Implicación de la adición de N-acetilcisteína en los medios de cultivo de gametos y embriones criopreservados

Gamete and embryo cryopreservation is a widespread assisted reproductive technique. It has been demonstrated that the cryoprotectants used in the cryopreservation extenders as well as the process itself alter the chemical and physical proprieties of the plasma membrane of gametes/embryos. Furthermore, tolerance for cryopreservation notably varies depending upon the type of genetic material to be cryopreserved. Specifically, epididymal sperm cryopreservation is less successful than ejaculated sperm because it has had no contact with seminal plasma (the main source of spermatozoa antioxidant and cholesterol). On the other hand, oocytes and early embryonic stages exhibit lower tolerance for vitrification; in addition, the quality of the embryos produced in vitro is lower than the quality of those produced in vivo, being more susceptible to irreversible damage during vitrification. Therefore, in the experiments carried out in the present Doctoral Thesis we tried to improve gamete and embryo cryopreservation at the more susceptible stages to cryopreservation-induced damage. To achieve this goal, we analyzed the effect of N-acetylcysteine addition to vitrified murine oocytes and embryos (2-cell stage) at different time points as well as to cryopreserved Lidia bull epididymal spermatozoa in order to determine the effects of this antioxidant on cryopreservation outcome. In addition, the use of dimethylformamide (DMF) was tested on freezing extenders of Lidia bull epididymal sperm after prolonged storage at 4° C (24-96 hours).