EunYoung Lee

Sungkyunkwan University, Sŏul, Seoul, South Korea

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Publications (18)52.75 Total impact

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    ABSTRACT: Autophagy is known to be regulated by the PI3K-AKT and/or MEK1/2-ERK1/2 pathways, leading to activation of mammalian target of rapamycin (mTOR), a major negative regulator of autophagy. However, some reports have also suggested that autophagic regulation by the PI3K-AKT and/or MEK1/2-ERK1/2 pathways may not be mediated by mTOR activity, and there is no direct evidence of the involvement of these pathways in luteal cell autophagy regulation. To elucidate the luteal cell-specific regulatory mechanisms of autophagy induction during corpus luteum (CL) regression, we evaluated whether luteal cell autophagy is regulated by the PI3K-AKT pathway and/or MEK1/2-ERK1/2 pathway and if this regulation is mediated by mTOR. We found that autophagy induction increased despite mTOR activation in luteal cells cultured with prostaglandin F2α (PGF2α), an important mediator of CL regression, suggesting that PGF2α-induced autophagy is independent of mTOR regulation. We also found that PGF2α-induced autophagy was not mediated by AKT activity, because AKT inhibition using a PI3K inhibitor (wortmannin) did not change autophagy induction or mTOR activity. In contrast, ERK1/2 activity increased in PGF2α-treated luteal cells, as did the levels of autophagy induction despite increased mTOR activity. Furthermore, PGF2α-mediated up-regulation of luteal cell autophagy was reversed by addition of ERK1/2 inhibitors, despite a decrease in mTOR activity. These in-vitro results suggest that luteal cell autophagy is induced by increased ERK1/2 activity during CL regression, and is independent of mTOR activity. This finding was further supported by in-vivo experiments in a pseudopregnant rat model, which showed that induction of luteal cell autophagy increased during luteal stage progression and that this was accompanied by increased ERK1/2 and mTOR activity. Taken together, our findings indicate that activation of ERK1/2 is a key event in the induction of luteal cell autophagy during CL regression which is not associated with mTOR regulation.
    Molecular Human Reproduction 08/2014; · 4.54 Impact Factor
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    ABSTRACT: Mammalian target of rapamycin (mTOR) is known to be a major negative regulator of autophagy. Recent studies have shown that mTOR activity is abnormally increased in endometriotic lesions. In endometriosis, abnormal mTOR activity may contribute to the alteration of endometrial cell autophagy, which may affect apoptosis because endometrial cell autophagy is directly involved in regulation of apoptosis. To test this hypothesis, we investigated whether endometrial cell autophagy is altered by aberrant mTOR activity and is associated with apoptosis in ovarian endometriotic cysts. Our results show that endometrial cell autophagy induction was increased by mTOR inhibition as the menstrual cycle progresses in normal endometrium, and that it is correlated with apoptosis. However, in endometriotic tissue from ovarian endometriotic cysts, autophagy, mTOR activity and apoptosis were constant throughout the menstrual cycle, suggesting that a constant level of autophagy is maintained by disinhibition of mTOR activity during the menstrual cycle in endometriotic tissue and is related to decreased apoptosis. Indeed, compared with normal endometrium, increased mTOR activity during the secretory phase in endometriotic tissues inhibited autophagy and apoptosis induction. In addition, to determine the direct effect of autophagy induction mediated by mTOR on endometriotic cell apoptosis, endometriotic cells were treated with rapamacin (mTOR inhibitor) with and without 3-methyladenine (3-MA, autophagy inhibitor). Although rapamycin treatment induced autophagy and led to apoptosis promotion, the pro-apoptotic effect of rapamycin was reversed by the addition of 3-MA, suggesting that mTOR inhibition promotes endometriotic cell apoptosis via autophagy induction. In conclusion, our results suggest that aberrant mTOR activity in ovarian endometriotic cysts leads to alteration of endometrial cell autophagy, which is associated with abnormal apoptosis.
