Ting AY, Yeoman RR, Lawson MS, Zelinski MB. Hum Reprod. 2011 Jun 24.
Background: Ovarian tissue cryopreservation is the only option for preserving fertility in prepubertal girls and cancer patients requiringimmediate treatment. Following ovarian tissue cryopreservation, fertility can be restored after tissue transplant or in vitro follicle maturation.
Methods: Macaque (n ¼ 4) ovarian cortex was cryopreserved using slow-rate freezing (slow freezing) or vitriﬁcation. Tissues were ﬁxed for histology or phosphohistone H3 (PPH3) analysis, cultured with bromodeoxyuridine (BrdU) or used for three-dimensional secondary follicle culture. Follicular diameter and steroid hormones were measured weekly.
Results: Slow freezing induced frequent cryo-injuries while vitriﬁcation consistently maintained morphology of the stroma and secondary follicles. PPH3 was similar in fresh and vitriﬁed, but sparse in slow-frozen tissues. BrdU uptake appeared diminished following both methods compared with that in fresh follicles. In vitro follicle survival and growth were greater in fresh than in cryopreserved follicles. Antrum formation appeared similar after vitriﬁcation compared with the fresh, but was reduced following slow freezing. Steroid production was delayed or diminished following both methods compared with fresh samples.
Conclusions: Secondary follicle morphology was improved after vitriﬁcation relative to slow freezing. Following vitriﬁcation, stroma was consistently more compact with intact cells typical to that of fresh tissue. BrdU uptake demonstrated follicle viability post-thaw/warming. For the ﬁrst time, although not to the extent of fresh follicles, macaque follicles from cryopreserved tissue can survive, grow, form an antrum and produce steroid hormones, indicating some functional preservation. The combination of successful ovarian tissue cryopreservation with in vitro maturation of follicles will offer a major advancement to the ﬁeld of fertility preservation