Pancreatic atrophy: a new model using serial intra-peritoneal injections of L-arginine.

No simple rat model for chronic pancreatitis exists at present. A single dose of arginine has recently been shown to induce acute pancreatitis in rats. This study was designed to assess whether serial injections of arginine would induce reproducible chronic pancreatic damage. Forty rats received an intra-peritoneal injection of 500 mg per 100 g body weight of L-arginine followed by three injections of 250 mg per 100 g over 10 days. The rats were killed 24 h after each injection and at intervals of up to 6 months. Serum amylase levels were increased in the acute phase only. Examination of the pancreas at 24 h showed a severe oedematous pancreatitis. By day 5 there was up to 90% acinar destruction with adipose tissue replacement, although ductal, vascular, and islet cells appeared undamaged. These changes were present 6 months after injection. This is proposed as a new, simple, and reproducible method of inducing chronic pancreatic damage in the rat.