Lipid solubilization during bile salt-induced esophageal mucosal barrier disruption in the rabbit

Bile salts in the gastric contents are one of the harmful agents that may contribute to the mucosal injury found in clinical reflux esophagitis. To clarify the mechanism by which bile salts can injure the esophageal mucosa, we studied the effects of exposure to the bile salts taurocholate and deoxycholate in an in vivo perfused rabbit model of esophagitis. Specifically we examined the roles of accumulation of bile salt by the mucosa and solubilization of mucosal lipid into the lumen during bile salt-induced mucosal injury. Results showed a consistent association between bile salt accumulation by the esophageal mucosa and bile salt-induced disruption of the physiologic barrier to diffusion. Under certain conditions, bile salts caused barrier disruption with no release of lipid from the mucosa. Whenever exposure to bile salt did cause release of mucosal lipid into the lumen, a significant amount of morphologic injury was also observed by light microscopy. The findings suggest that the presence of bile salt in the mucosa is an important aspect of the mechanism of bile salt-induced barrier disruption. Solubilization of mucosal lipids into the lumen occurs when bile salts cause an injury that is severe enough to result in light microscopic evidence of morphologic damage.