Oocyte cryopreservation is a promising technology that could benefit women undergoing assisted reproduction. Most studies examining the effects of cryopreservation on fertilization and developmental competence have been done using metaphase II-stage oocytes, while fewer studies have focused on freezing oocytes at the germinal vesicle (GV) stage, followed by in vitro maturation. Herein, we exami...

Background: Induction of in vitro maturation and development of immature oocyte is one of the methods that has been frequently used recently in artificial reproduction techniques and has drawn attention of many investigators. This method is useful especially in women who are affected by cancer and polycystic ovary syndrome. Despite using many types of in vitro media, an appropriate environment ...

oocyte maturation and embryo development are controlled by intra-ovarian factors such as steroid hormones. progesterone (p4) exists in the follicular fluid that contributes to normal mammalian ovarian function and has several critical functions during embryo development and implantation, including endometrial receptivity, embryonic survival during gestation and transformation of the endometrial...

Mitochondria (mt) have been reported to be closely related to the maturation of mammalian oocytes, but their function in oocyte maturation has not been elucidated. In this study, we examined the kinetics of mt and chromatin configuration during in vitro maturation of mouse oocytes to clarify the relationship between oocyte maturation and mitochondrial distribution morphologically. Oocytes were ...

Background: The developmental competence of oocytes matured in vitro (IVM) is yet far below than in vivo counterparts. Recent studies suggest that the asynchrony between nuclear/cytoplasmic maturation and the initial low/heterogeneous quality of oocytes are the most important factors affecting IVM success. We investigated whether selection of growing oocytes (based on their glucose 6- phosphate...

Abstract The African lion is an excellent model species for the highly endangered Asiatic lion. lions reproduce well in zoos, leading to fact that occasionally ovaries and testis are available in-vitro experiments. We previously performed maturation (IVM) fertilization of oocytes were able produce advanced embryos after intracytoplasmic sperm injection (ICSI) with cryopreserved sperm. Here we e...

Background: Melatonin (N-acetyl-5-methoxytryptamine) is a multifunctional molecule that mediates several circadian and seasonal processes in animal reproduction. Melatonin and its metabolites are antioxidants and free radical scavengers. Furthermore, melatonin has been shown to act as an indirect antioxidant, and it is able to increase the activity of glutathione synthesis, and many others dire...

This study examined effects on the developmental competence of pig oocytes after somatic cell nuclear transfer (SCNT) or parthenogenetic activation (PA) of : 1) co-culturing of oocytes with follicular shell pieces (FSP) during in vitro maturation (IVM); 2) different durations of maturation; and 3) defined maturation medium supplemented with polyvinyl alcohol (PVA; control), pig follicular fluid...

Pesticides can significantly harm reproduction in animals and people. Pyrethroids are often used as insecticides, and their toxicity for mammals is considered to be low. However, cypermethrin, deltamethrin and fenvalerate - as potent specific inhibitors of protein phosphatase calcineurin - can influence the meiosis of mammalian oocytes. The objective of this study was to evaluate the effects of...

BACKGROUND In some couples, not all retrieved oocytes mature, even after prolonged in vitro culture. The underlying mechanisms are not known, although ionophore treatment may alleviate metaphase I (MI) arrest in some mouse strains. We attempted to induce first polar body (PB) extrusion and fertilization using assisted oocyte activation (AOA) after ICSI in maturation-resistant human MI oocytes. ...