Indomethacin decreases carrageenan-induced peritoneal adhesions

For evaluation of a rat intra-abdominal adhesion model, 48 study rats were each given an intraperitoneal injection of 1 ml of 1.5% carrageenan solution and 48 control rats were each given 1 ml of sterile saline solution. Thereafter, 6 control and 6 study rats were killed on days 2, 3, 4, 5, 7, 9, 14, and 21 for assessment of the temporal nature of adhesion formation. No peritoneal reaction or adhesions occurred from saline solution. Carrageenan induced a generalized peritonitis between days 2 and 7. The frequency of adhesions from day 5 onward was 66%. The effects of celiotomy and of systemic indomethacin on carrageenan-induced adhesion formation were then examined. Rats underwent a standardized celiotomy and, on closure of the abdomen, received either an intraperitoneal injection of saline solution (n = 72) or an intraperitoneal injection of carrageenan solution (n = 96). Both groups were then randomized to receive either no indomethacin (IND-0), a single preoperative dose of indomethacin (IND-1), or four perioperative doses of indomethacin (IND-4). Then, 2, 5, 14, and 21 days later, rats from each group were killed, the extent of intraperitoneal adhesions was assessed, and the nature of any adhesions was histologically examined. Celiotomy plus intraperitoneal saline solution produced no adhesions. Celiotomy plus intraperitoneal carrageenan solution (IND-0) significantly increased adhesions to 83%. Preoperatively and perioperatively administered indomethacin significantly decreased the adhesion formation rate to 49%.