Effect of pre-in vitro maturation using PACAP on nuclear and cytoplasmic maturation in porcine cumulus-oocyte complexes derived from small follicle

Low development of IVM canine oocytes could be in part attributed to an impaired cytoplasmic maturation. In mammalian oocytes, migration and the redistribution of cortical granules (CGs) around the periphery of the oocyte contribute to the inhibition of polyspermy and it is an important criterion to evaluate cytoplasmic maturation. The state of nuclear maturation and the distribution of CGs were evaluated in canine oocytes cultured for different periods in order to compare the synchrony of nuclear and cytoplasmic maturation during in vitro maturation. Bitch ovaries at different stages of the estrous cycle were obtained following ovariectomy. COCs with compact cumulus cells showing a homogeneous cytoplasm were selected for experiments. Thirty-six COCs were processed at immature stage, placed in PBS medium until evaluation. A total of 275 COCs were matured in vitro for 48, 72, and 96 h in TCM-199 with Earle’s salt supplemented with 25 mM Hepes, 10% FCS, 0.25 mM pyruvate, 10 IU mL-1 of hCG, 300 IU mL-1 penicillin, and 20 mg mL-1 streptomycin, at 38.5°C and 5% CO2. At each culture period, the oocytes were stained with Lens culinaris agglutinin (LCA), labeled with fluorescein isothiocyanate, and the CGs distributions were examined under a fluorescent microscope. The nuclear status of the denuded oocytes was determined by DAPI staining under a fluorescence microscope. For each treatment, at least four replicates were performed and the data was analyzed by ANOVA using Tukey’s test to determine the differences P < 0.05. Three types of CGs distribution were distinguished during canine oocyte maturation: (1) homogeneous distribution throughout the cytoplasm including the cortex; (2) heterogeneous (clusters) within the cytoplasm and (3) densely distributed beneath the oolemma. Nuclear stages were classified as immature or germinal vesicle (GV) stage; resumption of meiosis or germinal vesicle break down (GVBD); metaphase I to telophase I (MI toTel I); and mature or second metaphase (MII). The distribution patterns of GCs were different (P < 0.05) among oocytes cultured for different periods and the nuclear maturation status also differed between oocytes cultured for different intervals (P < 0.05). Most (>84%) of the immature oocytes at GV showed a uniform distribution of CGs throughout the cytoplasm. At 48 h of culture, CGs distribution was mainly Type 2 (25%) and 3 (61%) and the oocytes were at GVBD (33%) and MI-Tel I (33%) stages. Most nuclei of the type 3 oocytes were in the MI (40%) and MII (11%) stages, corresponding to those oocytes matured for 72 (88%) or 96 h (71%). These results indicate that canine oocytes migrate to the cortex during IVM and this process is not finished before 72 h of culture. In addition, although the re-distribution of the CGs occurred in parallel with nuclear maturation, the oocytes cannot always proceed to the MII stage; however, in such oocytes the CGs are distributed beneath the oolemma. Supported by Grant FONDECYT 1080618.

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Porcine follicular fluid derived from > 8 mm sized follicles improves oocyte maturation and embryo development during in vitro maturation of pigs

Zygote ◽

10.1017/s0967199420000398 ◽

2020 ◽

pp. 1-6

Author(s):

Ji-Eun Park ◽

Sang-Hee Lee ◽

Yong Hwangbo ◽

Choon-Keun Park

Keyword(s):