    Molecular Human Reproduction 12/2013; · 4.54 Impact Factor
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    ABSTRACT: In this study we examined whether granulosa cell autophagy during follicular development and atresia was regulated by the class I phosphoinositide-3 kinase (PI3K)/protein kinase B (AKT) pathway which is known to control activity of mammalian target of rapamycin (mTOR), a major negative regulator of autophagy. Ovaries and granulosa cells were obtained using an established gonadotropin-primed immature rat model that induces follicular development and atresia. Autophagy was evaluated by measuring the expression level of microtubule-associated protein light chain 3-II (LC3-II) using Western blots and immunohistochemistry. The activity of AKT and mTOR were also examined by observing the phosphorylation of AKT and ribosomal protein S6 kinase (S6K), respectively. After gonadotropin injection, LC3-II expression was suppressed and phosphorylation of AKT and S6K increased in rat granulosa cells. In contrast, gonadotropin withdrawal by metabolic clearance promoted LC3-II expression and decreased phosphorylation of AKT and S6K. In addition, in-vitro FSH treatment of rat granulosa cells also indicated inhibition of LC3-II expression accompanied by a marked increase in phosphorylation of AKT and S6K. Inhibition of AKT phosphorylation using AKT inhibitor VIII suppressed FSH-mediated phosphorylation of S6K, followed by an increase in LC3-II expression. Furthermore, co-treatment with FSH and AKT inhibitor increased the levels of apoptosis and cell death of granulosa cells compared to the single treatment with FSH. Taken together, our findings indicated that AKT-mediated activation of mTOR suppresses granulosa cell autophagy during follicular development and is involved in the regulation of apoptotic cell death.
    Reproduction 10/2013; · 3.56 Impact Factor
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    ABSTRACT: Autophagy appears to play an important role in the normal development and maintenance of homeostasis in a variety of tissues, including the female reproductive tract. However, the role of autophagy and the association between autophagy and apoptosis in cyclic remodeling of the human endometrium have not been described. Therefore, we investigated the involvement of autophagy during the human endometrial cycle and its association with apoptosis. Endometrial samples were obtained from 15 premenopausal, nonpregnant women who underwent hysterectomies for benign gynecological reasons. The autophagy-associated protein, microtubule-associated protein 1 light chain 3 alpha (MAP1LC3A), was immunolocalized, and its expression level was measured by Western blot analysis. Apoptosis was evaluated by measuring the expression level of cleaved caspase 3 protein. MAP1LC3A protein was primarily expressed within the endometrial glandular cells and increased during the secretory phase. The expression level of the membrane-bound form of MAP1LC3A (MAP1LC3A-II) also increased as the menstrual cycle progressed, reaching a maximum level during the late secretory phase. This pattern coincided with the expression of cleaved caspase 3. Furthermore, expression of MAP1LC3A-II and cleaved caspase 3 increased in the in vitro-cultured endometrial cancer cells when estrogen and/or progesterone were withdrawn from the culture media to mimic physiological hormonal changes. These findings suggest that endometrial cell autophagy is directly involved in the cyclic remodeling of the human endometrium and is correlated with apoptosis. In addition, we inhibited autophagic processes using 3-methyladenine (3-MA) or bafilomycin A1 (Baf A1) to evaluate the role of autophagy in apoptosis induction in endometrial cancer cells. While the inhibition of autophagosome formation using 3-MA did not decrease apoptosis or cell death, the inhibition of autophagosome degradation by fusion with lysosomes using Baf A1 increased apoptosis and cell death, suggesting that the accumulation of autophagosomes induces apoptosis. Furthermore, Baf A1-induced apoptotic cell death was decreased by the apoptosis inhibitor N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone (Z-VAD-FMK). In conclusion, these results indicate that autophagy is involved in the endometrial cell cycle affecting apoptosis and is most prominent during the late secretory phase.
