Respirometric reserve capacity of cumulus cell mitochondria correlates with oocyte maturity.

ABSTRACT

PURPOSE: Oocyte competence is critical in success of assisted reproduction. Metabolic signaling between oocyte and cumulus cells within the cumulus-oocyte complex procure oocyte development. This study evaluated the relationship between respirometric activity of cumulus cells and maturity of corresponding oocytes. METHODS: In prospective cohort study, 20 women of age 28-42 undergoing IVF procedure were involved. To evaluate oocyte maturity, the cumulus cells from individual oocytes were assessed flow cytometrically by double labeling of cells with mitochondria specific dyes. The respirometric stress analysis using ATPase inhibitor oligomycin was applied to assess mitochondria metabolic abnormalities. RESULTS: The cumulus cells from each of 327 oocytes were analyzed. The respirometric index of cumulus cells (O'R) strongly correlates with maternal ovarian reserve, showing to be higher in patients with higher AMH (p < 0.0017). Cumulus cells from immature oocytes had severe mitochondria deficiency, i.e., low O'R, than those from mature oocytes (p < 0.02). No significant difference in respirometric capacity was found between cumulus cells associated with good vs poor-quality embryos. CONCLUSIONS: The oocyte maturity is potentially related to the mitochondria activity of cumulus cells.