Embryonic Development ◽

Follicular Fluid ◽

In Vitro Maturation ◽

Developmental Competence ◽

Control Group ◽

Cumulus Expansion ◽

Treatment Groups ◽

Nuclear Maturation ◽

Cytoplasmic Maturation

Summary The aim of the present study was to investigate the effects of porcine follicular fluid (pFF) from large-sized (LFF; >8 mm in diameter) and medium-sized (MFF; 3–6 mm in diameter) follicles on the maturation and developmental competence of porcine oocytes. Cumulus–oocyte complexes (COCs) were collected from follicles 3–6 mm in diameter. The collected COCs were incubated for 22 h with LFF or MFF (in vitro maturation (IVM)-I stage) and were incubated subsequently for 22 h with LFF or MFF (IVM-II stage). Cumulus expansion was confirmed after the IVM-I stage and nuclear maturation was evaluated after the IVM-II stage. Intracellular glutathione (GSH) and reactive oxygen species (ROS) levels were measured and embryonic development was evaluated. Relative cumulus expansion and GSH levels were higher in the LFF group compared with in the MFF group after the IVM-I stage (P < 0.05). After the IVM-II stage, the numbers of oocytes in metaphase-II were increased in the LFF group and GSH content was higher in all of the LFF treatment groups compared with in the MFF treatment groups during both IVM stages (P < 0.05). ROS levels were reduced by LFF treatment regardless of IVM stage (P < 0.05). Blastocyst formation and the total numbers of cells in blastocysts were increased in all LFF treatment groups compared with the control group (P < 0.05). These results suggested that pFF from large follicles at the IVM stage could improve nucleic and cytoplasmic maturation status and further embryonic development through reducing ROS levels and enhancing responsiveness to gonadotropins.

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253 OOCYTE PREMATURATION IN THE PRESENCE OF MILRINONE IMPROVES NUCLEAR BUT NOT CYTOPLASMIC MATURATION OF MACAQUE OOCYTES

Reproduction Fertility and Development ◽

10.1071/rdv23n1ab253 ◽

2011 ◽

Vol 23 (1) ◽

pp. 224 ◽

Cited By ~ 1

Author(s):

E. C. Curnow ◽

J. P. Ryan ◽

D. M. Saunders ◽

E. S. Hayes

Keyword(s):

In Vitro Maturation ◽

Germinal Vesicle ◽

Cumulus Cells ◽

Molecular Probes ◽

Developmental Competence ◽

Oocyte Growth ◽

North West ◽

Significant Difference ◽

Cytoplasmic Maturation

During oocyte growth chromatin configuration of the germinal vesicle (GV) oocyte undergoes modification in relation to changes in transcriptional activity crucial for conferring meiotic as well as developmental competence on the oocyte. In the macaque oocyte, there are 3 distinct GV states: GV1, noncondensed chromatin; GV2, an intermediate state; and GV3, condensed chromatin. The aim of this study was to test the effects of a prematuration culture (PMC) system, using the phosphodiesterase type 3 inhibitor milrinone (MIL), on the synchronization of GV chromatin to the GV3 stage and assess metaphase II (MII) oocyte reduced glutathione (GSH) content as a measure of cytoplasmic maturation. Reagents were purchased from Sigma (St. Louis, MO, USA) unless stated otherwise. To assess the effect of PMC on GV chromatin status, immature oocytes retrieved from unstimulated ovaries were either fixed (2% paraformaldehyde+0.1% Triton-X100) immediately after follicular aspiration (t = 0) or after culture in a humidified atmosphere of 6% CO2 in air at 37°C for 24 h in modified Connaught Medical Research Laboratories medium (mCMRL) supplemented with 10% FCS (Hyclone, Logan, UT, USA) and 12.5 μM MIL in the absence (MILNil) or presence of 1.0 IU of FSH (MILFSH). For chromatin assessment, fixed GV oocytes were stained with 5 μg mL–1 of 4′,6-diamidino-2-phenylindole (Molecular Probes, Leiden, the Netherlands) and imaged using confocal microscopy. Following PMC, MILFSH oocytes were transferred to fresh mCMRL+FCS supplemented with 1.0 IU of recombinant human FSH and 1.0 IU of hLH and cultured for a further 30 h. Control and MILFSH oocytes were denuded of cumulus cells and assessed for maturation. The MII oocytes were prepared for GSH analysis, and total GSH content was determined using a commercial 5,5′-dithio-bis(2-nitrobenzoic acid) (DTNB)-GSH reductase recycling assay kit (North-West Life Science). The MII rates were compared using chi-square. Differences in oocyte GSH content were compared using t-test. Significant differences were determined at P < 0.05. There was no significant difference in the proportion of oocytes remaining at the GV stage following 24 h of PMC in MILNil or MILFSH (42/44, 96% v. 32/35, 91%, respectively). However, there was a significant reduction in GV1 chromatin (15/49, 31% v. 28/54, 52% and 22/58, 38%) and a significant increase in GV3 chromatin (23/49, 47% v. 14/54, 26% and 16/58, 28%) observed in MILFSH oocytes compared with both MILNil and t = 0 oocytes, respectively. The MII rate of MILFSH oocytes following in vitro maturation was significantly higher compared with the MII rate of control in vitro matured oocytes (91/167, 55% v. 83/243, 34%). There was no significant difference in the GSH content of GV oocytes from the time of oocyte collection (t = 0) or GV oocytes following PMC in MILFSH (3.69 ± 0.16 and 4.14 ± 0.28 pmol/oocyte, n = 39–49 oocytes). The GSH content of control in vitro matured MII oocytes was significantly greater than that of MILFSH-treated MII oocytes (3.13 ± 0.16 v. 2.02 ± 0.04 pmol/oocyte, n =53–54 oocytes). The PMC supported high rates of nuclear maturation, but cytoplasmic maturation, assessed by GSH content, was negatively affected. Further assessment following fertilization and development is required to determine the practical utility of PMC in a primate in vitro maturation setting.

