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1.
This study aimed to evaluate the effects of certain embryo transfer parameters on the pregnancy rate after equine embryo transfer of the Brazilian Jumper Horse breed. The size, embryonic development stage, embryo quality, and synchronization of ovulation between the donor (n = 120) and recipient (n = 420) were evaluated in 396 embryos. Embryo recovery was performed on Day 6-9 after ovulation (Day 0 = day of ovulation). The recipient mares were chosen on the day of embryo recovery, and the transfers were performed that same day. The embryo size (diameter including envelopes; n = 396) ranged from 150 to 3000 μm; 67.1% measured between 400 and 1199 μm. The embryo size (400-1199 μm vs. ≤399 μm); stage of development (n = 396; blastocyst and expanded blastocyst versus compact morula and early blastocyst); quality (n = 396; grade 1 [excellent]), 2 [good], or 3 [poor]); and synchronization of ovulation between the donor and recipient (0, 1, 2, 3, and 4 days versus −1, 5, and 6 days, respectively) all affected pregnancy rate (P < .05). The pregnancy rate did not differ significantly among transfers performed on Days 0, 1, 2, 3, and 4. In conclusion, embryos measuring 400-1199 μm produced higher pregnancy rates in recipients than embryos measuring 150-399 μm, and blastocysts and expanded blastocysts produced pregnancy more efficiently than morulae and early blastocysts. The embryo quality also affected the pregnancy rate. Synchronization of donor and recipient ovulation to Days 0-4 improved the efficiency of embryo transplant.  相似文献   

2.
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3.
[目的]为了评估胚胎质量和发育阶段对奶牛胚胎移植妊娠率的影响。[方法]使用63头青年奶牛作为供体进行超数排卵,评估回收胚胎质量和发育阶段。选择334头青年奶牛作为受体鲜胚移植不同质量和发育阶段胚胎。对胚胎质量分布、发育阶段分布、不同质量胚胎和不同发育阶段胚胎移植30 d妊娠率进行统计分析。[结果]可用胚胎中A级胚胎比例(60.78%)显著高于B级和C级胚胎比例(36.70%和2.52%)(P<0.05);致密桑椹胚比例(54.36%)显著高于早期囊胚,囊胚和扩张囊胚比例(18.35%,25.0%和2.29%)(P<0.05)。A级和B级胚胎移植30 d妊娠率(63.55%和64.35%)显著高于C级胚胎移植30 d妊娠率(44.44%)(P<0.05);致密桑椹胚、早期囊胚、囊胚和扩张囊胚移植30 d妊娠率差异不显著(P<0.05),早期囊胚、囊胚移植30 d妊娠率高于致密桑椹胚、扩张囊胚移植30 d妊娠率(P<0.05)。[结论]选择不同发育阶段的A级和B级胚胎能够获得较高胚胎移植妊娠率,增加早期囊胚和囊胚阶段胚胎移植数量能够提高胚胎移植妊娠率。  相似文献   

4.
This study was designed to examine the effects of age and developmental stage of in vitro‐produced bovine embryos on the cell number of the embryos and to investigate the correlation between the cell number and diameter in the embryos. The diameter and cell number in blastocysts and expanded blastocysts collected on days 7–9 after in vitro fertilization (IVF) were examined. Although the diameters of the blastocysts collected on days 7 and 8 after IVF were smaller than those of the expanded blastocysts collected on day 9, the cell number in both types of embryos was similar. The cell numbers of the blastocysts and expanded blastocysts decreased with increasing embryo age. There were positive correlations between the cell number and diameter in bovine embryos at each stage collected on each day after IVF. However, the value of the correlation coefficient in the day‐9 expanded blastocyst group tended to be higher than that in the other groups. These results indicate that the cell number of in vitro‐produced embryos is affected by the embryonic stage and age. The diameter of the embryo may be potentially used for the viability testing of the expanded blastocysts collected on day 9 after IVF.  相似文献   

