Estrogen Enhances Esophageal Barrier Function by Potentiating Occludin Expression.

Area of Science:

• Gastroenterology
• Endocrinology
• Cell Biology

Background:

• Estrogen, a female sex hormone, was previously shown to suppress esophageal injury in a rat model.
• The exact mechanism by which estrogen influences gastro-esophageal reflux disease (GERD) progression remains unclear.

Purpose of the Study:

• To investigate the role of estrogen in maintaining esophageal barrier function.
• To elucidate the molecular mechanisms underlying estrogen's protective effects on the esophageal epithelium.

Main Methods:

• Male rabbits received 17β-estradiol or placebo for two weeks.
• Excised esophageal mucosa underwent Ussing chamber analysis with luminal irritants (HCl, sodium nitrite).
• Epithelial barrier function was assessed via transmembrane resistance and permeability; tight junction proteins (occludin, claudins) were analyzed by immunoblotting and electron microscopy.

Main Results:

• 17β-estradiol pre-treatment significantly reduced the decrease in transmembrane resistance and increase in permeability caused by irritants.
• Estrogen administration alleviated intercellular space dilation induced by HCl.
• Baseline occludin expression was significantly increased by 17β-estradiol.

Conclusions:

• This study provides the first evidence that 17β-estradiol administration enhances esophageal barrier function.
• The findings suggest that a lack of estrogen's protective effect may contribute to the higher incidence of erosive reflux esophagitis in males.