X-Ray fluorescence imaging and other analyses identify selenium and GPX1 as important in female reproductive function

Area of Science:

• Reproductive Biology
• Trace Element Metabolism
• Cellular Physiology

Background:

• Selenium (Se) is recognized as essential for fertility, but its precise role in female reproduction remains unclear.
• Understanding the localization and function of Se in ovarian tissues is crucial for reproductive health.

Purpose of the Study:

• To investigate the importance of Se in bovine female reproductive function.
• To determine the localization and expression of Se and related selenoproteins in ovarian follicles.

Main Methods:

• X-ray fluorescence (XRF) imaging to map elemental distribution in bovine ovaries.
• Inductively Coupled Plasma - Mass Spectrometry (ICP-MS) for quantitative Se analysis.
• Gene expression analysis (GPX1, GPX3, VIMP, SELM) and Western immunoblotting for protein detection in granulosa cells.
• Analysis of human cumulus cells from IVF patients.

Main Results:

• Se was consistently localized to the granulosa cell layer of large, healthy bovine follicles.
• Follicle walls showed tenfold higher Se concentrations than corpora lutea.
• The selenoprotein gene GPX1 was significantly upregulated in large, healthy bovine follicles and its protein was detected.
• GPX1 expression was also higher in human cumulus cells associated with successful pregnancies.

Conclusions:

• Selenium is specifically localized to granulosa cells in large, healthy ovarian follicles.
• Elevated levels of Se and the selenoprotein GPX1 suggest a critical antioxidant function during late follicular development.
• These findings highlight a potential mechanism for Se's role in female fertility.