Vitrification of domestic cat oocytes--effect on viability and integrity of subcellular structures

Cryopreservation of female gametes is a crucial part of assisted reproduction techniques. The domestic cat is a model for both wild felids and human research. The aim of this study was to evaluate the effect of different vitrification protocols applied to feline oocytes at different maturational stages on the preservation of oocyte viability and integrity of subcellular structures. The vitrification solutions consisted of 20% ethylene glycol, 20% DMSO, 20% FCS, and 1.5 m Trehalose with and without 10% Ficoll PM-70. Markers for cell viability (PI/FDA), cytoskeleton organization (Anti-α-Tubulin-FITC antibody, Phalloidin-TRITC), as well as nuclear configuration (DAPI) were used for evaluation of vitrified-warmed oocytes. Our results show that 52% and 41% of live mature and immature oocytes, respectively and until 32% of microtubules, 28% of nuclear configuration and 36% of microfilaments in the normal pattern can be obtained with protocol described in this paper. According to our data, Ficoll PM-70 essentially improves the oocytes survival upon vitrification.