304INFLUENCE OF ELECTRICAL STIMULUS ON ACTIVATION OF PIG OOCYTES MATURED 
IN VITRO

Electrically induced activation of pig oocytes deserves particular attention for research on parthenogenesis. The aim of this study was to improve electrical activation of in vitro matured pig oocyte. The medium used for oocyte maturation was TCM-199 supplemented with 26.19mM sodium bicarbonate, 0.9mM sodium pyruvate, 10μgmL−1 insulin, 2μgmL−1 vitamin B12, 25mM HEPES, 10μgmL−1 bovine apotransferrin, 150μM cysteamine, 10IUmL−1 PMSG, 10IUmL−1 hCG, 10ngmL−1 EGF, 0.4% BSA, 75μgmL−1 sodium penicillin G, 50μgmL−1 streptomycin sulfate and 10% pFF. After about 22h of maturation, oocytes were cultured without cysteamine and hormones for 22h at 38.5°C, 5% CO2 in air. Cumulus-free oocytes involving first polar body were selected for activation. For electrical activation, oocytes were rinsed twice in 0.3M mannitol solution supplemented with 0.1mM CaCl2, 0.2mMMgCl2, 0.5mM HEPES and 0.01% BSA, and transferred to a chamber consisting of two electrodes 1mm apart which were overlaid with the same activation solution. Experiment 1 was conducted to investigate the effect of electrical pulse on oocyte activation. Oocytes were activated with DC pulses of 1.0, 1.5, 2.0 and 2.5kVcm−1 for 30, 60 and 90μs, respectively. Experiment 2 was carried out to investigate the effect of electrical stimulus frequency on oocyte activation. Oocytes were activated one, two and three times, with a DC pulse of 1.0kVcm−1 for 60μs. After activation, oocytes were transferred into 500μL NCSU-23 culture medium containing 0.4% BSA and cultured for 20h. Activated oocytes were fixed for 48h in 25% acetic acid (v:v) in ethanol at room temperature, and stained with 1% orcein (w:v) in 45% acetic acid (v:v) to examine pronucleus formation. Data were analyzed by ANOVA and Duncan’s multiple range test using the SAS program. The rate of activation was highest in the DC pulse of 1.0kVcm−1 for 60μs (75.1%) compared with the other durations and strengths (62.5–63.1%). Activation rate by electrical stimulus frequency was highest (76.0%) when oocytes were activated by a one-time pulse. In conclusion, the results suggested that electrical stimulus with a single DC pulse of 1.0kVcm−1 for 60μs might be more efficient than other strengths and durations for activation of pig oocytes.

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303PARTHENOGENETIC DEVELOPMENT OF PIG OOCYTES BY CHEMICAL ACTIVATION

Reproduction Fertility and Development ◽

10.1071/rdv16n1ab303 ◽

2004 ◽

Vol 16 (2) ◽

pp. 271

Author(s):

C.S. Park ◽

D.I. Jin ◽

M.Y. Kim ◽

Y.J. Chang ◽

Y.J. Yi

Keyword(s):

