[Enhancing effect of a high salt diet on gastrointestinal carcinogenesis]

Epidemiological studies have demonstrated an association of pathological conditions in the stomach with high intake of salted foods. Utilizing a two-step carcinogenesis model in rats treated with MNNG plus high salt diet as the initiator, we concluded the possible promoting effects of sodium chloride in gastric carcinogenesis and compared the results with the actions of other chemicals. Biological changes of the gastric mucosa were examined after chronic administration or a single oral intubation of NaCl. Morphological lesions observed included diffuse mild erosions, atrophy of the glands and hyperplasia of the foveolar epithelium when rats were given 10% NaCl diet chronically. Increased tritiated thymidine labeling index was evident in the pyloric and fundic mucosa after the oral administration of NaCl. These results suggest that NaCl exerts an enhancing effect at both initiation and promotion steps in the two stage model system applied, and that these effects of NaCl are related to its mucosal damaging activity.