Human sperm cryopreservation update in treatment of infertility: a review study

Cryopreservation is the most effective method for long-term maintenance of sperm. There are several procedures for freeze-thawing of semen and each may impose damage on sperm function, viability and finally decreases semen quality and fertility potential. In addition to decreased percentage of sperm viability and motility after freeze-thawing, percentage of DNA damage is also increases due to high level of oxidative stress. To minimize these damages, we need to increase our insights regarding different cryopreservation procedures, cryoprotectant and antioxidant supplements, which can protect sperm membrane during cryopreservation. Therefore, by using these experiments, we can improve the efficiency of these procedures. In this review, we discuss about principles of cryopreservation, types of freeze-thawing methods, advantages and disadvantages of each of these methods, effects of freezing on sperm parameters and clinical outcomes, and finally role of antioxidants in preservation of sperm integrity during freeze-thawing. For this review, all relevant information was collected via databases such as PubMed and Google Scholar during the period of 1966-2017.