Acute acid exposure increases rabbit esophageal cell proliferation

Area of Science:

• Gastroenterology
• Cell Biology
• Esophageal Physiology

Background:

• Esophageal mucosal injury can lead to cellular changes.
• The role of acid in esophageal cell proliferation requires further investigation.

Purpose of the Study:

• To determine if acute hydrochloric acid (HCl) infusion in rabbits increases esophageal cellular proliferation independently of visible cell injury.
• To investigate the temporal relationship between acid exposure, cell proliferation markers, and esophageal structural changes.

Main Methods:

• Infusion of 40 mmol/L HCl or normal saline (control) into the distal esophagus of rabbits for 1 hour.
• Assessment of cellular proliferation using bromodeoxyuridine (BrDu) labeling and ornithine decarboxylase (ODC) enzyme activity at 24 and 48 hours post-infusion.
• Histological examination for evidence of cell injury and measurement of rete peg prominence.

Main Results:

• A significant increase in BrDu-labeled basal cell nuclei (31% vs. 15% in controls) and threefold higher ODC enzyme activity were observed 24 hours after HCl infusion.
• No gross or microscopic evidence of cell necrosis or inflammation was present at 24 hours.
• Rete peg prominence significantly increased by 48 hours after acid infusion (22 vs. 4 per 100 microm in controls).

Conclusions:

• Acute esophageal acid exposure stimulates mucosal proliferation even in the absence of overt cell injury.
• Esophageal cell acidification may act as a direct or indirect mitogen, promoting cell division.
• These findings highlight a potential mechanism for esophageal changes following acid reflux events.