Cerulein pancreatitis is similar to human edematous pancreatitis, manifesting with dysregulation of digestive enzyme production and cytoplasmic vacuolization, the death of acinar cells, edema formation, and infiltration of inflammatory cells into the pancreas. Reactive oxygen species are involved in nuclear factor-kappaB activation, cytokine expression, apoptosis and pathogenesis of pancreatitis. There is recent evidence that cerulein activates NADPH oxidase, which is a major source of reactive oxygen species during inflammation and apoptosis in pancreatic acinar cells. In addition, the Janus kinase/signal transducer and activator of transcription pathway has been suggested as being involved in inflammatory signaling in the pancreas. This review discusses the involvement of oxidative stress in inflammation and apoptosis in pancreatic acinar cells stimulated with cerulein as an in vitro model of pancreatitis.
Acinar Cells ; Apoptosis ; Caerulein ; Cytoplasm ; Edema ; Humans ; Inflammation ; NADPH Oxidase ; Oxidative Stress ; Pancreas ; Pancreatitis ; Reactive Oxygen Species ; Transducers

BACKGROUND/AIMS: Heat shock proteins (HSPs) protect rats from cerulein-induced acute pancreatitis (AP) by preventing the subcellular redistribution of cathepsin B and the activation of trypsinogen. Autophagy plays a critical role in the secretion of digestive enzymes and triggering of cerulein-induced AP via the colocalization of trypsinogen and lysosomes. Therefore, using a rat cerulein-induced AP model, we investigated whether HSPs prevent AP by regulating autophagy. METHODS: Twelve hours after fed standard laboratory chow and water, the experimental groups (cerulein, water-immersion [WI]-cerulein and heat-shock [HS]-cerulein) and the control groups (control, WI, and HS) received one intraperitoneal injection of cerulein (50 microg/kg) or saline, respectively. All of the rats were sacrificed at 6 hours after injection. The severity of the AP was assessed based on the serum amylase level and the histological and electron microscopy findings. Western blotting was also performed for HSP60/70 and LC3B-II. RESULTS: WI and HS induced HSP60 and HSP70, respectively. The induced HSP60/70 effectively prevented the development of cerulein-induced AP. Autophagy developed in the rats with cerulein-induced AP and was documented by the expression of LC3-II and electron microscopy findings. The WI-stressed rats and HS-treated rats did not develop cerulein-induced autophagy. CONCLUSIONS: HSPs exert protective effects against cerulein-induced AP in rats by inhibiting autophagy.
Amylases ; Animals ; Autophagy ; Blotting, Western ; Caerulein ; Cathepsin B ; Heat-Shock Proteins ; Hot Temperature ; Injections, Intraperitoneal ; Lysosomes ; Microscopy, Electron ; Pancreatitis ; Rats ; Trypsinogen ; Water

Pancreatic polypeptie (PP) is released from the pancreas in response to vagal stimulation. Amongst other effects, PP has been reported to inhibit pancreatic exocrine function. Apart from any potential physiological role, such inhibition could have important consequences for in vitro studies of pancreatic function employing acetylcholine as a stimulus. We have therefore tested the effect of bovine PP on two in vitro pancreatic preparations: the incubated, uncinate pancreas of young rats and the perfused cat pancreas. In the former, PP (10(-10)-10(-8)M) had little or no effect on enzyme discharge or45Ca efflux under basal conditions or during stimulation with caerulein, CCK-PZ or acetylcholine. In the perfused cat pancreas, similar concentrations of PP were also without effect on fluid secretion evoked by secretin infusion, or enzyme discharge evoked by CCK-PZ injection or infusion. We conclude that bovine PP has no direct effects on the cellular mechanisms responsible for pancreatic electrolyte secretion or enzyme discharge in the species studied.
Acetylcholine/pharmacology ; Amylases/secretion* ; Animal ; Caerulein/pharmacology ; Calcium/metabolism* ; Cats ; Cholecystokinin/pharmacology ; Electrolytes/secretion* ; In Vitro ; Pancreas/drug effects ; Pancreas/metabolism* ; Pancreatic Polypeptide/pharmacology* ; Perfusion ; Rats ; Secretin/pharmacology

In the pathogenesis of pancreatitis, oxidative stress is involved in the activation of the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway and cytokine expression. High serum levels of cholecystokinin (CCK) have been reported in patients with acute pancreatitis, and treatment with cerulein, a CCK analogue, induces acute pancreatitis in a rodent model. Recent studies have shown that cerulein-activated nicotinamide adenine dinucleotide phosphate oxidase elicits reactive oxygen species, which trigger the phosphorylation of the JAK1, STAT1, and STAT3 proteins and induce the production of inflammatory cytokines, such as tumor necrosis factor-alpha, interleukin (IL)-1beta, and IL-6, in pancreatic acinar cells. The JAK/STAT pathway also stimulates cell proliferation and malignant transformation and inhibits apoptosis in the pancreas. This review discusses the possible role of the JAK/STAT pathway in the pathogenesis of pancreatitis and pancreatic cancer in response to oxidative stress.
Acinar Cells ; Apoptosis ; Caerulein ; Cell Proliferation ; Cholecystokinin ; Cytokines ; Humans ; Interleukin-6 ; Interleukins ; NADP ; Oxidative Stress ; Oxidoreductases ; Pancreas ; Pancreatic Neoplasms ; Pancreatitis ; Phosphorylation ; Reactive Oxygen Species ; Rodentia ; STAT3 Transcription Factor ; Transducers ; Tumor Necrosis Factor-alpha