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202 CHARACTERIZATION OF BOVINE OOCYTE CYTOPLASMIC MATURATION WITH COMMON IN VITRO MATURATION PROTOCOLS

Reproduction Fertility and Development ◽

10.1071/rdv28n2ab202 ◽

2016 ◽

Vol 28 (2) ◽

pp. 232

Author(s):

B. A. Foster ◽

F. A. Diaz ◽

P. T. Hardin ◽

E. J. Gutierrez ◽

K. R. Bondioli

Keyword(s):

Gap Junctions ◽

Gap Junction ◽

In Vitro Maturation ◽

Transvaginal Ultrasound ◽

Bovine Oocyte ◽

Hoechst 33342 ◽

Nuclear Maturation ◽

Mitochondrial Distribution ◽

Cytoplasmic Maturation

Modulators of 3′-5′-cyclic adenosine monophosphate have been extensively researched to delay nuclear maturation in in vitro maturation (IVM) systems to improve synchronization of nuclear and cytoplasmic maturation. However while normal maturation for many organelles has been characterised, there is a lack of information on how modulators affect cytoplasmic maturation. The goal of this study was to identify the effect of different components of bovine oocyte maturation systems on 3 aspects of cytoplasmic maturation. Bovine oocytes were collected from mixed breed beef cattle using transvaginal ultrasound guided oocyte aspiration. Oocytes were assigned to 1 of 4 treatments; staining immediately after collection (n = 249) or after 24 h of IVM (n = 270), 2 h of pre-IVM in Forskolin and 3-isobutyl-1-methylxanthine (IBMX; n = 254), or 2 h of pre-IVM followed by IVM (n = 259). Following treatment, half of the recovered oocytes were stained with Hoechst 33342 to determine nuclear maturation status, and Calcein AM for gap junction status. The other half were stained with Hoechst 33342, Mitotracker deep red to identify mitochondria distribution patterns and Alexa Fluor 488 conjugated phalloidin for F actin microfilament distribution. Organelle patterns were coded and statistically analysed using linear models to determine if treatment had an effect on the indicators of cytoplasmic maturation or their agreement with nuclear maturation. Results indicated that there was a high degree of variability in both cytoplasmic and nuclear maturation of oocytes irrespective of treatment group, with many oocytes exhibiting aberrant patterns in both mitochondrial and microfilament distribution. Gap junctions were classified as open (immature), partially open or closed (mature), based on the strength of Calcein fluorescence within the ooplasm. Both treatment and nuclear maturation had a significant effect on gap junction status (P < 0.001) with gap junctions tending to close as oocytes matured, while treatment in pre-IVM maintained open gap junctions, even as meiosis progressed. Mitochondria were classified as peripheral (immature), diffuse, central (mature) or too sparse to accurately classify. There was an unexpectedly high proportion of oocytes with few mitochondria (17%), suggesting an incomplete growth phase before collection. There was no correlation between meiotic stage and mitochondrial distribution (P = 0.73), with the majority of oocytes having diffuse mitochondrial distribution. As normal maturation proceeds, microfilaments aggregate and migrate peripherally. However, neither microfilament aggregation nor redistribution were correlated with nuclear maturation (P = 0.6 and P = 0.11 respectively) or mitochondrial distribution (P = 0.33 and P = 0.06 respectively). Overall, results show that while pre-IVM maintains open gap junctions, the system studied here is not sufficient for improving correlation between cytoplasmic and nuclear maturation. Many deviations from normal cytoplasmic maturation are seen with IVM and these irregularities are maintained with prematuration in Forskolin and IBMX.