5.
The objective of this study was to compare the effect of two culture media: modified synthetic oviductal fluid (mSOF) and G1.2/G2.2, on the developmental competence of bovine somatic cell–cloned embryos. Cloned embryos were produced by transferring adult skin fibroblasts into enucleated MII oocytes. After activation, the reconstructed embryos were randomly allotted to either mSOF or G1.2/G2.2 for culture (the embryos were transferred from G1.2 to G2.2 on days 3 of culture). The development competence of cloned embryos in these two culture systems was compared in terms of cleavage rate, blastocyst formation rate and apoptosis cell number in day 7 blastocyts. To investigate the in vivo developmental competence of cloned embryos in the two culture systems, a total of 87 and 104 blastocysts derived from mSOF and G1.2/G2.2 medium groups were transferred individually to recipient Angus cows, respectively. No differences were observed in terms of cleavage rate, day 7 blastocyst rate and blastocyst cell number between these two culture systems. However, the day 6 blastocyst formation rate was significantly higher in G1.2/G2.2 than that in mSOF. In addition, blastocysts cultured in mSOF have a higher percentage of apoptotic blastomeres compared to those in G1.2/G2.2 (8.5 ± 1.2 vs 16.8 ± 1.5, p < 0.05). Although difference in pregnancy rate was not observed 40 days after embryo transfer, significantly higher pregnancy rate was observed in G1.2/G2.2 group after 90 days of embryo transfer (12.4% vs 37.5%, p < 0.05). Moreover, calving rate was significantly improved in G1.2/G2.2 group compared to mSOF group (27.9% vs 6.7%, p < 0.05). In conclusion, our results indicate that G1.2/G2.2 can improve developmental competence of bovine SCNT embryos both in vitro and in vivo, which is more suitable for culture of bovine SCNT embryos than mSOF medium.  相似文献   

6.
This study was performed to investigate the effects, in terms of nuclear material and actin cytoskeleton quantities (fluorescent pixel counts), of four different bovine blastocyst culturing techniques (in vitro, stepwise in vitro‐to‐in vivo, or purely in vivo). Cumulus oocyte complexes from abattoir‐sourced ovaries were matured in vitro and allocated to four groups: IVP‐group embryos developed up to blastocyst stage in vitro. Gamete intra‐fallopian transfer (GIFT)‐group oocytes were co‐incubated with semen for 4 h before transfer to oviducts of heifers. Following in vitro fertilization, cleaved embryos (day 2 of embryo development, day 2–7 group) were transferred into oviducts on day 2. Multiple ovulation embryo transfer (MOET)‐group embryos were obtained by superovulating and inseminating heifers; the heifers’ genital tracts were flushed at day 7 of blastocyst development. Within each group, ten blastocysts were selected to be differentially dyed (for nuclei and actin cytoskeleton) with fluorescent stains. A novel computer program (ColorAnalyzer) provided differential pixel counts representing organelle quantities. Blastocysts developed only in vivo (MOET group) showed significantly more nuclear material than did blastocysts produced by any other technique. In terms of actin cytoskeleton quantity, blastocysts produced by IVP and by day 2–7 transfer did not differ significantly from each other. Gamete intra‐fallopian transfer‐ and MOET‐group embryos showed significantly larger quantities of actin cytoskeleton when compared with any other group and differed significantly from each other. The results of this study indicate that culturing under in vitro conditions, even with part time in vivo techniques, may adversely affect the quantity of blastocyst nuclear material and actin cytoskeleton. The software employed may be useful for culture environment evaluation/developmental competence assessment.  相似文献   

