Exploration of a Novel Ovarian Tissue Heterotopic Transplantation Method Using the Endometrium as the Target Organ

Abstract

One of the fertility preservation treatments is ovarian tissue cryopreservation and transplantation. Although orthotopic transplantation is the most common transplantation site following ovarian freezing, it has disadvantages such as the need for invasive surgical treatment. Therefore, in this study, we investigated the feasibility of ovarian tissue transplantation into the endometrium as a new target organ for ovarian tissue transplantation in mice, which was an ectopic transplantation. Eight-week-old ICR mice were used as recipients, and 7- to 10-day-old ICR mice were used as donors. Estrogen and progesterone were administered to the recipient mice under pituitary suppression, and the donor ovaries were implanted in the uterus. In the control group, 2 out of 12（16.6%）, in the estrogen group, 3 out of 9（33.0%）, and in the estrogen + progesterone group, 1 out of 11（9.1%）ovaries were successfully implanted. In addition, a developing follicle was observed in the successfully implanted ovarian tissue. Not only was the live attachment of the ovarian tissue to the endometrium confirmed, but it was also confirmed that the follicle was growing within the ovarian tissue that had grown. It is suggested that transplantation to the endometrium is feasible as a target site for ovarian transplantation after fertility preservation. Furthermore, it was shown that external control of the intrauterine environment during transplantation to the endometrium may improve the live-implantation rate.