Melatonin prevents peritoneal adhesions in rats.

BACKGROUND AND AIM: Intra-abdominal adhesions are important postoperative complications following abdominal surgery. The adhesions that develop form the basis of more advanced pathology such as intestinal obstruction or infertility. Melatonin is secreted from the pineal gland in a circadian pattern; this molecule has potent antioxidant characteristics and has beneficial effects in many models of inflammation. The aim of this study was to evaluate the effects of melatonin on peritoneal adhesions created in rats.

METHODS: A total of 28 Sprague-Dawley male rats were used and divided into four groups. In the first phase of the study, pinealectomy (PINX) was performed on half the animals. An incision was made and sutured in the cecum of all experimental animals in all groups 15 days after the PINX procedure. Some animals were given melatonin orally at a dose of 5 mg/kg daily following the adhesion operation and continued for 15 days. The rats were anesthetized and the abdomen opened after the 15th day (on day 30 of the study). After adhesion scoring based on macroscopic inspection, tissue samples were obtained from the sutured region of the cecum to measure malondialdehyde and hydroxyproline.

RESULTS: Peritoneal adhesion density was significantly higher in the PINX group compared to the control animals; exogenously administered melatonin significantly reduced adhesion formation. The degree of adhesion was also significantly lower in the intact rats given melatonin compared to the control group.

CONCLUSION: Antioxidant activity increases in the oxidative process. We conclude that melatonin may be an important molecule in preventing peritoneal adhesions.