    Biology of Reproduction 11/2011; 86(3):70. · 4.03 Impact Factor
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    ABSTRACT: Autophagy is associated with luteal cells death during regression of the corpus luteum (CL) in some species. However, the involvement of autophagy or the association between autophagy and apoptosis in CL regression are largely unknown. Therefore, we investigated the role of autophagy in CL regression and its association with apoptosis. Ovaries were obtained from pseudopregnant rats at Days 2 (early), 7 (mid-), and 14 and 20 (late-luteal stage) of the pseudopregnancy; autophagy-associated protein (microtuble-associated protein light chain 3 [LC3]) was immunolocalized and its expression level was measured. Luteal cell apoptosis was evaluated by measuring cleaved caspase 3 expression. LC3 expression increased slightly from early to mid-luteal stage, with maximal levels detected at the late-luteal stage in steroidogenic luteal cells. The expression level of the membrane form of LC3 (LC3-II) also increased during luteal stage progression, and reached a maximum at the end point of late-luteal stage (Day 20). This pattern coincided with cleaved caspase 3 expression. Furthermore, LC3-II expression increased, as did levels of cleaved caspase 3 in luteal cells cultured with prostaglandin F(2alpha) known to induce CL regression. These findings suggest that luteal cell autophagy is directly involved in CL regression, and is correlated with increased apoptosis. In addition, autophagic processes were inhibited using 3-methyladenine or bafilomycin A1 to evaluate the role of autophagy in apoptosis induction. Inhibition of autophagosome degradation by fusion with lysosomes (bafilomycin A1) increased apoptosis and cell death. Furthermore, inhibition of autophagosome formation (3-methyladenine) decreased apoptosis and cell death, suggesting that the accumulation of autophagosomes induces luteal cell apoptosis. In conclusion, these results indicate that autophagy is involved in rat luteal cell death through apoptosis, and is most prominent during CL regression.
    Biology of Reproduction 05/2011; 85(3):465-72. · 4.03 Impact Factor
  • Biology of Reproduction 05/2011; · 4.03 Impact Factor
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    ABSTRACT: This study evaluated the effect of autophagosome accumulation on apoptotic cell death in granulosa cells from developing follicles. Our results indicate that the accumulation of autophagosomes induces apoptotic cell death of granulosa cells through decreased bcl-2 expression and subsequent caspase activation.
    Fertility and sterility 03/2011; 95(4):1482-6. · 3.97 Impact Factor
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    ABSTRACT: Cryopreservation of ovarian tissue has been reported to delay the development of preantral follicles by temporary suppression of granulosa cell proliferation during in vitro culture. This delay might be overcome by treatment with activin A and/or IGF-I, known to stimulate granulosa cell proliferation. However, the effects of these growth factors, on delayed follicle development induced by ovarian tissue cryopreservation, have not been evaluated. Therefore, we studied the effects of activin A and/or IGF-I on granulosa cell proliferation and follicle development in preantral follicles isolated from mouse cryopreserved ovarian tissues. The preantral follicles isolated from fresh ovarian tissues were cultured with control medium (CM) for 10 days. The preantral follicles isolated from cryopreserved ovarian tissues were cultured with CM and with CM+activin A (100 ng/ml), IGF-I (50 ng/ml) or activin A+IGF-I added for 10, 12 and 14 days. The follicles were stimulated with hCG at the end of culture. The granulosa cell proliferation was evaluated by measuring the PCNA expression and the follicle development assessed by comparing the follicle diameter and oocyte maturation. The expressed level of PCNA was significantly decreased in the cryopreserved preantral follicles cultured with CM, compared to the fresh group (p<0.05), but increased to the level of the fresh group by the addition of activin A, IGF-I or activin A and IGF-I. The maximum follicle diameter and oocyte maturation rate were obtained in the fresh group after 10 days of culture, while the diameter and oocyte maturation rate of cryopreserved preantral follicles reached similar levels after 14 days. Under conditions of CM with added activin A or activin A+IGF-I, both the diameter and oocyte maturation rate of the cryopreserved preantral follicles improved to the levels of the fresh group after 12 days. However, the stimulatory effect was not different in comparisons between activin A and activin A+IGF-I. In addition, adding activin A significantly increased the survival rate of cryopreserved preantral follicles compared to IGF-I (p<0.05). On the other hand, the diameter of the cryopreserved preantral follicles did not increase to the level of the fresh group by addition of IGF-I, although the oocyte maturation rate was improved to the level of fresh group after 12 days of culture. These findings indicate that activin A has a greater stimulatory effect on the growth of preantral follicles than does IGF-I. In conclusion, the addition of activin A to culture media stimulated granulosa cell proliferation to overcome the delay in culture of the development of preantral follicles isolated from cryopreserved mouse ovaries.
