Rat Model Of Acute Pancreatitis Research Articles

Tryptophan catabolites in mesenteric lymph may contribute to pancreatitis-associated organ failure

Multiple organ failure (MOF) is the key determinant of mortality in acute pancreatitis (AP). Mesenteric lymph cytotoxicity contributes to organ failure in experimental models of systemic inflammation. The aim of this study was to evaluate the mesenteric lymph pathway and the lymph injury proteome in experimental AP-associated MOF, and to test the hypothesis that immunoregulatory tryptophan catabolites contribute to mesenteric lymph cytotoxicity. Using an experimental model of AP in rats, the humoral component of mesenteric lymph in AP was compared with that from sham-operated control animals, using in vitro and in vivo cytotoxicity assays, high-throughput proteomics and high-performance liquid chromatography. The experimental findings were corroborated in a cohort of 34 patients with AP. Compared with biologically inactive lymph from sham-operated rats, mesenteric lymph in AP became cytotoxic 3 h after induction. Hierarchical clustering of lymph proteomic mass spectra predicted the biological behaviour of lymph. Levels of the immunoregulatory tryptophan catabolite, 3-hydroxykynurenine, were increased in cytotoxic lymph and re-created cytotoxicity in vitro. In humans with AP, plasma kynurenine concentrations correlated in real time with MOF scores and preceded a requirement for mechanical ventilation and haemodialysis. These results support the concept that mesenteric lymph-borne kynurenines may contribute to pancreatitis-associated MOF.

Blocking of monocyte chemoattractant protein-1 (MCP-1) activity attenuates the severity of acute pancreatitis in rats

Monocyte chemoattractant protein-1 (MCP-1) has been shown to affect the progression of various inflammatory disorders, including pancreatitis. To investigate the role of MCP-1 in acute pancreatitis and to seek possible therapeutic means, we evaluated the effect of a plasmid expression vector containing a dominant-negative mutant MCP-1 gene (mMCP-1). Two rat models of acute pancreatitis were employed that used either cerulein (for mild pancreatitis) or a mixture of 5% taurocholic acid and trypsin (for severe pancreatitis). At 6 h after induction of acute pancreatitis with or without injection of mMCP-1, serum amylase levels and cytokine levels, as well as morphological evaluation of the pancreas, were determined. Survival rates were also evaluated. Severe pancreatitis was significantly reduced by mMCP-1 injection. mMCP-1 decreased serum levels of amylase, IL-6, IL-10, and LDH, and improved the survival rate 48 h after disease onset. Histopathological changes of pancreas and lungs were also improved by mMCP-1. MCP-1 appears to be involved in the progression of severe forms of acute pancreatitis. Our data suggested that MCP-1 is a candidate as a therapeutic target to treat acute pancreatitis.

EFFECT OF PERITONEAL LAVAGE ON SYSTEMIC INFLAMMATORY RESPONSES IN RATS WITH ACUTE PANCREATITIS.

Introduction: Acute pancreatitis (AP) is characterized by release of proteolytic enzymes from the pancreas and activation of the inflammatory cytokine cascade that mediates the systemic manisfestations of the disease. In fact, the peritoneal exudate that develops during AP attacks has been found to contain a number of biologically active components which may be harmful to the patient. Aim: To investigate the effect of peritoneal lavage on the systemic inflammatory response in a rat model of severe AP. Methods: AP was induced in male Wistar rats by intraductal 5% taurocholate injection. Peritoneal lavage was carried out by infusion of 200 ml of warm (37 °C) 1.5% glucose-based peritoneal dialysis fluid at a constant flow (50 ml/h). Animals were divided in 2 groups: Group I (n = 16): Animals with AP not treated by peritoneal lavage Group II (n = 16): Animals with AP treated by peritoneal lavage immediately after the induction of AP. After 4 hours of AP induction serum levels of amylase, TNF-α, IL-6 and IL-10 were determined. Systemic lesions were analyzed by phosphorylation of liver mitochondria and pulmonary MPO determination. Results: A significant decrease of TNF-α (7 ± 5 vs 32 ± 10 pg/ml) and IL-6 (141 ± 26 vs 258 ± 46 pg/ml) plasma levels was observed in animals submitted to peritoneal lavage (GII) when compared to animals that did not receive peritoneal lavage (GI) (p < 0.05). Also, a significant increase of IL-10 (133 ± 44 vs 39 ± 8 pg/ml) plasma levels was observed in animals of GII when compared to GI (p < 0.05). The group receiving peritoneal lavage had a significant reduction of liver mitochondria dysfunction: RCR (2.47 ± 0.08 vs 2.25 ± 0.06) and respiration state 4 (39.01 ± 2.29 vs 48.54 ± 3.28 nmol O2/mg prot/min) when compared to group not treated with peritoneal lavage (p<0.05). There were no significant differences on plasma amylase levels and pulmonary MPO between both groups. Conclusion: These results indicate that peritoneal lavage attenuates the systemic inflammatory response by a reduction on plasma levels of TNF-α and IL-6, an increase of IL-10, and through a protective effect on uncoupling of mitochondrial oxidative phosphorylation in this model of experimental AP.

