Leukocytes in the theca layers of preovulatory follicles in vehicle-treated rats, at 16:00 h in proestrus (A) and 01:30 h in estrus (B-F). A, B, ED1 immunostained macrophages (arrows) can be observed around preovulatory follicles. Neutrophils (C,D) and eosinophils (D-F) can be observed inside blood vessels (D) or extravassated (C,E,F). The ovarian surface epithelium (OSE) is indicated. Scale bar = 25 μm.