    Cryobiology 09/2008; 57(3):209-15. · 2.14 Impact Factor
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    ABSTRACT: To explain the unexpected low response to GnRH antagonist protocol in reproductive women with normal baseline hormone profiles. Retrospective study. University hospital. Twenty-five women undergoing their first IVF cycle. Follicular fluid (FF) from large follicles (>15 mm) was obtained during oocyte retrieval from unexpected low responders (n = 13, group A) and 12 age-matched normal responders (n = 12, group B). The FF markers known to reflect follicle environment (insulin-like growth factor [IGF] II, IGF-binding protein 4, müllerian-inhibiting substance, pregnancy-associated plasma protein A, soluble Fas, and vascular endothelial growth factor [VEGF]) were analyzed by ELISA. The baseline characteristics (age, day 3 serum LH, FSH, E(2), duration and dose of r-FSH, GnRH antagonist) were not different between the two groups. The number of large follicles, oocytes retrieved, and serum E(2) levels on the day of hCG injection were significantly higher in group B. Whereas the other follicular markers did not differ between the two groups, VEGF was significantly higher in group A. In addition, the VEGF concentration showed an inverse correlation with the total number of oocytes retrieved. The unexpected low response in women with normal basal hormone profiles, during GnRH antagonist protocol, was associated with altered follicular VEGF expression.
    Fertility and sterility 03/2008; 91(3):744-8. · 3.97 Impact Factor
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    ABSTRACT: Cryopreservation of ovarian tissue has been reported to delay the development of preantral follicles during in vitro culture, but the mechanism causing this impairment has not been brought to light. In order to elucidate the underlying mechanism of delayed follicular development, we evaluated the effects of cryopreservation on the proliferation of granulosa cells during culture of mouse preantral follicles, as a sufficient population of granulosa cells is critical for normal follicular development. Additionally the initial cell death of granulosa cells was estimated immediately after cryopreservation. The ovarian tissues obtained from 12-day-old female mice were cryopreservation by vitrification. The granulosa cell proliferation was evaluated by measuring the PCNA expression and the expression of cell cycle regulators such as cyclin D2, CDK4, cyclin E and CDK2 in preantral follicles isolated from fresh and cryopreserved ovarian tissues that were cultured for 48 h. The viability of granulosa cells was evaluated by measuring the proportion of necrotic areas. The granulosa cell proliferation of the cryopreserved preantral follicles was decreased significantly compared to that of the fresh controls at 0 and 24h after culture (P<0.05), and this was increased to the control levels after 48 h of culture. The expressions of cyclin D2, Cdk4, cyclin E and Cdk2 were also decreased in the cryopreserved ovarian tissues at 0 and 24h after culture (P<0.05), but they were increased to the control levels after 48 h of culture. The proportion of the necrotic area was significantly higher in cryopreserved preantral follicles compared to that of the fresh preantral follicles (P<0.05). This suggests that cryopreservation of ovarian tissues may delay the preantral follicle development by temporary suppressing the granulosa cell proliferation through the cell cycle regulators (cyclin D2, Cdk4, cyclin E and Cdk2) and by granulosa cell death immediately after warming.
