PCO group control group 30 days after EV injection. A. Survey view showing atretic follicles (1), regressing old corpora lutea (2), and growing "healthy" follicles (3), ×4 obj. B. Detailed view of an atretic follicle with mainly degenerated granulosa cells and macrophages, ×60 obj. C. Part of early atresia in a secondary follicle (right) and interstitial cells (right), ×60 obj. D. Part of a growing secondary "healthy" follicle (right) and interstitial cells (left), ×60 obj.