BACKGROUND In human oocytes, as in other mammalian ova, there is a significant variation in the pregnancy potential, with approximately 20% of oocyte-sperm meetings resulting in pregnancies. This frequency of successful fertilization decreases as the oocytes age. This low proportion of fruitful couplings appears to be influenced by changes in mitochondrial structure and function. In this study,...

Background: Intracytoplasmic sperm injection (ICSI) has become a useful technology to produce foals when availability of semen is limited or when in-vitro fertilization is desired, as is the need for subfertile mares. However, its application into clinical practice is challenging. The purpose of this review was to discuss some fundamental molecular aspects of oocyte maturation that should be co...

Background: The present study was carried out to investigate how the interactions between aging, vitrification, and post-warming interval affect the credibility of sheep MII-oocytes for in vitro fertilization (IVF), intracytoplasmic injection (ICSI), and parthenogenetic activation (PA). Materials and Methods: The vitrified-warmed oocytes, either immediately (immediate group: IG) or two hours po...

Background To assess embryos derived by the transfer of meiosis-II chromosomes (M-II-t) from aged mice oocytes into ooplasms from younger mice to overcome the problem of age-related decline in female fertility. MaterialsAndMethods The developmental capacity karyotype and ultrastructure of reconstructed oocytes derived from meiosis-II chromosome transplantation from aged mice into the ooplasms o...

Women over 35 have higher rates of infertility, largely due to deterioration of oocyte quality characterized by fragmentation, abnormal meiotic spindle-chromosome complexes, and oxidative stress. C-phycocyanin (PC) is a biliprotein enriched in Spirulina platensis that is known to possess antioxidant, anti-inflammatory, and radical-scavenging properties. D-galactose-induced aging acceleration in...

After becoming competent for resuming meiosis, fully developed mammalian oocytes are maintained arrested in prophase I until ovulation is triggered by the luteotropin surge. Meiotic pause has been shown to depend critically on maintenance of cAMP level in the oocyte and was recently attributed to the constitutive Gs (the heterotrimeric GTP-binding protein that activates adenylyl cyclase) signal...