Induction of intestinal metaplasia in the rat gastric mucosa by local X-irradiation.

Attempts were made to learn about an optimal condition for the induction of intestinal metaplasia in the gastric mucosa. The gastric region of 5-week-old female Wistar rats was irradiated with 500 rad of X-ray daily for 6 times (Group I) or with 1,000 rad of X-ray every two days for 3 times (Group III). In addition, the effect of immunization by allogeneic stomach antigen on the intestinalization was studied in rats irradiated with 500 rad of X-ray daily for 6 times (Group II). In a group of rats (Group II) injected with allogeneic stomach antigen and X-irradiated the process of intestinalization was more accelerated as compared to that in rats treated with X-ray (Group I). The similar results were obtained in rats irradiated with 1,000 rad of X-ray 3 times (Group II). Intestinal metaplasia developed more later in the fundic gland mucosa which became usually atrophic due to the loss of parietal cell mass. There was an intimate association among the parietal cell loss in the fundic gland, a rise in pH value and the development of intestinal metaplasia. In all groups, no case of gastric adenocarcinoma was detected during observation period up to 52nd week.