Abstract Background and aim The vitrification of mammalian oocytes is a crucial technique in assisted reproductive technology. Cryoprotectants are essential in the process to prevent ice crystal formation and maintain oocyte viability. There are various combinations of cryoprotectants used in oocyte vitrification, and the optimal combination remains unknown. This systematic review aimed to analyze the effectiveness of different combinations of cryoprotectants for mammalian oocyte vitrification. Methods A systematic search of electronic databases including PubMed, Web of Science, Scopus, and Google Scholar was conducted to identify relevant studies. The quality assessment of the studies was performed using the Critical Appraisal Skills Program (CASP) tool. The data extraction and synthesis were also conducted following the PRISMA guidelines. Results The findings demonstrated that ethylene glycol (EG) combined with dimethyl sulfoxide (DMSO) or glycerol yielded higher oocyte survival and maturation rates compared to other cryoprotectants. Moreover, the concentration and type of cryoprotectants used, as well as the presence of other additives such as sugars, influenced the outcome of oocyte vitrification. This study also indicated the importance of considering factors such as calcium concentration in the vitrification media. Conclusion The study revealed that the choice of cryoprotectant combination for mammalian oocyte vitrification should be based on careful consideration of the specific objectives and requirements of each individual case. Understanding the effects of cryoprotectants on oocyte quality and subsequent development is crucial for improving the success rates of assisted reproduction technologies using cryopreserved oocytes.
Sanaei et al. (Wed,) studied this question.