Purpose: The purpose of this study was to investigate whether slow-rate freezing or vitrification is better for cryopreservation of ovary tissues pretreated with gonadotropin-releasing hormone agonist.
Methods: In this nonclinical study performed in rats, leuprorelin acetate was administered to female Wistar rats, aged 6-8 weeks. After confirming arrest of the estrous cycle by examination of vaginal smears, ovarian tissue was cryopreserved by vitrification and slow-rate freezing prior to thawing and autotransplantation. The time required for estrous cycle recovery was assessed from vaginal smears in each group starting from day 1 of transplantation. Estradiol levels were also monitored after transplantation.
Results: The estrous cycle recovered after transplantation of ovarian tissue frozen by either method, but recovery was significantly faster after transplantation of vitrified tissue. The estradiol level also recovered by 10 days after transplantation.
Conclusions: Ovarian function was restored after transplantation of tissue preserved by either vitrification or slow-rate freezing after pretreatment with leuprorelin acetate. This method may be applicable for patients scheduled to undergo cryopreservation of ovarian tissue before chemotherapy.
Keywords: Fertility preservation; GnRH analogue; Rat; Slow freezing; Vitrification.