Abstract
Background: Ovarian surface epithelium (OSE) has the characteristics of a stem cell and the potential
for differentiation. Previous studies on this subject have succeeded in deriving oocytes
from OSE stem cells, leading to the belief that OSE could be used for infertility
treatment.
Methods: Each rat (n=10) was subjected to zinc and/or progesterone injection for 5 days after
conception. After a 6-day implantation period, ovarian tissues were removed and comprehensive
immunohistochemical analysis of stem cell markers was conducted: Sox2, Klf4, Oct3/4,
c-Myc, CD117, CD90, SSEA-1 and Notch pathway analysis; Notch1, Jagged1, and Delta1
in the OSE and ovarian stromal cells were evaluated after treatment with zinc, progesterone,
or both.
Results: Progesterone moderately affected Sox2 expression (p<0.001), while zinc application
strongly affected Klf4 and Oct3/4 and immunoreactivity (p<0.001). CD90 immunoreactivity
was decreased in the OSE and stroma of the progesterone group (p=0.006) compared with
the zinc (p = 0.244) and zinc/progesterone groups (p=0.910). On the other hand, SSEA-1
showed moderate staining in the OSE and weak staining in stromal cells in animals
treated with zinc (p=0.727), progesterone (p=0.626), and zinc/progesterone (p=0.371),
with no differences compared with control. Zinc application affected Notch pathway
immunoreactivity, with a significant increase in Notch1 (p=0.0015) and Jagged1 (p<0.001).
Conclusions: The expression of putative stem cell markers in the OSE was verified and stem cell
receptor activity was raised in the OSE and ovarian stromal cells by zinc and progesterone.
Thus, this increased expression allows the therapeutic use of zinc and progesterone
in ovary-related infertility and brings a different perspective to reproductive medicine.
Key words
stem cell - ovary - zinc - progesterone - infertility