Melatonin treatment is beneficial in pancreatic repair process after experimental acute pancreatitis

Current treatment options for acute pancreatitis are supportive and symptomatic. Due to lack of agents targeting the underlying pathophysiology a large amount of experimental work is going on to identify novel therapeutic agents. The present study was carried out to explore if melatonin can modulate the spontaneous regeneration process of the pancreas after experimentally induced acute pancreatitis. Rats were given two i.p. injections of l-arginine in a dose of 200 mg/100 g at an interval of 1 h for induction of pancreatitis. After this rats were randomly divided into three groups i.e. saline, CCK-8 and melatonin. Drug treatment was started 2 h after the last l-arginine injection and continued till the day of sacrifice. An additional only saline treated control group was included for comparison. Animals in each group were sacrificed at 24 h, days 3, 14 and 28 after pancreatitis induction for determination of biochemical parameters (serum amylase, lipase and IL-10 and pancreatic amylase, total proteins and nucleic acid content) and histological examination. For rate of DNA synthesis and immunohistochemical studies animals were sacrificed at day 3 and day 7. Melatonin treatment was found to be beneficial in acute pancreatitis. Severity of acute pancreatitis was significantly reduced in melatonin group. Nucleic acid content, rate of DNA synthesis, pancreatic proteins and pancreatic amylase content were significantly improved. Histopathological examination showed significantly lower total scores in melatonin group. Results of melatonin group were comparable to that of positive control, CCK-8 group. Thus melatonin treatment was found to promote the spontaneous regeneration process of pancreatic tissue.