O-9: Duration of Enzymatic and Mechanical Denudation: Have any Effect on Fertilization Rate and Embryo Development?

Background: Intracytoplasmic sperm injection (ICSI) is the choice option for treatment of couples with severe male infertility. Recent studies indicate that the ICSI procedure or the technique itself cannot increase chromosomal abnormalities observed in born children. It maybe result of the Materialss used during ICSI procedure such as PVP and hyalorunidase. Activation of the oocytes might be caused by pipetting procedure and exposure to the hyalorunidase. The microinjection technique has been completely standardized, but some other procedures such as oocyte denudation still need more attention. Materials and Methods: In the present study, 358 oocytes from 58 cycles were evaluated. Cumulus and corona cells were removed in two pipetting steps: first in a medium containing hyaluronidase, and then in a medium without enzyme. We recorded the exposure time of oocytes to hyaluronidase and mechanical pipeting duration (without enzyme). Oocytes were put in a single droplet of G1 media., Procedures were performed by a single embryologist in 6 month. Post-ICSI fertilization rate and blastomere number as well as embryo quality were assessed. Results: No statistically significant differences were found between the exposure time of oocytes to hyaluronidase with blastomere number, embryo quality and fertilization rate, but duration of mechanical pipetting had prominent effect on fertilization rate (p=0.001), embryo quality (p=0.02). Conclusion: Our result showed that mechanical denudation had adverse effect on subsequent oocyte fertilization potential. It is possible that, these effects are caused by suboptimal situation of oocyte out of incubator or mechanical effect due to pipetting. So, to achived the best result of ICSI procedure, we should minimize the time of oocyte denudation.