Acute Experimental Pancreatitis in Rats Is Ameliorated by Treatment with Pramlintide, a Synthetic Analogue of the β-Cell Hormone Amylin

Purpose: Acute pancreatitis is a common and major complication of endoscopic retrograde cholangiopancreatography (ERCP) and limits the use of this otherwise safe procedure. Antisecretory drugs such as somatostatin (SST) and its long-acting analogue octreotide, or protease inhibitors such as gabexate mesilate, have been tested as therapies for pharmacological prevention of post-ERCP pancreatitis, but uncertainty still exists over their clinical benefit. At physiologically relevant doses in animal models, the β-cell hormone amylin slows gastric emptying, inhibits gastric acid secretion and exocrine pancreatic secretion, and protects the gastric mucosa. The present study examined the effect of pramlintide (pram), a synthetic human amylin analogue, on prevention of caerulein-induced acute pancreatitis in anesthetized Sprague Dawley®TM (SD) rats. Methods: Saline, pram (300 μg/kg/h), SST (10 μg/kg bolus) or pram+SST in combination (N = 16, 5, 5, 6, respectively) was infused intravenously from 30 min before until 240 min after caerulein IP injection (10 μg/kg) into fasted, male, anesthetized SD rats (320–360 g). As an index of acute pancreatitis, plasma lipase and amylase were measured for up to 240 minutes after caerulein injection. Results: Following caerulein injection, plasma amylase increased 2.23-fold at 240 min in saline-treated controls compared to 1.40-, 1.61- and 1.51-fold in rats receiving pram, SST or the combination (P < 0.01, P < 0.04 and P < 0.01, respectively). Plasma lipase increased by 20.3-fold in the control saline group compared to 8.1-, 6.1- and 5.0-fold in pram, SST or combination groups (P < 0.02, P < 0.01 and P < 0.01, respectively). Although each was different from controls, there were no significant differences between SST, pram or pram+SST treatments in attenuating caerulein-induced increases in plasma amylase and lipase in this animal model of pancreatitis. Conclusion: Pramlintide ameliorated increases in pancreatic enzyme activity in this rat model of acute pancreatitis. Future studies are warranted to explore the potential use of pramlintide in the prevention of pancreatitis, which may occur during ERCP procedures. This research was funded in part by Amylin Pharmaceuticals, Inc., San Diego, CA.

Enterokinase induces severe necrosis and rapid mortality in cerulein pancreatitis: Characterization of a novel noninvasive rat model of necro-hemorrhagic pancreatitis

