Influence of polyethylene glycol 4000 and dextran 70 on adhesion formation in rats

Studies on the prevention of peritoneal adhesions often address the impairment of adhesion formation by a special drug without any attempts to elucidate the working principles. In the present study PEG 4000 was compared with dextran 70 with respect to the influence on adhesion formation, inflammatory reaction, and collagen deposition. Adhesions were created in 30 rats by standardized crushing of the cecum. The animals were randomly allocated to 3 experimental groups receiving an intraabdominal instillation of 5 ml 20% PEG, dextran 70, or 0.9% NaCl. On Day 7 the adhesions were scored; additionally, the amount of leukocytes in the peritoneal cavity and the incorporation of collagen into the adhesion strands were determined. Administration of PEG resulted in a significant reduction of the adhesion score from 10.3 (NaCl) to 2.3, whereas dextran had no effect (score 11.0). This finding correlated with the leukocyte number which was reduced by 44% after PEG but was not affected by dextran. The collagen content of the adhesion strands was significantly decreased by PEG as well as by dextran when compared to the NaCl controls. In our model PEG was highly effective in the impairment of adhesion formation. The positive effect was mediated by a reduction of the inflammatory reaction which resulted in a decreased deposition of collagen into the adhesion strands.