Sığır Oositlerinin ICSI Sonrası Aktivasyonu ve Embriyonun Gelişim Aşamalarına Göre Aktivasyonun Etkileri

In the present study the aim was investigate to Ca ionophore activation in fertilized oocytes by using Intracytoplasmic sperm injection (ICSI) method and the effects of activation considering the stages of embryo development. Cumulus-oocyte complexes (COCs) were collected by aspiration method from the ovaries of cattle and heifers slaughtered at an abattoir. In vitro maturation of A quality COCs (n=500) was performed in TCM 199 medium at 39°C in an atmosphere of 5% CO2 in air with maximum humidity for 22 h. Subsequently, ICSI was carried out to oocytes and randomly divided into two groups. In Group I (n=250; study group) consisted of oocytes activated with 5 μM Ca ionophore at 38.5°C for 5 min, and in Group II (n=250; control group) contained oocytes without any activation. In Group I cleavage, morula and blastocyst rates were determined as 44.8%, 17.2% and 11.6%, respectively. In Group II the rates were established as 26.8%, 9.2% and 3.2%, respectively. Statistically the difference between groups considering the cleavage rates were obtained significantly (P<0.001); however, difference between groups considering morula and blastocyst rates was not determined significantly (P>0.05). In conclusion, the activation of bovine oocytes after ICSI is obligated to apply, and Ca ionophore was a practical and rapid activator to incite cleavage, but inadequate for embryos to reach the morula and blastocyst stages.