| Abstract [eng] |
This doctoral dissertation explores the issue of fertility preservation and restoration in cancer patients, with a particular focus on still-experimental strategies — pre-transplantation manipulation of ovarian tissue (OT) and the construction of artificial ovaries. These are the first scientific studies in Lithuania to use cryopreserved human OT. The aim of this research is to develop safe and effective fertility restoration strategies by evaluating in vivo ovarian tissue transplantation, in vitro follicle activation, and artificial ovary construction models. The study applied OT cryopreservation techniques, xenotransplantation, microRNA and gene expression analyses, as well as follicle maturation and 3D structural engineering technologies to comprehensively assess the viability and functionality of OT. The results show that the applied slow-freezing and rapid-thawing protocol is effective in preserving tissue viability and functionality. Additional pre-treatment of OT with growth factor VEGF-A and antioxidant rutin before xenotransplantation did not produce a significant improvement in transplantation outcomes. Moreover, primordial follicles isolated from cryopreserved OT remained viable and successfully developed into functional higher development stage follicles within 3D structures in vitro, particularly when OT stromal cells were introduced into the artificial ovary model. The findings of this dissertation provide not only theoretical insights but also practical evidence supporting the clinical applicability of the slow-freezing method for ovarian tissue. One of the most significant outcomes of this work is an application of this technology’s use in Lithuania for prepubertal girls. |
