Gastric DNA synthesis rate in different experimental models of duodenal reflux.

The aim of our investigation was to study the gastric mucosa DNA synthesis pattern in different experimental models of duodenal reflux. The following operations were performed on male Wistar rats: (A) sham-operation; (B) Roux-Y gastrectomy; (C) Billroth I; (D) Polya-type partial gastrectomy; (E) Billroth II; and (F) simple gastroenterostomy. Fifteen weeks later rats were sacrificed and histological and in vitro 3H thymidine autoradiographic studies were carried out. Gastric mucosal DNA synthesis rate was also estimated. Besides group A, all other groups showed variable degrees of gastritis mainly located at the anastomosis or at the gastrostomy suture line. Severe gastritis was not present in group B rats and most commonly occurred in group F rats. Group C, D, E and F showed an intense epithelial proliferation with a labeling index significantly higher than in the controls. However, mucosal DNA synthesis rate appeared to decrease with the progression of gastritis and in group F, the group more exposed to duodenal reflux, was significantly lower than in the controls. It is postulated that progressive exposure to duodenal reflux and secondary atrophic gastric changes following gastric surgery is accompanied by a reduction in the mucosal layer of the DNA synthesis rate, due to the loss of epithelial elements and the increase in connective and inflammatory elements, together with an enhanced turnover of the residual epithelial cells.