166 MATURATION OF BOVINE OOCYTES IN POLY(DIMETHYLSILOXANE) MICROWELLS AND THEIR SUBSEQUENT DEVELOPMENT FOLLOWING IN VITRO FERTILIZATION

2014 ◽  
Vol 26 (1) ◽  
pp. 197
Author(s):  
K. Saeki ◽  
D. Iwamoto ◽  
S. Taniguchi ◽  
M. Kishi ◽  
N. Kato

During bovine oocyte maturation, a lower density of cumulus cells surrounding oocytes reduces the developmental competence of the oocytes after IVF. Adding more cumulus cells (Hashimoto et al. 1998) rescues the developmental competence of the corona-enclosed oocytes. In this study, we examined the effects of poly(dimethylsiloxane) (PDMS) microwells (MW) for bovine oocyte maturation on the developmental competence of the oocytes following IVF. In experiment 1, MW were produced by making holes on 0.5-mm-thick PDMS plates using a 0.5-mm-diameter biopsy punch. The punched plates were placed on the bottoms of culture dishes. Bovine cumulus oocytes complexes (COC) were collected from slaughterhouse ovaries. Cumulus layers were removed from COC to prepare corona-enclosed oocytes (CEO) and denuded oocytes (DO). Then, COC, CEO, or DO were individually matured in single MW for 24 h at 39°C under 5% CO2 in air with high humidity. Ten oocytes of each group were matured in 50-μL droplets of maturation medium (group culture, GC) as controls. Maturation medium was TCM-199 supplemented with 10% FCS, 0.02 AU mL–1 FSH, and 1 μg mL–1 E2. The matured oocytes were fertilized with frozen–thawed spermatozoa. The embryos were cultured in CR1aa medium for 168 h under 5% CO2, 5% O2 and 90% N2 with high humidity. In experiment 2, effects of depth of MW for maturation on subsequent development following IVF were examined. Microwells were produced by making 0.5-mm-diameter holes on 0.5- or 1.5-mm-thick PDMS plates. Then, COC or CEO were individually matured in the MW for 24 h. Matured oocytes were fertilized in vitro and cultured for 168 h. Oocytes that were matured by GC were used as controls. In experiment 1(N = 4), rates of maturation (76–100%, n = 26 to 38), normal fertilization (53–70%, n = 44 to 49), and cleavage (61–77%, n = 114 to 117) were not different among all groups (P > 0.05; Fisher's PLSD test following ANOVA). Blastocyst rates were the same (P > 0.05) for COC matured in MW (50%) and by GC (43%). The rate for CEO that matured in MW (46%) tended to be higher (P = 0.061) than the rate for CEO that matured by GC (31%), and was comparable to the rate for COC matured by GC (43%). The blastocyst rates for DO that matured in MW and by GC were low (6%). In experiment 2 (N = 3), rates of maturation (86–100%, n = 13 to 28), normal fertilization (60–78%, n = 22 to 40), and cleavage (67–73%, n = 85 to 90) were not different among all groups (P > 0.05). However, the blastocyst rate for COC that matured in 1.5-mm-deep MW (53%) was significantly higher than the rates for COC that matured in 0.5-mm-deep MW (38%) and by GC (31%; P < 0.05). The results indicate that the developmental competence of oocytes that matured individually in PDMS MW was greater than that of oocytes that matured by GC. The deeper (1.5 mm) MW were found to be more effective for oocyte maturation than shallow (0.5 mm) MW and GC. The MW might increase density of cumulus cells surrounding oocytes, and the high cell-density enhanced the developmental competence of the oocytes.

2014 ◽  
Vol 26 (1) ◽  
pp. 198
Author(s):  
E. Daly ◽  
A. G. Fahey ◽  
M. M. Herlihy ◽  
T. Fair

