Reduction of connexin 43 in human cumulus cells yields good embryo competence during ICSI.

PURPOSE: The purpose of this study was to predict developmental competence of human oocytes during ICSI via analysis of connexin 43 (Cx43) in cumulus cells surrounding mature oocytes. MATERIALS AND METHODS: Human cumulus cells were manually separated from the oocyte-cumulus complex under a microscope. Cx43 mRNA was expressed by real-time quantitative polymerase chain reaction (RT-PCR) measurement in cumulus cells. RESULTS: There was no significant relationship between expression of Cx43 and fertilisation or cleavage rate. However, Cx43 expression was lower in the good morphology group (blastomeres>7 cells with fragmentation<10% on day 3) when compared to the other groups (p=0.035). CONCLUSIONS: These results suggest that full reduction of Cx43 expression on cumulus cells at the time of oocyte collection during ICSI is essential for developmental competence of human oocytes.