Shortening the duration between ovarian removal and cryopreservation helps preserve fertility and maintain ovarian reserve after transplantation in mice

Abstract

To evaluate the effect of storage of ovaries before cryopreservation on long-term fertility and ovarian reserve after transplantation in mice. Experimental study. University hospital. C57BL/6J and C57BL/6J-Tg (CAG-GFP) female mice. Storage and cryopreservation of mouse ovaries. Long-term fertility analysis of mice transplanted with thawed ovaries. Estrous cycles, number of live births, ovarian weight, and follicular counts of ovarian grafts. At the first mating 3 months after ovarian transplantation, the mean number of live births was 2.6 ± 0.6 in the control group (no storage); in the storage groups, the mean number of live births was 2.9 ± 0.7 after 4 hours, 1.3 ± 0.5 after 8 hours, 0.2 ± 0.2 after 12 hours, and 0.8 ± 0.5 after 24 hours of storage; the difference from the control group was significant in the 12-hour storage group. At the second mating 6 months after ovarian transplantation, the mean number of live births was 1.8 ± 0.6 in the control group and 2.4 ± 0.6 and 0.3 ± 0.2 in the 4- and 8-hour storage groups, respectively; no live births occurred in the 12- and 24-hour storage groups. Seven months after ovarian transplantation, the numbers of primordial, primary, early secondary, and late secondary follicles were significantly lower in the 8-, 12-, and 24-hour storage groups than in the control group. In mice, shortening the storage time of ovaries before cryopreservation preserved fertility and ovarian reserve after transplantation, indicating that human ovaries might be cryopreserved immediately after harvesting or transported as quickly as possible to a cryopreservation facility to allow young patients with cancer to preserve long-term fertility and ovarian reserve.