AJP - Gastrointestinal and Liver Physiology, Vol 247, Issue 5 480-G485, Copyright © 1984 by American Physiological Society
Bile acid efflux precedes mucosal barrier disruption in the rabbit esophagus
E. J. Schweitzer, J. W. Harmon, B. L. Bass and S. Batzri
In a rabbit model of esophagitis, bile acids are one of the agents capable
of disrupting the normal esophageal mucosal barrier to diffusion. They are
of particular interest because they may play a central role in causing
reflux esophagitis, a major clinical problem. Bile acid efflux from the
lumen of the esophagus occurs when bile acids disrupt the normal esophageal
barrier. Whether this entry of bile acids into the mucosa is a critical
step in the pathophysiology of bile acid injury to the mucosa or a result
of the injury that is occurring by some other means is unknown. To
differentiate these two possibilities, the temporal relation between bile
acid efflux from the esophageal lumen and disruption of the mucosal barrier
was studied with an in vivo perfused model of esophagitis in anesthetized
New Zealand White rabbits. Solutions containing taurocholic acid or
chenodeoxycholic acid at pH 2 or 7 were perfused for 4 h while bile acid,
hydrogen ion, glucose, and erythritol flux rates were measured. In each
case in which the bile acid caused barrier disruption, the highest rate of
bile acid efflux occurred during the 1st h of perfusion. In contrast, the
increase in flux rates of hydrogen ion, glucose, and erythritol, indicators
of mucosal barrier disruption, were the highest during the 2nd or 3rd h of
exposure. These data suggest that entry of bile acids into the esophageal
mucosa is a cause rather than an effect of the bile-induced increase in
mucosal permeability.
