The present experiments were conducted to evaluate the effects of follicular fluid on maturation of bovine follicular oocytes. TC medium 199 seemed to be in adequate for this purpose since a high proportion (ranging 84.1. to 97.0%) of the oocytes were able to resume meiotic division in both media-with or without the addition of follicular fluid. This implies a possible similarity between TC medium 199 and follicular fluid with regard to the components initiating meiosis. Actually, TC medium 199 contains amino acids, vitamins and carbohydrates most of which are also found in follicular fluid. For this reason, the effect of follicular fluid on the ovum maturation was investigated by applying Krebs-Ringer bicarbonate solution (SECM), which was main1y composed of the salts, pyruvate and lactate. When the oocytes were cultured in SECM without the addition of follicular fluid, only 7-14% of them resumed meiotic division within 30 hours. However, when follicular fluid was added, the proportion of oocytes undergoing maturation was sharply increased to about 70%. Among the groups cultured in media containing different concentrations of follicular fluid, the proportion of the oocytes in meiosis remained constant, In pure follicular fluid, 87-89% of the oocytes showed enhancement of meiotic division. The presence of the follicular fluid contributed to a decrease in the production of degenerative oocytes. As a consequence it has been noted that addition of follicular fluid to the culture medium provides a more beneficial environment for cow oocytes. Meiotic division is initiated and production of degenerative oocytes is inhibited.
Animal ; Cattle ; Cells, Cultured ; Culture Media ; Female ; Meiosis ; Oocytes/physiology* ; Ovarian Follicle/physiology* ; Ovum/physiology*

Animals ; Oocytes ; metabolism ; physiology ; Receptors, G-Protein-Coupled ; physiology ; Receptors, Purinergic P2X ; physiology ; Xenopus laevis

We studied the effects of simulated microgravity on mouse oocytes maturation, and analyzed whether the tail-suspended model can be applied to investigate simulated microgravity effects on reproductive processes in female mice. Mouse oocytes were cultured in vitro with microgravity simulated by a rotating wall vessel bioreactor and by tail-suspended model, and the maturation rate of the mouse oocytes in the two models were examined in vivo. The maturation rate of mouse oocytes cultured in simulated microgravity was 8.93%, and that was 72.33% in 1g gravity. In ratio, oocyte maturation rate had no significant difference between the rotational group and control group. Microgravity simulated by the tail-suspended model inhibited mouse oocytes maturation and increased the rate of oocytes abnormity. The maturation rate of tail-suspended mouse oocytes was 14.54%, which was significantly lower than that of control group. Tail-suspended model should be an ideal model to investigate simulated microgravity effects on reproductive processes of female mice.
Animals ; Cells, Cultured ; Female ; Hindlimb Suspension ; Mice ; Oocytes ; cytology ; physiology ; Oogenesis ; physiology ; Weightlessness Simulation

This study evaluated the meiotic competence of buffalo oocytes with different layers of cumulus cells. A total of 588 oocytes were collected from 775 ovaries averaging 0.78 oocytes per ovary. Oocytes with homogenous cytoplasm (n = 441) were selected for in vitro maturation (IVM) and divided into four groups based on their cumulus morphology: a) oocytes with > or == 3 layers of cumulus cells, b) 1-2 layers of cumulus cells and oocytes with partial remnants or no cumulus cells to be cocultured c) with or d) without cumulus cells. Oocytes in all four groups were matured in 100 microL drop of TCM-199 supplemented with 10microgram/mL follicle stimulating hormone (FSH), 10microgram/mL luteinizing hormone (LH), 1.5microgram/mL estradiol, 75microgram/mL streptomycin, 100 IU/mL penicillin, 10 mM Hepes and 10% FBS at 39degrees C and 5% CO2 for 24 hours. After IVM, cumulus cells were removed from oocytes using 3 mg/mL hyaluronidase, fixed in 3% glutaraldehyde, stained with DAPI and evaluated for meiotic competence. The oocytes with > or ==3 layers of cumulus cells showed higher maturation rates (p <0.05: 64.5%) than oocytes with partial or no cumulus cells (8.6%) and oocytes co-cultured with cumulus cells (34.5%) but did not differ from oocytes having 1-2 layers of cumulus cells (51.4%). The degeneration rates were higher (p < 0.05) for oocytes with partial or no cumulus cells (51%) than rest of the groups (range: 13.8% to 17.4%). These results suggest that buffalo oocytes with intact layers of cumulus cells show better IVM rates than oocytes without cumulus cells and the co-culture of poor quality oocytes with cumulus cells improves their meiotic competence.
Animals ; Buffaloes/*physiology ; Female ; Fluorescent Dyes/chemistry ; Indoles/chemistry ; Meiosis/*physiology ; Microscopy, Fluorescence/veterinary ; Oocytes/cytology/growth&development/*physiology

