Intracellular communication between the cumulus cell complex and the oocyte is essential for numerous processes during oocyte maturation. The aim of this study was to determine the interaction between oocyte-secreted factors and the metabolic activity of bovine cumulus cell complexes during in vitro maturation (IVM). Cumulus-oocyte complexes (COCs) were aspirated from ovaries derived from an ab...

In the growing follicle, communication between the oocyte and its surrounding follicular cells is essential for normal oocyte and follicular development. Maturation of the fully grown oocyte in vivo is associated with the loss of cumulus cell-oocyte gap junctional communication, preventing entry of meiotic-modulating factors such as cAMP into the oocyte. We have previously shown that oocyte and...

Adhesion between the oocyte-cumulus complex and infundibulum plays an important, but poorly understood, role in oocyte pick-up. The purposes of this study were to determine which components of the oocyte-cumulus complex and oviductal epithelium function in adhesion, to measure adhesion under physiological conditions, and to examine the effect of modulation of adhesion on oocyte-cumulus complex ...

Acrylamide (ACR) is a chemical compound with severe neurotoxicity, genotoxicity, carcinogenicity and reproductive toxicity. Recent studies showed that ACR impairs the function of reproductive organs, e.g., epididymis and testes. In vitro maturation of mouse oocyte is a sensitive assay to identify potential chemical hazard to female fertility. The aim of this study was to evaluate the adverse ef...

Cumulus cells are a group of closely associated granulosa cells that surround and nourish oocytes. Previous studies have shown that cumulus cells contribute to oocyte maturation and fertilization through gap junction communication. However, it is not known how this gap junction signaling affects in vivo versus in vitro maturation of oocytes, and their subsequent fertilization and embryonic deve...

Cumulus-oocyte complexes were aspirated from small antral follicles (3-5 mm in diameter) and divided into 2 groups: complexes in which a dark rim of corona cells were visible around the zona pellucida (group 1); and those in which the corona displayed the same density as the rest of the cumulus cell mass (group 2). Cumulus complexes of both groups were evaluated by acetoorcein staining, scannin...

In the process of oocyte maturation, gonadotrophins are believed as main stimulators for oocyte meiosis resumption. However, which gonadotrophin (i.e. FSH or LH) is the key hormone in this process is still unknown. This study indicated a close relationship between LH and FSH on activating meiotic maturation of oocyte in vitro. FSH efficiently induced oocyte meiosis at concentration of 50 IU/L, ...

Previous our studies have shown that CD44, the principal receptor for hyaluronan, is present on cumulus cells during oocyte maturation. Although hyaluronan-CD44 interaction has been implicated in cumulus expansion and/or oocyte maturation, the full significance of CD44 remains unknown. The objective of the present study was to further investigate the role of CD44 in cumulus expansion and oocyte...

We sought to investigate whether miR-378 plays a role in cumulus cells and whether the manipulation of miRNA levels in cumulus cells influences oocyte maturation in vitro. Cumulus-oocyte complexes (COCs) from ovarian follicles had significantly lower levels of precursor and mature miR-378 in cumulus cells surrounding metaphase II (MII) oocytes than cumulus cells surrounding germinal vesicle (GV...

Assisted reproductive technologies in all mammals are critically dependent on the quality of the oocytes used to produce embryos. For reasons not fully clear, oocytes matured in vitro tend to be much less competent to become fertilized, advance to the blastocyst stage, and give rise to live young than their in vivo-produced counterparts, particularly if they are derived from immature females. H...