Changes in the morphology of three cohorts of GCs during the in vitro culture period from 7 to 168 h were observed under a microscope (×400). Arrows indicate the irregularly shaped voids. “A/B/C” represents the GCs of pre-hierarchical, F4–F2, and F1 follicles respectively.

“F1 GCs” represents the GCs from the largest follicle (F1) and “F4–F2 GCs” represents the GCs from the fourth to the second largest follicles (F4–F2).