7.
This study was conducted to examine the potential for implantation and sustainable fetal development of mouse embryos cultured from the pronuclear to blastocyst stage. Pronuclear embryos from ICR mice (Harlan Sprague‐Dawley) were cultured in Sydney IVF sequential media (Cook) to the blastocyst stage in medium only or co‐cultured with autologous cumulus cells. We also experimented with co‐culture in 100 µL drops. Drop co‐culture produced blastocyst formation rates with a mean of 47.0%, which was significantly higher (P < 0.05) compared to embryos cultured in identical culture conditions except without cumulus cells at 27.3%. Blastocysts obtained in vitro in Cook medium only and co‐cultured in Cook medium with cumulus cells were transferred to pseudopregnant females of ICR strain. The day of blastocyst transfer into surrogate females was designated as post‐transfer of blastocyst day 1 (PT 1). The implantation and fetal development was compared to embryo transfer of in vivo derived blastocysts, which served as controls. There were no statistical differences for implantation and fetal development rates for blastocysts cultured in vitro in either Cook medium only or co‐culture in Cook medium with cumulus cells compared to in vivo‐derived blastocysts. The advantage of the co‐culture system is in generating more blastocysts available for transfer.  相似文献   

8.
This study was conducted to evaluate the effectiveness of forced collapse of the blastocoel before slow‐rate freezing and vitrification of bovine blastocysts. Cryopreservation of bovine blastocysts has been proposed as a tool to improve the feasibility of cattle production using the embryo transfer technique. However, the low efficiency of frozen–thawed embryos survival and further development is a crucial problem. In this study, bovine in vitro and in vivo blastocysts were slow‐rate frozen and vitrified after forced blastocoele collapse (FBC) of the blastocyst cavity by puncturing the blastocoele with a pulled Pasteur pipet. Differences in the developmental potential of frozen–thawed blastocysts derived from FBC and non‐FBC groups were found in both slow‐rate freezing and vitrification. Furthermore, we found that the total cell number of blastocysts in FBC groups was increased and the index of apoptosis in FBC groups was decreased. Consistent with these results, real‐time RT‐PCR analysis data showed that expression of the anti‐apoptotic Bcl‐XL gene was significantly increased by FBC groups, whereas expression of the pro‐apoptotic Bax gene was significantly decreased by FBC groups. Our results also showed that pregnancy outcomes in both slow‐rate frozen and vitrified bovine in vivo blastocysts could be improved by reducing the fluid content after FBC of the blastocyst cavity. Therefore, we suggest that FBC of the blastocyst cavity with a pulled Pasteur pipet is an effective pre‐treatment technique for both slow‐rate freezing and vitrification of bovine blastocysts.  相似文献   

9.
A limited number of reports is available on cryopreservation of in vitro fertilization (IVF)‐derived cat blastocysts. In the present study, IVF‐derived domestic cat embryos which reached the blastocyst stage either on day 6 or day 7 were cryopreserved by vitrification using Cryotop as a cryodevice. Fresh control and post‐warm surviving blastocysts were examined by differential cell staining with Hoechst 33342 and propidium iodide to determine total cell number and inner cell mass (ICM) ratio, and the post‐warm survival rate was determined by re‐expansion of the blastocoel during 24 h of in vitro culture. In fresh control, the mean number of total cells of day 7 blastocysts (61.4 cells) tended to be smaller than that of day 6 blastocysts (81.9 cells, p = 0.096). The post‐warm survival rates of day 6 and day 7 blastocysts were not statistically different (73.8%; 31 of 42 vs 66.7%; 18 of 27). There were no significant differences in the total cell number and ICM ratio between fresh control and vitrified blastocysts, although the ICM ratio of surviving day 7 blastocysts was significantly smaller than that of fresh controls (stained at day 8, 18.9% vs 28.9%, p < 0.05). These results indicate that IVF‐derived domestic cat embryos that reached the blastocyst stage earlier can survive the Cryotop vitrification without a reduction in the parameters studied.  相似文献   

