Experimntal ulcers in the small intestine of rats

Part 1. The induction of ulcers in the rat small intestine and observations of the healing processes

Abstract

Male Sprgue-Dawley rats weighing about 200 g were used. For the induction of ulcers by laparotomy a catheter 1.7 mm in diameter was inserted directly into the intestinal lumen and hot water was flushed over the intestinal wall. As a result it was found that ulcers could be induced quite readily at any region of the intestine by this method, and the suitable temperature and amount of hot water proved to be 60°C-10 cc, 60°C-12 cc, 65°C-5 cc, and 80°C-3 cc.
The time required for complete healing of ulcers paralleled with the depth of ulcers; namely, the ulcers invading up to muscle layers healed within a month, and those reaching up to the serosa or penetrating further took more than two months. There were, however, a few cases that did not heal within 6 postoperative months.
Histological observations of these cases revealed regenerated villi and crypts to be irregular in the early stage but in the later stage smooth muscle cells reappeared in the stroma of the new villi and Paneth cells in the new crypts, showing a pattern of regenerated architecture bearing a close resemblance to the normal pattern.
The body weight of experimental rats with ulcers in the upper portion or in the terminal region of the small intestine increased normally up to 6 monhts, except for the first few days when there was a slight loss of weight.