Human spermatozoa cryopreservation: comparison of three different freezing protocols.

Human spermatozoa cryopreservation has significantly improved over the last few decades, but the actual protocols are neither optimal nor standardized between different laboratories in spite of the importance of preserving male fertility or treating severely infertile males. In the present study we aimed to determine the best in-house method of rapid freezing in terms of sperm motility and vitality by comparing three different rapid methods of human spermatozoa cryopreservation. Our data showed that M1 (triphasic cooling) is the method associated with a significantly lower deterioration of semen quality in comparison with mono or biphasic cooling. Differences observed among the three protocols were supported by statistical analysis. These data reinforce previous evidences about the influence of sperm quality on IVF outcome and suggest the importance of improving sperm cryopreservation techniques especially when semen is seriously compromised at baseline.