    Cryobiology 03/2008; 56(1):36-42. · 2.14 Impact Factor
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    ABSTRACT: The cryopreservation of ovarian tissue has been reported to affect the development of preantral follicles. However, the effect of cryopreservation of ovarian tissue on the development of primordial follicles remains to be elucidated. This study was conducted to evaluate the effect of cryopreservation on the development of frozen-thawed mouse primordial follicles. One-day-old mouse ovaries were cryopreserved by either slow-freezing or a vitrification method. The development of primordial follicles was evaluated histologically and also with markers for follicle development such as: GDF-9, inhibin-alpha subunit and ZP3 in fresh and frozen-thawed ovaries cultured for five days. The proportion of apoptotic and necrotic areas was analyzed in fresh and frozen-thawed ovaries at one and five days after culture, in order to examine the viability of ovarian cells that influence primordial follicle development. The development rate of primordial follicles was significantly lower in slow-frozen and vitrified ovaries than the fresh controls after five days of in vitro culture (P<0.05). The mRNA expression for all developmental markers was slightly decreased in the frozen-thawed ovaries; this difference was not significant. The proportion of apoptosis was significantly increased in the slow-frozen and vitrified ovaries compared to the fresh ovaries at one day (P<0.05); however, there was no difference at five days after culture. The proportion of the area of necrosis was significantly higher in slow-frozen and vitrified ovaries compared to the fresh ovaries at one and five days after culture (P<0.05). Our preliminary data suggest that ovarian tissue cryopreservation using slow-freezing and vitrification methods inhibits development of primordial follicles. This may be caused by the death of ovarian cells through apoptosis and necrosis after cryopreservation.
    Cryobiology 03/2007; 54(1):55-62. · 2.14 Impact Factor
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    ABSTRACT: This study was conducted to evaluate the involvement of apoptosis in the freeze-thaw process and to investigate the anti-apoptotic effect of vascular endothelial growth factor (VEGF) in the frozen-thawed granulosa cells. Isolated rat granulosa cells were cultured, frozen-thawed, and were cultured for 24h. Cell viabilities (by Trypan blue exclusion test) and apoptotic patterns (by Annexin-V/propidium iodide (PI) Double-Staining) were determined at each step. Apoptotic cell death was confirmed by following DNA degradation and caspase-3 activity. After freeze-thaw process and 24h of culture, reductions in the cellular viabilities and increases in the number of cells containing degraded DNA were lower in the VEGF pretreated group than in the control group (p<0.05). In the VEGF pretreated group, increases in the proportions of late apoptotic cells [Annexin-V (+)/PI (+)] were significantly lower and caspase-3 expression was prevented immediate after thawing (p<0.05). Furthermore, increases in the proportions of early apoptotic cells [Annexin-V (+)/PI (-)] and reductions in the proportions of viable cells [Annexin-V (-)/PI (-)] were significantly lower in the VEGF pretreated group after culture for 24h (p<0.05). Of the different doses of VEGF pretreated, 50ng/ml was found to be most effective with respect to protecting frozen-thawed granulosa cells from cryoinjury. Granulosa cell damage induced by cryopreservation is mediated, at least in part, by an apoptotic process. Our preliminary results suggest that VEGF treatment before freeze-thaw process reduces rat ovarian granulosa cell damage by inhibiting apoptosis.