Mammalian oocyte maturation and early embryo development processes are Ca(2+)-dependent. In this study, we used confocal microscopy to investigate the distribution pattern of Ca2+ and its dynamic changes in the processes of bovine oocytes maturation, in vitro fertilization (IVF), parthenogenetic activation (PA) and somatic cell nuclear transfer (SCNT) embryo development. During the germinal vesicle (GV) and GV breakdown stage, Ca2+ was distributed in the cortical ooplasm and throughout the oocytes from the MI to MII stage. In IVF embryos, Ca2+ was distributed in the cortical ooplasm before the formation of the pronucleus. In 4-8 cell embryos and morulas, Ca2+ was present throughout the blastomere. In PA embryos, Ca2+ was distributed throughout the blastomere at 48 h, similar to in the 4-cell and 8-cell phase and the morula. At 6 h after activation, there was almost no distribution of Ca2+ in the SCNT embryos. However, Ca2+ was distributed in the donor nucleus at 10 h and it was distributed throughout the blastomere in the 2-8 cell embryos. In this study, Ca2+ showed significant fluctuations with regularity of IVF and SCNT groups, but PA did not. Systematic investigation of the Ca2+ location and distribution changes during oocyte maturation and early embryo development processes should facilitate a better understanding of the mechanisms involved in oocyte maturation, reconstructed embryo activation and development, ultimately improving the reconstructed embryo development rate.
Aniline Compounds/chemistry ; Animals ; Calcium/*physiology ; Cattle/*physiology ; Embryonic Development/*physiology ; Female ; Fertilization in Vitro/*veterinary ; Microscopy, Confocal/veterinary ; Oocytes/*physiology ; Parthenogenesis/*physiology ; Xanthenes/chemistry

OBJECTIVETo compare the development of abnormal pronuclear zygotes after intracytoplasmic sperm injection (ICSI) and analyze their genetic polymorphism.

METHODSFour hundred and ninety three abnormal pronuclear zygotes after ICSI were divided into three groups based on the number of pronuclei: 347 nonpronuclear oocytes, 71 monopronuclear zygotes and 75 multipronuclear zygotes. All of them were cultured in the medium of Vitrolife G5 series(TM). Sixteen short tandem repeats (STR) of seven blastocysts were then analyzed by ABI3100.

RESULTSThe cleavage rate of nonpronuclear group (25.4%) was lower than that of the others (P<0.01), the proportion of blocked embryos in nonpronuclear group (48.9%) was significantly higher than that of the others (P<0.05), but the blastocyst rate showed no significant difference in three groups (P>0.05). The genetic polymorphism of the 16 STRs showed that the blastocysts from the nonpronuclear and multipronuclear were diploid, and one of the blastocysts from nonpronuclear oocyte was Y-bearing.

CONCLUSIONThe zygotes with abnormal pronuclei after ICSI might have development potential, and the blastocysts from nonpronuclear oocytes and multipronuclear zygotes could be diploid.

Blastocyst ; physiology ; Cell Nucleus ; physiology ; Embryonic Development ; genetics ; physiology ; Female ; Fertilization in Vitro ; adverse effects ; Humans ; Male ; Oocytes ; physiology ; Sperm Injections, Intracytoplasmic ; adverse effects ; Tandem Repeat Sequences ; Zygote ; physiology

Protein kinase C (PKC) family plays a critical role in many developmental events, including oocyte activation, completion of the second meiosis and initiation of the first mitosis, compaction, and blastocysts formation as well. But little is known of its many isozymes. Studies have shown that 10 isozymes of PKC and its anchor protein, RACK, are expressed in the course from 2 cell stage through blastocyst stage in mouse. We reviewed here the recent studies on the location pattern and expression levels of different PKC isozymes. Those studies indicated that the isozymes were very important for every stage of preimplantation embryonic development, especially at the early 4-cell stage. Some are increased temporarily in nucleus, which indicated that they might control and regulate the remolding of embryonic nucleus. We also analyzed the possible functions of PKCs in the somatic nuclear transferred embryos.
Animals ; Embryonic Development ; physiology ; Fertilization ; physiology ; Isoenzymes ; metabolism ; physiology ; Oocytes ; physiology ; Protein Kinase C ; metabolism ; physiology ; Receptors for Activated C Kinase ; Receptors, Cell Surface ; metabolism

BACKGROUNDIt is still unclear whether the vitrification procedure itself is associated with the incidence of abnormal DNA methylation during oocytes vitrification. The purpose of this study was to evaluate the epigenetic profile of mouse oocytes, which went through vitrification either at a mature stage or at an immature stage following in vitro maturation (IVM) by analyzing the global DNA methylation.