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Distribution of cortical granules and meiotic maturation of canine oocytes in bi-phasic systems

Reproduction Fertility and Development ◽

10.1071/rd14022 ◽

2015 ◽

Vol 27 (7) ◽

pp. 1082 ◽

Cited By ~ 5

Author(s):

Maricy Apparicio ◽

Giuliano Q. Mostachio ◽

Tathiana F. Motheo ◽

Aracelle E. Alves ◽

Luciana Padilha ◽

...

Keyword(s):

In Vitro Maturation ◽

Germinal Vesicle ◽

Meiotic Maturation ◽

Cortical Granule ◽

Cortical Granules ◽

Germinal Vesicle Breakdown ◽

System A ◽

Cytoplasmic Maturation ◽

Positive Effect

The aim of this study was to evaluate the influence of different bi-phasic systems with gonadotrophins and steroids on in vitro maturation rates of oocytes obtained from bitches at different reproductive stages (follicular, luteal, anoestrous). In System A (control) oocytes were matured for 72 h in base medium (BM) with 10 IU mL–1 human chorionic gonadotrophin (hCG), 1 μg mL–1 progesterone (P4) and 1 μg mL–1 oestradiol (E2); in bi-phasic System B oocytes were matured for 48 h in BM with hCG and for 24 h in BM with P4; in bi-phasic System C oocytes were matured for 48 h in BM with hCG, P4 and E2, and for 24 h in BM with P4; in System D, oocytes were cultured in BM without hormonal supplementation. Data were analysed by ANOVA. There was a positive effect of the bi-phasic systems on germinal vesicle breakdown, metaphase I and metaphase II rates, irrespective of reproductive status (P < 0.05). Bi-phasic systems were also beneficial for cortical granule distribution (an indication of cytoplasmic maturation) and its relationship to nuclear status: 74.5% of the oocytes cultured in System B and 85.4% of those cultured in System C presented both nuclear and cytoplasmic maturation (P < 0.001). The stage of the oestrous cycle did not influence maturation rates.

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Development of a reliable in vitro maturation system for zebrafish oocytes

Reproduction ◽

10.1530/rep-07-0416 ◽

2008 ◽

Vol 135 (3) ◽

pp. 285-292 ◽

Cited By ~ 39

Author(s):

Shinsuke Seki ◽

Toshimitsu Kouya ◽

Ryoma Tsuchiya ◽

Delgado M Valdez ◽

Bo Jin ◽

...

Keyword(s):

