Apoptosis in human ovarian tissue after conventional freezing or vitrification and xenotransplantation.

One of the new emerging techniques to preserve reproductive potential of cancer patients is cryopreservation of ovarian fragments prior to medical treatment and their retransplantation after healing. In order to investigate and compare apoptosis in human ovarian tissue after conventional ("slow") freezing and vitrification, we used a xenograft model in which conventionally frozen, vitrified and fresh non treated human ovarian tissue pieces were subcutaneously transplanted in SCID mice. The tissue samples were weekly, during four weeks, recovered from scarified SCID mice. The apoptosis was examined by immunohistochemical staining with the anti-caspase-3 antibody. There was a significant difference between the amount of apoptotic cells in cryopreserved ovarian tissue independent from mode of cooling compare to the control. The ovarian tissue after vitrification showed a significantly higher amount of apoptotic cells, than in slow frozen. The results obtained after comparative study of two different cryopreservation methods show that vitrification of human ovarian tissue could become a practice-relevant alternative to slow cryopreservation only after further improvement.