Cytochalasin B ◽

Polar Body ◽

Chemical Activation ◽

Formation Rate ◽

Penicillin G ◽

Oocyte Activation ◽

Blastocyst Formation ◽

Parthenogenetic Development ◽

First Polar Body

Efficient activation is essential for the success of animal cloning by nuclear transfer. The aim of this study was to investigate the effects of chemical activation agents on parthenogenetic development of pig oocytes matured in vitro. The medium used for oocyte maturation was TCM-199 supplemented with 26.19mM sodium bicarbonate, 0.9mM sodium pyruvate, 10μgmL−1 insulin, 2μgmL−1 vitamin B12, 25mM HEPES, 10μgmL−1 bovine apotransferrin, 150μM cysteamine, 10IUmL−1 PMSG, 10IUmL−1 hCG, 10ngmL−1 EGF, 0.4% BSA, 75μgmL−1 sodium penicillin G, 50μgmL−1 streptomycin sulfate and 10% pFF. After about 22h of maturation, oocytes were cultured without cysteamine and hormones for 22h at 38.5°C, 5% CO2 in air. Cumulus-free oocytes showing first polar body were selected for activation. Oocytes were activated as follows. First, all oocytes were activated with 25mM HEPES buffered NCSU-23 medium containing 8% ethanol for 10min. After that, in treatment 1, oocytes were incubated in the NCSU-23 medium supplemented with 7.5μgmL−1 cytochalasin B for 3h. In treatment 2, oocytes were incubated in the NCSU-23 medium supplemented with 10μgmL−1 cycloheximide for 3h. In treatment 3, oocytes were incubated in the NCSU-23 medium supplemented with 7.5μgmL−1 cytochalasin B for 1.5h, and then were incubated in the NCSU-23 medium supplemented with 10μgmL−1 cycloheximide for 1.5h. In treatment 4, oocytes were incubated in the NCSU-23 medium supplemented with 7.5μgmL−1 cytochalasin B plus 10μgmL−1 cycloheximide for 3h. Following activation, oocytes were transferred into 500μL NCSU-23 culture medium containing 0.4% BSA for further culture for 20 and 144h. Activated oocytes were fixed and stained for evaluation of activation rate, cleaved oocytes, blastocyst formation rate and cell numbers per blastocyst. Data were analysed by ANOVA and Duncan’s multiple range test using the SAS program. The rate of oocyte activation was higher in treatment 4 (62.1%) than in treatment 1, 2 and 3 (52.0, 49.6 and 58.0%, respectively). The percentage of cleaved oocytes was lower in treatment 1 and 2 (56.9 and 55.2%) than in treatment 3 and 4 (68.8 and 68.5%). The rate of blastocyst formation from the cleaved oocytes was higher in treatment 3 and 4 (19.8 and 22.0%) than in treatment 1 and 2 (12.1 and 11.7%). Mean cells per blastocyst were lowest in treatment 2 (21.2±0.9) compared to treatment 1, 3 and 4 (27.3±2.2, 30.4±3.8 and 30.9±3.4, respectively). In conclusion, cytochalasin B combined with cycloheximide was more efficient for parthenogenetic development of pig oocytes matured in vitro.

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315 EFFICIENCY OF CHEMICAL OR ELECTRICAL ACTIVATION OF BOVINE OOCYTES

Reproduction Fertility and Development ◽

10.1071/rdv18n2ab315 ◽

2006 ◽

Vol 18 (2) ◽

pp. 265

Author(s):

M. P. Milazzotto ◽

W. B. Feitosa ◽

R. Simões ◽

C. M. Mendes ◽

M. E. O. A. Assumpção ◽

...

Keyword(s):

Nuclear Transfer ◽

Embryo Quality ◽

Calcium Influx ◽

Polar Body ◽

Chemical Activation ◽

Electrical Activation ◽

Activation Process ◽

Oocyte Activation ◽

Blastocyst Formation ◽

First Polar Body

Activation of in vitro matured oocytes is essential for the success of nuclear transfer embryo production. Oocyte activation is promoted by the release of intracellular calcium and influx of extracellular ions, and can be chemically induced by calcium ionophores such as A23187 (CA) or ionomycin (IO). Electrical stimulation (EL) is an essential stage in nuclear transfer protocols for the fusion of enucleated oocytes with the donor's cell nucleus. Moreover, EL can be used as an alternative method to induce calcium influx through the formation of pores in the plasma membrane. This work aimed to evaluate the effect of electrical pulse vs the use of different calcium ionophores (A23187 or ionomycin) as primary agents of bovine oocyte activation, with or without the addition of BSA, on the rate of blastocyst formation and blastocyst quality. BSA was used to quench the activation process after a 5-min exposure to CA or IO. Cumulus-oocyte complexes were matured in TCM-199 medium with FCS and hormones for 18 h at 38.5�C and 5% CO2 in air. After removal of cumulus cells, oocytes presenting the first polar body were selected and maintained in SOFaa medium to complete 24 h of maturation. They were then divided into five treatments groups 1-CA (CA 5 mM, 5 min); 2-CAB (CA 5 mM, 5 min; BSA, 5 min); 3-IO (IO 5 mM, 5 min); 4-IOB (IO 5 mM, 5 min; BSA, 5 min); and 5-EL (EL 1.5 kV/cm, 20 �s, 2 pulses). After treatments, oocytes were kept in 6-dimethylaminopurine for 3 h and cultured in SOFaa medium for 7 days at 38.5�C and 5% CO2 in air. Rates of cleavage and blastocyst were evaluated respectively on Days 2 and 7 of culture. To evaluate embryo quality, Hoechst 33342/propidium iodide staining was used. Data were evaluated by ANOVA and submitted to LSD test for embryo rates and t-test for embryo quality. Four replicates were carried out with a total of 89 oocytes per treatment. There was a difference (P < 0.05) in rate of development to blastocyst between treatments 1-CA (54.4%a), 3-IO (51.4%a), and 5-EL (54.5%a) compared with 4-IOB (18.3%b). Treatment 2-CAB (39.8%ab) did not show any difference from the others. There was no difference (P > 0.05) among treatments in total number of cells: 1-CA (63.1a), 2-CAB (57.2a), 3-IO (60.9a), 4-IOB (72.4a), and 5-EL (58.4a). However, there was a difference (P < 0.01) in the percentage of viable cells between treatments 1-CA (49.9%a), 2-CAB (45.8%a), 3-IO (64.9%a), and 4-IOB (50.9%a) in comparison to 5-EL (82.7%b). In conclusion, BSA, when associated with IO, had a negative effect on embryonic developmental rates. The different calcium ionophores used and the BSA did not improve embryo quality. Although there were no significant differences between electrical and chemical activation on the rate of blastocyst formation, it is important to point out that higher quality embryos were achieved by using electrical activation. This work was supported by FAPESP 03/00156-9.

