Fig. 7.

FSHR expression on cells obtained by scraping sheep ovary surface after FSH treatment in vitro. a Low magnification showing epithelial cells and stem cells in close vicinity with FSHR expression only on the stem cells. b Various fields were photographed to study stem cells division. Two distinct size of FSHR positive stem cells were visualized including slightly small VSELs (arrow) and bigger OSCs (asterix). Both asymmetric and symmetric cell divisions and germ cell nest-like structures (circled) were clearly visualized. Please note that both (a) and (b) are actually composites prepared by putting together various fields as these cells are spread far apart on the slides. c Stem cells are linearly arranged to understand their biology. (i) Small sized VSEL undergoes asymmetric cell division to give rise to slightly bigger OSCs which (ii) OSC (iii) undergo symmetric cell division (iv-v) and clonal expansion with incomplete cytokinesis to form a germ cell nest-like structure. Similar germ cell nest-like structures in adult ovary have been reported earlier also [6, 7]. d Representative confocal images showing FSHR expression on VSELs/OSCs/germ cell nest-like structure and negative control