An enhanced formation of nitric oxide(NO), due to the induction of inducible nitric oxide synthase(iNOS), has been implicated in the pathogenesis of shock and inflammation, but its role in acute pancreatitis still remains controversial. To clarify the role of NO in acute pancreatitis, the present experiment investigated the expression of iNOS and the effect of NOS inhibition on cerulein-induced pancreatitis in rats. Group I received intraperitoneal (ip) injection of normal saline. Group II received two ip injections of cerulein (20 microgram/kg). Group III received injections of N(G)-nitro-L-arginine methyl este(L-NAME) (30 mg/kg) with cerulein. Group IV received L-arginine(250 mg/kg) with cerulein and L-NAME. The expression of iNOS in the pancreas was examined by western blot analysis. The plasma concentration of NO metabolites was measured. The severity of pancreatitis was assessed by measuring serum amylase, pancreas water content and histopathological examination. Compared with controls, the cerulein group displayed significantly increased expression of iNOS and raised plasma NO metabolites. Treatment with L-NAME significantly decreased hyperamylasemia, plasma NO level, and the extent of pancreatic injury. Treatment with L-arginine reversed the effects of L-NAME. These findings suggest that an enhanced formation of NO by iNOS plays an important role in the development of acute pancreatitis, and inhibition of NO production has the beneficial effects in reducing pancreas injury.
Amylases/blood ; Animals ; Arginine/pharmacology ; Blotting, Western ; Caerulein/*pharmacology ; Enzyme Inhibitors/pharmacology ; Inflammation ; Male ; NG-Nitroarginine Methyl Ester/pharmacology ; Necrosis ; Nitric Oxide/metabolism/*physiology ; Nitric-Oxide Synthase/metabolism ; Pancreatitis/*chemically induced/*metabolism ; Rats ; Rats, Sprague-Dawley

BACKGROUND/AIMS: Cerulein pancreatitis is similar to human edematous pancreatitis with dysregulation of the production and secretion of digestive enzymes, edema formation, cytoplasmic vacuolization and the death of acinar cells. We hypothesized that membrane proteins may be altered as the early event during the induction of acute pancreatitis. Present study aims to determine the differentially expressed proteins in the membranes of cerulein-treated pancreatic acinar cells. METHODS: Pancreatic acinar AR42J cells were treated with 10(-8) M cerulein for 1 hour. Membrane proteins were isolated from the cells and separated by two-dimensional electrophoresis using pH gradients of 5-8. Membrane proteins were identified by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) analysis of the peptide digests. The differentially expressed proteins, whose expression levels were more or less than three-fold in cerulein-treated cells, were analyzed. RESULTS: Two differentially expressed proteins (mannan-binding lectin-associated serine protease-2, heat shock protein 60) were up-regulated while four proteins (protein disulfide isomerase, gamma-actin, isocitrate dehydrogenase 3, seven in absentia homolog 1A) were down-regulated by cerulein treatment in pancreatic acinar cells. These proteins are related to cell signaling, oxidative stress, and cytoskeleton arrangement. CONCLUSIONS: Oxidative stress may induce cerulein-induced cell injury and disturbances in defense mechanism in pancreatic acinar cells.
Acinar Cells ; Actins ; Caerulein ; Cytoplasm ; Cytoskeleton ; Edema ; Electrophoresis ; Heat-Shock Proteins ; Humans ; Isocitrate Dehydrogenase ; Isocitrates ; Mass Spectrometry ; Membrane Proteins ; Membranes ; Oxidative Stress ; Pancreatitis ; Protein Disulfide-Isomerases ; Proteins ; Proteome ; Proton-Motive Force ; Serine

Acute pancreatitis is a multifactorial disease associated with the premature activation of digestive enzymes. The genes expressed in pancreatic acinar cells determine the severity of the disease. The present study determined the differentially expressed genes in pancreatic acinar cells treated with cerulein as an in vitro model of acute pancreatitis. Pancreatic acinar AR42J cells were stimulated with 10(-8) M cerulein for 4 h, and genes with altered expression were identified using a cDNA microarray for 4,000 rat genes and validated by real-time PCR. These genes showed a 2.5-fold or higher increase with cerulein: lithostatin, guanylate cyclase, myosin light chain kinase 2, cathepsin C, progestin-induced protein, and pancreatic trypsin 2. Stathin 1 and ribosomal protein S13 showed a 2.5-fold or higher decreases in expression. Real-time PCR analysis showed time-dependent alterations of these genes. Using commercially available antibodies specific for guanylate cyclase, myosin light chain kinase 2, and cathepsin C, a time-dependent increase in these proteins were observed by Western blotting. Thus, disturbances in proliferation, differentiation, cytoskeleton arrangement, enzyme activity, and secretion may be underlying mechanisms of acute pancreatitis.
Acinar Cells ; Animals ; Antibodies ; Blotting, Western ; Caerulein ; Cathepsin C ; Cytoskeleton ; Gene Expression ; Guanylate Cyclase ; Lithostathine ; Myosin-Light-Chain Kinase ; Oligonucleotide Array Sequence Analysis ; Pancreatitis ; Proteins ; Rats ; Real-Time Polymerase Chain Reaction ; Ribosomal Proteins ; Trypsin

