SILVER CLOSED VITRIFICATION SYSTEM VERSUS SLOW FREEZING METHOD FOR THE CRYOPRESERVATION OF HUMAN OVARIAN TISSUE

BACKGROUND: We developed a hand-made silver container as a closed vitrification system (CVS) which avoid bacterial or viral contamination. OBJECTIVE: The aim of this study was to evaluate the preservation outcomes by comparing silver CVS and slow freezing (SF) method. MATERIALS AND METHODS: Donated human ovarian tissues were collected from nine patients. The fragments from each patient were randomly and evenly assigned to three groups: fresh control, silver CVS and SF group. The histology of the thawed ovarian tissue was investigated and the levels of secretion of estradiol (E-2) and progesterone (P-4) in the culture media were used to evaluate the development and function of thawed ovarian tissue. RESULTS: The results showed that the proportion of morphologically normal primordial follicles was higher in silver CVS group than in SF (P<0.005). E2 and P4 concentrations were significantly higher in the silver CVS group than in the SF group at any time point after day 6 (E2: P<0.05; P4: P<0.05). CONCLUSION: This study showed that human ovarian tissue cryopreserved with silver CVS had better morphology and higher E2 and P4 levels during in vitro ovarian tissue growth compared with SF. It implies that silver CVS has a better potential for ovarian tissue development in future clinical use.