The Effect of Vitrification on Follicular Morphology of Ovarian Rat

Background & Objective: Some efforts have been made for keeping cryopreservation of gametes and embryos safe, including new vitrification methods of the ovary. This study evaluates the effect of ethylene glycole vitrification on follicular morphology of ovarian rat. Materials & Methods: Eighty ovaries belonging to 40 rats are divided into 2 groups. Twenty five ovaries are control group, 25 the vitrification, and30 toxicologic effects. For freezing, equilibrium solution, ethylene glycole and methyl sulfoxide are used. For defreezeing, different concentrations of saccharose and for morphological evaluation, H&E staining are undertaken. The number of healthy and atretic follicles are determined after 24 hours, 1 week and one month after vitrification. Results: No morphological changes are observed in all follicular cells. The percent of primordial, primary, secondary, anthral and developed follicles in the vitrification group are 34.5%, 17.7%, 17.4%, 15.2% and 50.3%. In vitrification and toxicological groups, the percent of both normal and atretic follicles is 47.5% and 11.9%. These figures for the control group were 59.7% and 16.9%. In vitrification method, 91% of oocytes are viable, 81% have mitosis, and 50% enters blastocyst stage. Conclusion: Because in vitrification of ovary in comparison with the follicles, many types of follicles in different cycles can be recovered with no morphological and structural changes, vitrification of ovary can be a safe method for cryopreservation of the oocytes