Caerulein-induced Pancreatitis Research Articles

Loss of Ifnar1 in Pancreatic Acinar Cells Ameliorates the Disease Course of Acute Pancreatitis.

Type I interferon constitutes an essential component of the combinational therapy against viral disease. Acute pancreatitis is one side effect of type I interferon-based therapy, implying that activation of type I interferon signaling affects the homeostasis and integrity of pancreatic acinar cells. Here, we investigated the role of type I interferon signaling in pancreatic acinar cells using a caerulein-induced murine model of acute pancreatitis. Pancreas-specific ablation of interferon (alpha and beta) receptor 1 (Ifnar1) partially protected animals from caerulein-induced pancreatitis, as demonstrated by reduced tissue damage. Profiling of infiltrating immune cells revealed that this dampened tissue damage response correlated with the number of macrophages in the pancreas. Pharmacologic depletion of macrophages reversed the protective effect of Ifnar1 deficiency. Furthermore, expression of chemokine (C-C motif) ligand 2 (Ccl2), a potent factor for macrophage recruitment, was significantly increased in the Ifnar1-deficient pancreas. Thus, type I interferon signaling in pancreatic acinar cells controls pancreatic homeostasis by affecting the macrophage-mediated inflammatory response in the pancreas.

Cystathionine-gamma-lyase gene silencing with siRNA in monocytes/macrophages protects mice against acute pancreatitis.

Hydrogen sulphide (H2S) is an endogenous inflammatory mediator produced by cystathionine-γ-lyase (CSE) in monocytes/macrophages. To determine the role of H2S and macrophages in inflammation, we used small interference RNA (siRNA) to target the CSE gene and investigated its effect in a mouse model of acute pancreatitis. Acute pancreatitis is characterised by increased levels of plasma amylase, myeloperoxidase (MPO) activity and pro-inflammatory cytokines and chemokines in the pancreas and lung. SiRNA treatment attenuated inflammation in the pancreas and lungs of mice following caerulein-induced acute pancreatitis. MPO activity increased in caerulein-induced acute pancreatitis (16.21 ± 3.571 SD fold increase over control) and treatment with siRNA significantly reduced this (mean 3.555 ± 2.522 SD fold increase over control) (p < 0.0001). Similarly, lung MPO activity increased following treatment with caerulein (3.56 ± 0.941 SD fold increase over control) while siRNA treatment significantly reduced MPO activity (0.8243 ± 0.4353 SD fold increase over control) (p < 0.0001). Caerulein treatment increased plasma amylase activity (7094 ± 207U/l) and this significantly decreased following siRNA administration (5895 ± 115U/l) (p < 0.0001). Cytokine and chemokine levels in caerulein-induced acute pancreatitis reduced following treatment with siRNA. For example, siRNA treatment significantly decreased pancreatic and lung monocyte chemoattractant protein (MCP)-1 (169.8 ± 59.75 SD; 90.01 ± 46.97 SDpg/ml, respectively) compared to caerulein-treated mice (324.7 ± 103.9 SD; 222.8 ± 85.37 SDpg/ml, pancreas and lun,g respectively) (p < 0.0001). These findings show a crucial pro-inflammatory role for H2S synthesised by CSE in macrophages in acute pancreatitis and suggest CSE gene silencing with siRNA as a potential therapeutic approach for this condition.

