Mammalian oocytes are surrounded by numerous layers of cumulus cells, and the loss of gap junctional communication in the outer layers of cumulus cells induces meiotic resumption in oocytes. In this study, we investigated the dynamic changes in the gap junctional protein connexin-43 in cumulus cells during the meiotic resumption of porcine oocytes. The amount of connexin-43 in all layers of cum...

background: in vitro maturation (ivm) of oocytes is a promising technique to reduce the costs and avert the side-effects of gonadotropin stimulation for in vitro fertilization (ivf). the pregnancy rates from oocytes matured in vitro are much lower than those of in vivo stimulation cycles, indicating that optimization of ivm remains a challenge. objective: in this study, we investigated the effe...

The present paper shows through conventional light microscopy, silver nitrate impregnation and Transmission Electron Microscopy, the changes in nuclear activity that occurs in the ovary cells during vitellogenesis of Apis mellifera (Linnaeus, 1758). The material impregnated by silver nitrate was detected in nurse cells, oocyte germinal vesicle and follicular cells, whose amounts are greater in ...

rate of in vitro maturation of oocytes is one of the challenges of assisted reproductive techniques. in this study we investigated the effects of supplementation of cysteamine on the rate of in vitro maturation of oocytes in two different media. germinal vesicle oocytes were collected from mouse ovary and cultured in two media (tcm199 and meme) with 0, 50, 100, 200, 500 µm/ml cysteamine. number...

In order to determine the most effective hormones on the in vitro oocyte maturation (germinal vesicle breakdown GVBD) in a hybrid sturgeon bester, ovarian follicles were incubated at the migratory nucleus stage in the presence of several steroids, gonadotropin preparations and forskolin. Occurrence of GVBD and 17,20β-dihydroxy-4-pregnen-3 -one (DHP) production were followed during an experiment...

Background The utilization of immature oocytes derived from stimulated cycles could be of great importance, specially for urgent fertility preservation cases. The aim of the current study was to determine whether in-vitro maturation is more successful before or after the vitrification of these oocytes. MaterialsAndMethods The study was performed in a private IVF center. 318 germinal vesicle (GV...

objective: mitochondria is a critical organelle within the cell and has important role in the oocyte development, thus the aim of this study was the comparison of mitochondrial distribution within the mouse oocyte at germinal vesicle (gv), germinal vesicle breakdown (gvbd) and metaphase ii (mii) stages using laser confocal microscopy (lscm). materials and methods: after superovulation of adult...

Based on new knowledge coming from marine perciform species, the origin of oocytes and their development in the Ostariophysi, Gymnotus sylvius is described. In both Gymnotus sylvius and marine perciform fish, oogonia are found in the germinal epithelium that forms the surface of the ovarian lamellae. At the commencement of folliculogenesis, proliferation of oogonia and their entrance into meios...

RGS2 is a negative regulator of G protein signaling that contains a GTPase-activating domain and a β-tubulin binding region. This study aimed to determine the localization and function of RGS2 during mouse oocyte maturation in vitro. Immunofluorescent staining revealed that RGS2 was widely expressed in the cytoplasm with a greater abundance on both meiotic spindles and first/second polar bodies...

Background: Cryopreservation of oocytes, which is an interesting procedure to conserve female gametes, is an essential part of reproductive biotechnology. The objective of the present study was to investigate the effects of cumulus cells on survival,in vitro maturation,fertilization and subsequent developmental capacity of mouse germinal vesicle stage oocytes during vitrification. Materials and...