    European Journal of Obstetrics & Gynecology and Reproductive Biology 04/2006; 125(2):233-8. · 1.84 Impact Factor
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    ABSTRACT: We examined rat ovarian granulosa cells at different follicular stages and evaluated the apoptosis pattern of the mitochondria-dependent genes during folliculogenesis. After down-regulating ovarian function with gonadotropin-releasing hormone agonist (GnRHa), granulosa cells were collected from the rat ovary at different stages of the following different hormonal treatment paradigms: stage E (after estrogen treatment), EF (after E + follicle-stimulating hormone [FSH] treatment), and EF hCG (after E + FSH + human chorionic gonadotropin treatment). To evaluate the in vitro susceptibility of granulosa cells at different developmental stages to apoptosis, the collected cells were cultured in a serum-free medium with or without E2 for 24 hours. The regulation of apoptosis in the granulosa cells was analyzed using fluorescein-activated cell sorting, quantitative competitive polymerase chain reaction, and western blot methods. The apoptosis rate of the freshly isolated granulosa cells tended to increase according to the hormonal treatment paradigm. In addition, during the hormone treatment, mitochondria-dependent apoptosis genes showed the following changes: although the Bax mRNA level did not change, the Bcl-2 mRNA level decreased significantly (P <.05). The p53 mRNA level increased significantly (P <.05) and closely matched the apoptosis rate (R = 0.7, P <.05). The expression of the active form of the caspase-3 protein (the final executioner of cell death) tended to increase and showed a good correlation with the apoptosis rate (R = 0.96, P <.01). After an in vitro culture of the granulosa cells, the apoptosis rate tended to increase at all stages, particularly stage EF hCG (P <.05). Bax and p53 mRNA tended to increase and showed a good correlation with the apoptosis rate (R = 0.64, P <.05 and 0.86, P <.01). The Bcl-2 mRNA level tended to decrease at all stages showing no correlation with the apoptosis rate. The expression level of the active caspase-3 protein tended to increase at all stages and showed a good correlation with the apoptosis rate (R = 0.93, P <.01). Apoptosis of rat ovarian granulosa cells tends to increase according to the stage of follicular development. Among the mitochondria-dependent genes, p53 closely correlates with granulosa cell apoptosis during follicular development.
    Journal of the Society for Gynecologic Investigation 07/2004; 11(5):311-7. · 2.26 Impact Factor
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    ABSTRACT: To determine the effect of dose of GnRH agonist on the follicular environment in controlled ovarian hyperstimulation (COH) cycles. Twenty-eight IVF patients with normal ovarian function were divided into three groups: group I received GnRHa (nafarelin acetate/Synarel) intranasally at 200 microg daily, group II received 400 microg daily until hCG injection, and group III was given 400 microg daily before the initiation of ovarian stimulation, then 200 microg daily before the day of hCG injection. Serum estradiol, progesterone, and leptin levels were measured on the day of hCG injection. After aspiration, expression of pregnancy-associated alpha-plasma protein (PAPP)-A in the follicular fluid of dominant follicles (>20 mm) was determined by Western blot analysis. No significant difference was noted in serum estradiol, progesterone, and leptin levels. But intrafollicular PAPP-A expression was significantly higher in group II compared to other groups (P<0.05). The dose of GnRHa may have an impact on the intrafollicular environment of dominant follicles in COH cycles.
    European Journal of Obstetrics & Gynecology and Reproductive Biology 02/2004; 112(1):65-8. · 1.84 Impact Factor
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    ABSTRACT: This study was undertaken to investigate cyclin D2 mRNA and protein expression in human endometrium during the menstrual cycle. Endometrial samples were obtained from 15 premenopausal nonpregnant women who had hysterectomies for benign gynecologic reasons. They were divided into the following five groups according to histologic dating: early proliferative (n = 3), mid to late proliferative (n = 3), early secretory (n = 3), mid secretory (n = 3), and late secretory (n = 3). Cyclin D2 mRNA and protein expression were analyzed using reverse transcriptase-polymerase chain reaction, Western blotting, and immunohistochemistry. Cyclin D2 mRNA and protein were expressed in human endometrial tissue throughout the menstrual cycle. Cyclin D2 mRNA and protein expression of proliferative phase endometrium were significantly higher than those of secretory phase endometrium (P <.05). The staining intensity of cyclin D2 in proliferative phase endometrium was higher than that in secretory phase (P <.05). Cyclin D2 mRNA level showed good correlation with cyclin D2 protein level (R = 0.579, P <.03), and cyclin D2 protein also showed good correlation with immunohistochemical staining intensity (R = 0.562, P <.03). Cyclin D2 was expressed in human endometrium throughout the menstrual cycle. Cyclin D2 mRNA and protein were expressed at high levels in proliferative phase endometrium, especially in the early proliferative phase, and then decreased in the secretory phase.