Unlike edematous pancreatitis, induction of severe necrotizing pancreatitis in rats generally requires an invasive laparotomy with infusion and/or ligation of the pancreatic duct or duodenal or arterial occlusion. The aim of this study was to establish and characterize a noninvasive model of severe acute pancreatitis in rats. Wistar rats were infused intravenously with cerulein or a combination of cerulein and enterokinase. Saline (154-mmol/L NaCl) or enterokinase only was infused in controls. In a first set of experiments, intrapancreatic protease activation and the release of cytokines were correlated with the severity of organ injury. Pancreatic and pulmonary injuries were determined at 6 h. In a second set of experiments, we assessed 24-h survival, serum parameters possibly reflecting the course of the disease, and morphologic changes later in the course of the disease. The severity of pancreatic injury and survival were correlated strongly with the amount of enterokinase infused simultaneously with cerulein. Trypsin as well as elastase and cathepsin B activity in pancreatic tissue samples were increased markedly in these animals. Marked pancreatic hemorrhage, necrosis, and leukocyte infiltration were present in animals with the greatest amounts of enterokinase infused. IL-6 and LDH, but not IL-1beta, CRP, and amylase, in serum correlated with the severity of pancreatitis. This noninvasive rat model of acute pancreatitis is characterized by major pancreatic necrosis, hemorrhage, and fatality. The simple and noninvasive induction technique may have advantages for future studies on inflammatory changes and sepsis in necrotizing pancreatitis compared with other currently available invasive models.

Modification of intestinal flora with multispecies probiotics reduces bacterial translocation and improves clinical course in a rat model of acute pancreatitis

Infection of pancreatic necrosis by gut bacteria is a major cause of morbidity and mortality in patients with severe acute pancreatitis. Use of prophylactic antibiotics remains controversial. The aim of this experiment was assess if modification of intestinal flora with specifically designed multispecies probiotics reduces bacterial translocation or improves outcome in a rat model of acute pancreatitis. Male Sprague-Dawley rats were allocated into 3 groups: (1) controls (sham-operated, no treatment), (2) pancreatitis and placebo, and (3) pancreatitis and probiotics. Acute pancreatitis was induced by intraductal glycodeoxycholate and intravenous cerulein infusion. Daily probiotics or placebo was administered intragastrically from 5 days prior until 7 days after induction of pancreatitis. Tissue and fluid samples were collected for microbiologic and quantitative real-time PCR analysis of bacterial translocation. Probiotics reduced duodenal bacterial overgrowth of potential pathogens (Log(10) colony-forming units [CFU]/g 5.0 +/- 0.7 [placebo] vs 3.5 +/- 0.3 CFU/g [probiotics], P < .05), resulting in reduced bacterial translocation to extraintestinal sites, including the pancreas (5.38 +/- 1.0 CFU/g [placebo] vs 3.1 +/- 0.5 CFU/g [probiotics], P < .05). Accordingly, health scores were better and late phase mortality was reduced: 27% (4/15, placebo) versus 0% (0/13, probiotics), respectively, P < .05. This experiment supports the hypothesis that modification of intestinal flora with multispecies probiotics results in reduced bacterial translocation, morbidity, and mortality in the course of experimental acute pancreatitis.

In Vitro and in Vivo Nuclear Factor-κB Inhibitory Effects of the Cell-Penetrating Penetratin Peptide

Penetratin is a cationic cell-penetrating peptide that has been frequently used for the intracellular delivery of polar bioactive compounds. Recent studies have just revealed the major role of polyanionic membrane proteoglycans and cholesterol-enriched lipid rafts in the uptake of the peptide. Both proteoglycans and lipid-rafts influence inflammatory processes by binding a wide array of proinflammatory mediators; thus, we decided to analyze the effect of penetratin on in vitro and in vivo inflammatory responses. Our in vitro luciferase gene assays demonstrated that penetratin decreased transcriptional activity of nuclear factor-kappaB (NF-kappaB) in tumor necrosis factor (TNF)-stimulated L929 fibroblasts and lipopolysaccharide-activated RAW 264.7 macrophages. Penetratin also inhibited TNF-induced intercellular adhesion molecule-1 expression in human endothelial HMEC-1 cells. Exogenous heparan sulfate abolished the in vitro NF-kappaB inhibitory effects of the peptide. Uptake experiments showed that penetratin was internalized by all of the above-mentioned cell lines in vitro and rapidly entered the cells of the lung and pancreas in vivo. In an in vivo rat model of acute pancreatitis, a disease induced by elevated activities of stress-responsive transcription factors like NF-kappaB, pretreatment with only 2 mg/kg penetratin attenuated the severity of pancreatic inflammation by interfering with IkappaB degradation and subsequent nuclear import of NF-kappaB, inhibiting the expression of proinflammatory genes and improving the monitored laboratory and histological parameters of pancreatitis and associated oxidative stress.