10.
The aim of this study was to evaluate if blastocysts arising from in vitro culture of Grade 3 bovine morulae produced in vivo can promote acceptable pregnancy rates when transferred into recipients. Embryos of different stages and qualities were recovered from superovulated Bos taurus and B. indicus donors. Grade 3 morulae were cultured in either Holding Plus® or TCM‐199 (supplemented with 10% bovine fetal serum) media for 24 h at 38.5°C. After this culture period, the resulting blastocysts were morphologically classified (Grades 1, 2 and 3) and transferred into recipients previously synchronized with the donors. Non‐cultured Grades 1 and 3 morulae were used as control. Pregnancy diagnosis was carried out 60 days after embryo transfer and the data were analysed by logistic regression, considering variables, such as embryo quality (Grade), donor breed, culture medium, donor‐recipient synchrony and seasonality. Embryo quality was the only variable, showing significant effect on the pregnancy rate. Pregnancy rates for non‐cultured Grade 1 and 3 morulae, and blastocysts arising from cultured Grade 3 morulae were 58.1% (n = 31), 17.1% (n = 35) and 51.1% (n = 47), respectively (p < 0.05). There were no statistical differences between non‐cultured Grade 1 morulae and cultured blastocysts. Pregnancy rates for Grades 1 (65.0%) and 2 (60.0%) were higher than Grade 3 (29.4%) cultured blastocysts (p < 0.05). It was concluded that short‐term in vitro culture is a very convenient method of identifying morphologically low quality morulae with higher chances of continuing development after the transfer into recipients.  相似文献   

11.
The bovine embryonic signal interferon‐τ (IFN‐τ) produced by the trophoblast is known to pass through the uterine fluid towards the endometrium and further into the maternal blood, where IFN‐τ induces specific expression of interferon‐stimulated gene expression (ISG), for example in peripheral leucocytes. In sheep, it was shown experimentally by administration of IFN‐τ that ISG is also detectable in the liver. The objective was to test whether ISG can be detected in liver biopsy specimens from Holstein–Friesian heifers during early pregnancy. Liver biopsies were taken on day 18 from pregnant and non‐pregnant heifers (n = 19), and the interferon‐stimulated protein 15 kDa (ISG‐15) and myxovirus‐resistance protein‐1 (MX‐1) gene expression was detected. The expression of both MX‐1 (p: 24.33 ± 7.40 vs np: 9.00 ± 4.02) and ISG‐15 (p: 43.73 ± 23.22 vs 7.83 ± 3.63) was higher in pregnant compared to non‐pregnant heifers (p < 0.05). In conclusion, pregnancy induced ISG‐15 and MX‐1 gene expression in the liver already at day 18 in cattle.  相似文献   

12.
Interferon‐τ (IFN‐τ) has been recognized as the primary embryonic signal responsible for maternal recognition of pregnancy. Uterine endometrium produces both prostaglandin F2α (PGF2α) and prostaglandin E2 (PGE2). PGF2α is responsible for the luteolysis; however, PGE2 favours establishment of pregnancy by its luteoprotective action. In this study, the dose‐response effect of recombinant bovine IFN‐τ (rbIFN‐τ) on prostaglandin (PG) production by buffalo endometrial stromal cells cultured in vitro was studied. Buffalo endometrial stromal cells were isolated by double enzymatic digestion, initially with trypsin III followed by a cocktail of trypsin III, collagenase type II and DNase I and subsequently cultured till confluence. Further, cells were treated with different doses of rbIFN‐τ (0.001, 0.01, 0.1, 1.0 and 10 μg/ml) and keeping a separate set of control. Culture supernatant was collected after 6, 12 and 24 h of treatment. PG levels in the culture supernatant were measured by enzyme immune assay (EIA) and total cellular protein estimated by Bradford method. Results indicated that buffalo endometrial stromal cells following rbIFN‐τ treatment enhanced the secretion of both PGE2 and PGF2α, and also its ratio in a strict dose‐dependent manner with a significant increase (p < 0.01) in PGE2 production at 1 μg/ml dose of rbIFN‐τ and maximal stimulation for both PG was observed at 10 μg/ml. Further, both PG production and its ratio were increased significantly (p < 0.01) in a time‐dependent fashion in all the groups at 6, 12 and 24 h post‐treatment with highest level achieved at 24 h as compared with control. Absolute levels of PGE2 remained higher than PGF2α indicating PGE2 as the major PG produced by endometrial stromal cells. The dose‐dependent response of rbIFN‐τ signifies the importance of optimum concentration of IFN‐τ for the embryonic development especially during the critical period to establish successful pregnancy.  相似文献   

