Effects of EC3-derived stable cell line expressing FGF2 (EC3F) as the feeder cells on the growth of enriched ovarian cell populations. 1.5 × 104 cells of enriched ovarian populations that were labelled with PKH26 were co-cultured on embryonic cell line 3 (EC3) or EC3F as feeder cells for 10 days at 28°C with an air atmosphere. (A) Morphology of cell aggregates after culture. The formation of cell aggregates was observed in all treatment groups after culture. Scale bar = 20 mm. (B) Growth of enriched ovarian cell populations. All ovarian cells proliferated after culture regardless of treatment groups but no significant difference in cell number was detected among treatment SD. (-F) indicates that recombinant human bFGF was removed from the culture media.