Fig. 2

Distinct developmental patterns of growing follicles exist in postnatal and adult ovaries. a Showing a comparable morphology of dormant primordial follicles (arrowheads) in the ovaries at 60 dpp and 7 dpp. DDX4, red; FOXL2, green. b Distinct developmental patterns of growing follicles exist in the postnatal and adult ovaries. With the increase of oocyte size (DDX4, red), major GCs (FOXL2, green) differentiated to a cuboidal state with the oocyte enlargement in the 60 dpp ovaries, whereas a dramatic retardation of GC development (arrows) was found in follicles at 7 dpp. c Counting the increase of GC number with oocyte enlargement showing different growth kinetics of the follicle growth in the ovaries at 60 dpp and 7 dpp. Showing the average number of GCs increased from 3 to 30 in the 60 dpp ovaries (n = 7), while just increased from 3 to 18 in 7 dpp (n = 7). Each dot showed the index of a single follicle. d The ratio of growing follicles with flattened preGCs, showing a large proportion of growing follicles at 7 dpp (red column) contained flattened preGCs (n = 4). e The model of distinct developmental patterns of follicle growth in the ovaries. Showing the differentiation and proliferation of GCs are the leading events of adult wave follicles, whereas the growth of oocytes initiates activation of first wave follicles. All experiments were repeated more than three times, and representative images are shown. Data are presented as the mean ± SD and analyzed by a two-tailed unpaired Student’s t-test, n.s. P ≥ 0.05, **P < 0.01 and *** P < 0.001. Scale bars, 20 μm