    Journal of the Society for Gynecologic Investigation 01/2002; 9(1):41-6. · 2.26 Impact Factor
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    ABSTRACT: Purpose: We carried out this study to evaluate the biological significance of phospholipase C 1 gene mutation in mouse sperm in the acrosome reaction, fertilization, and embryo development.Methods: Study subjects were divided into two groups according to the sperm [intact phospholipase C (PLC) 1 and PLC 1–/– C57BL/6J CBA F1 mouse sperm] used. The positive acrosome reaction rate labeled with fluorescein isothiocyanate–Pisum sativum agglutinin, the fertilization rate, and the rate of embryos developed to the stage of morula or blastocyst in the two groups were compared.Results: The mouse sperm null for the PLC 1 gene showed a lower acrosome reaction rate than control sperm (69.2 vs 50.9%, P < 0.05).="" and="" the="" fertilization="" rate="" and="" the="" rate="" of="" embryos="" developed="" to="" the="" stage="" of="" morula="" or="" blastocyst="" were="" also="" lower="" in="" the="" group="" using="" plc="">1–/– mouse sperm compared to the intact group (P < 0.05;="" 73.5="" vs="" 51.8%="" and="" 15.7="" vs="" 4.3%,="">Conclusions: Mutation of the PLC 1 gene in the mouse sperm reduces the acrosome reaction rate, fertilization rate, and embryo development rate, which may be the etiologic factors responsible for the low reproductive rate of PLC 1–/– mouse.
    Journal of Assisted Reproduction and Genetics 04/2001; 18(5):305-310. · 1.82 Impact Factor
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    ABSTRACT: Purpose: Our purpose was to investigate the expression pattern of cyclin D2 and pseudogene cyclin D2 mRNA in the human ovary with age.Methods: After extraction of the total RNA from ovarian tissues of 23 premenopausal patients, cyclin D2 and pseudogene cyclin D2 mRNAs were measured by the reverse transcription–polymerase chain reaction technique using cyclin D2 and pseudogene cyclin D2 specific primers. Analysis of the cyclin D2 and pseudogene cyclin D2 mRNA expression pattern with age and correlation analysis were carried out.Results: A 489-bp cyclin D2 band and a 441-bp pseudogene cycin D2 mRNA band were detected in the human ovarian tissue. While cyclin D2 mRNA expression showed a decreasing tendency with age (P = 0.17), pseudogene cyclin D2 mRNA expression increased with age (P < 0.05).="" pseudogene="" cyclin="" d2="" mrna="" expression="" showed="" a="" negative="" correlation="" with="" cyclin="" d2="" mrna="" (r="–0.35," p="">Conclusion: The expression of pseudogene cyclin D2 mRNA in the human ovary increases with age, which may be a novel marker for decreased ovarian function associated with the aging process.
    Journal of Assisted Reproduction and Genetics 01/2001; 18(2):110-113. · 1.82 Impact Factor
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    ABSTRACT: Purpose: This study was carried out to investigate the efficacyof electric stimulation before and/or after intracytoplasmicsperm injection (ICSI) on bovine oocyte activation andembryo development. Methods: The oocytes were treated with electric shock before(B), before and after (B&A), and after (A) sperm injection.In each group, sham ICSI (ICSI-s) was performed to excludethe effect of parthenogenesis (B ICSI-s, B&A ICSI-s, and AICSI-s). An electric pulse was applied with a single directcurrent (DC) pulse (0.8 kV/cm, 70 sec). Results: One pronucleus (PN) formation in the B&A ICSI-sgroup was slightly higher than that found in B and B&AICSI group; however, the difference was not significant. TwoPN formation in B&A ICSI group was higher than that foundin sham ICSI groups (P < 0.05).="" there="" were="" no="" differencesamong="" treatment="" groups="" in="" the="" cleavage="" rate;="" however,="" morulaeand="" blastocyst="" formation="" in="" the="" b&a="" embryos="" wassignificantly="" higher="" than="" that="" of="" other="" groups="">P < 0.05)and="" got=""> Conclusions: Electric stimulation before and after injectionwas an effective method in inducing bovine oocyte activationand in sustaining embryo development to the morulae andblastocyst stage.
    Journal of Assisted Reproduction and Genetics 06/2000; 17(6):310-314. · 1.82 Impact Factor