Objective　To establish a simple rat model of acute necrotizing pancreatitis (ANP) with typical pathological lesion and good stability.　Methods　One hundred rats were randomly divided into ANP group (group A) and control group (group C)

50 rats in each group. Rats in group C received normal saline. Rats in group A were intra-peritoneally injected with L-arginine (1.5 g/kg each time

3 times

at 1 h interval) at the concentration of 80 g/L to establish a rat ANP model. Changes in pancreatic pathology and serum amylase level were observed 6

12

24

48 and 72 h after last injection.　Results　The lobule and interstitial edema

mild and moderate inflammatory infiltration were observed respectively

6 and 12 h after establishment of the model. The acinar architecture was partially destroyed with focal necrosis and severe inflammatory infiltration

mass coagulation necrosis and acinar architecture were markedly disrupted 24 and 72 h after establishment of the model. The histopathological score for pancreas was higher in group A and in group C at different time points after establishment of the model (5.26±1.30 vs 0.67±0.52 at 6 h

6.83±1.2 vs 0.57±0.43 at 12 h

24th 7.43±1.40 vs 0.47±0.63 at 24 h

48th 8.27±1.10 vs 0.43±0.65 at 48 h

7.63±1.20 vs 0.67±0.52 at 72 h

P0.01). The serum amylase level was also higher in group A than in group C at different time points after establishment of the model (6 090±475 U/L vs 1 465±106 U/L at 6 h

19 975±962 U/L vs 1 535±157 U/L at 12 h

20 970±1 027 U/L vs 1 620±174 U/L at 24 h

48th 2 390±233 U/L vs 1 450±97 U/L at 48 h

1 680±205 U/L vs 1 560±162 U/L at 72 h

P0.05).　Conclusion　Intraperitoneal injection with excessive dose of L-arginine (three times at one-hour interval) can induce a simple and noninvasive rat ANP model with typical lesion and good stability.