13.
The conditions of embryo transfer by the stepwise method, in which frozen-thawed embryos are transferred on day 7 (day 0=onset of estrus), were investigated with the aim of increasing pregnancy rates in frozen-thawed embryo transfer. The use of a vaginal speculum to prevent bacterial infection when passing an embryo transfer gun through the vagina yielded a pregnancy rate equal to or higher than that with application of a sheath cover to the transfer gun. Administration of a sedative, xylazine, to recipient cattle for preventing movement at the time of embryo transfer improved the pregnancy rate. The influence of the time from thawing of frozen embryos to transfer and of the transportation of the recipient by truck upon pregnancy rate was investigated. Embryo transfer within 60 minutes after aspiration into a straw or transportation of the bovine recipient, 1.5 hours each way before and after transfer, had no influence on pregnancy rate. Relations of the embryonic developmental stage and morphological quality after thawing of frozen embryos to pregnancy rate were investigated in recipients of nulliparous Holstein heifers. The pregnancy rate increased as the embryonic developmental stage advanced from compacted morula, early blastocyst, and blastocyst in that order. The pregnancy rate obtained with blastocyst stage embryos was significantly (P<0.05) higher than that with compacted morula stage embryos, and there was no significant difference in pregnancy rates between excellent morphological quality and good morphological quality for compacted morula stage embryos. When correlation of luteal function and pregnancy rate was investigated in bovine recipients, pregnancy rate showed a tendency to increase with increasing blood progesterone (P) concentration on the day before (on day 6 after estrus) and the day of embryo transfer. The pregnancy rate in bovine recipients, which showed a blood P concentration of > or =2.5 ng/ml on the day before embryo transfer, was significantly (P<0.05) higher than that in those with a blood P concentration of <2.5 ng/ml. Pregnancy rate showed a tendency to increase with decreasing blood estradiol-17beta (E2) concentration on the day of embryo transfer. Activation of luteal function by administration of human chorionic gonadotropin (hCG) in cycling cattle was investigated for its effect on increasing pregnancy rate in bovine recipients. A follicle coexisting with cyclic CL ovulated and induced CL formed after injection of hCG 1,500 IU 5 days after ovulation. The blood P concentration was significantly (P<0.05) higher in the administration group than in the control group, and the blood E2 concentration rapidly decreased, showing a lower concentration than in the control group. These results suggest the possibility that the pregnancy rate could be improved by administration of hCG. Pregnancy rate following intramuscular injection hCG 1,500 IU was comparatively investigated in parous Japanese Black beef cattle receiving frozen-thawed embryos 7 days after estrus. Pregnancy rate was 67.5% in the group in which hCG was administered on day 6 after estrus, and was significantly (P<0.05) higher than that in the control group (45.0%) and the group in which hCG was administered on day 1 after estrus (42.5%), revealing that hCG administration facilitated pregnancy. Transfer of frozen-thawed embryos in the blastocyst stage within 60 minutes after the aspiration into a straw, with a vaginal speculum after administration of xylazine is suggested as a way of improving pregnancy rate in bovine recipients with favorable luteal function and in those with luteal function activated by administration of hCG on the day before embryo transfer.  相似文献   

14.
Vitrification has been the method of choice for the cryopreservation of bovine oocytes, as rapid cooling decreases chilling sensitivity. The aim of this study was to determine the in vitro and in vivo survival and the viability of immature oocytes vitrified using super‐cooled liquid nitrogen. Immature oocytes were randomly allocated to three groups: (i) non‐vitrified control group, (ii) vitrified in normal (?196°C) liquid nitrogen (LN2) and (iii) vitrified in super‐cooled LN2 (≤?200°C). Open‐pulled glass micropipettes were used as vitrification containers. Immature oocytes were in vitro‐matured, fertilized and cultured to the blastocyst stage. In vitro viability was assessed by cleavage and blastocyst rates on days 2 and 7 of culture respectively. Vitrified blastocysts derived from the immature vitrified oocytes were directly transferred to synchronous recipients. The in vitro embryo development of vitrified immature oocytes was not influenced by the LN2 state. After direct transfer (one embryo per recipient) of 16 embryos obtained from immature vitrified oocytes (eight from each vitrified group), two healthy calves were born in each group. These results indicated that vitrification of immature bovine oocytes using glass micropipettes under normal or super‐cooled LN2, resulted in viable blastocysts and live calves following in vitro embryo production.  相似文献   