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272 BIRTH OF A CALF AFTER INTRACYTOPLASMIC SPERM INJECTION WITH FROZEN - THAWED EPIDIDYMAL SPERM FROM A POSTMORTEM BULL

Reproduction Fertility and Development ◽

10.1071/rdv20n1ab272 ◽

2008 ◽

Vol 20 (1) ◽

pp. 216

Author(s):

C. A. Guerrero ◽

J. Smith ◽

J. W. Lynn ◽

K. R. Bondioli ◽

R. A. Godke

Keyword(s):

Intracytoplasmic Sperm Injection ◽

Polar Body ◽

Fertilization Rate ◽

Post Injection ◽

Oocyte Activation ◽

Epididymal Sperm ◽

Bull Calf ◽

First Polar Body ◽

Pronuclear Formation

The use of postmortem epididymal sperm for intracytoplasmic sperm injection (ICSI) will allow a more effective use of valuable gametes if a breeding male dies unexpectedly. The objective of this study was to determine pronuclear formation and embryo development rates of frozenâthawed bovine epididymal sperm-injected oocytes. Epididymal sperm were harvested by multiple incisions in the cauda epididymides of an abattoir-derived mature, mixed breed beef bull within 5 h postmortem and frozen in 7% glycerol. Oocytes were matured in vitro for 21 h, selected for extrusion of the first polar body, and centrifuged at 6000g to assist in visualizing the microinjection procedure. Oocytes were injected with either frozen–thawed epididymal sperm, frozenâthawed ejaculated sperm (laboratory control), or were sham-injected (control). Piezo-injected oocytes were chemically activated 4 h post-injection in 7% ethanol for 5 min (Treatment A) or exposure to 5 μm ionomycin for 5 min followed by incubation in 10 μg mL–1 of cycloheximide for 5 h (Treatment B). The sperm-injected oocytes were cultured in CR1aa medium from day 0 to day 3 post-injection and then in CR1aa medium supplemented with 5% fetal bovine serum from day 3 to day 8 of in vitro culture. Pronuclear formation was assessed 18 to 20 h after sperm injection. A summary of oocyte activation by treatments indicated that ethanol was more successful than the ionomycin + cycloheximide treatment (Table 1). Cleavage and blastocyst rates were assessed on day 3 and day 8 of culture, respectively. A significantly higher (P ≤ 0.05) fertilization rate was achieved when ejaculated (43%) rather than epididymal (31%) sperm was used in the ICSI procedure. However, this difference in fertilization rate was only noted when ethanol was used for the exogenous activation. Furthermore, the blastocyst rate for epididymal sperm-injected oocytes was significantly greater when using ethanol (14%) compared with ionomycin followed by cycloheximide (4%). The birth of a live bull calf (42.2 kg; 292-day gestation) resulted from the nonsurgical transfer of 2 ethanol-activated Grade 1 day ICSI blastocysts into each of 2 beef recipient females (50%). To our knowledge, this is the first calf produced by piezo ICSI using cryopreserved bovine caudal epididymal sperm. We can conclude that postmortem epididymal sperm can be collected from genetically valuable males and used for the production of offspring using piezo ICSI. Table 1. Summary of bovine oocyte activation using ethanol and ionomycin + cycloheximide (Iono + Cyclo) treatments

