Effect of melatonin on the severity of L-arginine-induced experimental acute pancreatitis in rats

Annamaria Szabolcs, Russel J. Reiter, Tamas Letoha, Peter Hegyi, Gabor Papai, Ilona Varga, Katalin Jarmay, Jozsef Kaszaki, Reka Sari, Zoltan Rakonczay, Janos Lonovics, Tamas Takacs

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Abstract

Aim: To determine the effect of melatonin pre- and post-treatment on the severity of L-arginine (L-Arg) -induced experimental pancreatitis in rats. Methods: Male Wistar rats (25) were divided into five groups. Tho se in group A received two injections of 3.2 g/kg body weight L-Arg i.p. at an interval of 1 h. In group MA, the rats were treated with 50 mg/kg body weight melatonin i.p. 30 min prior to L-Arg administration. In group AM, the rats received the same dose of melatonin 1 h after L-Arg was given. In group M, a single dose of melatonin was administered as described previously. In group C the control animals received physiological saline injections i.p. All rats were exsanguinated 24 h after the second L-Arg injection. Results: L-Arg administration caused severe necrotizing pancreatitis confirmed by the significant elevations in the serum amylase level, the pancreatic weight/body weight ratio (pw/bw), the pancreatic IL-6 content and the myeloperoxidase activity, relative to the control values. Elevation of the serum amylase level was significantly reduced in rats given melatonin following L-Arg compared to rats injected with L-Arg only. The activities of the pancreatic antioxidant enzymes (Cu/ Zn-superoxide dismutase (Cu/Zn-SOD) and catalase (CAT)) were significantly increased 24 h after pancreatitis induction. Melatonin given in advance of L-Arg significantly reduced the pancreatic CAT activity relative to that in the rats treated with L-Arg alone. In the liver, L-Arg significantly increased the lipid peroxidation level, and the glutathione peroxidase and Cu/Zn-SOD activities, whereas the Mn-SOD activity was reduced as compared to the control rats. Melatonin pre-treatment prevented these changes. Conclusion: Melatonin is an anti oxidant that is able to counteract some of the L-Arg-induced changes during acute pancreatitis, and may therefore be helpful in the supportive therapy of patients with acute necrotizing pancreatitis.

Original languageEnglish
Pages (from-to)251-258
Number of pages8
JournalWorld journal of gastroenterology
Volume12
Issue number2
DOIs
Publication statusPublished - Jan 14 2006

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Keywords

  • Acute pancreatitis
  • Melatonin
  • Scavengers

ASJC Scopus subject areas

  • Gastroenterology

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