Restoration of a normal reproductive lifespan after grafting of cryopreserved mouse ovaries

Fresh and frozen ovaries from 10 day old C57BL/6J-Gpi-1(a) mice were grafted orthotopically into ovariectomized B6CBF1 (homozygous Gpi-1(b)) recipients. The recipients were mated with B6CBF1 males. The birth and size of each litter was recorded. The electrophoretic variant of glucose phosphate isomerase was determined for each neonate. Twelve of 13 recipients of fresh ovary and 10 of 12 recipients of frozen ovary were fertile. Of these, 10 (fresh) and eight (frozen) had litters derived from the ovarian grafts only, or from the graft and native ovary. The breeding characteristics of recipients of fresh and frozen grafts were similar. The reproductive lifespan of the recipients of fresh (6.2 litters) and frozen (8.4 litters) grafts was similar to that of unoperated C57BL/6-Gpi-1(a) control females mated with B6CBF1 males (6.3 litters). Litter size was similar in recipients of grafted ovaries (fresh, 5.4 pups/litter; frozen, 6.3 pups/litter) and C57BL/6-Gpi-1(a) females (6.3 pups/litter). The results suggest that cryopreservation per se does not affect the long-term viability of ovarian tissue and provides an option for storing female germ cells. This is the first unequivocal demonstration that a normal reproductive lifespan can be restored by orthotopic grafting of frozen ovary.