Proceedings of the Physiological Society, 20‐21 September 1991, Dublin Meeting: Communications

Abstract

No simple experimental model exists for chronic pancreatitis in the rodent. Inducing a reproducible acute necrotizing pancreatitis in the rat using intraperitoneal arginine has been only recently described (Tani et al. 1990). This study investigates the role of L-arginine in developing a model of chronic pancreatitis.Fasting male Sprague-Dawley rats (196-379 g) were divided into control (n = 10) and pancreatitis groups (n = 40). Each experimental animal received 500 mg/100 g of intraperitoneal L-arginine (Sigma) as a 20% solution in 0.15 M NaCI on days 1, 4, 7 and 10. Procedures were performed under ether anaesthesia.Each group then underwent serial assessment of pancreatic histology, serum amylase, weight, haemoglobin and white cell count with differential over a period of three months. At three months, plain abdominal X-rays were taken of each group.Although control animals had a 66% increase in weight, experimental animals gained only 25% (P < 0.01, Student's t test). Amylase levels increased from 8840 to 15918 i.u./l (Phadebas) in the acute phase, but were normal at three months. Haemoglobin dropped from 15.2 to 13.6 g/dl (P < 0.01) at one month but then returned to normal. Although the overall white cell count remained normal from day 1 to 14, the neutrophil count increased from 20.8% to 63.6% (P < 0.001). At three months the white count dropped from 18.2 to 12.8 x 109/l (P < 0.05) although the differential returned to normal. Fasting glucose levels remained normal at all times. Light microscopy showed marked acinar degeneration with replacement by adipose tissue. Ductal, vascular and connective tissue structure was well preserved, as were the islets of Langerhans. X-rays showed no evidence of pancreatic calcification.These data support L-arginine as a simple method of producing severe, nonresolving pancreatic damage. It is proposed as a new model of a chronic pancreatitis which warrants further investigation.