The cumulus cell gene expression profile of oocytes with different nuclear maturity and potential for blastocyst formation

Purpose Gene expression in human ART cumulus cell (CC) has been related to oocyte maturity and competence but requires further validation. Expression dynamics were investigated in CC of oocytes at different maturational stages and with different developmental competence in a standard in vivo mouse superovulation model. Methods Quantitative PCR analysis of Has2 , Vcan , Sdc4 , Alcam , Grem1 , Ptgs1 and Ptgs2 in CC collected at regular time intervals from 0 to 24 h post hCG injection. Results Three expression patterns were observed each with strong regulation (4–230× differences). Immediately prior to ovulation CC of GVBD oocytes have 5× less Sdc4 and Ptgs1 and 5× more Ptgs2 when compared to the CC of freshly ovulated PB oocytes. When compared to the latter, the post-ovulatory aged PB oocytes had a 2× reduced blastocyst forming capacity and their CC expressed 2× more Sdc4 and 6× less Alcam . Conclusions Morphologically identical cumulus oocyte complexes with different developmental competence can be differentiated by CC gene expression.