The effects of granulosa cell apoptosis on the developmental competence of bovine oocytes: A study using the well-in-well culture system

In the present study, we succeed to establish the well in the well (WIW) oocyte/embryo culture system. Under this system we studied the effect of granulosa cell apoptosis on oocyte developmental competence. The results show that the hatching rates of blastocysts did not differ (P > 0.05) between oocytes cultured in the WIW system (13 %) and those cultured in the group system (16%). In 4-8mm follicles, oocyte developmental competence is higher (P <; 0.05) in early atretic follicles (percentage of apoptosis 10-40%) than in the non-atretic follicles (percentage of apoptosis <;10%) or in the late atretic follicles (percentage of apoptosis >40%). But in 2-3mm follicles, even though in early atretic follicles the developmental competence of oocyte is also poor (P >0.05). It was indicated that the granulosa cell apoptosis affected the oocyte developmental competence significantly.