We have previously demonstrated the importance of progesterone (P4) synthesis by cumulus cells during oocyte maturation in vitro (IVM) for bovine oocyte acquisition of developmental competence and subsequent embryo development (Aparicio et al. 2011 Biol. Reprod. 84). The aim of this study was to identify key processes that may be deregulated by the inhibition of P4 signalling in the cumulus–oocyte complex (COC) during IVM. To this end, good quality immature COC were placed in IVM medium [TCM-199 supplemented with 10% (vol/vol) FCS and 10 ng mL–1 epidermal growth factor] and cultured at 39°C for 22 h in a humidified atmosphere containing 5% CO2, in the presence or absence of 10 μM trilostane (which blocks P4 synthesis by inhibiting 3 β-hydroxysteroid dehydrogenase; Stegram Pharmaceuticals Ltd., Surrey, UK). Matured COC were washed and placed in 250 μL of fertilization medium (25 mM bicarbonate, 22 mM Na-lactate, 1 mM Na-pyruvate, 6 mg mL–1 fatty acid-free BSA, and 10 mg mL–1 heparin). In vitro fertilization (IVF) was performed with 250 μL of frozen–thawed semen at a final concentration of 1 × 106 spermatozoa mL–1 at 39°C under 5% CO2 during 20 h. Presumptive zygotes were denuded, washed, and transferred to 25-μL culture droplets (SOF + 5% FCS) at 39°C under 5% CO2, 90% of N2, and 5% O2 atmosphere with maximum humidity. Subsets of presumptive fertilized eggs and developing embryos were recovered at 6, 72, 120, and 192 h postinsemination (hpi) and processed for confocal whole-mount immunocytochemistry. The meiotic and mitotic spindles and chromosomes were visualised by immunofluorescent labelling of α-tubulin and 4′,6-diamindino-2-phenylindole (DAPI), respectively, and classified as normal if the chromosomes were correctly aligned or appropriately segregated, or abnormal if lagging chromosomes or abnormal chromosome segregation were observed. Samples were collected from 5 replicates (n = 50 zygotes/embryos per treatment, per timepoint) and a total of 157 spindles were observed. Logistic regression analysis was conducted to determine the probability of abnormal spindle formation. The incidence of spindle abnormality was regressed on time, treatment, and treatment by time. For all time points, there was significant reduction in the odds of abnormal spindle formation in control samples versus trilostane-treated samples (P < 0.001). In conclusion, our data imply a role for P4 signalling in maintaining spindle integrity during oocyte meiotic maturation and progression through the initial mitotic divisions of early embryo development in cattle.


2020 ◽  
Vol 18 (2) ◽  
pp. 249-255
Author(s):  
Nguyen Viet Linh ◽  
Nguyen Thi Hiep

In pigs, embryo productivity is still lower than that in other livestocks. One of the reasons is incomplete maturation of porcine oocytes in in vitro conditions. Therefore in vitro maturation (IVM) plays a crucial role in in vitro production of porcine embryos. It provides prerequisite condition to in fertilization and subsequent development of porcine embryos. In a previous study, effects of NCSU-37-based medium and TCM-199-based media supplemented with porcine follicular fluid (pFF) or Fetal Bovine Serum (FBS) on in vitro maturation of Landrace oocytes collected in Vietnam have been compared, suggesting that NCSU-37 medium supplemented with 10% of porcine follicular fluid (pFF) had the highest rate of oocytes reach to metaphase II stage in comparison to those of the other two TCM-199-based media. In the present study, further experiments were carried out to evaluate the contribution of IVM media on fertilization capability and developmental competence. Porcine oocytes matured in vitro in 3 media: NCSU-37 supplemented with 10% pFF, TCM-199 supplemented with either 10% pFF or 10% FBS were subjected to in vitro fertilization and subsequent in vitro culture to monitor fertility and embryo development. The results showed that penetration and normal fertilization rates in both TCM-199 groups are both higher than that of NCSU-37 group. Moreover, the cleavage and blastocyst rates, and cell numbers of blastocysts which is a criterion for embryo quality were all higher in TCM-199 groups, especially in the group supplemented with pFF. It might be concluded that TCM-199 media supplemented with either pFF or FBS are suitable for effective in vitro maturation of Landrace porcine oocytes collected in Vietnam.


Author(s):  
Er-Meng Gao ◽  
Bongkoch Turathum ◽  
Ling Wang ◽  
Di Zhang ◽  
Yu-Bing Liu ◽  
...  

AbstractThis study evaluated the differences in metabolites between cumulus cells (CCs) and mural granulosa cells (MGCs) from human preovulatory follicles to understand the mechanism of oocyte maturation involving CCs and MGCs. CCs and MGCs were collected from women who were undergoing in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) treatment. The differences in morphology were determined by immunofluorescence. The metabolomics of CCs and MGCs was measured by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) followed by quantitative polymerase chain reaction (qPCR) and western blot analysis to further confirm the genes and proteins involved in oocyte maturation. CCs and MGCs were cultured for 48 h in vitro, and the medium was collected for detection of hormone levels. There were minor morphological differences between CCs and MGCs. LC-MS/MS analysis showed that there were differences in 101 metabolites between CCs and MGCs: 7 metabolites were upregulated in CCs, and 94 metabolites were upregulated in MGCs. The metabolites related to cholesterol transport and estradiol production were enriched in CCs, while metabolites related to antiapoptosis were enriched in MGCs. The expression of genes and proteins involved in cholesterol transport (ABCA1, LDLR, and SCARB1) and estradiol production (SULT2B1 and CYP19A1) was significantly higher in CCs, and the expression of genes and proteins involved in antiapoptosis (CRLS1, LPCAT3, and PLA2G4A) was significantly higher in MGCs. The level of estrogen in CCs was significantly higher than that in MGCs, while the progesterone level showed no significant differences. There are differences between the metabolomes of CCs and MGCs. These differences may be involved in the regulation of oocyte maturation.