In Vitro Maturation ◽

Saline Solution ◽

Stage Iii ◽

Hatching Rate ◽

Cleavage Rate ◽

Immature Oocytes ◽

Nuclear Maturation ◽

Cytoplasmic Maturation

In zebrafish oocytes, it has been reported that a 60 or 75% Leibovitz L-15 medium or simple balanced saline solution containing 17α, 20β-dihydroxy-4-pregnen-3-one (DHP) is effective for nuclear maturation. However, most of the oocytes that matured under these conditions were not fertilized and did not hatch. Thus, thesein vitromaturation methods could not support the cytoplasmic maturation of zebrafish oocytes. Therefore, we tried to develop a reliablein vitromaturation method for zebrafish oocytes, which supports their ability to be fertilized and to develop till hatching. When zebrafish oocytes at stage III were cultured in 50–100% Leibovitz L-15 medium supplemented with DHP, the highest rates of cleavage (24%) and hatching (12%) were obtained from oocytes matured in 90% Leibovitz L-15 medium. When we examined the suitable pH (7.5–9.5) of the 90% medium, higher rates of cleavage (45%) and hatching (33%) were obtained in oocytes matured at pH 9.0 than at pH 7.5, 8.5, or 9.5 (cleavage rate, 16–29%; hatching rate, 8–21%). In oocytes matured in 90% Leibovitz L-15 medium at pH 9.0, high rates of cleavage (70%) and hatching (63%) were obtained when oocytes were cultured for 270 min with 0.5 mg/ml BSA. Thus, 90% Leibovitz L-15 medium at pH 9.0 containing 0.5 mg/ml BSA was effective for normal maturation of zebrafish oocytes. This method will become a powerful tool for understanding the mechanism ofin vitromaturation in zebrafish oocytes and for the practical use of immature oocytes.

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Effects of glucose metabolism during in vitro maturation on cytoplasmic maturation of mouse oocytes

Scientific Reports ◽

10.1038/srep20764 ◽

2016 ◽

Vol 6 (1) ◽

Cited By ~ 18

Author(s):

Hong-Li Xie ◽

Yan-Bo Wang ◽

Guang-Zhong Jiao ◽

De-Ling Kong ◽

Qing Li ◽

...

Keyword(s):

Glucose Metabolism ◽

In Vitro Maturation ◽

Mouse Oocytes ◽

Cytoplasmic Maturation

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Oxygen tension and oocyte density during in vitro maturation affect the in vitro fertilization of bovine oocytes

Semina Ciências Agrárias ◽

10.5433/1679-0359.2015v36n6sup2p4277 ◽

2015 ◽

Vol 36 (6Supl2) ◽

pp. 4277

Author(s):

Angelo Bertani Giotto ◽

Daniela Dos Santos Brum ◽

Francielli Weber Santos ◽

Antonio Carlos Galarça Guimarães ◽

Cibele Garcia Moreira Gonçalves ◽

...

Keyword(s):

Antioxidant Activity ◽

In Vitro Fertilization ◽

Oxygen Tension ◽

In Vitro Maturation ◽

Ros Production ◽

Vitro Fertilization ◽

Nuclear Maturation ◽

Cytoplasmic Maturation ◽

Bovine Oocytes

Oocyte maturation is the key factor affecting the fertilization and embryonic development. Factors such as oocyte density and oxygen tension can directly influence the IMV. Thus, the objective of this study was to evaluate the effect of the association of oxygen tensions (5% or 20%) with different oocyte densities (1:10?l or 1:20?l) in the in vitro maturation (IVM) of bovine oocytes on maturation and fertilization rates, ROS production and antioxidant activity. Three experiments were performed with bovine oocytes that were obtained from slaughterhouse ovaries. After selection, the oocytes were randomly distributed in four treatments: 1:10/5%; 1:10/20%; 1:20/5%and 1:20/20% for each experiment. In experiment I, nuclear maturation status and cytoplasmic maturation were evaluated through detection of the first polar body by immunofluorescence and the mitochondrial reorganization assay. In experiment II, ROS production and antioxidant activity were analyzed in oocytes and IVM medium after 24 h of maturation through detection of ROS, reduced glutathione (GSH) and Superoxide dismutase activity by spectrofluorimetric methods. In experiment III, fertilization was evaluated through pronucleus formation, sperm penetration with or without decondensation and polyspermy rates by immunofluorescence. In experiment I, the nuclear maturation and cytoplasmic maturation were similar among treatments (P>0.05). In experiment II, reactive oxygen species in oocytes were elevated in treatments with low oxygen tension which was independent of oocyte density (P<0.05). Additionally, ROS levels in IVM medium were higher in treatments with high oocyte density by volume of medium, which was independent of oxygen tension (P<0.05). In Experiment III, the fertilization and penetration rates were higher in the treatment with 20% oxygen tension and high oocyte density (P<0.05). Furthermore, a high incidence of polyspermy was observed in groups with high oxygen tension and low oocyte density (P<0.05). In conclusion, the results of this study indicate an interaction between oxygen tension and oocyte density, which increases ROS production in certain associations and subsequently influences the rates of in vitro fertilization of bovine oocytes. The improved rates of IVF were obtained when IVM was conducted using 20% oxygen tension and high oocyte density (1:20 ul).

