Effects of sucrose concentration on the developmental potential of human frozen-thawed oocytes at different stages of maturity

BACKGROUD: Success of human oocyte cryopreservation depends on multiple cryobiological factors that could influence the developmental potential of the oocytes. The objective of this study was to examine the effects of different sucrose concentrations on the developmental potential of human frozen-thawed oocytes at different maturity stages. METHODS: A total of 355 oocytes collected from small follicles were randomly divided into three groups and two groups (B and C) were cryopreserved using slow-freezing method. Group A included 131 oocytes at different maturity stages without freezing. Another 119 oocytes in Group B were cryopreserved with 0.1 M sucrose and 105 oocytes in Group C with 0.2 M sucrose concentration. RESULTS: The post-thaw survival rate of the oocytes and the cleavage rate in Group C were significantly higher than that of Group B (P<0.05). For immature metaphase I (MI) stage oocytes, a significant difference was found in the maturation rate between Group C and Group B (P<0.05). The maturation rate for the GV oocytes in Groups A and C was significantly higher than Group B (P<0.01). CONCLUSIONS: The results suggested that sucrose concentration of 0.2 M in the cryoprotectant solution is more suitable for human oocyte cryopreservation.