Time of the first polar body extrusion influences the developmental competence of equine oocytes after ICSI

RODRIGUEZ, MB; GAMBINI, A; CLERICO, G.; YNSAURRALDE-RIVOLTA, AE; BRISKI, O; LARGEL, H; SANSINENA, M; SALAMONE D

REPRODUCTION FERTILITY AND DEVELOPMENT

CSIRO PUBLISHING

Lugar: Collingwood; Año: 2019 vol. 31 p. 1805 - 1811

1031-3613

Assisted reproduction techniques have become widespread in the equine breeding industry. Particularly, the combination of oocyte recovery from live mares followed by in vitro maturation (IVM) and intracytoplasmic sperm injection (ICSI) has remarkably increased among the advanced reproduction techniques applied to valuable or low fertility animals. There is currently no consensus regarding the optimal oocyte maturation period to produce high quality embryos. In this study, we report the maturation dynamics of equine oocytes from 20 h to 40 h (Experiment 1). Equine ICSI blastocysts were produced from oocytes that exhibited an early extrusion of the first polar body (PB): Group I, up to 24 h; or a late PB extrusion: Group II, 28 to 30 h (Experiment 2). Blastocyst rates and diameter were recorded; embryo quality assessed by the analysis of apoptotic cells and expression of YAP1. Results showed that 42% of oocytes were mature by 20 h of IVM, whereas the remaining oocytes matured within the following 17 hours of IVM. Although we found no differences in YAP1 or TUNEL+ cells between groups, oocytes from Experiment 1 exhibited an improved total cell number and blastocyst rate (18.60% vs 10.17%).