An update of oocyte vitrification: A modification of sucrose and trehalose as extracellular cryoprotectant

As well as the development of assisted reproductive technology (ART), as the current treatment of woman who failed in achieving pregnancy, the development of an advance vitrification method also grows rapidly. The successful of oocyte vitrification depends on the type and the concentration of cryoprotectant. This study was addressed to elaborate empirical evidence and recent studies of sucrose and trehalose as an extracellular CPA with the aim of achieving the success of oocyte vitrification. Several researchers in agreement that trehalose, as extracellular cryoprotectant, also has a role as intracellular cryoprotectant by microinjection with high survival rates as the outcome. Moreover, the combination of sucrose or trehalose as an extracellular cryoprotectant and others intracellular cryoprotectant have different survival rates which might occur because of the differences between the composition and concentration of sucrose or trehalose. The appropriate type and concentration of sugar as an extracellular cryoprotectant for oocyte cryopreservation are sucrose or trehalose in 0.5M concentration. Nevertheless, it requires further study to optimize oocyte vitrification process.