15.
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16.
The occurrence of apoptosis in a fraction of blastomeres in the preimplantation embryo is well known but the consequences of this phenomenon for the developmental potential of the blastocyst has not been well established. Here we demonstrate that blastocysts with low amounts of activated group II caspase activity have increased potential for development to the hatched blastocyst stage. Bovine blastocysts produced in vitro were assayed using a non-invasive fluoregenic substrate that is cleaved by activated group II caspases (i.e., caspase-2, -3 and -7). Subsequently, blastocysts were cultured until Day 10 post-insemination and the proportion undergoing hatching determined. In Experiment 1, blastocysts were cultured without respect to stage of development (expanded or non-expanded); blastocysts classified as having low caspase activity had higher hatching rates than blastocysts with medium or high caspase activity. In Experiment 2, embryos were categorized as nonexpanded or expanded blastocysts. Caspase activity was lower and hatching rate higher for expanded blastocysts than for nonexpanded blastocysts. For nonexpanded blastocysts, embryos classified as having low caspase activity had higher hatching rates as compared to embryos with medium or high caspase activity. In conclusion, the capacity for blastocysts to undergo further development is related to degree of group II caspase activity. Conditions that enhance the incidence of apoptosis in blastocysts may reduce developmental competence. In addition, determination of caspase activity may be useful for selection of embryos for transfer into recipients.  相似文献   

17.
The objective of the present study was to determine whether sperm incubation prior to oocyte insemination in vitro affects the sex ratio of resulting blastocyst. Cumulus–oocyte‐complexes (COCs) collected from slaughterhouse ovaries were matured in vitro and inseminated with frozen‐thawed semen of three proven artificial insemination (AI) bulls pre‐incubated in vitro in Sperm‐Talp for 6 and 24 h. On day‐9 blastocysts were collected and processed for sex determination. More than 80% of blastocyst were successfully sexed. There were no significant differences in cleavage and blastocyst rates using sperm pre‐incubated for 6 h as compared with the 0‐h pre‐incubation control group. The cleavage and blastocyst rates were significantly lower in the 24‐h pre‐incubation group. The male to female ratio, when compared with the theoretical 1 : 1, differed significantly in favour of females among hatched (viable) blastocysts derived from sperm pre‐incubated for 24 h prior to insemination as well as among all blastocytsts in the 6‐h group. Moreover, when the sperm treatment was considered, the sex ratio was affected only among hatched blastocysts in 24‐h pre‐incubation group. It was concluded that prolonged sperm pre‐incubation influences the rate of development and the sex ratio among hatched blastocysts.  相似文献   

