Cumulus contributions in timing of mouse oocytes maturation and developmental potential [electronic resource].

Includes reference.

A mandatory step in performing micromanipulation techniques, studying spermoocyte interactions after fertilization and evaluating morphological aspects of oocyte quality is the removal of cumulus cells from oocytes or zygotes at various stages. In mice, cumulus removal before maturation of oocytes in vitro inhibits sperm penetration rates. The aim of the study was to investigate timing of maturation and pronuclei formation and developmental competence of oocytes matured in vitro in the presence of loose cumulus cells. Germinal vesicle breakdown (2-3h) and timing extrusions of first polar bodies (9-13h) occurred approximately at the same time of the starting maturation regardless of the presence or absence of cumulus cells (+/-). Furthermore, timing extrusions of second polar bodies (1.30-2.45h) and pronuclei formation (3.30-4.30h) occurred from the starting fertilization at the same time (+/-). Cumulus cells increased markedly the cleavages and development of zygotes to the blastocyst stages upon activation.

Summary in Arabic.

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