Effects of different cryoprotectant combinations on primordial follicle survivability and apoptosis incidence after vitrification of whole rat ovary.

This study was aimed at obtaining best vitrification conditions for preservation of primordial follicles after vitrification of whole ovarian tissue of rats. Ovaries of prepubertal ~5-week old female Wistar rats were divided randomly into 7 groups: Control (non-vitrified), V1 (EG+DMSO), V2 (EG+PROH), V3 (DMSO+PROH), V4 (EG+DMSO+Sucrose), V5 (EG+PROH+Sucrose) and V6 (DMSO+PROH+Sucrose). Control and vitrified-warmed samples were sectioned serially and stained either with HE or anti and pro active caspase-3 kit. The number of intact follicles in different stages of development was lower and the number of atretic and apoptotic follicles was higher in vitrification groups than those of the control group. Cryoprotectant combinations in V4 group showed better follicular preservation especially for primordial follicle. V3, V4 and V5 were best cryoprotectant mixtures, after the control group, according to the number of atretic follicles but the incidence of apoptotic primordial follicles was lowest in V3, V4 and V6. Incidence of apoptosis and the number of atretic follicles were lowest in V3 and V4 groups, and there was better primordial follicle preservation and survivability in VIV group. Thus, the combination of EG + DMSO with sucrose appears to be better suited for vitrification of whole ovarian tissue of rats.