Figure 1. The effects of caffeine on the cumulus cells attaching and parthenogenetic activation during oocyte aging.

A. Fresh oocytes with full cumulus cells attached. B. Caffeine-treated aged oocytes for 24 hr with most cumulus cells attached. C. Oocytes aged for 24 hr in vitro with few cumulus cells attached. D. The activation of fresh oocytes, caffeine treated oocytes and oocytes aged in vitro after parthenogenetic activation. All graphs show mean ± s.e.m. Abbreviations used in this and all subsequent figures: CA, caffeine treated; IVA, in vitro aging. a-c: Values without a common letter in their superscripts differ significantly (P < 0.05). The black arrows indicate the unattached cumulus cells in aged COCs. Bar, 80 μm.