Cryopreservation of murine ovarian tissue

To determine the feasibility of ovarian transplantation using cryopreserved tissue, ovaries were removed from anesthetized 12- to 20-week-old female mice. The controls consisted of a sham-operated group and an oophorectomized group, and the experimental groups were autologous transplants with and without cryopreservation. Ovaries for cryopreservation were suspended in 1.4 M dimethyl sulfoxide Tyrode's solution, at 22 degrees C for 5 min and cooled at a controlled rate (0.5 degrees C/min) to -55 degrees C. The ovaries were stored in liquid nitrogen for 1 to 30 days and then thawed at room temperature. Thawed ovarian tissue was washed free of dimethyl sulfoxide and transplanted. Subsequent daily examination of vaginal cytology indicated ovarian endocrine activity in all groups except those oophorectomized without transplants. Animals receiving ovarian tissue, fresh and cryopreserved, were euthanized at diestrus I, 6 weeks postoperatively, for ovarian histology; both groups demonstrated folliculogenesis. The histology and endocrine function of autotransplanted cryopreserved ovaries were similar to those of nonfrozen transplanted ovaries and of ovaries in sham-operated groups.