Objective: To compare the survival rate of mouse oocytes and fertilization rate between using open pulled straws (OPS) and needles for vitrification.

Material and Method: Meiosis II oocytes from female C57B/6J mice aged 7-8 weeks were collected and allocated to two groups for vitrification by using OPS or needles. Vitrified oocytes were thawed, morphological survival and fertilization rate were examined.

Results: There was no obvious difference between the morphological survival rates of vitrified mouse oocytes using OPS and needles (66.7% vs. 64.8%). Proportions Difference 1.9% (95% CI -7.1, 10.7). The vitrified oocytes from the needle had significantly higher percentages of fertilization rate than OPS (76.8% vs. 62.5%). Proportions Difference -14.3% (95% CI -24.5, -3.6).

Conclusion: Vitrification method of mouse oocytes using needles when compared to OPS provides a similar morphological survival rate and higher fertilization rate.

Keywords: Mouse oocytes, Oocyte vitrification, Open pulled straws, Needles, Survival rate, Fertilization rate