Abstract PR01: Downregulation of PTF1A is a crucial and rate-limiting step in pancreatic cancer initiation

Abstract The goal of this study is to understand the endogenous mechanisms limiting the ability of oncogenic KRAS to initiate pancreatic tumorigenesis. Recently, our lab and others discovered that although pancreatic ductal adenocarcinoma (PDAC) shares phenotypic characteristics with normal pancreatic duct cells, it actually originates from mature exocrine acinar cells. In analyzing the initiating events of PDAC, we have identified the acinar cell transcription factor, PTF1A, as a critical factor inhibiting KRAS from reprogramming acinar cells to ductal tumor precursors. Binding sites for PTF1A are found upstream of essentially all acinar differentiation products and, importantly, PTF1A maintains its own expression through a positive autoregulatory loop. Given the central role of PTF1A in regulating acinar-specific gene expression, we wanted to determine if loss of this transcription factor plays a role in pancreatic intraepithelial neoplasia (PanIN) formation. Importantly, we find that PTF1A is downregulated in early (stage 1) PanINs of humans and mouse models, suggesting that loss of PTF1A expression could be a rate-limiting step in pancreatic cancer initiation. To test whether PTF1A loss is a functionally important step in PanIN development, we deleted the Ptf1a gene in mice using an acinar-specific inducible Cre (Ptf1a cKO). These studies confirm that PTF1A downregulation is an essential step in PanIN formation, as Cre-mediated deletion of acinar cell Ptf1a in the presence of oncogenic KRAS (KrasG12D) acutely and dramatically accelerates PanIN formation. Widespread PanINs are observed within two weeks of combined KRAS activation/Ptf1a deletion, by which time KRAS alone has induced few or no PanINs. At six weeks post-recombination, the combination of KRAS/Ptf1a cKO induces &amp;gt;15-fold more PanINs than KRAS alone. Additionally, we have found that Ptf1a heterozygosity sensitizes pancreatic cells to KRAS-mediated PanIN formation, indicating that transformation requires reduction of PTF1A activity below a critical autoregulatory threshold needed to maintain acinar identity. Based on these current studies, we hypothesize the existence of mutual antagonism between acinar differentiation, which is maintained through PTF1A, and transformation driven by KRAS. KRAS normally transforms acinar cells only weakly, but both endogenous and mutant KRAS activity can be increased by inflammation, such as that stimulated by caerulein-induced pancreatitis. As KRAS is potentiated by Ptf1a deletion, we asked whether inflammation would be sufficient to transform Ptf1a-deficient acinar cells even without mutant KRAS. In the absence of pancreatitis, Ptf1a deletion alone has relatively little short-term effect: Ptf1a-deficient acinar cells eventually lose their differentiated phenotype and express ductal markers, but they do not undergo hyperplasia or dysplasia. After subjecting Ptf1a cKO mice to caerulein-induced pancreatitis, however, we observed widespread acinar-to-ductal metaplasia, histological structures that resemble PanINs and stain positively with Alcian blue, and loss of amylase staining throughout the pancreas. Our current data indicate that PTF1A has a critical role in guarding against genetic (oncogenic KRAS) and environmental (pancreatitis) insults, and demonstrate that loss of Ptf1a expression is the critical event of acinar cell transformation. Going forward, we will use gene expression profiling and ChIP-seq analysis to identify PTF1A target genes responsible for inhibiting KRAS, and to characterize the epigenetic processes by which KRAS and inflammation reprogram acinar cells to a PanIN phenotype. This abstract is also presented as Poster A3. Citation Format: Nathan Michael Krah, Mary P. Bronner, Christopher V. Wright, L. Charles Murtaugh. Downregulation of PTF1A is a crucial and rate-limiting step in pancreatic cancer initiation. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Innovations in Research and Treatment; May 18-21, 2014; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2015;75(13 Suppl):Abstract nr PR01.

