Effects of bile acids and hydrogen ion on the fine structure of oesophageal epithelium.

Oesophageal mucosal biopsies were incubated in 20, 0, and 0.2mM solutions of cholic, chenodeoxycholic, ursodeoxycholic, and deoxycholic bile acids. Both conjugated and unconjugated bile acids were studied at pH 1 and 7 singly and in combination. Observations were also made using 0.1 N hydrochloric acid and human gastric juice at pH 1-3 and 7-8. After incubation for up to 15 minutes the mucosa was examined under transmission electron microscopy. We concluded that high and moderate concentration of all the common bile acids damaged the oesophagus irrespective of the pH, that low concentrations of bile acids were damaging only at high acid levels, and that damage to the epithelium did not occur when the pH of the gastric juice had been raised.