Figure 1

H & E staining of human OSE cells prior and post culture. (A) Cell smear obtained after scraping OSE comprises of two distinct populations of stem cells, viz. small sized VSELs (asterix) and slightly larger OGSCs (arrowhead) with intensely Hematoxylin stained nuclei. These stem cells are spherical in shape with high nucleo-cytoplasmic ratio (B) Epithelial cells with abundant cytoplasm and pale stained nuclei and RBCs are also visualized in the smears. Small clusters of cells with dark stained nuclei like the OGSCs are also observed in some fields. Similar observations were confirmed in OSE scrapings of sheep (Figure 2) (C) After 5 days in culture, OGSCs interspersed with few VSELs are visible. An increase in size and reduced nucleo-cytoplasmic ratio of the OGSCs is observed indicative of their growth and differentiation in vitro (D) After one week culture, small oocyte-like structures with abundant cytoplasm are observed (E-J) Larger oocyte-like structures are observed by the end of three weeks in culture in close vicinity of mesenchymal fibroblast cells. Small oocytes of 30–50 μm diameter attained a maximum size of 100 μm after three weeks of culture. Scale bar = 20 μm.