Comparison of pancreas specific promoters from mouse and rat genome

s / Pancreatology 15 (2015) S1eS141 S51 stomach and identified in the pancreas. GHRL has been demonstrated to protect pancreatic tissue from caerulein-induced pancreatitis (CIP). Aims: To investigate the effect of GHRL and caerulein on gene expression and on protein signals of GHS-R1a, GHRL and of an antioxidant enzyme; superoxide dysmutase (SOD) -3 in the isolated pancreatic acini. Materials & methods: Pancreatic acini were isolated by collagenase digestion from control rats and from rats pretreated with GHRL (50 ug/kg i. p.) administered 48 hours before the isolation, then the acinar cells were stimulated by using of caerulein (10-8M). The gene expression were determined by RT-PCR, whereas the protein contents were assessed employing Western-blot. Results: Protein expressions and mRNA signals for GHS-R1a, GHRL and for SOD-3 have been detected in the pancreatic acini under basal conditions and have been significantly upregulated following application of GHRL to the rats. Caerulein markedly downregulated signals GHS-R1a and SOD-3 in pancreatic acini, but failed to affect these for GHRL. Pretreatment of rats with GHRL reversed caerulein-induced suppression of GHS-R1a and SOD-3 signals. Conclusion: Caerulein is able to modify the GHS-R1a in the pancreatic acini and this effect could be prevented by pretreatment of rats with GHRL. Beneficial effect of GHRL could be dependent, at least in part, on the activation of SOD-3 and improvement of antioxidant system in the pancreas.

Inhibition of hydrogen sulfide synthesis by gene silencing protects mice against caerulein-induced acute pancreatitis

Inhibition of hydrogen sulfide synthesis by gene silencing protects mice against caerulein-induced acute pancreatitis

Identification of key transcription factors in caerulein-induced pancreatitis through expression profiling data.

The current study aimed to isolate key transcription factors (TFs) in caerulein-induced pancreatitis, and to identify the difference between wild type and Mist1 knockout (KO) mice, in order to elucidate the contribution of Mist1 to pancreatitis. The gene profile of GSE3644 was downloaded from the Gene Expression Omnibus database then analyzed using the t-test. The isolated differentially expressed genes (DEGs) were mapped into a transcriptional regulatory network derived from the Integrated Transcription Factor Platform database and in the network, the interaction pairs involving at least one DEG were screened. Fisher’s exact test was used to analyze the functional enrichment of the target genes. A total of 1,555 and 3,057 DEGs were identified in the wild type and Mist1KO mice treated with caerulein, respectively. DEGs screened in Mist1KO mice were predominantly enriched in apoptosis, mitogen-activated protein kinase signaling and other cancer-associated pathways. A total of 188 and 51 TFs associated with pathopoiesis were isolated in Mist1KO and wild type mice, respectively. Out of the top 10 TFs (ranked by P-value), 7 TFs, including S-phase kinase-associated protein 2 (Skp2); minichromosome maintenance complex component 3 (Mcm3); cell division cycle 6 (Cdc6); cyclin B1 (Ccnb1); mutS homolog 6 (Msh6); cyclin A2 (Ccna2); and cyclin B2 (Ccnb2), were expressed in the two types of mouse. These TFs were predominantly involved in phosphorylation, DNA replication, cell division and DNA mismatch repair. In addition, specific TFs, including minichromosome maintenance complex component 7 (Mcm7); lymphoid-specific helicase (Hells); and minichromosome maintenance complex component 6 (Mcm6), that function in the unwinding of DNA were identified to participate in Mist1KO pancreatitis. The DEGs, including Cdc6, Mcm6, Msh6 and Wdr1 are closely associated with the regulation of caerulein-induced pancreatitis. Furthermore, other identified TFs were also involved in this type of regulation.

Loss of Bace1 in mice does not alter the severity of caerulein induced pancreatitis.

