Vitrification of domestic cat (Felis catus) ovarian tissue: Effects of three different sugars

We aimed to evaluate the effect of three extracellular cryoprotectants on the morphology of vitrified feline preantral follicles. Feline ovarian fragments (0.5 x 2 x 2 mm) collected from five domestic adult cats subjected to ovariohysterectomy for routine castration were vitrified with ethylene glycol (EG) 40% combined or not with sucrose (0.1 or 0.5 M), trehalose (0.1 or 0.5 M), or raffinose (0.1 M). After vitrification using the solid-surface method and warming of the tissues, cryoprotectants were washed out of the ovarian tissues, which were fixed for histological analysis. The percentages of normal follicles were similar to the control (fresh) (62.9 +/- 4.1%) only for tissues exposed and cryopreserved with EG + trehalose at concentrations of 0.1 (35.8 +/- 8.3%) and 0.5 M (33.4 +/- 5.4%). All the other sugars decreased the percentages of morphologically normal follicles as compared to the control group and the trehalose groups. Based on the results of the present study, we recommend the use of trehalose as the extracellular cryoprotectant for the vitrification of feline ovarian tissue.