Morphology of two layered preantral follicles embedded in 3 mg/ml HA gel or HA combined with extracellular matrix (ECM-HA) is depicted. (A,G) Follicles from both culture models 24 hours after embedding. Follicle morphology on Day 7 in HA gel alone (B-D) or in ECM-HA (H-J). HA- embedded follicles grew in a more spherical fashion, with an intact basement membrane and thecal cell (TH) layer. Antral cavity (AC) formation is clearly visible (arrow). Follicle morphology in ECM-HA was quite different from HA alone but a 3-D growth pattern was maintained. By Day 12 of culture (E-F and K-L), follicles in both HA and ECM-HA gels formed antrums (arrows). Magnification 40X (Day 1), 200X (Days 7 and 12).