Normal developmental competence to the blastocyst stage is preserved in rabbit ovarian tissue following cryopreservation and autografting to the mesometrium

Abstract

The aim of the present study was to evaluate mesometrial autotransplantation of frozen–thawed ovarian tissue in the adult rabbit and investigate the developmental competence of oocytes retrieved from grafts by in vitro maturation, fertilisation and blastocyst formation. Twenty-five rabbits were divided into control, fresh tissue transplantation and frozen–thawed tissue transplantation groups. Rabbits were stimulated with follicle-stimulating hormone (FSH) and oocytes were retrieved 3 months after transplantation. Oocytes matured in vivo or in vitro were then fertilised by conventional in vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI), followed by observation and evaluation of fertilisation and blastocyst formation rates. No significant differences were found in the percentage of oocytes, maturation, fertilisation, cleavage and blastocyst formation among the three groups. Significantly higher fertilisation rates of in vitro-matured (IVM) oocytes were observed with ICSI compared with IVF in each group (81.1% v. 58.5%, 79.2% v. 59.6% and 80.4% v. 56.0% in the control, fresh tissue transplantation and frozen–thawed tissue transplantation groups, respectively). The blastocyst formation rate of IVM oocytes was significantly lower than that of in vivo-matured oocytes in each group (25.5% v. 65.7%, 22.4% v. 61.8% and 28.9% v. 63.0% in the control, fresh tissue transplantation and frozen–thawed tissue transplantation groups, respectively). In concusion, the mesometrium is a promising site for ovarian autografts in the rabbit. Oocytes retrieved from mesometrial grafts can develop to the blastocyst stage.