Mouse follicular oocytes, denuded and intact, were cultured in pyruvate salt sol and glutamine salt sol supplemented bovine serum albumin to compare the maturation rate. Glutamine has no effect on maturation of the denuded mouse oocyte but has an effect on maturation of the intact oocyte by increasing the maturation rate, depending on the increased concentration of glutamine (0.4 mM to 2 mM). Changes in osmolarity of the operation medium from 280 mOsm to 310 mOsm has no discernible effect on the oocyte maturation. A high frequency of abnormal 1st polar bodies was observed in pyruvate salt sol. and this may be due to the increased energy source in the cytoplasm of the 1st polar body when the po1ar body was extruded into the perivitelline space after the 1st meiosis.
Animal ; Cell Division ; Female ; Glutamine/metabolism ; In Vitro ; Mice ; Oocytes/cytology ; Oocytes/metabolism* ; Ovum/metabolism* ; Pyruvates/metabolism

Mouse follicular oocytes, denuded and intact, were cultured in pyruvate salt sol and glutamine salt sol supplemented bovine serum albumin to compare the maturation rate. Glutamine has no effect on maturation of the denuded mouse oocyte but has an effect on maturation of the intact oocyte by increasing the maturation rate, depending on the increased concentration of glutamine (0.4 mM to 2 mM). Changes in osmolarity of the operation medium from 280 mOsm to 310 mOsm has no discernible effect on the oocyte maturation. A high frequency of abnormal 1st polar bodies was observed in pyruvate salt sol. and this may be due to the increased energy source in the cytoplasm of the 1st polar body when the po1ar body was extruded into the perivitelline space after the 1st meiosis.
Animal ; Cell Division ; Female ; Glutamine/metabolism ; In Vitro ; Mice ; Oocytes/cytology ; Oocytes/metabolism* ; Ovum/metabolism* ; Pyruvates/metabolism

Parthenogenetic embryos, created by activation and diploidization of oocytes, arrest at mid-gestation for defective paternal imprints, which impair placental development. Also, viable offspring has not been obtained without genetic manipulation from parthenogenetic embryonic stem cells (pESCs) derived from parthenogenetic embryos, presumably attributable to their aberrant imprinting. We show that an unlimited number of oocytes can be derived from pESCs and produce healthy offspring. Moreover, normal expression of imprinted genes is found in the germ cells and the mice. pESCs exhibited imprinting consistent with exclusively maternal lineage, and higher X-chromosome activation compared to female ESCs derived from the same mouse genetic background. pESCs differentiated into primordial germ cell-like cells (PGCLCs) and formed oocytes following in vivo transplantation into kidney capsule that produced fertile pups and reconstituted ovarian endocrine function. The transcriptome and methylation of imprinted and X-linked genes in pESC-PGCLCs closely resembled those of in vivo produced PGCs, consistent with efficient reprogramming of methylation and genomic imprinting. These results demonstrate that amplification of germ cells through parthenogenesis faithfully maintains maternal imprinting, offering a promising route for deriving functional oocytes and having potential in rebuilding ovarian endocrine function.
Animals ; Female ; Mice ; Mice, Transgenic ; Mouse Embryonic Stem Cells/metabolism* ; Oocytes/metabolism* ; Parthenogenesis

OBJECTIVE: To explore the correlation between sperm-originated miRNAs and embryo quality by detecting the expression levels of miR-21, miR-34c, miR-140 and miR-375 in the sperm from in vitro fertilization (IVF) patients.
 METHODS: The fresh semen specimens were collected from 44 male patients who received the IVF cycle in the Xiangya Hospital Reproductive Center from September to December in 2012. The expression levels of miR-34c, miR-140, miR-21 and miR-375 were detected by real-time fluorescent quantitative PCR. The embryos on day 2 and day 3 after fertilization were divided into the experimental and the control group, with an average embryo scores less or greater than 8, respectively. Then we compared the general and experimental data between the 2 groups respectively and analyzed the correlation between the miRNAs levels in sperm and embryo quality.
 RESULTS: The expression of miR-34c, miR-140, miR-21 and miR-375 in sperms from the experimental group was significantly lower than that in the control group (P<0.05). There was no significant difference in retrieved follicles, metaphase II stage ovocytes, fertilized oocytes, cleavage number and fertilization rate between the experimental group and the control group (P>0.05), while the cleavage rate on day 2 in the experimental group was significantly lower than that of the control group (P<0.05). There was a negative correlation between the expression levels of miRNAs (miR-21, miR-34c, miR-140 and miR-375) and the ratio of fragment on day 2 or day 3. The expression levels of miR-21, miR-34c, miR-140 and miR-375 was positively correlated with the embryo score and the blastomere quantity on day 3, respectively. 
 CONCLUSION The up-regulated levels of miR-21, miR-34c, miR-140 and miR-375 in sperm may function as positive regulators in the development of cleavage stage in embryo and thus influence embryonic quantity.
Fertilization ; Fertilization in Vitro ; Humans ; Male ; MicroRNAs ; metabolism ; Oocytes ; Spermatozoa ; metabolism ; Up-Regulation

Extracellular vesicles (EVs) are membrane-bound particles actively released by cells. In prokaryotes and eukaryotes, EVs are effective bridges for communication between cells. EVs carry biological macromolecules, including proteins, lipids and nucleic acid, which affects different physiological functions of parent cells and recipient cells. Among them, the microRNA carried by EVs is the most reported and plays an important role in physiological function of organisms. During the development of follicles, only a few follicles can fully develop and ovulate, whereas most of them undergo atresia at different stages of development. In the whole process of follicular development, the changes at each stage and the regulation mechanism of follicular atresia are not completely understood. In this paper, we introduced the types, characteristics, isolation methods and uses of EVs, and emphasized how microRNA carried by EVs in follicular fluid regulated follicular atresia from the aspects of different cytokines and hormones. Additionally, the application prospect of microRNA carried by EVs in follicular fluid in reproductive regulation and reproductive disease diagnosis was discussed. This paper is significant for studying the regulation of follicular development and the effective utilization of oocytes.
Animals ; Extracellular Vesicles/metabolism* ; Female ; Follicular Atresia ; Follicular Fluid ; MicroRNAs/metabolism* ; Oocytes

AIMTo explore a method of the stable and persistent expression of HERG(human ether-a-go-go-related gene) channels in Xenopus oocytes, and investigate the alteration of rest membrane potential of oocytes and electrophysiological properties of expressed channel in different culture duration.

