Determination of granular cell apoptosis by Annexin-V/propidium iodide (PI) staining A: before freezing; B: immediately after thawing; C: after thawing and culturing for 24 h. In the VEGF pretreated group, increases in the proportions of late apoptotic cells [Annexin-V (+)/PI (+)] were significantly lower in the un-pretreated control immediately after thawing (***p < 0.05), and reductions in the proportions of viable cells [Annexin-V (−)/PI (−)] (*p < 0.05) and increases in the proportions of early apoptotic cells [Annexin-V (+)/PI (−)] were significantly lower after culturing for 24 h (**p < 0.05) [81].