Ginsenosides promote proliferation of cultured ovarian germ cells involving protein kinase C-mediated system in embryonic chickens

The effect of ginsenosides (GS) on germ cell proliferation was evaluated with a chicken ovarian germ-somatic cell coculture model and the mechanism involving protein kinase C (PKC) pathway was investigated. Ovarian cells were cultured in serum-free McCoy's 5A medium and challenged with GS alone or in combinations with PKC activator (phorbol 12-myristate 13-acetate, PMA) or inhibitor (H-7) for 48 h. The number of germ cells was counted and the proliferating cells were identified by immunocytochemistry of proliferating cell nuclear antigen (PCNA). Results showed that GS significantly increased germ cell proliferation and this stimulating effect was further increased by PMA, but inhibited by H-7, in a dose-dependent manner. Moreover, GS-elevated PCNA expression and the PCNA-labeling index of germ cells displayed similar changes with the increased numbers of germ cells. These results indicated that GS stimulated proliferation of ovarian germ cells with involvement of the PKC-mediated system.