OBJECTIVETo explore the changes in hemorheology and expression of neutrophil adhesion molecules CD18 and CD62L in pancreatic microcirculation of Caerulein induced experimental acute pancreatitis (AP).

METHODSThe Wistar rats (n = 21) were randomized into three groups. The model of AP was established by subcutaneous injection of Caerulein. The changes of apparent viscosity of whole blood were measured by Low- shear 30 rheometer. The expression of adhesion molecules on the surface of neutrophil in duced by shear stress was used with stationary control. CD18 expression was increased on neutrophils treated with shear rate, and andanalyzed using flow cytometry.

RESULTSRat treated with Caerulein showed hyperamyleimia (t = 69.029, t = 79.734, P < 0.05). Blood viscosity of two AP groups were significantly elevated (0.512 s(-1): t = 10.725, t = 16.945; 5.96 s(-1): t = 12.781, t = 11.992, P < 0.05). Compared with stationary control, CD18 expression was increased on neutrophil treated with shear rate, and significantly induced with shear rate >/= 94.5 s(-1) (94.5 s(-1): t = 7.403, t = 13.323, t = 16.655; 128.5 s(-1): t = 10.092, t = 28.531, t = 24.563, P < 0.05). The expression of CD62L was less sensitive to low shear rate, and began to be down-regulated significantly when the shear rate >/= 94.5 s(-1) (94.5 s(-1): t = 10.687, t = 19.376, t = 12.848; 128.5 s(-1): t = 26.152, t = 48.402, t = 56.814, P < 0.05).

CONCLUSIONSThe changes of apparent viscosity of whole blood, and the effect of fluid shear stress on the expression of neutrophil adhesion molecules CD18, CD62L may play an important role in the pancreatic microcirculatory failure of acute pancreatitis.

OBJECTIVETo set up a convenient nontraumatic mouse model of severe acute pancreatitis(SAP).

METHODSMice received intraperitoneal injections with caerulein and lipopolysaccharide (LPS). Serum amylase and pancreatic moisture content were measured during experiment. The histo pathological changes of pancreas and relevant organs were observed under light microscope.

RESULTSSerum amylase and pancreatic moisture content increased and pancreatic interstitial edema, inflammatory cellular infiltration, parenchymal necrosis as well as parenchymal hemorrhages were happened in the caerulein plus LPS group, and the lesions of other organs including stomach, ileum, spleen, and lung were seen as well. In the careulein group, there was only pancreatic interstitial edema with no parenchmal necrosis or hemorrhage, and the rest organs were normal.

CONCLUSIONSThe SAP mouse model induced by caerulein plus LPS has the same pathological characteristics of human SAP, which can be used for human SAP studies.

Cerulein-induced pancreatitis is similar to human edematous pancreatitis, characterized by the dysregulation of digestive enzyme production, edema formation, and an infiltration of inflammatory cells into the pancreas. We previously showed that the Janus kinase 2 (JAK2)/STAT3 pathway mediates inflammatory signaling in cerulein-stimulated pancreatic acinar cells. PPAR-γ has been implicated in the regulation of inflammatory responses in several cells. In the present study, we investigated the role of PPAR-γ in cerulein-induced activation of JAK2/STAT3 in pancreatic acinar cells. Treatment with cerulein induced the activation of JAK2/STAT3 and PPAR-γ expression in AR42J cells. Cerulein-induced PPAR-γ expression was inhibited by AG490, a JAK2/STAT3 inhibitor, in AR42J cells. An immunoprecipitation analysis showed that PPAR-γ binds to STAT3 in cerulein-stimulated AR42J cells. Down-regulation of PPAR-γ by siRNA increased STAT3 phosphorylation in AR42J cells stimulated with cerulein. These results show that PPAR-γ inactivates STAT3 by directly interacting with STAT3 in cerulein-stimulated pancreatic acinar cells. Overexpression of PPAR-γ may be beneficial for preventing pancreatitis by suppressing the activation of STAT3 in pancreatic acinar cells.
Acinar Cells* ; Ceruletide ; Down-Regulation ; Edema ; Humans ; Immunoprecipitation ; Janus Kinase 2 ; Pancreas ; Pancreatitis ; Peroxisomes* ; Phosphorylation ; RNA, Small Interfering