2014 ◽  
Vol 26 (1) ◽  
pp. 200 ◽  
Author(s):  
C. de Frutos ◽  
R. Vicente-Perez ◽  
P. J. Ross

In vitro maturation (IVM) of oocytes in domestic animals is a widespread practice of research and commercial relevance. Gonadotropic hormones are typically supplemented to the IVM medium to stimulate resumption of meiosis, progression to metaphase II (MII), and oocyte developmental competence. The common use of pituitary-derived products presents 2 problems: contamination from other pituitary hormones and inconsistences from batch-to-batch variation. Recombinant hormones can help circumvent these issues and identify specific gonadotropin requirements for in vitro maturation. The aim of the present study was to determine the effect of supplementing recombinant bovine LH and/or FSH (AspenBio) to the maturation of ovine oocytes in terms of cumulus expansion and progression to the MII stage. Abattoir-derived sheep cumulus–oocyte complexes (COC) were obtained from 1- to 5-mm-diameter antral follicles by ovary slicing. Oocytes with a homogeneous cytoplasm surrounded by at least 3 layers of cumulus cells were selected and cultured in serum-free IVM medium (Cotterill et al. 2012 Reproduction 144, 195–207) at 38.5°C and 5% CO2. The COC obtained from 8 replicates were allocated into 4 experimental groups: (1) no hormones; (2) 1.5 μg mL–1 recombinant bovine LH (rbLH); (3) 1.5 μg mL–1 recombinant bovine FSH (rbFSH); and (4) rbLH and rbFSH. The expansion of cumulus cells was recorded in each group after 24 h of IVM and COC classified as (1) very poor or no cumulus expansion (grade 1); (2) limited cumulus expansion (grade 2); and (3) full cumulus expansion (grade 3). Nuclear maturation in the 4 treatments was evaluated by assessing progression to the MII stage via DNA staining with Hoechst 33342 and fluorescence imaging. The effect of treatment on the observed proportion of MII oocytes was evaluated using a mixed logit model including treatment and replicate as fixed and random effects, respectively. Culture in IVM medium in the absence of gonadotropins or in the presence of rbLH resulted in poor cumulus expansion (grade 1). The supplementation of IVM medium with rbFSH (with or without rbLH) yielded a high degree of cumulus expansion (grades 2–3). Likewise, addition of rbFSH enhanced progression of oocytes to the MII stage, whereas use of rbLH, although it had an effect on progression to MII, did not augment the effect of rbFSH (Table 1). These results indicate that rbFSH is necessary and sufficient to induce sheep oocyte maturation in a high proportion of oocytes. Table 1.Cumulus expansion and oocyte nuclear stage after IVM


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Zhenwei Jia ◽  
Xueli Wang

Abstract The present study aimed to evaluate the effects of C-type natriuretic peptide (CNP) on meiotic arrest and developmental competence of bovine oocyte derived from follicles of different sizes. Collected immature cumulus-oocyte complexes from small follicles (< 3 mm) and medium follicles (3–8 mm) were cultured for 6 h in basal medium supplementated without or with 200 nM CNP. We observed that CNP effectively sustained meiotic arrest at germinal vesicle stage in in vitro cultured bovine oocytes from follicles of different sizes. Moreover, CNP treatment significantly improved the levels of cGMP in both cumulus cells and oocytes, as well as the levels of cAMP in oocytes regardless of follicle size. Based on the above results, we tested the effect of a novel in vitro maturation (IVM) system based on CNP-pretreatment, including a pre-IVM phase for 6 h using 200 nM CNP, followed by a extended IVM phase for 28 h, on developmental competence of bovine oocyte derived from small follicles (< 3 mm) and medium follicles (3–8 mm) compared to standard IVM system. The results showed that athough the novel IVM system based on CNP-pretreatment enhanced the developmental potencial of oocytes obtained from large follicles, but had no effect on the developmental comptence of oocytes obtained from small follicles.


2012 ◽  
Vol 24 (5) ◽  
pp. 656 ◽  
Author(s):  
Islam M. Saadeldin ◽  
Ok Jae Koo ◽  
Jung Taek Kang ◽  
Dae Kee Kwon ◽  
Sol Ji Park ◽  
...  