ContextBeta-site alpha-amyloid protein cleaving enzyme1 (BACE1) plays a key role in the pathogenesis of Alzheimer’s disease. Additional to its moderate expression in the brain, high levels of BACE1 mRNA were found in the pancreas. Murine Bace1 has been immunohistochemicaly detected at the apical pole of acinar cells within the exocrine pancreas of mice and Bace1 activity was observed in pancreatic juice. In vitro experiments revealed enteropeptidase as a putative substrate for Bace1 suggesting a role in acute pancreatitis.ObjectiveThe aim of this study was to address a protective mechanism of Bace1 in acute experimental pancreatitis in mice.MethodsAcute experimental pancreatitis was induced by intraperitoneal injection of caerulein in homozygote Bace1 -/- mice and wild type mice. Serum and tissue analyses were carried out after 4 h, 8 h and 24 h. Measurement of plasma amylase and lipase was performed to confirm pancreatitis induction. In order to assess the severity of pancreatitis H&E stained pancreatic sections were examined regarding edema, inflammation and apoptosis. Immunohistochemical detection of myeloperoxidase (MPO) positive cells was carried out to further quantify the extent of inflammation. Expression of Bace2 within the pancreas was analyzed by immunohistochemistry and RT-qPCR.ResultsWe demonstrate that total loss of Bace1 in mice leads to no alterations in the course of acute experimental caerulein-pancreatitis. Bace1-/- mice develop a moderate pancreatitis that is comparable in histomorphological and serological features with those seen in wild type mice.DiscussionWe discuss the results in the context of the applied caerulein induced edematous pancreatitis model and possible compensatory mechanisms via Bace2 that might be responsible for the observed results.

Can Melatonin Protect the Endometrium from the Adverse Effects of Caerulein?

We investigated the effects of a caerulein-induced acute pancreatitis (AP) on uterus and possible uterine protective effects of melatonin administration. Twenty-eight animals were divided into four groups: (1) control group (n = 7); (2) melatonin group (n = 7); (3) caerulein group (n = 7); (4) melatonin + caerulein group (n = 7). AP was induced by 4 intraperitoneal injection of caerulein given hourly (50 μg/kg) into young female animals. Melatonin (20 mg/kg) was given via intraperitoneal injection 30 min prior to the induction of AP. The rats were sacrificed by decapitation 12 h after the last injection of caerulein and their uterus were taken for histopathological evaluation. Mean body weight and uterine wet weight was recorded. The H-Score method was used to score the degree of histological changes of endo-myometrium edema, hemorrhage, necrosis, leucocyte infiltration, endometrial proliferation and endometrial thickness. There was no significant difference in the mean body weight observed after treatment in each group. The uterine wet weight differences between the control and caerulein given rats were significant (P<0.01). The endometrial thickness, edema, hemorrhage, necrosis and leucocyte infiltration of the caerulein group was significantly higher than the control and melatonin groups (P<0.01). It was observed that preteratment with melatonin normalized histological abnormalities and significantly reduced uterine wet weight as compared with the caerulein only group. Melatonin application may play an important role in the prophylaxis of uterine endometrium arising from adverse effects of caerulein.

Role of Kinase Epidermal Growth Factor Receptor and SRC in the Caerulein-Induced Acute Pancreatitis in Mice.

In this study, we identified the protein kinases that play the most distinct roles in the occurrence of acute pancreatitis (AP). Gene expression profile data were downloaded from Gene Expression Omnibus database (GSE3644). The sample was from caerulein-induced AP mice. The intersection of the differentially expressed genes in AP mice taken from a protein kinase database was obtained for screening of the protein kinase encoded genes that were differentially expressed. Database for annotation, visualization, and integrated discovery was used for the functional enrichment analysis. Kinase inhibitors that regulated these kinases were retrieved from PubMed through text mining. Twenty-nine differentially expressed kinase encoded genes were identified through screening. The functional enrichment analysis demonstrated that the functions of these genes were primarily enriched in "mitogen-activated protein kinase signaling pathway," followed by "extracellular regulated protein kinases pathway," "neurotrophin signaling pathway," "adherens junction," and "gap junction." SRC and epidermal growth factor receptor (EGFR) were related to extracellular regulated protein kinases pathway and also related to adherens junction as well as gap junction. On the basis of the regulated kinases, the kinase inhibitors reported in the literature were classified into multiple groups. EGFR and SRC may be coexpressed in AP. The kinase inhibitors working together in SRC and EGFR may play better efficacy in the treatment of AP.

