[Experimental alkaline reflux esophagitis. Role of the refluxed material]

Alkaline reflux is new recognised to play an important place in gastroesophageal reflux disease. In order to investigate the role of refluxate in the development of esophagitis we have performed an experimental study in laboratory animals submitted to alkaline reflux inducing operations. We produced esophagitis in two experimental groups of Sprague-Dawley rats: group I, end-to-side esophagojejunostomy (EY) and group II, esophagojejunostomy with partial derivation of afferent loop by an omega-like conduit (EO) designed to attain lesser reflux. Group III consisted of sham laparotomized animals (L). RESULTS. At day 14, all the animals of experimental groups have developed esophagitis, but the macroscopic extent and histological grade in group EO (med: 27 mm; grade 2) were significantly lower than in group EY (med: 35 mm; grade 3). Biochemical measurements (med) in esophageal washout revealed: a) pH were alkaline in all groups with a decrease in experimental groups that was only significant in group EY; b) Amylase, lipase and bile acids in groups EY (8090; 498; 32) and EO (12840; 449; 50) were similar, but significantly more higher than in group L (920; 24; 0). The analysis of correlation between esophagitis parameters and biochemical measurements revealed no significant ones except for pH (r = -.437 and -.417). CONCLUSIONS. 1- The alternative model (EO) presents lesser grade and extent of esophagitis. 2) The refluxate was rich in bile acids and pancreatic enzymes what is proof of the actual occurrence of reflux and supports its determinant contribute to the development of esophagitis. 3) Esophagitis has developed at alkaline pH but with no alkalinity increase in the experimental groups what indicate that "alkaline reflux esophagitis" is not an appropriate denomination. 4) The discrepancy between the biochemical analysis in esophageal washout and the extent and grade of esophagitis suggests that others than the nature and amount of refluxate (e.g. mucosal resistance) could play a role in reflux esophagitis.