Kisspeptin (Kp) is best known as a multifunctional peptide with roles in reproduction, the cardiovascular system and cancer. In the present study the expression of kisspeptin hierarchy elements (KISS1, GNRH1 and LHB) and their receptors (KISS1R, GNRHR and LHCGR, respectively) in porcine ovary and in cumulus–oocyte complexes (COCs) were investigated, as were its effects on the in vitro maturation (IVM) of oocytes and their subsequent ability to sustain preimplantation embryo competence after parthenogenetic electrical activation. Kp system elements were expressed and affected IVM of oocytes when maturation medium was supplemented with 10–6 M Kp. Oocyte maturation, maternal gene expression (MOS, GDF9 and BMP15), blastocyst formation rate, blastocyst hatching and blastocyst total cell count were all significantly increased when oocytes were matured in medium containing Kp compared with the control group (without Kp). A Kp antagonist (p234) at 4 × 10–6 M interfered with this hierarchy but did not influence the threshold effect of gonadotrophins on oocyte maturation. FSH was critical and permissive to Kp action on COCs by increasing the relative expression of KISS1R. In contrast, Kp significantly increased apoptosis, the expression of pro-apoptotic gene, BAK1, and suppressed trophoblast outgrowths from hatched blastocysts cultured on feeder cells. The present study provides the first functional evidence of the Kp hierarchy in porcine COCs and its role in enhancing oocyte maturation and subsequent developmental competence in an autocrine–paracrine manner. However, Kp supplementation may have a harmful impact on cultured hatched blastocysts reflecting systemic or local regulation during the critical early period of embryonic development.


2008 ◽  
Vol 14 (6) ◽  
pp. 549-560 ◽  
Author(s):  
Morten R. Petersen ◽  
Michael Hansen ◽  
Birthe Avery ◽  
Ingrid B. Bøgh

AbstractOocyte maturation is known to affect the chances for successful fertilization, embryonic development, establishment of pregnancy and delivery of a live, healthy, and viable offspring. Two-photon laser scanning microscopy (TPLSM) has previously been used to evaluate early embryonic development without a detectable impairment of subsequent development, but has never been applied to assess mammalian oocytes throughout in vitro maturation (IVM). Visualization of structures within live oocytes during IVM, followed by fertilization and embryo culture, may improve the understanding of oocyte maturation. To visualize structures within bovine oocytes using TPLSM, it is necessary to remove the cumulus cells that normally surround the oocyte during maturation. Repeated visualization of structures within the same oocyte is possible, if movement of the oocyte can be avoided. In this article, we describe the development of a method for repeated intravital imaging of denuded bovine oocytes using an upright TPLSM equipped with a specially constructed incubator. Oocytes were stained with Hoechst 33258, and the nuclear structures were evaluated. Oocyte fertilization rate was not affected by TPLSM exposure, but the developmental capacity of the denuded oocytes was significantly reduced. This is, to our knowledge, the first article describing repeated intravital imaging during mammalian oocyte maturation using TPLSM.


Reproduction ◽  
2011 ◽  
Vol 141 (4) ◽  
pp. 425-435 ◽  
Author(s):  
Radek Procházka ◽  
Michal Petlach ◽  
Eva Nagyová ◽  
Lucie Němcová

The aim of this work was to assess the FSH-stimulated expression of epidermal growth factor (EGF)-like peptides in cultured cumulus–oocyte complexes (COCs) and to find out the effect of the peptides on cumulus expansion, oocyte maturation, and acquisition of developmental competencein vitro. FSH promptly stimulated expression of amphiregulin (AREG) and epiregulin (EREG), but not betacellulin (BTC) in the cultured COCs. Expression ofAREGandEREGreached maximum at 2 or 4 h after FSH addition respectively. FSH also significantly stimulated expression of expansion-related genes (PTGS2,TNFAIP6, andHAS2) in the COCs at 4 and 8 h of culture, with a significant decrease at 20 h of culture. Both AREG and EREG also increased expression of the expansion-related genes; however, the relative abundance of mRNA for each gene was much lower than in the FSH-stimulated COCs. In contrast to FSH, AREG and EREG neither stimulated expression ofCYP11A1in the COCs nor an increase in progesterone production by cumulus cells. AREG and EREG stimulated maturation of oocytes and expansion of cumulus cells, although the percentage of oocytes that had reached metaphase II was significantly lower when compared to FSH-induced maturation. Nevertheless, significantly more oocytes stimulated with AREG and/or EREG developed to blastocyst stage after parthenogenetic activation when compared to oocytes stimulated with FSH alone or combinations of FSH/LH or pregnant mares serum gonadotrophin/human chorionic gonadotrophin. We conclude that EGF-like peptides do not mimic all effects of FSH on the cultured COCs; nevertheless, they yield oocytes with superior developmental competence.


Sign in / Sign up

Export Citation Format

Share Document