[Carcinogenesis effects of gastric and duodenal refluxate on esophageal mucosa]

To investigate the effects of different refluxant on esophageal carcinogenesis in rats.

The animal models of gastroesophageal reflux (G), duodenoesophageal reflux (D) and duodenogastroesophageal reflux (DG) and no reflux as control (C) were made by operations. The rats in all of the groups were given carcinogen (methyl-n-amyl nitrosamine, MANA). They were killed at 4, 20, 26, 40-week, then their esophagi were taken to the morphologic study and the expression of p53, cyclinD(1), CDK(4) studied with immunohistochemical studies.

At 4-week without carcinogen, most of rats in reflux groups displayed evidence of esophageal mucosal injury. The degree of mucosal injury in D group was greater than that in DG which was greater than that in G; and became severity with the time. At 40 weeks, the incidences of papillomas in group D, DG, G were 94.7%, 95.2%, 70.5%, respectively. All of them compared to the group C (38.5%) were significant difference. Only in both D and DG group, there were 24 with esophageal columnar metaplasia, 20 with dysplasia and 11 with cancer. The overexpression of p53, CDK(4), cyclin D(1) was seen in D and DG groups, while in G group, the overexpression of p53 and cyclin D(1) were seen only.

Both of gastric juice and duodenal contents reflux can promote tumourgenesis of MANA on esophagi by changing the expression of cell cycle-related protein. The effect of duodenal contents is stronger. It may play an important role in tumourgenesis of gastroesophageal reflux disease.