Effects of oocyte diameter, chromatin configuration in GV and evaluation of p34cdc2 kinase activity in in vitro maturation of canine oocytes.

• Grant number: 11/13197-1
• Support Opportunities: Scholarships in Brazil - Master
• Start date: March 01, 2012
• End date: January 31, 2014
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Reproduction
• Principal Investigator: Maria Denise Lopes
• Grantee: Leda Maria Costa Pereira
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil

Abstract

Most protocols for oocyte maturation in vitro has shown poor results, ie, the oocytes remain in the germinal vesicle stage, regardless of culture conditions used. Among the most important proteins that regulate the mechanism of maturation are the MPF (maturation promoting factor) subunits composed of the cdk1 and cyclin B1 or p34cdc2. The acquisition of meiotic competence is associated with activation of p34cdc2 at the end of oocyte development, this protein plays a more central role in regulating the activation of MPF. Studies indicate that the activity of MPF is regulated by the spatial location and concentration of its subunits in the cell cytoplasm and that the activity of these proteins is shown in time-dependent maturation process. Thus, the study of proteins can collaborate with the establishment of an optimal period for in vitro maturation of canine oocytes. This study aims to evaluate the influence of oocytes from different stages of the estrous cycle in the diameter of oocytes in GV chromatin configuration, the competence of oocytes and to evaluate the kinetics of p34cdc2 kinase activity during in vitro maturation of oocytes canines in 24, 48 and 72 hours. Ovaries are collected from dogs considered healthy on clinical examination and various breeds, aged between 1 and 5 years, subject to ováriosalpingohisterectomia (OSH) elective. The ovaries are classified according to reproductive condition (luteal phase, follicular phase and anestrus). The oocytes will be selected based on the measurement of its diameter, and are used for in vitro maturation only oocytes with a diameter greater than 130 m m including the zona pellucida. Assessment of canine oocyte nuclear configuration will be performed before (0h) and after (72 h) maturation in vitro. The configuration of chromatin in VG will be determined using fluorescence microscopy based on the description of Chohan and Hunter (2003). The evaluation of the kinetics of p34cdc2 kinase activity will be performed by enzyme immunoassay (ELISA) at different times of maturation in vitro.

Academic Publications

(References retrieved automatically from State of São Paulo Research Institutions)

PEREIRA, Leda Maria Costa. Efeitos do diâmetro oocitário, configuração da cromatina em VG e avaliação da atividade quinase p34cdc2 na maturação in vitro de oócitos caninos. 2014. Master's Dissertation - Universidade Estadual Paulista (Unesp). Faculdade de Medicina Veterinária e Zootecnia. Botucatu Botucatu.