Novel methods for fertility preservation in cancer patients: Role of improved ovarian tissue cryopreservation and culture systems.

Cancer is still among the major medical concerns worldwide. Although, improvements in chemotherapy and radiotherapy has improved the survival rates of cancer patients, most patients receiving such treatment suffer from some degree of ovarian failure and infertility in future. Ovarian tissue cryopreservation pre-treatment and subsequent transplantation has emerged as a promising strategy for fertility preservation in cancer affected women. However, current cryopreservation protocols are yet to be optimized to ensure minimal damage and long term sustenance of the preserved material post warming. Hence, for the first time in literature, we propose the use of slush nitrogen that could greatly improve the cooling rates in ovarian tissue vitrification as opposed to liquid nitrogen. Slush nitrogen vitrification was clearly seen to improve follicle quality, viability and long term functional potential of the vitrified strips evidencing the efficacy of this technique. Furthermore, in-situ follicle culture is a major focus in reproductive biology research due to the risk of transmitting malignant cells during tissue transplantation. Although, several attempts have been made to attain complete folliculogenesis in vitro, this is yet to be realised in higher mammals and the human model. We demonstrated a critical role of oxygen in ovarian follicle growth in vitro. Optimal modulation of oxygen during ovarian cortical strip culture helped us obtain notably better follicle quality and secondary follicle progression as opposed to conventional cultures. Hence, this research thesis aims at advancing current fertility preservation strategies further, by exploiting the roles of optimal cryopreservation and culture systems.