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156 EFFECTS OF MORPHOLOGY TYPE OF POLAR BODY ON PORCINE OOCYTE QUALITY AND DEVELOPMENTAL POTENTIAL AFTER IN VITRO FERTILIZATION

Reproduction Fertility and Development ◽

10.1071/rdv26n1ab156 ◽

2014 ◽

Vol 26 (1) ◽

pp. 192

Author(s):

L. Cai ◽

E. Kim ◽

S. U. Hwang ◽

J. D. Yoon ◽

Y. Jeon ◽

...

Keyword(s):

Polar Body ◽

Oocyte Quality ◽

Developmental Competence ◽

Penicillin G ◽

Cleavage Rate ◽

Developmental Potential ◽

Vitro Fertilization ◽

First Polar Body

Evaluation of morphology of first polar body (1st PB) could be a method for the oocyte's quality and developmental competence. The developmental potential of oocyte with fragmented PB after in vitro maturation (IVM) is a controversial issue. The aim of this study is to investigate the effects of PB morphology type on oocyte quality and developmental competence after IVF. Porcine ovaries were obtained from prepubertal gilts at a local slaughterhouse and transported to the laboratory within 2 h in physiological saline supplemented with 100 IU mL–1 penicillin G and 100 mg mL–1 streptomycin sulfate. The cumulus–oocyte complexes (COC) were aspirated using an 18-gauge needle attached to a 10-mL disposable syringe from superficial follicles 3 to 6 mm in diameter followed by IVM. After IVM, oocytes were classified into 3 types as follows, oocytes with normal PB (A type), oocytes with a little of fragmented PB (B type), and oocytes with separated 2 PBs (C type), respectively. As classification of PB types, we analysed the distribution ratio of each PB type after IVM, and then performed IVF for analysis of fertilization rate and developmental potential. The ratio of oocyte with A type (73%) was significantly (P < 0.05) higher than that of B type (24.5%) or C type (2.5%) after IVM. Only mature oocytes were selected from A and B type and were subjected to IVF because of a small number of oocytes with C type. In the IVF experiment, the efficiency of monospermy and fertilization were significantly higher in oocytes of A type (46.7%) than those of type B (20.0%). The cleavage rate of oocytes with A type (63.9%) was significantly (P < 0.05) higher than the oocytes with B type (43.8%). Embryonic developmental competence to the blastocyst stage after IVF was significantly (P < 0.05) higher in the A-type oocytes (26.3%) than in the B-type oocytes (16.9%). The levels of glutathione and reactive oxygen species were not affected by the morphological classification of the PB. In summary, these results suggest that polar body morphology could be a marker of oocyte quality after IVM. We are currently studying gene expression of each oocytes and blastocysts. This work was supported, in part, by a grant from the Next-Generation BioGreen 21 Program (No. PJ00956901), Rural Development Administration, and the National Research Foundation of Korea Grant funded by the Korean Government (NRF-2012R1A1A4A01004885, NRF-2013R1A2A2A04008751), Republic of Korea.

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Triphenyltin chloride induces spindle microtubule depolymerisation and inhibits meiotic maturation in mouse oocytes

Reproduction Fertility and Development ◽

10.1071/rd12332 ◽

2014 ◽

Vol 26 (8) ◽

pp. 1084 ◽

Cited By ~ 2

Author(s):

Yu-Ting Shen ◽

Yue-Qiang Song ◽

Xiao-Qin He ◽

Fei Zhang ◽

Xin Huang ◽

...