トリプシンとトリプシンレセプターの急性膵炎における役割

トリプシンとトリプシンレセプターの急性膵炎における役割

Proinflammatory Role of Trypsin and Protease-activated Receptor-2 in a Rat Model of Acute Pancreatitis

The pathophysiology of acute pancreatitis is strongly associated with autoactivation of trypsin. The biologic activity of trypsin on cells is attributed to the activation of protease-activated receptor-2 (PAR-2). We hypothesize that trypsin may activate acinar cells or inflammatory cells through PAR-2 signals in acute pancreatitis. We immunochemically analyzed the expression of PAR-2 in the rat acinar cell line, ARIP, and the rat pancreas, using anti-rat PAR-2 cleavage site (PCS) and anti-rat PAR-2 N-terminal fragment (PNF) antibodies. Plasma levels of PNF were determined. Furthermore, the effects of the anti-rat PCS antibody and nafamostat mesylate, a potent trypsin inhibitor, on PAR-2 activation during acute pancreatitis were also analyzed. ARIP cells expressed PAR-2, which was activated by exogenous trypsin activity. We also showed that PAR-2 is strongly expressed in pancreatic acinar and duct cells and that it is activated in rat cerulein-induced acute pancreatitis. The anti-rat PCS antibody and nafamostat mesylate reduced interleukin-6 and interferon gamma production and alleviated distant organ injury. These results suggest that trypsin and its specific receptor, PAR-2, play an important role in cytokine production and the resultant development of distant organ injury during rat acute pancreatitis.

Effect of resveratrol on activation of nuclear factor kappa-B and inflammatory factors in rat model of acute pancreatitis

To observe the effect of resveratrol on nuclear factor Kappa-B (NF-kappaB) activation and the inflammatory response in sodium taurocholate-induced pancreatitis in rats. Seventy-two male SD rats were randomly divided into three groups: sham operation group (control), severe acute pancreatitis (SAP) group, and severe acute pancreatitis group treated with resveratrol (RES). A SAP model was established by injecting 4% sodium taurocholate 1 mL/kg through puncturing the pancreatic duct. In Res group, Res was given at 30 mg/kg b.m. intraperitoneally after the SAP model was successfully established. Eight animals from each group were sacrificed at 3, 6 and 12 h after modeling. The expression of NF-kappaB activation of pancreas was detected by immunohistochemical staining, whereas the levels of TNF-alpha and IL-8 in pancreatic tissues were estimated by radioimmunoassay. The pathological changes of pancreas and lungs were examined microscopically. Much less hyperemia, edema, dust-colored necrotic focus and soaps were noticed in pancreas in RES group than in SAP group. In RES group, hemorrhage, exudates and infiltration of inflammatory cells in pancreas and interstitial edema, destruction of alveolar wall in lung were significantly less than in SAP group. In the SAP group, the activation of NF-kappaB in pancreatic tissues was enhanced significantly at any measure point compared with control group (64.23+/-10.72% vs 2.56+/-0.65%, 55.86+/-11.34% vs 2.32+/-0.42%, 36.23+/-2.30% vs 2.40+/-0.36%,P<0.01), TNF-alpha,IL-8 were also increased and reached their peak at 6 h and then declined. The activation of NF-kappaB and the levels of TNF-alpha and IL-8 in RES group were significantly lower than those in SAP group (P<0.01): activation (52.63+/-9.45% vs 64.23+/-10.72%, 40.52+/-8.40% vs 55.86+/-11.34%, 29.83+/-5.37% vs 36.23+/-2.30%), TNF-alpha (132.76+/-15.68 pg/mL vs 158.36+/-12.58 pg/mL, 220.32+/-23.57 pg/mL vs 247.67+/- 11.62 pg/mL, 175.68+/-18.43 pg/mL vs 197.35+/-12.57 pg/mL) and IL-8 (0.62+/-0.21 microg/L vs 0.83+/-0.10 microg/L, 1.10+/-0.124 microg/L vs 1.32+/-0.18 microg/L, 0.98+/-0.16 microg/L vs 1.27+/-0.23 microg/L). The activation of NF-kappaB is involved in the inflammatory response of rats with SAP. Resveratrol could effectively inhibit the expression of NF-kappaB activation, alleviate the severity of SAP through its anti-inflammatory effects and regulate the inflammatory mediators.

