Article

Effect of preantral mouse follicle culture period on meiotic maturation and developmental competence of oocytes

Reproductive Medicine and Biology 06/2010; 9(2):83-89. DOI: 10.1007/s12522-009-0043-8

ABSTRACT

Purpose
The aim of this study is to determine the optimal culture period for meiotic maturation and developmental competence of in vitro-grown mouse oocytes.
Methods
Early preantral follicles with diameter of 100–130 μm were collected mechanically from day 14 mouse ovaries and cultured for 8, 10, and 12 days. The diameters of follicles and oocytes were measured, and chromatin configuration in oocytes was observed. We also examined meiotic maturation by human chorionic gonadotropin (hCG)/epidermal growth factor (EGF) stimulation, developmental competence of fertilized oocytes to blastocysts, and apoptosis in blastocysts.
Results
The follicular diameter increased significantly from days 4 to 10, and the diameter of day 12 oocytes was significantly larger than day 8 or earlier oocytes. Chromatin configuration around the nucleolus was transformed from “nonsurrounded (immature)” to “surrounded (mature)” after 10 days. Furthermore, MII rate of day 10 and 12 oocytes was significantly higher than that of day 8 oocytes. The blastocyst rate of day 10 oocytes was higher than that of day 8 or 12 oocytes. The blastocyst apoptotic rate of day 12 oocytes was higher than that of day 10 oocytes.
Conclusions
Long culture periods of in vitro-grown oocytes affect meiotic maturation, developmental competence to blastocysts, and apoptosis.

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Available from: Toshitaka Horiuchi, Mar 24, 2014
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