P-120: Meiotic Spindle Visualization and Zona Pellucida Birefringence in Relation to Morphology of In Vivo and In Vitro Matured Human Oocytes of In Vivo and In Vitro Matured Human Oocytesof In Vivo and In Vitro Matured Human Oocytes

Background: The meiotic spindle plays an important role in the oocyte during chromosome alignment and separation at meiosis. The zona pellucid (ZP) is a dynamic matrix composed of filaments with the properties that might reflect the history of oocyte cytoplasmic maturation. Since, spindle and ZP in living oocytes are highly birefringent, their structures can be viewed noninvasively by using a Polscope. The aim was to investi gate the relationship between the presence of the meiotic spindle and ZP birefringence with morphology of in vivo and in vitro matured human oocytes. Materials and Methods: The oocytes were obtained from stimulated ovaries of patients undergoing ICSI. Germinal vesicles (GV; n=13) and metaphase I (MI; n=18) oocytes underwent in vitro maturation (IVM) using maturation medium supplemented with FSH + LH. They were checked for maturity 24 hours after culture. With the aid of Polscope, the presence of spindles and ZP birefringence (ZPB) were assessed in in vivo (n=21) and in vitro (n=21) matured oocytes. In addition, the morphology of each matured oocyte was evaluated using inverted microscope. Results: The rate of IVM in GV and MI oocytes was 53% and 77%, respectively. Spindle was present in 52.3% and 42.8% of the in vivo and in vitro matured oocytes, respectively. Spindle detection rates in oocytes derived from GV and MI stage were similar. The percentage of high birefringence oocytes was higher in in vitro than in-vivo matured oocytes (76.1 vs. 61.9%). Also, insignificant increases in rates of morphologic abnormalities were seen in in vitro in comparison with in vivo matured oocytes. Conclusion: The Findings indicates that IVM is a safe technology for maturation of human immature oocytes. However, application of Polscope is recommended in IVM technology to detect the most suitable oocytes for ICSI.