Cryopreservation Of Limited Numbers Of Ejaculated And Surgically Retrieved Human Spermatozoae Within Empty Human Zona Pellucida

Document Type : Original Article


Anatomy Department,Tarbiat Modarres University, Tehran, Iran


Introduction: Cryopreservation of single human spermatozoa is a new technique designed to improve the management of male infertility, it was first introduced in 1997 and was reported by others latter. The aim of this research was to evaluate the efficiency of this method in preserving either ejaculated or surgically retrieved spermatozoae.
Materials and Methods: Spermatozoae were obtained from patients attending the ICSI program at Koassar Fertility Center, Tehran, Iran, and the cases were divided into three groups according to the method of sperm retrieval : a-ejaculated sperm, b-PESA and c-TESE (both with shaking sperm). For each group, 10 empty zonae were prepared using degenerated, immature or unfertilized human oocytes. Spermatozoa (8-10) were transferred inside each empty zona. The zonae were put in a droplet of follicular fluid + 15% glycerol (V/V) for five minutes before it was loaded in 0.25 ml straws and plunged in liquid nitrogen. After thawing, spermatozoa were extracted from the zonae and sperm viability and motility were recorded and analyzed statistically.
Results: The results showed that less than 12% of the sperms were lost prior to cryopreservation and that there was no significant difference among the groups. Post -thaw viability rate was 80-84% and it was the same for all the groups. Motility rate was 70-74%, again with no significant difference among the groups.
Conclusion: This sperm cryopreservation method is suitable for oligozoospermia patients because of high recovery and motility rates. It can also help azoospermic patients by preventing repeated surgeries.