Cell turnover in normal cycling human ovary

Area of Science:

• Reproductive Biology
• Cellular Biology
• Gynecology

Background:

• Understanding cell turnover, including proliferation and apoptosis, is crucial for comprehending human ovarian function.
• The dynamic processes of follicular and luteal development involve complex cellular events that require detailed investigation.

Purpose of the Study:

• To investigate cell proliferation and apoptosis during various stages of human ovarian follicular and luteal development.
• To determine the significance of cell turnover in granulosa cells during folliculogenesis and luteogenesis.

Main Methods:

• Utilized immunostaining for Ki67 and PCNA to assess cell proliferation.
• Employed silver staining of nucleolar organizer regions (AgNORs) for proliferation assessment.
• Examined apoptosis using 3'-hydroxy nick-end labeling and Ley antigen immunostaining.

Main Results:

• Significantly increased labeling indexes for Ki67, PCNA, and AgNORs were observed in antral follicles.
• No significant differences in proliferation markers were found between dominant and nondominant follicles.
• Proliferation markers were predominantly observed in the functioning corpus luteum, not the degenerating corpus luteum.
• Apoptosis markers were rarely detected, except in scattered cells within the degenerating corpus luteum.

Conclusions:

• Granulosa cell transformation from quiescence to active growth is vital in early human folliculogenesis.
• Cell proliferation occurs during the luteal phase, specifically within the functioning corpus luteum.
• The low incidence of apoptosis suggests a slow process of follicular growth and atresia in human ovaries.