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

Reproductive Medicine and Biology 01/2010; 9(2):83-89. DOI: 10.1007/s12522-009-0043-8

ABSTRACT PurposeThe aim of this study is to determine the optimal culture period for meiotic maturation and developmental competence of invitro-grown
mouse oocytes.

MethodsEarly preantral follicles with diameter of 100–130μm were collected mechanically from day14 mouse ovaries and cultured for
8, 10, and 12days. 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.

ResultsThe follicular diameter increased significantly from days4 to 10, and the diameter of day12 oocytes was significantly larger
than day8 or earlier oocytes. Chromatin configuration around the nucleolus was transformed from “nonsurrounded (immature)”
to “surrounded (mature)” after 10days. Furthermore, MII rate of day10 and 12 oocytes was significantly higher than that
of day8 oocytes. The blastocyst rate of day10 oocytes was higher than that of day8 or 12 oocytes. The blastocyst apoptotic
rate of day12 oocytes was higher than that of day10 oocytes.

ConclusionsLong culture periods of invitro-grown oocytes affect meiotic maturation, developmental competence to blastocysts, and apoptosis.

KeywordsApoptosis-Culture period-Invitro growth-Mouse-Preantral follicle

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