Keyword(s):

Polar Body ◽

Meiotic Maturation ◽

Dependent Manner ◽

Germinal Vesicle Breakdown ◽

Mouse Oocytes ◽

First Polar Body ◽

Triphenyltin Chloride ◽

Dose Dependent

Meiosis produces haploid gametes for sexual reproduction. Triphenyltin chloride (TPTCL) is a highly bioaccumulated and toxic environmental oestrogen; however, its effect on oocyte meiosis remains unknown. We examined the effect of TPTCL on mouse oocyte meiotic maturation in vitro and in vivo. In vitro, TPTCL inhibited germinal vesicle breakdown (GVBD) and first polar body extrusion (PBE) in a dose-dependent manner. The spindle microtubules completely disassembled and the chromosomes condensed after oocytes were exposed to 5 or 10 μg mL–1 TPTCL. γ-Tubulin protein was abnormally localised near chromosomes rather than on the spindle poles. In vivo, mice received TPTCL by oral gavage for 10 days. The general condition of the mice deteriorated and the ovary coefficient was reduced (P < 0.05). The number of secondary and mature ovarian follicles was significantly reduced by 10 mg kg–1 TPTCL (P < 0.05). GVBD decreased in a non-significant, dose-dependent manner (P > 0.05). PBE was inhibited with 10 mg kg–1 TPTCL (P < 0.05). The spindles of in vitro and in vivo metaphase II oocytes were disassembled with 10 mg kg–1 TPTCL. These results suggest that TPTCL seriously affects meiotic maturation by disturbing cell-cycle progression, disturbing the microtubule cytoskeleton and inhibiting follicle development in mouse oocytes.

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H1foo is essential for in vitro meiotic maturation of bovine oocytes

Zygote ◽

10.1017/s0967199414000021 ◽

2014 ◽

Vol 23 (3) ◽

pp. 416-425 ◽

Cited By ~ 13

Author(s):

Yan Yun ◽

Peng An ◽

Jing Ning ◽

Gui-Ming Zhao ◽

Wen-Lin Yang ◽

...

Keyword(s):

Oocyte Maturation ◽

Polar Body ◽

Linker Histone ◽

Meiotic Maturation ◽

Control Group ◽

Bovine Oocyte ◽

First Polar Body ◽

Effective Sirnas ◽

Bovine Oocytes

SummaryOocyte-specific linker histone, H1foo, is localized on the oocyte chromosomes during the process of meiotic maturation, and is essential for mouse oocyte maturation. Bovine H1foo has been identified, and its expression profile throughout oocyte maturation and early embryo development has been established. However, it has not been confirmed if H1foo is indispensable during bovine oocyte maturation. Effective siRNAs against H1foo were screened in HeLa cells, and then siRNA was microinjected into bovine oocytes to down-regulate H1foo expression. H1foo overexpression was achieved via mRNA injection. Reverse transcription polymerase chain reaction (RT-PCR) results indicated that H1foo was up-regulated by 200% and down-regulated by 70%. Based on the first polar body extrusion (PB1E) rate, H1foo overexpression apparently promoted meiotic progression. The knockdown of H1foo significantly impaired bovine oocyte maturation compared with H1foo overexpression and control groups (H1foo overexpression = 88.7%, H1foo siRNA = 41.2%, control = 71.2%; P < 0.05). This decrease can be rescued by co-injection of a modified H1foo mRNA that has escaped from the siRNA target. However, the H1e (somatic linker histone) overexpression had no effect on PB1E rate when compared with the control group. Therefore we concluded that H1foo is essential for bovine oocyte maturation and its overexpression stimulates the process.

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Effects of oocyte age, cumulus cells and injection methods on in vitro development of intracytoplasmic sperm injection rabbit embryos

Zygote ◽

10.1017/s0967199404002643 ◽

2004 ◽

Vol 12 (1) ◽

pp. 75-80 ◽

Cited By ~ 13

Author(s):

Yue-Liang Zheng ◽

Man-Xi Jiang ◽

Yan-Ling Zhang ◽

Qing-Yuan Sun ◽

Da-Yuan Chen

Keyword(s):

