The effects of melatonin on postoperative intraabdominal adhesion formation

Abstract

Purpose: Postoperative intraabdominal adhesion formation is a major clinical problem. No previous study was found, reporting the relationship between adhesion formation and melatonin administration, but melatonin, a strong antioxidant, is recognized to have certain effects on the progression of adhesion formation mechanism. It was therefore decided to investigate the effects of melatonin on postoperative adhesion formation.

Materials and methods: A total number of 24 Sprague-Dawley rats were utilized. Three groups, described as: Group A, sham laparatomy (n=8), Group B, rats that underwent only ischemia-reperfusion (n=8) and Group C, rats that underwent ischemia- reperfusion and were given 10 mg/kg melatonin solution i.v. (n=8). For Groups B and C, the ileocolic vessels were clamped. Blood glutathione peroxidase levels of all study groups were assessed, then microscopic and macroscopic adhesion scores were evaluated.

Results: Glutathione peroxidase levels of the melatonin-treated group were significantly higher and fibroblast proliferation and macroscopic adhesion scores were significantly lower, than in the melatonin-free group.

Conclusion: The results of this study supported the hypothesis, that melatonin administration may prevent intraabdominal adhesions resulting from surgery.

Fig. 1

Current hypothesis of adhesion formation (from Holmdahl et al.6).

Fig. 2

An area of the fibrous band and/or peritoneum. H & E stain (original magnification 100 ×). (A) Microscopic view of a subject from the ischemia-reperfusion group. (B) Microscopic view of a subject in which ischemia-reperfusion was established after melatonin administration. Significant fibroblast proliferation was observed in A compared to B.