Expression of early growth response factor-1 in rats with cerulein-induced acute pancreatitis and its significance

To observe the expressions of early growth response factor-1 (Egr-1) and tissue factor (TF) in rats with cerulein-induced acute pancreatitis and to explore its significance. A large dose of cerulein was used to create the experimental acute pancreatitis model in rats. The changes of Egr-1 mRNA and protein in rats were observed during 30 min to 4 h after the treatment and immunohistochemical method was used to observe the localized expression of Egr-1 in tissues. In addition to the mRNA expression of Egr-1 target gene, TF was also observed. A blank control group, and a bombesin-administered group were used for comparison. After the stimulation of a large dose of cerulein, the rats showed typical inflammatory changes of acute pancreatitis. Thirty minutes after the stimulation, the mRNA expression of Egr-1 in the pancreatic tissue reached its peak and then declined, while the expression of Egr-1 protein reached its peak 2 h after the stimulation. Histologically, 2 h after the stimulation, almost all pancreatic acinar cells had the expression of Egr-1 protein, which was focused in the nuclei. The mRNA expression of TF occurred 1 h after the stimulation and gradually increased within 4 h. However, a large dose of bombesin only stimulated the pancreatic tissue to produce a little mRNA expression of Egr-1 and no mRNA expression of Egr-1 protein and TF. Egr-1 as a pro-inflammatory transcription factor may play an important role in the pathogenesis of acute pancreatitis by modulating the expression of TF.

Nitric oxide protects against pancreatic subcellular damage in acute pancreatitis.

Oxidative stress involvement in damage to the pancreas in acute pancreatitis (AP) is well documented. However, little is known about oxidative damage occurring in the different subcellular fractions of pancreatic cells. The aim of this study was to ascertain the main targets of oxidative damage inside cells after AP and the role of endogenous nitric oxide (NO) in it. A model of cerulein-induced AP in rats was used and N-nitro-l-arginine methyl ester (l-NAME) was administered as an NO production inhibitor. After pancreatitis induction, indicative parameters of lipid peroxidation and protein oxidation together with some enzymatic and nonenzymatic endogenous free radical scavengers were assessed in serum and pancreatic subcellular fractions. In pancreatitic rats, malondialdehyde and protein carbonyl group concentrations were significantly increased (P < 0.05) in serum and some fractions. The increases were higher in l-NAME-treated rats (P < 0.05). Superoxide dismutase and catalase activities were also increased (P < 0.05) but were decreased (P < 0.05) with l-NAME. The alpha-tocopherol concentration diminished (P < 0.05) in serum and all the studied subcellular fractions and the decrease was stronger in l-NAME-treated rats. Our data suggest that microsomes followed by lysosomal + mitochondrial are the fractions most susceptible to oxidative damage in AP. Endogenous NO plays a protective role against oxidative damage to subcellular fractions.

Inhibition of inducible nitric oxide synthase reduces bacterial translocation in a rat model of acute pancreatitis.

Translocation of bacteria from the gut into pancreatic necrosis is an important factor in the development of septic complications and mortality in acute pancreatitis. S-methylisothiourea (SMT) is an inducible nitric oxide synthase inhibitor that has been shown to decrease bacteria] translocation in sepsis and thermal injury. To investigate whether SMT could affect bacterial translocation in acute necrotizing pancreatitis. Forty-five Sprague-Dawley rats were studied. Acute pancreatitis was induced in Group I and Group II by injection of taurocholate and trypsin into the common biliopancreatic duct. Group III underwent laparotomy with the manipulation (but not cannulation) of the pancreas and received saline injection. Group I rats received normal saline as a placebo, and Group II rats received SMT after surgery for 2 days. At 48 hours, blood was drawn for serum amylase determinations. Bacterial translocation to mesenteric lymph nodes and distant sites (pancreas, liver, and peritoneum) were examined. A point scoring system of histologic features was used to evaluate the severity of pancreatitis. Plasma amylase levels and pancreatic histologic score were significantly reduced in Group II rats given SMT compared with those in Group I rats given saline (p < 0.01, p < 0.05, respectively). All Group I rats had bacterial translocation to mesenteric lymph nodes compared with 7 of 12 rats in Group II (p < 0.05). There was no difference in bacterial translocation to distant organs between the two groups, although rates tended to be lower in Group II compared with Group I (p > 0.05). Bacterial counts in the pancreas were significantly reduced in Group II rats compared with those in Group I rats (p < 0.05). Treatment with SMT appears to have ameliorated the course of acute pancreatitis; however, mortality was not affected.

