Live Imaging Reveals the Link Between Decreased Glucose Uptake in Ovarian Cumulus Cells and Impaired Oocyte Quality in Female Diabetic Mice

Maternal diabetes has been demonstrated to adversely affect preimplantation embryo development and pregnancy outcomes. Emerging data suggest that these effects are associated with compromised oocyte quality. However, direct evidence of a pathway by which maternal diabetes exerts its effects on the oocyte is still lacking. Cumulus cells are metabolically coupled to oocytes, and bidirectional communication between them is essential for the development and functions of both compartments. The primary focus of this work was to evaluate the connection between glucose uptake in cumulus cells and oocyte quality in diabetic mice. This experiment has been difficult, because cumulus cells need to be separated from oocytes and labeled with isotope in the process of measuring glucose uptake. Here, we report a method for live imaging glucose transport in single cumulus-oocyte complexes using a fluorescent glucose analog (6-(N-(7-nitrobenz-2-oxa-1,3-diazol- 4-yl)amino)-6-deoxyglucose). By tracking the ATP content and spindle/chromosome status in individual oocytes surrounded by cumulus cells with differing glucose uptake activity, we reveal that compromised oocyte quality in diabetic mice is linked to decreased glucose uptake in cumulus cells.