In-vitro development of vitrified–warmed bovine oocytes after activation may be predicted based on mathematical modelling of cooling and warming rates during vitrification, storage and sample removal

SANSINENA, MARINA; SANTOS, MARIA VICTORIA; CHIRIFE, JORGE; ZARITZKY, NOEMI

REPRODUCTIVE BIOMEDICINE ONLINE

REPRODUCTIVE HEALTHCARE LTD

Año: 2018

1472-6483

The finite element method has been previously applied for the prediction of heattransfer performance in vitrification and also to describe thermodynamic conditions during gamete storage and warming. The objective of this study was to correlate previously published numerical modeling predictions of vitrification cooling and warming rates with in vitro development after diploid parthenogenetic activation in the bovine model. Results indicated oocytes vitrified using Cryotop and Cryoloop (highest cooling rates) had significantly better embryo cleavage and blastocyst rates than those vitrified in Miniflex orOPS carriers. Previous modeling of warming process indicated that samples could reach glass transition temperatures and undergo devitrification under incorrect storage or handling conditions. These conditions were replicated in vitro, results were also consistent with numerical modeling: a significant reduction in oocyte survival was observed with 2-step removal from N2-vapor storage (with 15 sec pause at neck of Dewar) when compared with 1-step removal from either LN2-storage or N2 vapor-storage. Embryo cleavage was also significantly reduced with 2-step when compared with 1-step removal in LN2-storage or N2 vapor-storage. In conclusion, numerical modeling provides a useful tool for the evaluation of cooling and warming performances, and might be a qualitative predictor of oocyte survival and embryo development.