Background: Ovarian transplantation in nonhuman primates (NHP) has been used as a strategy for the development of
experimental models for biomedical research in the reproductive area. The prospects for application of this technique range
from the restoration of female fertility to the conservation of endangered wild animals. However, studies with NHP were
performed mostly focusing on the ovarian transplantation of cryopreserved tissue, in order to simulate the reality of human species, as well as aiming to obtain experimental models suitable for comparative studies. On the other hand, ovarian
transplantation could be applied also in NHP species preservation.
Review: According to the last census (2012-2014) of the International Union for Conservation of Nature (IUCN), currently,
more than half of the 633 types of primates known around the world are in danger of disappearing forever due to the continued destruction of their natural habitat by human activities. Thus, there is an interest to expose the possible methods of
ovarian preservation followed by transplantation that can be employed to promote the conservation of endangered NHP.
Despite the positive results obtained with avascular autograft of fresh ovarian tissue in NHP, it is important to bring in
mind the significant loss of follicles as a result of this procedure due to ischemia and reperfusion during the first days after
grafting. This phenomenon leads to the production of reactive oxygen species (ROS) such as hydrogen peroxide, superoxide
anion and hydroxyl radical, which are responsible by lipid peroxidation, cell membrane damage and subsequent follicular
atresia. An alternative to counteract this oxidative stress consists in the application/administration of different sources of
antioxidants previously or during grafting, in the grafted tissue or in the animal receiving the transplant. The most used
compounds with a claimed radical scavenger activity are catalase, trolox and some vitamins. In some cases, antioxidants are
combined with angiogenic factors, e.g. vascular endothelial growth factor (VEGF) to stimulate revascularization. Another
option to avoid the damage caused by ischemia is the whole ovarian transplantation with vascular anastomosis. Therefore,
a greater proportion of the pool of follicles survives the procedure and the complete ovary is grafted and not only tissue
fragments. However, the vascular microsurgical procedure is complex and, when it is associated with cryopreservation
the risks of follicular loss and tissue damage due to improper perfusion are larger. In this context, the aim of this review
is to cover important concepts about ovarian transplantation and its current situation in NHP, showing its importance and
its advances to reproduction, especially to preserve those endangered ones.
Conclusion: Despite advances in tissue response to various applications of the ovarian tissue transplantation reported
in this review, it is clear that this technique has been used with paucity as a tool for the conservation of species of PNH
endangered. The need for optimization of transplantation techniques, so as to reduce the loss of the follicles during the
grafting processes and revascularization, determining the ideal location for the graft, the graft longevity and where in the
amount of ovarian tissue required to preserve fertility still are points to be clarified. In this sense, research is ongoing and
the perspectives are positive not only to use NHP as a model for human, but also for those endangered species.
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