Experimental studies on the effect of shaking stress on the production of gastric ulceration of the rats.

의학과/박사[한글] [영문] Singer (1913) produced first experimental gastric ulcer in the rats. Then thereafter many investigators reported about the experimental gastric ulcers. The production of gastric ulceration in the rat by the acute stress of restraint was first demonstrated by Selye (1936 a. b.). Ulceration was produced by restraining rats by tying the fore and hind limbs together or by wrapping the rat in a towel for 24 hours. The signs of stress were indicated by thymus involution and adrenal enlargement. Many investigators investigated the factors involved in the productions of restraint ulcers (Bonfils et al. 1959,Brodie and Hanson 1960, Guth and Mendick 1964). Most of this work has involved acute restraint for from 4 to 24 hours and has resulted in mucosal ulceration of the glandular portion of the stomach. Rarely did the ulcerations involved the submucosa, and duodenal ulceration was not produced. The chronic restraint stress was studied by French et al. (1957), Sawrey et at. (1956), Brodie and Hansom (1960) and Guth and Mendick (1964). They produced superficial ulceration primarily of the gastric rumen in the rats. In contrast, French et al. (1954) produced deeper chronic ulceration not only of the stomach, but also of the duodenum in monkeys subjected to chronic stress, Brodie and Hanson (1960) reported that repeated periods of restraint, 18 hours a day increased the incidence and severity of gastric ulcers. Levrat and Lambert (1959) produced also gastric ulceration in the rat by the chronic stress of photic and mechanical excitation. Rats were placed in a cage moved back and forth by an electric motor and subjected to intermittent photic stimulation. Excitation was continued for several days, 23 hours out of 24, 80 Percent subjected to a motion with frequency of 120 to 130 Per minute for Periods of 5 to 17 days developed gastric ulcers. 20percent congestive gastritis. No ulcers were found in rats subjected to milder frequency, 80-90 per minute for 34 days. Ulceration occured all in glandular portion. Lee (1964) and Moon (1964) in this laboratory produced gastric ulceration in the rat by the chronic stress of mechanical excitation. The rats were placed in a cage moved back and forth by an electric shaker according to the method of Levrat-Lambert (1959). Only glandular mucosal damage was found in the rats subjected to a motion with a frequency of 183 to 293 par minute for 3 to 5 hours a day for several days. Forestomach ulcers were produced in the rats subjected to more severe frequency in addition to glandular mucosal damage. The purpose of this experiment is to clarify the extent of shaking stress to produce the ulceration of the forestomach and to know the mechanism of the production of the ulceration. Materials and Methods The apparently healthy female rats were used for this experiment. The rats were placed in cage moved back and forth by an electric Power with frequency of 189 to 240 Per minute 3 hours a day for 4 to 6 days. After the experiment was over the rats were sacrificed and the stomachs were investigated. Vitamin A and C were administered to know if vitamin A and C might have any effect on the production of forestomach ulceration. Results and Discussion First Experiment: Shaking stress with frequency of from 180 to 240 per minute was given to the rats 3 hours a day for 4 to 6 days. The results were as follows: 1. Macroscopic findings a. Bleeding: Usually bleeding was appeared as small spots, and sometimes brown black blood clots also appeared. There were found only at glandular portion. No bleeding was found at forestomach. b. Ulceration at glandular portion: No definite ulcer was found which could be identified macroscopically at glandular portion. If any, it was only small and superficial. c. Edema at forestomach portion: When shaking stress with frequency of 180 to 200 per minutew as given, edema on the mucus membrane of forestomach was appeared. The edema was round or elliptic. The center of the edema thickened and keratinized. d. Ulceration of forestomach: When shaking stress with frequency of 220 to 240 per minute was given, hyperplasia and ulceration of forestomach was produced. Ulceration seems to be made by fissure of keratinized mucus membrane. Second and Third Experiments: As the forestomach ulceration has connection with the hyperkeratosis, vitamin A and C were given to the rats subjected to the shaking stress with frequency of 240 per minute. Vitamin A and C had shown no inhibitic effect on the production of the ulceration. Shay et al. (1945) Produced forestomach ulceration in the rats by ligation of the Pylorus. He mentioned 3 types of ulcer in the rats. Type Ⅰ. Initially proliferative and secondarily ulcerative and this lesion develops primarily in the forestomach. Type Ⅱ. Ulcerative only, has been found in vitamin B^^l and other nutrients deficiency states. These lesions develop only in the glandular part of the stomach. They are present as hemorrhagic erosions. Type Ⅲ. Purely ulcerative, most predominently in the rumen. Shay rat's ulcer belongs to Type Ⅲ. Shay rat's ulcer was explained to be caused by the reduction of the mucus in the stomach tissue. The stomach tissue in such a state is easily attacked by the pepsin and by acid. Corticoids reduce forestomach ulceration but increase the production of ulceration in the glandular portion, corticoids increase the excretion of stomach but reduce the formation of mucus which are the cause of the production of the ulceration in the glandular portion. But because of antiphlogistic property, corticoids reduce the ulceration in the Shay rats. The forestomach ulceration by the shaking stress with frequency of 220 to 240 per minute in this experiment is quite different from Say rat's ulcer and it may belong to Type I which Shay et al. mentioned. Levrat and Lambert produced ulceration in the glandular portion by shaking stress and intermittent photic stimulation. The site of the ulcer produced by Levrat and Lambert is quite different from the site of the ulcer produced in this experiment. which seems to be quite strange when we think that our experiment is quite similar except we omitted intermittent photic stimulation. As there is no many experiments on this kind of ulceration, the mechanism of this ulceration is not Pet clear. The further study will be necessary. Summary 1. The forestomach ulceration was produced in the rats by the shaking stress. The formation of the ulcer was as follows: a. When the shaking stress with frequency of 180 per minute was given to the rats 3 hours a day for a week, edema on forestomach was found. b. When the frequency increased to 220 to 240 Per minute, in more than 50 Percent of the rats subjected to the shaking stress, hyperplasia, hyperkeratosis and ulceration on forestomach was found. At first edema appeared then developed hyperplasia and hyperkeratosis. When the hyperkeratic membrane was defected, ulcers were produced. 2. Vitamin A and C had no effect on the formation of the ulceration. 3. Ulceration in this experiment was compared with experiments by other investigators and the mechanism was discussed. Further experiments will be necessary to know the mechanism.restrictio