Intracytoplasmic Sperm Injection ◽

Polar Body ◽

Cumulus Cells ◽

Fertilization Rate ◽

First Polar Body ◽

Injection Methods ◽

Blastocyst Rate ◽

Repeated Aspiration ◽

Rabbit Embryos

This study assessed the effects of oocyte age, cumulus cells and injection methods on in vitro development of intracytoplasmic sperm injection (ICSI) rabbit embryos. Oocytes were recovered from female rabbits superovulated with PMSG and hCG, and epididymal sperm were collected from a fertile male rabbit. The oocyte was positioned with the first polar body at 12 o'clock position, and a microinjection needle containing a sperm was inserted into the oocyte at 3 o'clock. Oolemma breakage was achieved by aspirating ooplasm, and the aspirated ooplasm and sperm were re-injected into the oocyte. The injected oocytes were cultured in M199 medium containing 10% fetal calf serum at 38 °C with 5% CO2 in air. The results showed that oocytes injected at 1 h post-collection produced a higher (p<0.05) fertilization rate than those injected at 4 or 7 h post-collection. Blastocyst rate in the 1 h group was higher (p<0.05) than in the 7 h group. Denuded oocytes (group A) and oocytes with cumulus cells (group B) were injected, respectively. Rates of fertilization and development of ICSI embryos were not significantly different (p<0.05) between the two groups. Four ICSI methods were applied in this experiment. In methods 1 and 2, the needle tip was pushed across half the diameter of the oocyte, and oolemma breakage was achieved by either a single aspiration (method 1) or repeated aspiration and expulsion (method 2) of ooplasm. In methods 3 and 4, the needle tip was pushed to the oocyte periphery opposite the puncture site, and oolemma breakage was achieved by either a single aspiration (method 3) or repeated aspiration and expulsion (method 4) of ooplasm. Fertilization rate in method 2 was significantly higher (p<0.05) than in methods 1 and 3. Blastocyst rates were not significantly different (p<0.05) among methods 1, 3 and 4, but method 2 produced a higher (p<0.05) blastocyst rate than method 3.

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Different activation treatments for successful development of bovine oocytes following intracytoplasmic sperm injection

Zygote ◽

10.1017/s0967199403001096 ◽

2003 ◽

Vol 11 (1) ◽

pp. 69-76 ◽

Cited By ~ 21

Author(s):

S.A. Ock ◽

J.S. Bhak ◽

S. Balasubramanian ◽

H.J. Lee ◽

S.Y. Choe ◽

...

Keyword(s):

Intracytoplasmic Sperm Injection ◽

Chromosomal Abnormality ◽

Polar Body ◽

Ultrastructural Changes ◽

Time Interval ◽

Oocyte Activation ◽

Group 4 ◽

Group 5 ◽

Bovine Oocytes

In this study, the developmental capacity and cytogenetic composition of different oocyte activation protocols was evaluated following intracytoplasmic sperm injection (ICSI) of in vitro matured bovine oocytes. Motile spermatozoa selected by Percoll density gradient were treated with 5 mM dithiothreitol (DTT) and analysed for ultrastructural changes of the head using transmission electron microscopy (TEM). The alterations in sperm morphology after DTT treatment for different times (15, 30 and 60 min) were 10%, 45-55% and 70-85%, respectively. Further, a partial decondensation of sperm heads was observed after DTT treatment for 30 min. Oocytes were injected with sperm treated with DTT for 30 min. In group 1, sperm injection was performed without any activation stimulus to the oocytes. In group 2, sham injection without sperm was performed without activating the oocytes. Oocytes injected with sperm exposed to 5 μM ionomycin for 5 min (group 3), 5 μM ionomycin + 1.9 mM dimethylaminopurine (DMAP) for 3 h (group 4) and 5 µM ionomycin + 3 h culture in M199 + 1.9 mM DMAP (group 5) were also evaluated for cleavage, development and chromosomal abnormality. Cleavage and development rates in groups 1, 2 and 3 were significantly (p < 0.05) lower than those in groups 4 and 5. The incidence of chromosomal abnormality in the embryos treated directly with DMAP after ionomycin (group 4) was higher than in group 5. We conclude that immediate DMAP treatment after ionomycin exposure of oocytes results in arrest of release of the second polar body, and thus leads to changes in chromosomal pattern. Therefore, the time interval between ionomycin and DMAP plays a crucial role in bovine ICSI.

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Effect of Melatonin on the In Vitro Maturation of Porcine Oocytes, Development of Parthenogenetically Activated Embryos, and Expression of Genes Related to the Oocyte Developmental Capability

Animals ◽

10.3390/ani10020209 ◽

2020 ◽

Vol 10 (2) ◽

pp. 209 ◽

Cited By ~ 8

Author(s):

Ling Yang ◽

Qingkai Wang ◽

Maosheng Cui ◽

Qianjun Li ◽

Shuqin Mu ◽

...

