio from Ferbruary to May. The results obtained in these experiments are as follows: 1. Serum LH levels began to increase sharply in March, coinciding with the onset of rapid ovarian development. 2. LH levels were well correlated with changes in gonadosomatic index. 3. Dramatic increase in gonadosomatic index occured during the months of March. 4. Ripe stage(Stage VII) rapidly increase in March. 5. Early perinucleolus oocyte rapidly develop into late perinucleolus oocytes in March. 6. The vitellogenic phase begins as these late perinucleolus oocytes become transformed into early maturing oocytes through the accumulation of yolk. 7. The cytoplasm completely fills with yolk as oocytes reach the late maturing stage. 8. Changes in the microscopic appearances of the ovaries were well correlated with changes in both gonadosomatic index and macroscopic appearance. 9. It is concluded from these observations that LH plays a major role in sexual maturating of the Israeli carp.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.5
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• pp.1231-1243
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• 2016

The ultrastructural study on oocyt development and the process of vitellogensis in the oocytes during oogenesis in female Pampus echinogaster were investigated by electron microscope observations. In the previtellogenic phase, in particular, several intermitochondrial cements appear in the cytoplasms of the chromatin nucleleolus oocyte and perinuclear oocyte. The number of intermitochondrial cements are associated with the multiplication of the number of mitochondria in the early developmental stage. In the early vitellogenic phase, the Golgi complex in the cytoplasm of the yolk vesicle oocyte is involved in the formation of yolk vesicles containing carbohydrate yolks. At this time, many pinocytotic vesicles containing yolk precursors (exogenous substances) by pinocytosis are observed in the cytoplasm near the region of initial formation of the zona pellucida. In the late vitellogenic phase, two morphological different bodies, which formed by the modified mitochondria, appeared remarkably in the yolked oocytes. The one is the multivesicular bodies and another is yolk precursors. The multivesicular bodies were transformed into the primary yolk globules, while yolk precursors were connected with exogeneous pinocytotic vesicles near the zona pellucida. After the pinocytotic vesicles were taken into yolk precursors, the yolk precursors were transformed into the primary yolk globules. Thereafter, primary yolk globules mixed with each other, eventually, they developed into secondary and tertiary yolk globules. In this study, vitellogenesis of this species occurred by way of endogenous autosynthesis and exogenous heteogenesis. Vitellogenesis occurred through the processes of endogeneous autosynthesis, involving the combined activity of the Golgi complex, mitochondria and multivesicular bodies formed by modified mitochondria. However, the process of heterosynthesis involved pinocytotic incorporation of extraovarian precursors (such as vitellogenin in the liver) into the zona pellucida (by way of granulosa cells and thecal cells) of vitellogenic oocytes.

• Clinical and Experimental Reproductive Medicine
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• v.17 no.2
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• pp.115-121
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• 1990

Ultrasonically guided oocyte collection gradually replaces laparoscope in many IVF center. In present study, we compare the efficacy of both methods in our IVF program. Totally 377 cycles which were undertaken in vitro fertilization treatment were divided into 2 groups. Ultrasonically guided transvaginal follicular aspiration was performed in 188 cycles and laparoscopic follicular aspiration was performed in 189 cycles under local anesthesisa. The mean age for both groups was similar. Follicular recruitment was achieved with human menopausal gonadotropin (hMG) or a com bination of clomiphene citrate and hMG or a combination of FSH and hMG. In the ultrasonically guided aspiration group, 1821 follicles were aspirated with 61.8% of recovery rate (1125 oocytes), 81.5% of embryo transfer rate (145 cycles) and (17%), 26 cases intrauterine pregnancies were estabilished. In the laparoscopic group, 604 follicles were aspirated with 68.7% recovery rate (445 oocytes) and a 79.9% ET rate (127 cycles), 11 cases (8.7%) intrauterine pregnancies were estabilished. A valid comparison of these data is not possible because the 2 groups are dissimilar for factors known to influence oocyte development and recovery. No statistically significant differences could be demonstrated between 2 groups in all but the recovery rate and clinical pregnancy rate, In ultrasound group, the clinical pregnancy rate was significantly higher than that of laparoscope group. The potentially detrimental effect of CO2 pnemoperitonium present during laparoscope but not in ultrasound guided recovery on ova quality may underlie the observed difference in the clinical pregnancy rate between the 2 groups. Ultrasound guided aspiration seems to be as effective as laparoscopy in terms of oocyte retrieval and conception rate. Furthermore, the procedure is simple and inexpensive, it may replace laparoscopy as a method for oocyte collection in most patients who undergo IVF.

• Clinical and Experimental Reproductive Medicine
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• v.21 no.3
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• pp.285-296
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• 1994

Follicular oocytes were released from the graafian follicles of ovaries from 3-4 weeks old mice. The spontaenous maturation of these follicular oocyes was inhibited by the treatment of dbcAMP and progesterone and these oocytes were cultured for 2-8hr in the Modified Hank's balanced salt solution(MHBS). Ethylenediaminetetraaceticacid(EDTA) and calmoudulin antagonist, trifluoperazine (TFP) were treated to the culture medium in order to investigate whether these chemical agents inhibit calcium uptake into the oocyte and oocyte maturation. $^{45}Ca^{2+}$, 10-${\mu}$Ci/ml was added to the culture medium during the culture period. $^{45}Ca^{2+}$uptake into the oocytes was examined whether and when various kind of oocyte maturation inhibiting agents inhibit or stimulate the influx of calcium into oocytes. Dibutyryl cAMP and progesterone decrease $^{45}Ca^{2+}$uptake into the oocytes and synergistic inhibiting effect of dbcAMP and progesterone was prominent at much lower dosages. Calcium uptake into oocytes seems to be higher during first 2 hour culture period rather than next 4hr culture. After 8hr culture, calcium uptake level of the oocytes which GVBD already took place gradually approached to the level of those which were maintained at GV by the treatment of dbcAMP and progesterone. However, $^{45}Ca^{2+}$uptake into the GV maintained oocytes did not change at all even after 8hr culture period. In addition, calcium chelating agent, EDTA inhibited calcium uptake into oocytes as well as nuclear maturation of oocytes. Lower dosage used in the present study did not inhibit calcium uptake as well as oocyte maturation.