Development of Experimental Peritoneal Adhesion in Rats and Its Prevention

Choi, Kyung Hyun; Lee, Sang Ho; Park, Yong Rai; Seo, Kyung Ho

Abstract

Peritoneal adhesion is one of the most common cause of intestinal obstruction in most parts of the world. In 1989, Thompson and others proposed reduced peritoneal plasminogen activating activity as a possible mechanism of adhesion formation. We used adult Sprague-Dawley rats weighing between 250~350 gm of both sexes. An ether jar was used to induce anesthesia, and a 15 to 20 mg intramuscular injection of ketamine into the hind leg was used to maintain anesthesia. The rat was fixed supine on a rat board, its midabdomen shaved, and povidone-iodine applied. Then the abdomen was opened using Metzenbaum scissors and 2.5 2.5 cm2 area of the parietal peritoneum was abraded in the flank area, left or right side, using sterilized electro-surgical tip cleaner until the preperitoneal fat layer was completely destroyed and blood ooze was emitted from the burst capillaries. The procedure lasted 2~3 minutes. Then, the animals were randomly selected either to apply topically one cc of saline as a control group or to apply drugs dissolved in one cc of saline as on experimental groups. The drugs were disodium cromolycate, verapamil, and urokinase. Disodium cromolycate was used 3 mg/animal, verpamil 0.5 mg, and urokinase 2,000 units/on the animal. The same drugs and the same amounts were used at the same site topically on the 2nd and the 3rd postoperative days without anesthesia by using smooth-tipped needle. Then the animals were examined on the 7th postoperative day under ether anesthesia to find adhesion formations and to grade them into no adhesion, mild, moderate, or severe adhesions according to severity of the adhesions. We used about 15 animals in each group. The results for the peritoneal adhesions were expressed as present or not present to compare the presence of adhesion between the control group and the study groups. The Chi-square test was used, and p values below 0.05 were regarded as significant. In the control rats, there were no adhesions in 3 animals, and adhesions in 12 animals. In the disodium cromolycate-treated groups, there were no adhesions in 8 and adhesions in 8 rats, indicating less frequent adhesion formation, but the p value was 0.081. In the verapamil group, the ratio of no adhesion to adhesion was 4 : 11 which was almost the same as that of the control group(p=0.666). However, in the urokinase group, the ratio was 8 : 6 and the p value was 0.039, so the effects are ignificantly different. With these result, we can conclude that intraperitoneal topical application of urokinase is effective in prevention of rat peritoneal adhesion formation. The effect of disodium cromolycate was only marginal. Verapamil was not effective in prevention of peritoneal adhesion in this study.