Intestinal metaplasia in experimental atrophic gastritis. Sucrase activity in the gastric mucosa of guinea-pigs after stomach irradiation

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.

The effects of ranitidine and cysteamine on intestinal metaplasia induced by X-irradiation in rats

The influence of ranitidine and cysteamine on intestinal metaplasia was examined in 7-month-old male Crj: CD (SD) rats. At the age of 5 weeks, the animals were treated with 10 Gy doses of X-rays at 3-day intervals up to a total of 20 Gy in the gastric region, and 6 months after irradiation, the rats received either ranitidine (0.02% in diet) or cysteamine (0.1% in drinking water) for 2 months. The incidence and number of intestinal metaplasia with alkaline phosphatase-positive foci in rats given X-rays and cysteamine (group 4) were significantly low compared with those in rats given X-rays and ranitidine (group 3) (p less than 0.01). In both the pyloric and the fundic gland mucosae, the average numbers of type C metaplasia (intestinal crypts with Paneth cells) and total numbers of metaplastic foci in rats of group 3 were much higher than those in group 4 (P less than 0.05). The present results showed that the occurrence of intestinal metaplasia was significantly increased after administration of ranitidine and decreased by cysteamine.

Inhibitory effect of prolonged administration of tetragastrin on experimentally induced intestinal metaplasia in Wistar rats

The effect of tetragastrin on the induction of intestinal metaplasia by intragastric administration of 5% NaOH solution was investigated in Wistar rats. The prolonged administration of tetragastrin in depot form from 1 week after NaOH treatment resulted in a significant increase in basal gastric acid secretion and a significant reduction in the incidence and number of intestinal metaplasia in experiment week 35. A histologic examination showed goblet cell metaplasia and intestinal metaplasia without Paneth cells in rats treated only with olive oil. Only goblet cell metaplasia was found in rats treated with tetragastrin. These results show that the prolonged administration of tetragastrin to rats after NaOH treatment increases gastric acid secretion and suppresses the induction of intestinal metaplasia.

The induction of intestinal metaplasia in rats by pyloroplasty or pyloroplasty plus vagotomy

The influence of increased gastric pH on induction of intestinal metaplasia in the stomach of male JCL/SD rats was examined following surgical procedures of pyloroplasty or pyloroplasty and vagotomy. Twelve months after pyloroplasty plus vagotomy serum gastric concentrations were significantly higher (group II) than in rats receiving only pyloroplasty (group I) or in sham operated animals (group III). Additionally, trehalase activity was also higher in group II than in groups I and III. The incidence of intestinal metaplasia was significantly higher in groups I and II compared with the sham operated control animals (group III). This study indicates that intestinal metaplasia could be induced by surgical procedures such as pyloroplasty with or without vagotomy. Furthermore, elevation of the pH on gastric mucosa by such procedures may play a significant role in the subsequent development of metaplasia in the stomach.