The present study was undertaken to explore the regulatory mechanisms for meiotic resumption of pig cumulus-oocyte complexes (COCs) by assessing the nuclear status of oocytes, the degree of gap junction cell-to-cell communication and cumulus expansion after culture of various numbers of COCs in 10 microl droplets of medium for 24 h. Gap junction communication was examined by confocal laser scan...

STUDY QUESTION Are there associations between early time-lapse parameters, expression of candidate embryo viability genes in cumulus cells and embryo quality on Day 5? SUMMARY ANSWER Early time-lapse parameters correlate to the expression levels of candidate embryo viability genes in cumulus cells but a combined analysis including both time-lapse and candidate gene expression did not identify...

cAMP and intracellular Ca2+ are important second messengers involved in mammalian follicular growth and oocyte meiotic maturation. We investigated the capacity of the neurohormone serotonin (5-hydroxytryptamine, 5-HT) to regulate intracellular cAMP and Ca2+ in mouse oocytes and surrounding cumulus cells. On the basis of a reverse transcription-polymerase chain reaction study, 5-HT7 receptor mRN...

Pig oocytes in different maturational stages--germinal vesicle (GV), metaphase I (MI) and metaphase II (MII)--were cultured in vitro with [3H]-fucose. The incorporation of the precursor was followed by LM or EM autoradiography on air-dried preparations and on semithin or thin sections. The cumulus cells connected with the oocytes at the GV stage were intensely labelled, while the labelling of t...

CONTEXT FSH is routinely administered to in vitro fertilization patients to induce follicle maturation. During this process, granulosa cells differentiate and acquire specific functional characteristics that are required to coordinate ovulation and oocyte maturation. OBJECTIVE The objective of the study was to gain insight into the molecular mechanisms regulating human granulosa cell differen...

During follicle development, oocytes secrete factors that influence the development of granulosa and cumulus cells (CCs). In response to oocyte and somatic cell signals, CCs produce extracellular matrix (ECM) molecules resulting in cumulus expansion, which is essential for ovulation, fertilisation, and is predictive of oocyte quality. The cumulus ECM is largely made up of hyaluronan (HA), TNF-s...

Background: For several years, mammalian cloning by splitting an early embryo or nuclear transfer into oocytes method has been successfully performed. Cloning is now also possible using adult somatic cells. Although it has now been 15 years since the first cloned mammals were generated from somatic cells using nuclear transfer (NT), the success rate for producing live offspring by cloning is lo...

STUDY QUESTION Is the activity of sirtuin 3 (SIRT3) altered in granulosa and cumulus cells from young women with reduced ovarian reserve or women of advanced maternal age? SUMMARY ANSWER SIRT3 mRNA and active protein in granulosa and cumulus cells were decreased in women with reduced ovarian reserve and advanced maternal age. WHAT IS KNOWN ALREADY Young women with reduced ovarian reserve or...

Studies aimed at the influence of smoking on reproductive functions have found out fertility disorders in smokers occurring at any stage of reproductive processes. In our experiments the role of cadmium, nicotine and anabasine was investigated in the expansion of oocyte-cumulus complexes (OCC) isolated from large antral porcine follicles. Suppression of FSH-induced cumulus expansion and signifi...

We previously reported that when midkine (MK), a heparin-binding growth differentiation factor was used in in vitro maturation (IVM) culture of bovine cumulus-enclosed oocytes (CEOs), their developmental competence to the blastocyst stage after in vitro fertilization (IVF) was enhanced and the effect of MK might be mediated by its action upon mural granulosa cells and cumulus cells that closely...