P-199: The comparison of combination of EG and PROH to EG as cryoprotectant

OBJECTIVE: This study was conducted to investigate whether combination of ethylene glycol (EG) and propanediol (PROH) has influence on the survival and spindle presence compared to EG only when mice oocytes were vitrified-thawed. DESIGN: Animal study. MATERIALS AND METHODS: Oocytes were collected from superovulated BD F1 mice. The metaphase II (MII) oocytes (n 148) divided into two groups. After the meiotic spindle was evaluated by Polscope, group I was vitrified in DPBS with 20% hFF, 0.3 M sucrose, and 1.5 M EG and group II was vitrified in DPBS with 20% hFF, 0.3 M sucrose, 1.5 M EG, and 1.5 M PROH. The vitrified oocytes were thawed in DPBS with 20% hFF and 0.5 M sucrose. The meiotic spindle of the survival oocytes in each group was evaluated by Polscope 2 h after thawing. RESULTS: The recovery rate of thawed oocytes was 90.9% (80/88) in group I and 86.7% (52/60) in group II. The survival rate of recovered oocytes was 77.5% (62/80) in group I and 73.1% (38/52) in group II. The rate of meiotic spindle captured in group II was 100% (22/22), which was higher than that in group I (68.6%, 28/44). CONCLUSION: This result suggested that combination of ethylene glycol (EG) and propanediol (PROH) could cryopreserve more stable spindle than using EG only. Supported by: