Background: This study was designed to respond to the controversy regarding the necessity of oocyte activation after the ICSI procedure for normal embryo development in sheep. Materials and Methods: The effect of chemical stimulation with either 5mM ionomycin (I) for 5 minutes or ionomycin + 2 mM 6-dimethylaminopurine (6-DMAP) for 3 hours on the efficiency of ICSI, was compared in six experimen...

Background Failed fertilization occurs 1-3% in the infertile couples. Failure of oocyte activation (OA) is mainly attributed to failed fertilization. ICSI alone artificial oocyte activation (AOA) is only treatment approach for these individuals. Three procedures are introduced for AOA: chemical, mechanical and electrical. Most of the clinical Centers have commonly used ionomycin for activation ...

Background: Oocyte vitrification and assisted oocyte activation have increasingly important implications in assisted reproductive technology. However, an important area of concern with matured oocyte cryobiology is that elements of oocytes intimately involved in metaphase-II arrest may be modified by cryopreservation. In a comparison between different cellular characteristics of unvitrified, vi...

It is well established that in addition to generating the diploid state in the zygote, the sperm also endows the oocyte with paternal centrioles, proteins and RNAs. Although the exact roles of mRNA introduced into the oocyte by the sperm are not completely understood. However, literature background, suggested that RNAs may have a vital role in embryo cleavage and further development. Therefore,...

Background Following sperm penetration, oocyte is activated by sperm oocyte activating factors (SOAFs) released by sperm. Spermspecific phospholipase C isoform ζ (PLCζ) and post acrosomal WW binding protein (PAWP) are two nominees for the SOAF. PLCζ is located back-to-back with another testis-specific gene called CAPZA3. These two genes share a common bidirectional promoter. In this study we as...

Background: Heat shock may affect different aspects of oocyte maturation and its subsequent development to the blastocyst stage. A series of in vitro experiments was performed to determine whether physiologically heat shock (41°C) disrupts the progression of the ovine oocytes through meiosis, activation and blastocyst formation. Materials and Methods: The cumulus-oocyte complexes (COCs) were as...

Intracytoplasmic sperm injection (ICSI) has increased the potential of the assisted reproductive technologies to propagate mammalian species and has provided an opportunity for research into cell cycle control and the mechanisms involved in sperm-induced oocyte activation. We have investigated the efficacy of ICSI in the rhesus monkey, the mechanism of fertilization following sperm injection an...

Assisted oocyte activation (AOA) is the technique that simulates the effect of sperm penetration into an oocyte inducing oocyte activation. This technique is used in combination with intracytoplasmic sperm injection (ICSI) to improve the outcome of the fertilization process. It is mostly beneficial and recommended in those cases, when classic ICSI fails. This accounts approximately up to 5 % of...