METHODSMetaphase II (M II) stage and germinal vesicle (GV) stage oocytes were collected from adult female mice and were vitrified respectively. The M II oocytes were assessed for cryo-survival and global DNA methylation. The GV oocytes were assessed for cryo-survival and only the surviving GV oocytes were cultured in vitro for subsequent assessment of global DNA methylation in mature oocytes. In vivo matured fresh M II oocytes without undergoing vitrification were used as control. The level of global DNA methylation in the M II oocytes was then examined by immunofluorescence using an anti-5-methylcytosine (anti-5-MeC) monoclonal antibody and fluorescein isothiocyanate (FITC)-conjugated goat anti-mouse IgG under a laser scanning confocal microscope.

RESULTSIn terms of the effect of vitrification on global DNA methylation status in matured oocytes, in the M II-v group, all the examined oocytes (90/90) were found with hypermethylation, including 63.3% (57/90) of them displaying DNA methylation of a very high level, 25.6% (23/90) with a high level, and 11.1% (10/90) with an intermediate level, whereas in the GV-v group, all the matured oocytes (129/129) were also examined with hypermethylation, including 67.4% (87/129) of them displaying DNA methylation of a very high level, 23.3% (30/129) with a high level, and 9.3% (12/129) with an intermediate level. Statistically, it was similar between both groups, which were similar to the control: 68.6% (83/121) of fresh M II oocytes displayed DNA methylation of a very high level, 21.5% (26/121) with a high level, and 9.9%(12/121) with an intermediate level (P > 0.05). In terms of the effect of IVM on global DNA methylation status in matured oocytes, in the in vivo matured oocytes group, all oocytes examined (94/94) were found with hypermethylation, including 80.9% (76/94) displaying DNA methylation of a very high level and 19.1% (18/94) with a high level, whereas in the in vitro matured oocytes group, all oocytes examined (69/69) were also found with hypermethylation: 85.2% (56/69) of them displayed with DNA methylation of very high level, 11.9% (11/69) with high level, and 2% (2/69) with intermediate level. This result was similar to that in in vivo matured fresh M II oocytes (P > 0.05).

CONCLUSIONThe vitrification procedure at GV stage does not induce widespread alteration of global DNA methylation status of mouse oocytes subsequently matured in vitro.

Animals ; DNA Methylation ; physiology ; Female ; Fertilization in Vitro ; Mice ; Microscopy, Confocal ; Oocytes ; cytology ; metabolism ; Vitrification

The successful cryopreservation of reproductive cells has important practical significance in many fields. In order to improve the recovery rate and viability of cryopreserved cells, it is necessary to study the permeability characteristics of cell membrane to both water and cryoprotectant. In this paper we review the studies on membrane permeability of animal reproductive cell for the recent years. We firstly list the typical permeability data of spermatozoa and oocyte membrane for water and cryoprotectant. We then analyze the effects of these characteristics on the design of cryopreservation protocol. We also introduce the latest experimental methods to measure the cell membrane permeability.
Animals ; Cell Membrane Permeability ; physiology ; Cryopreservation ; methods ; Female ; Humans ; Male ; Oocytes ; cytology ; Spermatozoa ; cytology

This paper describes the use of piezo-driven micropipette for intracytoplasmic sperm injection of mice eggs. The head of fresh spermatozoa from KM (Kunming) fertile mice was individually injected into mature oocytes of hybrid mice B6D2F1. Approximately eighty three percent of sperm-injected oocytes survived, and 84.0% of them fertilized normally (extrusion of the second polar body and formation of male and female pronuclei). The eggs fertilized by sperm injection could develop in vitro to 2-cell (98% vs 94.7%), 4-cell (89.5% vs 92.1%) stages, no significantly (P > 0.05) different from embryos fertilized in vivo but there were significantly (P < 0.01) few morulae (63.8% vs 84.2%) and blastocysts (25.7% vs 68.4%) developed in vitro after further culture in vitro in the group of ICSI. When 120 embryos at the pronuclear stage were transferred to seven pseudopregnant KM female, 23.3% of the embryos (0 - 50%, depending on the host) reached the full term. Except for three that were cannibalized soon after birth, all of the young (25 pups) developed into normal and fertile adult. Here we report the first birth of mouse offspring following ICSI in China. These studies may increase understanding of the fertilization process and of how ICSI works.
Animals ; Embryo Transfer ; Female ; Fertilization in Vitro ; methods ; Male ; Mice ; Oocytes ; physiology ; Pregnancy ; Sperm Injections, Intracytoplasmic ; methods