Background: Most studies show that 9 to 24% of people who are in in vitro fertilization (IVF) cycles are women who respond poorly to ovarian stimulation. Women with poor ovarian response (POR) are a group of infertile patients whose ovarian reserve, ovarian response to medication, and the quality of ovum are declining. Therefore, the number of female cycles, the number of fetuses from the oocyt...

The morphology of canine cumulus-oocyte complexes (COCs) before puberty is still unknown. Therefore, the aim of our study was to elucidate the morphological characteristics of pre-pubertal oocytes and cumulus cells by light microscopy, scanning electron microscopy and transmission electron microscopy. The pre-pubertal oocyte was characterized by accumulation of lipid yolk droplets in the cytopl...

This study investigated the effect of different harvesting techniques on the recovery rate and quality of bovine cumulus oocyte complexes (COCs) and their subsequent developmental competence including in vitro maturation, fertilization and blastocyst formation. The COCs were retrieved from slaughter ovaries using aspiration, slicing, or aspiration followed by slicing. The COCs were examined mic...

31 32 In the growing follicle, communication between the oocyte and its surrounding follicular 33 cells is essential for normal oocyte and follicular development. Maturation of the fully34 grown oocyte in vivo is associated with the loss of cumulus cell-oocyte gap junctional 35 communication, preventing entry of meiotic-modulating factors such as cAMP into the 36 oocyte. We have previously show...

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...

BACKGROUND The complex relationship between oocyte morphology, specific follicular fluid metabolites, gene expression in cumulus granulosa cells, and oocyte competence toward fertilization and embryo development still needs further clarification. METHODS Forty-six oocytes retrieved from the largest pre-ovulatory follicle of patients undergoing intra-cytoplasmic sperm injection (ICSI) were con...

Paracrine factors secreted by the oocyte regulate a broad range of cumulus cell functions. Characteristically, cumulus cells have a low incidence of apoptosis and we proposed that this is due to oocyte-secreted factors acting in an anti-apoptotic manner. Bovine cumulus-oocyte complexes (COC) were aspirated from abattoir-derived ovaries and oocytectomized (OOX) by microsurgical removal of the oo...

The two principal functions of ovarian follicles are developmental and endocrine. The cumulus cells surrounding the oocyte are specialized to serve the development of the oocyte and steroidogenesis is a principal role of mural granulosa cells that line the follicle wall. The findings in this report demonstrate that oocytectomy or treatment with an inhibitor of SMAD2/3 activation results in decr...

Energy balance is regulated by ghrelin that is a neuroendocrine modulator. Ghrelin is expressed in reproductive organs. However, the role of ghrelin during in vitro maturation and bovine preimplantational development is limited. The purpose of this study was to determine the expression of ghrelin (GHRL) and its receptor growth hormone secretagogue receptor 1A (GHS-R1A) mRNA expression, and cumu...