METHODSHERG mRNA for injection was prepared with in intro transcription using vector plasmid pSP64 containing HERG cDNA fragment. Expressed HERG current was recorded using standard two-microelectrode voltage-clamp technique.

RESULTS(1) Functional channels, with electrophysiological properties consistent with those of HERG channels were persistently expressed in oocytes membrane with this method. Furthermore, channel current could be recorded stably in 10-15 days. (2) The negative value of rest membrane potential increased gradually in the 3, 6, and 9 days of culture, and then decreased in the 12 days. The potential of peak value of inward rectification shifted gradually to the positive direction in 3, 6 and 9 days, and recovered in 12 days. Half-maximal activation potential (V1/2) of heterological expressed current shifted gradually to the negative direction in 3, 6 and 9 days of culture and then recovered in 12 days, the tendency of change was coincident with that of membrane rest potential.

CONCLUSIONThe investigation provides a method of persistent expression of HERG channel in Xenopus oocytes and offers evidences for the difference of electrophysiological experimental data of studies of molecular site and drugs effect of HERG channel in different experimental conditions.

Animals ; Ether-A-Go-Go Potassium Channels ; genetics ; metabolism ; Humans ; Membrane Potentials ; Oocytes ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Xenopus laevis

OBJECTIVETo investigate the characteristic and effect of cadmium on ATP-activated currents (I(ATP)) mediated by P2X4 purinoceptors.

METHODSTranscribe cDNA coding for the rat P2X4 receptor to cRNA in vitro. Inject the cRNA to oocytes of an xenopus laevis using the microinjection technique. Reveal the effect of cadmium on I(ATP) mediated by P2X4 receptor using the two-electrode whole-cell voltage clamp technique.

RESULTS(1) Within a certain concentration range, cadmium was found to reversibly magnify I(ATP) mediated by P2X4 receptors expressed in oocytes of an xenopus. When the concentration of cadmium reached 30 micromol/L, the increase of I(ATP) was the most significant. I(ATP) turned to decrease when the concentration of cadmium was more than 30 micromol/L; (2) The concentration-response curve was shifted to left by applying cadmium at 10 micromol/L; the EC50 was reduced from (17.1 +/- 1.5) micromol/L to (9.8 +/- 1.8) micromol/L (n = 6, P < 0.01) and the Hill coefficient was increased from 1.14 +/- 0.13 to 1.57 +/- 0.36; (3) The effect of cadmium on I(ATP) showed no dependence on membrane voltage; (4) The magnifying effect on I(ATP) reached maximum when preincubating cadmium for 120 seconds.

CONCLUSIONThe increase I(ATP) by cadmium is reversible, concentration-dependent, time-dependent, and voltage-independent. One reason of this augment effect could be the allosteric modulation on P2X4 receptors.

Adenosine Triphosphate ; metabolism ; Animals ; Cadmium ; toxicity ; Microinjections ; Oocytes ; drug effects ; metabolism ; physiology ; Rats ; Receptors, Purinergic P2X4 ; metabolism ; Xenopus laevis

Animals ; Cdc20 Proteins/metabolism* ; Cell Line ; Embryo, Mammalian/embryology* ; Embryonic Development ; Female ; Infertility, Female/metabolism* ; Mice ; Mutation ; Oocytes/metabolism*

Oogenesis is the basic reproductive process of female mammals and is essential for fertilization and embryo development. Recent studies have shown that epigenetic modifications play an important role in the regulation of mammalian reproductive processes (such as oogenesis, spermatogenesis, preimplantation embryo development and sex differentiation). Taking histone acetylation as an instance, the dynamic changes of histone acetyltransferases (HATs) and deacetylases (HDACs) are involved in the regulation of gene activation and inactivation when numerous key physiological events occur during reproduction. Thereinto, HDAC1 and HDAC2, which are highly homologous in terms of both structure and function, play a pivotal role in murine oogenesis. HDAC1 and 2 jointly regulate the global transcription and the incidence of apoptosis of growing oocytes and affect its subsequent growth and development, which reflects their compensatory function. In addition, HDAC1 and 2 also play a specific part in oogenesis respectively. It has shown that HDAC2 is more critical than HDAC1 for oocyte development, which regulates de novo DNA methylation and chromosome segregation. Reciprocally, HDAC1 is more critical than HDAC2 for preimplantation development. Deficiency of HDAC1 causes the decreased proliferation of embryonic stem cells and the smaller embryoid bodies with irregular shape. In this review, we summarized the role and the current research progress of HDAC1/2 in murine oogenesis, to provide a reference for further understanding the relationship between epigenetic modifications and reproductive regulation.
Acetylation ; Animals ; Embryonic Development ; Female ; Histone Deacetylase 1/metabolism* ; Histone Deacetylase 2/metabolism* ; Histone Deacetylases/metabolism* ; Male ; Mice ; Oocytes ; Oogenesis

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