Profound Morphological Changes Following Ulceration in the Prostomach of Rats

Abstract

After finding that ulcers could be produced in the prostomach of rats by protein restriction or starvation (Hoelzel and DaCosta 1 ) our attention was directed toward determining whether such ulcers might become malignant. Marked overgrowths were seen early in ulcerated areas, but, as the work of Bullock and Rohdenburg 2 indicated, this is not a malignant change. Simple overgrowths were particularly prominent in the prostomach of rats in which ulceration was produced with diets high in fat and low in protein. This corresponds to the results obtained by Fujimaki and his coworkers, 3 except that these workers believed that they were dealing with cancerous changes due to disturbances in nutrition and independent of ulceration.

The first indication that the changes were like Fibirger's 4 came when a young rat died after 58 days on a diet of white bread. The prostomach showed numerous small nodular prominences on the outer surface. On the inner surface there was some ulceration but with only moderate overgrowth. Experiments were undertaken to produce similar or greater gross changes in other rats. Distinct single or multiple nodules were produced in the prostomach of 31 rats and somewhat vague nodules in 9 others. Considering only those rats with distinct nodules, only 2 occurred among about 200 rats on low protein diets for less than 40 days. Eight appeared among 79 rats on similar diets for 40 to 230 days, with or without starvation of less than 15 days. No distinct nodules were seen in any of 10 rats that died after single periods of starvation of from 15 to 20 consecutive days, but 3 out of 4 rats that died after starving from 26 to 29 days showed nodules.