18.
The aim of this study was to evaluate three different cloning strategies in the domestic cat (Felis silvestris) and to use the most efficient to generate wild felid embryos by interspecific cloning (iSCNT) using Bengal (a hybrid formed by the cross of Felis silvestris and Prionailurus bengalensis) and tiger (Panthera tigris) donor cells. In experiment 1, zona‐free (ZP‐free) cloning resulted in higher fusion and expanded blastocyst rates with respect to zona included cloning techniques that involved fusion or injection of the donor cell. In experiment 2, ZP‐free iSCNT and embryo aggregation (2X) were assessed. Division velocity and blastocyst rates were increased by embryo aggregation in the three species. Despite fewer tiger embryos than Bengal and cat embryos reached the blastocyst stage, Tiger 2X group increased the percentage of blastocysts with respect to Tiger 1X group (3.2% vs 12.1%, respectively). Moreover, blastocyst cell number was almost duplicated in aggregated embryos with respect to non‐aggregated ones within Bengal and tiger groups (278.3 ± 61.9 vs 516.8 ± 103.6 for Bengal 1X and Bengal 2X groups, respectively; 41 vs 220 ± 60 for Tiger 1X and Tiger 2X groups, respectively). OCT4 analysis also revealed that tiger blastocysts had higher proportion of OCT4‐positive cells with respect to Bengal blastocysts and cat intracytoplasmic sperm injection blastocysts. In conclusion, ZP‐free cloning has improved the quality of cat embryos with respect to the other cloning techniques evaluated and was successfully applied in iSCNT complemented with embryo aggregation.  相似文献   

19.
Ghrelin, apart from its metabolic role, is nowadays considered as a basic regulator of reproductive functions of mammals, acting at central and gonadal levels. Here, we investigated for possible direct actions of ghrelin on in vitro maturation of bovine oocytes and for its effects on blastocyst yield and quality. In experiment 1, cumulus oocyte complexes (COCs) were matured in the presence of four different concentrations of ghrelin (0, 200, 800 and 2000 pg/ml). In vitro fertilization and embryo culture were carried out in the absence of ghrelin, and blastocyst formation rates were examined on days 7, 8 and 9. In experiment 2, only the 800 pg/ml dose of ghrelin was used. Four groups of COCs were matured for 18 or 24 h (C18, Ghr18, C24 and Ghr24), and subsequently, they were examined for oocyte nuclear maturation and cumulus layer expansion; blastocysts were produced as in experiment 1. The relative mRNA abundance of various genes related to metabolism, oxidation, developmental competence and apoptosis was examined in snap‐frozen cumulus cells, oocytes and day‐7 blastocysts. In experiment 1, ghrelin significantly suppressed blastocyst formation rates. In experiment 2, more ghrelin‐treated oocytes matured for 18 h reached MII compared with controls, while no difference was observed when maturation lasted for 24 h. At 18 and 24 h, the cumulus layer was more expanded in ghrelin‐treated COCs than in the controls. The blastocyst formation rate was higher in Ghr18 (27.7 ± 2.4%) compared with Ghr24 (17.5 ± 2.4%). Differences were detected in various genes’ expression, indicating that in the presence of ghrelin, incubation of COCs for 24 h caused over‐maturation (induced ageing) of oocytes, but formed blastocysts had a higher hatching rate compared with the controls. We infer that ghrelin exerts a specific and direct role on the oocyte, accelerating its maturational process.  相似文献   

20.
Cilostazol (CLZ) is a cyclic adenosine monophosphate (cAMP) modulator that influences the steady state of the meiotic stage. This study was conducted to determine the effects of CLZ treatment during in vitro maturation (IVM) on developmental competence of pig oocytes. Immature oocytes were exposed to 0 (control), 0.5, 2 and 4 μm CLZ during the first 22 h of IVM. Nuclear maturation, intraoocyte glutathione content and embryo cleavage after parthenogenesis (PA) and somatic cell nuclear transfer (SCNT) were not influenced by CLZ at any concentrations. However, 4 μm CLZ significantly (p < 0.05) improved blastocyst formation after PA (52.1% vs 38.7–46.0%) and SCNT relative to other concentrations (40.8% vs 25.0–30.7%). The mean cell numbers of SCNT blastocysts were significantly increased by 4 μm CLZ compared to the control (42.6 cells vs 35.3 cells/blastocyst). CLZ treatment significantly increased the intraoocyte cAMP level and effectively arrested oocytes at the germinal vesicle (GV) and GV break down stages compared to the control (74.5% vs 45.4%). Our results demonstrated that improved developmental competence of PA and SCNT pig embryos occurred via better synchronization of nuclear and cytoplasmic maturation induced by increased cAMP and delayed meiotic resumption after CLZ treatment.  相似文献   

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