Estrogenic in vitro assay on mouse embryonic Leydig cells

Area of Science:

• Reproductive Biology
• Endocrinology
• Toxicology

Background:

• Mouse embryonic testes contain somatic cells expressing estrogen receptor alpha (ERalpha).
• Estrogen signaling is crucial for mammalian reproductive development.
• Understanding early testicular responses to estrogens is vital for reproductive health.

Purpose of the Study:

• To provide evidence for direct estrogen effects on differentiating mammalian testes.
• To establish an in vitro culture and transfection method for ERalpha-expressing embryonic Leydig cells.
• To assess the functional genomic response of these cells to 17-beta estradiol and xenoestrogens.

Main Methods:

• Isolation and in vitro culture of ERalpha-expressing cells from 12.5 days post coitum mouse testes.
• Transfection with luciferase reporter plasmids containing estrogen responsive elements (ERE-Luc and AP-1-Luc).
• Treatment with 17-beta estradiol (E2), anti-estrogen ICI 182.780, xenoestrogens (lindane, BPA, DEHP), and phytoestrogen zeralenone.

Main Results:

• ERalpha-expressing cells were identified as embryonic Leydig cells via StAR immunopositivity.
• 17-beta estradiol significantly induced ERE-Luc activity in embryonic Leydig cells, an effect blocked by ICI 182.780.
• Embryonic Leydig cells showed ERE-Luc induction by xenoestrogens and zeralenone, but not AP-1-Luc stimulation.

Conclusions:

• Functional estrogen receptor alpha-dependent genomic pathways exist in embryonic Leydig cells.
• An in vitro assay using these cells can evaluate the activity of estrogenic compounds.
• This model is suitable for assessing potential endocrine disruptors during early testicular development.