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176 IN VITRO MATURATION OF DOG OOCYTES IN CANINE FOLLICULAR FLUID

Reproduction Fertility and Development ◽

10.1071/rdv26n1ab176 ◽

2014 ◽

Vol 26 (1) ◽

pp. 202

Author(s):

K. Reynaud ◽

S. Canguilhem ◽

S. Thoumire ◽

S. Chastant-Maillard

Keyword(s):

Follicular Fluid ◽

In Vitro Maturation ◽

Assisted Reproductive Technologies ◽

Cumulus Cells ◽

Reproductive Technologies ◽

Control Group ◽

Limiting Factor ◽

Cytoplasmic Maturation

In the canine species, assisted reproductive technologies, especially in vitro maturation (IVM) and IVF, are still ineffective. The main limiting factor remains the immaturity of the oocytes collected from anestrus ovaries. The ability of an oocyte to reach the MII stage in vitro is linked to the diameter of its follicle and anestrus oocytes, collected from small (<1 mm) follicles, are profoundly immature (De Lesegno et al. 2008). The objective of this study was to improve cytoplasmic quality by mimicking in vivo conditions; that is, to test the effect of pure preovulatory follicular fluid (FF) on survival and IVM rates of anestrus dog oocytes, in order to improve the nuclear and cytoplasmic maturation of these immature oocytes. Follicular fluids samples were collected from 54 Beagle bitches at 2 stages: before the LH peak (n = 23 bitches) and after the LH peak (n = 31 bitches). Only follicular fluid samples from large (>4 mm) follicles were collected and pooled by stage. Control oocytes were matured in 20% FCS/M199 medium. Groups of 5 oocytes were in vitro matured in 30 μL of follicular fluid, in half-area 96-well plates (5% CO2, 38°C). After 72 h of IVM, oocytes were denuded, fixed, and stained for DNA and tubulin before observation by confocal microscopy, and nuclear stages were classified as GV-A to GV-E, MI, and MII (Reynaud et al. 2012). A total of 460 oocytes were collected from 13 anestrus bitches and allocated to either the control medium (n = 155), the Pre-LH FF (n = 145) or the Post-LH FF (n = 160) groups. After 72 h of IVM, the morphology of the cumulus–oocyte complexes (COC) in the post-LH group was different from that of the others: cumulus cells appeared more compact and darker. Analysis of the nuclear stages showed that the degeneration rate was significantly higher (P < 0.05) in the post-LH group (58.7%) than in the pre-LH (40.9%) or in the control group (34.4%). No significant differences (P > 0.05) were observed between the 3 groups in the rate of immature GVA-B oocytes (36.4, 28.5, and 25.3% in the control, Pre-LH, and Post-LH groups, respectively), in the rate of meiotic resumption (GV-C/D/E, MI, MII stages, 44.4, 51.9, and 38.7% in the control, Pre-LH, and Post-LH groups, respectively). Metaphase II rates were not significantly different (12.1, 8.6, and 4.8% in the control, Pre-LH, and Post-LH groups, respectively). In conclusion, canine COC may survive when exposed to IVM in pure follicular fluid, but the degeneration rate was higher in the post-LH group. The presence of follicular fluid did not inhibit meiosis resumption, but did not significantly improve IVM rates. To better mimic in vivo conditions, IVM in a sequence of media, such as IVM in follicular fluid followed by IVM in oviducal fluid remains to be tested.

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