Enteral nutrition prevents bacterial translocation but does not improve survival during acute pancreatitis.

To evaluate the effect of enteral nutrition (EN) in attenuating bacterial and/or endotoxin translocation, maintaining immune responsiveness, and improving outcome in early acute pancreatitis (AP) in Wistar male rats. Acute pancreatitis was induced in rats receiving total parenteral nutrition (TPN) (AP/TPN group) (n=34) and EN (AP/EN group) (n=35) by pressure injection of 1% deoxycholate into the biliopancreatic duct (0.6 mg/kg of body weight). Rats in the sham/TPN and sham/EN groups (n=10 each) underwent laparotomy without induction of AP. Catheters for TPN and EN were placed into the external jugular vein and jejunum, respectively. Rats were infused with Ringer lactate solution for 48 hours followed by TPN in the AP/TPN and sham/TPN groups, and EN in the AP/EN and sham/EN groups until day 7. The fluid volume and energy (calories) intake were similar in all groups. Medical school research laboratory. Survival, blood endotoxin level, villus height, 5-bromo-2'-deoxyuridine (BrdU) uptake in the jejunum and ileum, bacterial culture of mesenteric lymph nodes, and CD4/CD8 ratio of T cells in mesenteric lymph nodes, spleen, and peripheral blood. There was no difference in survival and pancreatic healing between the AP/TPN and AP/EN groups. Colony-forming units of the mesenteric lymph nodes and the endotoxin level were significantly lower in the AP/EN group than in the AP/TPN group (P<.05). Villus height and BrdU intake was significantly higher in the AP/EN group than in the AP/TPN group (P<.05). The CD4/CD8 ratio of T cells in spleen and peripheral blood was higher in the AP/EN group than in the AP/TPN group (P<.05), whereas there was no difference in mesenteric lymph nodes. Jejunal administration of EN is well tolerated in early AP, maintains immune responsiveness and gut integrity, and reduces bacterial and/or endotoxin translocation. However, compared with TPN, EN does not improve outcome. These results suggest that factors other than bacterial and/or endotoxin translocation may be responsible for mortality in this rat model of early AP. However, additional studies of both early bacterial and/or endotoxin translocation and late assessment of outcome are indicated.

Increased nitric oxide activity in a rat model of acute pancreatitis

Background—Overproduction of nitric oxide (NO) via induction of the inducible NO synthase (iNOS) is an important factor in the haemodynamic disturbances of several inflammatory states.Aims—To identify the role of NO...

Neutrophil behavior in pancreas and liver and the role of nitric oxide in rat acute pancreatitis.

The behavior of neutrophils in a rat acute pancreatitis model was observed in the pancreas and liver using fluorescence microscopy with an image analyzing system after labeling with a specific fluorescent reagent. Nonviable cells of both organs were also labeled and quantified. The role of nitric oxide in neutrophil accumulation and organ damage was estimated by administering a relatively selective inhibitor of constitutive nitric oxide synthase, N-nitro-L-arginine (L-NNA). The animal model of acute pancreatitis was induced by cerulein injection (80 mg/kg). Two groups were created, one given and the other not given L-NNA (2.5 mg/kg) prior to the induction of pancreatitis. The number of accumulated neutrophils in the pancreas and liver increased in a time-dependent manner. There was a close relation between the distribution of the neutrophils and inviable acinar cells or hepatocytes. When pretreated with L-NNA, the numbers of accumulated neutrophils and nonviable cells increased significantly in the pancreas. In the liver, a more pronounced accumulation of neutrophils was observed after treatment with L-NNA. Although hepatocyte injury was mild despite the neutrophil accumulation in the control, such injury was marked in the group treated with L-NNA. This suggests that neutrophils serve an important role in exacerbating acute pancreatitis and that nitric oxide provides a defense mechanism against neutrophil accumulation in pancreas and liver.

