OBJECTIVE To evaluate the effect of the use of cumulus-aided embryo transfer on pregnancy rates. To study the proximity of expanded cumulus cells to the developing embryo. To document by light microscopy the anchoring of day 3 to day 4 embryos by the expanded cumulus cells. To demonstrate by transmission electron microscopy the cellular activity of the expanded cumulus cells. To evaluate the ex...

BACKGROUND To investigate whether cumulus cell removal after a 3 h co-incubation of gametes can affect the outcomes of in vitro fertilization. METHODS A prospective randomized sibling-oocyte study was performed in which sibling oocytes obtained from each patient were randomly assigned to either a 3 h or 20 h group (cumulus cells removed at 3 h or 20 h after insemination, respectively). Same o...

The present study was conducted to assess the effect of supplementation of L-ascorbic acid (vitamin C) on in-vitro maturation (IVM) of vitrified-thawed bovine oocytes. A total of 264 normal vitrified-thawed bovine follicular oocytes were divided into four experimental groups consisting of 66 oocytes in each group. In-vitro maturation was done in the medium supplemented with different concentrat...

BACKGROUND The objective of this study was to investigate whether the steroid hormone(s) secreted from cumulus-oocyte complexes (COCs) is a prerequisite for bovine oocyte maturation and cumulus expansion using aminoglutethimide (AGT), a P450 cholesterol side-chain cleavage inhibitor. METHODS In experiment 1, COCs were cultured in maturation medium with various concentrations of AGT for 22 h t...

Background: A mouse model of lipopolysaccharide (LPS)-induced inflammation was used to investigate the effect of pharmacological inhibition of nuclear enzyme PARP-1 on oocyte maturation, apoptotic and necrotic death, as well as DNA integrity of follicular cells. Also, the relative expression of cumulus genes (HAS2, COX2, and GREM1) associated with oocyte developmental competence was assessed. M...

Hydrogen sulfide (H2S) has been revealed to be a signal molecule with second messenger action in the somatic cells of many tissues, including the reproductive tract. The aim of this study was to address how exogenous H2S acts on the meiotic maturation of porcine oocytes, including key maturation factors such as MPF and MAPK, and cumulus expansion intensity of cumulus-oocyte complexes. We observ...

BACKGROUND Polycystic ovary syndrome (PCOS) is a common endocrine and metabolic disorder in women. The developmental competence of oocytes and embryos in PCOS patients is reduced to a certain extent (comparing to non-PCOS patients, the high quality embryo rate was decreased by 16% from the data of our centre) during the in vitro fertilization (IVF) process. Cross-talk between the oocyte and cum...

Background: The hyaluronidases are the enzymes hydrolyze β-1, 4 glycosidic linkage of hyaluronan. Hyaluronan is a polymer consisting of a repeating disaccharide unit found in cumulus ovuforus complex, semen liquid and other tissue. Addition to hydrolyzing the hyaluronan, hyaluronidase can penetrate through the cumulus cells layer that surrounds the oocyte, thus it terms spreading factor. Moreov...