Figure 4

Maternal diabetes induces ER redistribution defects in MII oocytes. MII oocytes were labeled with ER Tracker Green to visualize ER localization. ER distribution patterns were evaluated using fluorescence microscopy. Equatorial (left) and cortical (middle) sections are shown. A, in MII oocytes, three distinct patterns of ER distribution in equatorial sections and two distribution patterns in cortical sections were detected: no labeling in the area assumed to be the meiotic spindle poles (left i), perinuclear distribution pattern (left ii), and small areas of ER fluorescence within the deeper cytoplasm (left iii); cortical cluster distribution pattern (middle i) and absence of cortical clusters (middle ii). B, quantitative analysis of oocytes with morphological abnormalities in control and diabetic mice. The numbers of oocytes scored were 45 pooled from 3 control mice and 39 pooled from 4 diabetic mice. Bar = 20 μm.