Effect of cumulus cell mass and follicle quality on in-vitro maturation of cynomolgus monkey oocytes.
Cynomolgus monkey oocytes were recovered from healthy or atretic follicles greater than 1000 micron in diameter at day 8 of gonadotrophin stimulated cycles and cultured in vitro, cumulus enclosed or cumulus free, for 2 days. Germinal vesicle breakdown (GVBD) occurred in 26.7% of healthy cumulus enclosed oocytes (n = 60) compared to 52.6% of atretic cumulus enclosed oocytes (n = 38). The mechanical removal of the cumulus cell mass increased the GVBD rate of the healthy oocytes (56.5%, n = 23) and accelerated the passage of the atretic oocytes (n = 23) from metaphase I (4.3%) to metaphase II (47.8%). In the healthy primate follicle, the dictyate stage could be maintained by an inhibitory substance secreted by the cumulus; follicular atresia could either decrease the synthesis of this substance and/or induce the metabolism of a stimulatory substance.
Lefèvre
B
B
INSERM Unité 187, Clamart, France.
Gougeon
A
A
Peronny
H
H
Testart
J
J
D000818:Animals; D002478:Cells, Cultured; D005260:Female; D008252:Macaca fascicularis; D009865:Oocytes / Q000254:growth & development*; D006080:Ovarian Follicle / Q000502:physiology*