Calcium channel blockade inhibits release of TNF alpha and improves survival in a rat model of acute pancreatitis.

Tumor necrosis factor-alpha (TNF alpha) has been implicated as one of the numerous likely mediators of the systemic complications of acute pancreatitis. Recent suggestions that calcium (Ca2+) acts as a signal not only for TNF alpha release but also for TNF alpha action at distant sites led us to hypothesize that the calcium channel blocker diltiazem could inhibit TNF alpha release in acute pancreatitis, ameliorating the severity of the disease and improving overall survival. A rat model of acute pancreatitis induced by retrograde ductal infusion of bile was used for two experiments (n = 120). Experiment 1 was designed to determine the effects of calcium channel blockade using diltiazem on the severity of pancreatitis as measured by changes in biochemistry, pathology, and serum TNF alpha levels. In experiment 2, effects of calcium channel blockade on animal survival were measured over 72 h. Calcium channel blockade was associated with a significant reduction in serum TNF alpha levels as well as amelioration of pancreatitis by biochemical and pathological criteria. Overall survival from bile-induced pancreatitis was dramatically improved in rats pretreated with diltiazem (80%) compared to untreated animals (40%). Our data suggest that calcium channel blockade is associated with TNF alpha inhibition and improved outcome in a rat model of acute pancreatitis.

Studies of lymphocyte trafficking in a microvascular rat model of acute pancreatitis.

Studies of lymphocyte trafficking in a microvascular rat model of acute pancreatitis.

Morphogenesis of a canalicular-hypertensive model of pancreatitis

A rat model of acute pancreatitis is presented. Its conformity to the pancreatic changes during human pancreatitis is shown. The morphology of experimental pancreatitis development in rats is studied.

Stimulus secretion coupling and regeneration in various animal models of acute pancreatitis

Objective: The pathogenic steps in acute pancreatitis may depend on the aetiology of the disease. Thus, we studied various cellular functions in three rat models of acute pancreatitis. Methods: (a) Oedematous acute pancreatitis was induced by hyperstimulation with caerulein; (b) mild necrotizing pancreatitis by a 20 min ligation of the pancreatitic and bile duct combined with intravenous stimulation by secretin and caerulein, and intraperitoneal application of ethanol; (c) severe necrotizing pancreatitis by retrograde duct injection of sodium taurocholate. The pancreases were removed 6 h (a and c) or 24 h (b) later and isolated acini were prepared by collagenase digestion to measure secretagogue-stimulated amylase secretion and increases in intracellular calcium. Regeneration was determined by flow cytometric DNA analysis. Redistribution of cellular compartments was determined in homogenized pancreas by measuring amylase and cathespin B after various centrifugation steps. Results: Maximal cholecystokinin octapeptide (CCK-8)-stimulated amylase secretion was significantly decreased and occurred in all cases at 100 pmol/l CCK-8 (control, 17.5±1.9; a, 14.8±1.5; b, 12.0±1.6; c, 9.2±0.8). Sham operation with or without intraperitoneal ethanol application did not cause any alteration in secretion. In the three models, the dose-response curves of CCK-8-stimulated amylase secretion were slightly shifted to the right. CCK-8− and carbachoi-stimulated calcium increases were not altered in the two necrotizing forms of pancreatitis. However, despite measurable secretagogue-stimulated amylase secretion, there was no calcium increase in caerulein pancreatitis. Subcellular fractionation studies revealed a redistribution of cathespin B from the 12000 g to the 1300 g fraction in all models. With regard to regeneration, the G1 phase was significantly decreased in caerulein pancreatitis while G2 increased. Conclusion: Alterations in pancreatic acinar cell function in acute pancreatitis are very similar despite various aetiologies and degrees of severity.