Influence of duodenogastric reflux in the gastric mucosa histological changes of rats infected with Helicobacter pylori Influência do refluxo duodenogastrico nas alterações histológicas da mucosa gástrica de ratos infectados com Helicobacter pylori

Objective: to evaluate the influence of Duodenal reflux in histological changes of the gastric mucosa of rats infected with Helicobacter pylori submitted to pyloroplasty. Methods: after two weeks of acclimation, we infected 30 male Wistar rats with Helicobacter pylori. We randomly divided them into three groups: one submitted to pyloroplasty, another to partial gastrectomy and the third, only infected, was not operated. After six months of surgery, euthanasia was carried out. Gastric fragments were studied by light microscopy to count the number of H. pylori, and to observe the histological changes (gastritis, metaplasia, dysplasia and neoplasia). We confirmed these changes by immunohistochemistry using the molecular markers PCNA and TGF-beta. Results: the animals submitted to pyloroplasty had higher percentage of colonization by H. pylori (median=58.5; gastrectomy=16.5; control=14.5). There was a positive correlation between the amount of H. pylori and the occurrence of chronic gastritis present in the antral fragments. Neoplasia occurred in 40% of rats from the group submitted to pyloroplasty. The staining with PCNA and TGF-ß confirmed the histopathological changes visualized by optical microscopy. Conclusions: the antral region was the one with the highest concentration of H. pylori, regardless of the group. There was a positive correlation between the appearance of benign disorders (chronic gastritis, metaplasia, dysplasia) and cancer in mice infected with H. pylori submitted to pyloroplasty.