Keyword(s):

In Vitro Maturation ◽

Polar Body ◽

Melatonin Receptors ◽

Melatonin Treatment ◽

In Vitro Development ◽

First Polar Body ◽

Mitochondrial Distribution ◽

Polar Body Extrusion ◽

Vitro Development

Melatonin treatment can improve quality and in vitro development of porcine oocytes, but the mechanism of improving quality and developmental competence is not fully understood. In this study, porcine cumulus–oocyte complexes were cultured in TCM199 medium with non-treated (control), 10−5 M luzindole (melatonin receptor antagonist), 10−5 M melatonin, and melatonin + luzindole during in vitro maturation, and parthenogenetically activated (PA) embryos were treated with nothing (control), or 10−5 M melatonin. Cumulus oophorus expansion, oocyte survival rate, first polar body extrusion rate, mitochondrial distribution, and intracellular levels of reactive oxygen species (ROS) and glutathione of oocytes, and cleavage rate and blastocyst rate of the PA embryos were assessed. In addition, expression of growth differentiation factor 9 (GDF9), tumor protein p53 (P53), BCL2 associated X protein (BAX), catalase (CAT), and bone morphogenetic protein 15 (BMP15) were analyzed by real-time quantitative PCR. The results revealed that melatonin treatment not only improved the first polar body extrusion rate and cumulus expansion of oocytes via melatonin receptors, but also enhanced the rates of cleavage and blastocyst formation of PA embryos. Additionally, melatonin treatment significantly increased intraooplasmic level of glutathione independently of melatonin receptors. Furthermore, melatonin supplementation not only significantly enhanced mitochondrial distribution and relative abundances of BMP15 and CAT mRNA, but also decreased intracellular level of ROS and relative abundances of P53 and BAX mRNA of the oocytes. In conclusion, melatonin enhanced the quality and in vitro development of porcine oocytes, which may be related to antioxidant and anti-apoptotic mechanisms.

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Proline-rich tyrosine kinase2 is involved in F-actin organization during in vitro maturation of rat oocyte

Reproduction ◽

10.1530/rep.1.01212 ◽

2006 ◽

Vol 132 (6) ◽

pp. 859-867 ◽

Cited By ~ 13

Author(s):

Xiao-Qian Meng ◽

Ke-Gang Zheng ◽

Yong Yang ◽

Man-Xi Jiang ◽

Yan-Ling Zhang ◽

...

Keyword(s):

Oocyte Maturation ◽

Actin Filaments ◽

Laser Scanning ◽

Polar Body ◽

Laser Scanning Microscopy ◽

Meiotic Spindle ◽

Confocal Laser ◽

Cell Cortex ◽

First Polar Body

Microfilaments (actin filaments) regulate various dynamic events during meiotic maturation. Relatively, little is known about the regulation of microfilament organization in mammalian oocytes. Proline-rich tyrosine kinase2 (Pyk2), a protein tyrosine kinase related to focal adhesion kinase (FAK) is essential in actin filaments organization. The present study was to examine the expression and localization of Pyk2, and in particular, its function during rat oocyte maturation. For the first time, by using Western blot and confocal laser scanning microscopy, we detected the expression of Pyk2 in rat oocytes and found that Pyk2 and Try402 phospho-Pyk2 were localized uniformly at the cell cortex and surrounded the germinal vesicle (GV) or the condensed chromosomes at the GV stage or after GV breakdown. At the metaphase and the beginning of anaphase, Pyk2 distributed asymmetrically both in the ooplasm and the cortex with a marked staining associated with the chromosomes and the region overlying the meiotic spindle. At telophase, Pyk2 was observed in the cleavage furrows in addition to its cortex and cytoplasm localization. The dynamics of Pyk2 were similar to that of F-actin, and this kinase was found to co-localize with microfilaments in several developmental stages during rat oocyte maturation. Microinjection of Pyk2 antibody demolished the microfilaments assembly and also inhibited the first polar body (PB1) emission. These findings suggest an important role of Pyk2 for rat oocyte maturation by regulating the organization of actin filaments.

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