Determination of quantitative parameters of the birefringence of the zona pelucida on in vitro matured oocytes cryopreserved and fresh and its correlation with oocyte quality, using a bovine experimental model.

• Grant number: 12/05668-7
• Support Opportunities: Scholarships in Brazil - Master
• Start date: March 01, 2013
• End date: February 28, 2014
• Field of knowledge: Health Sciences - Medicine - Maternal and Child Health
• Principal Investigator: Ana Carolina Japur de Sá Rosa e Silva
• Grantee: Luciene Aparecida Batista
• Host Institution: Faculdade de Medicina de Ribeirão Preto (FMRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

Although improvements in the techniques used in cancer treatment has significantly increased survival rates, the effects of gonadotoxic radio and / or chemotherapy may lead to permanent infertility. In this sense fertility preservation programs based on cryopreservation of gametes has been widely employed to safeguard the reproductive potential of these patients. However, as the oocytes are extremely sensitive to cryopreservation, the successful clinical implementation of this technique is still limited. The development of noninvasive techniques capable of selecting oocytes with good reproductive potential, whether fresh or cryopreserved, has been the subject of numerous studies. The polarized light microscopy is a noninvasive technique that ensures rapid visualization of structures birefringent oocitárias, in which case the zona pellucida, oocytes structure highly sensitive to cryopreservation, determines scores birefringence that has been linked to oocyte quality. However, to date, there is still no studies that correlate the scores of the zona pellucida birefringence with the ultrastructural features oocitárias and subsequent embryonic development as well as the determination of an index or range of values of birefringence indicate that safely oocyte viability . This study aims to determine the quantitative parameters of the score of the zona pellucida birefringence of fresh or cryopreserved bovine oocytes and correlate them with the ultrastructure analyzed by transmission electron microscopy as well as the rates of embryo formation after parthenogenetic activation.