SEW2871 Alleviates the Severity of Caerulein-Induced Acute Pancreatitis in Mice.

Sphingosine-1-phosphate type-1 receptor (S1P1) agonists have the potential to inhibit the egress of lymphocytes, and have been demonstrated to provide protective effects on some acute inflammatory diseases. However, the value of S1P1 agonists on acute pancreatitis (AP) remains unclear. The aim of this study was to explore the effect of SEW2871, a S1P1-selective agonist, on caerulein-induced AP in mice. AP was induced by giving eight intraperitoneal injections of caerulein (50 µg/kg/h) at hourly intervals. SEW2871 was administered by gavage, at a dose of 20 mg/kg, at 0 h and 12 h after the first intraperitoneal injection of caerulein. The mice were sacrificed at 24 h. Severity of AP, serum amylase and lipase activity, levels of serum cytokines, pancreatic myeloperoxidase (MPO) activity, CD45+CD4+ T lymphocytes in blood, CD4+ T cell infiltration in the pancreas, and proinflammatory cytokine production were assessed. Furthermore, the expression of signal transducer and activator of transcription (STAT) 3 and phospho-STAT3 (p-STAT3) in the pancreas was also evaluated. The results revealed that the administration of SEW2871 ameliorated the severity of AP, by a reduction of serum pancreatic enzyme activity and levels of cytokines, decreased pancreatic MPO activity, depletion of CD4+CD45+ T lymphocytes in the blood and a reduction of CD4+ T cell infiltration in the pancreas. Furthermore, the expression of proinflammatory cytokines mRNA and p-STAT3 were also suppressed by SEW2871 treatment. These results suggest that SEW2871 treatment attenuates the severity of caerulein-induced AP in mice, which may provide a new therapeutic approach for AP therapy.

Protective effects and mechanisms of G5 PAMAM dendrimers against acute pancreatitis induced by caerulein in mice.

In this study, generation 5 (G5) polyamidoamine (PAMAM) dendrimers with two different surface groups, G4.5-COOH and G5-OH, were investigated for their protective effects on pancreas injury in a caerulein-induced acute pancreatitis (AP) mouse model. Both dendrimers significantly decreased pathological changes in the pancreas and reduced the inflammatory infiltration of macrophages in pancreatic tissues. In addition, the expression of pro-inflammatory cytokines was significantly inhibited by the two dendrimers, not only in pancreatic tissues from AP mice but also in vitro in mouse peritoneal macrophages with LPS-induced inflammation. G4.5-COOH, which had better in vivo protective effects for AP than G5-OH, led to a significant reduction in the total number of plasma white blood cells (WBCs) and monocytes in AP mice, and its anti-inflammatory mechanism was related to inhibition of the nuclear translocation of NF-κB in macrophages.

Changes of zymophagy during cell model of caerulein-induced experimental acute pancreatitis

Objective To observe the changes of zymophagy during experimental acute pancreatitis (AP) induced by caerulein.Methods Pancreatic acinar cell line AR42J cells were cultured in 6-well plates till 90％ confluent and then divided into AP group and control group.Caerulein (1 × 10-8 mol/L) was added into AP group to establish AP cell model,and 1640 cell culture medium was added into control group.After caerulein treated for one,four,six,eight,12 and 24 hours,cells and cell culture supernatant were collected.The levels of cytokine interleukin (IL)-1,tumor necrosis factor (TNF)α,trypsinogen activation (TAP) and amylase were measured with enzyme-linked immunosorbent assay (ELISA) method.The expression of LC3 and Beclin1 at mRNA of each group were detected by reverse transcription-polymerase chain reaction (RT-PCR).The LC3B protein level of each group were detected by Western blotting.The changes of autophagosome and zymophagosome were observed by transmission electron microscopy.The difference between AP group and control group was analyzed by analysis of variance.Results The level of IL-1,TNFα,amylase and TAP in cell culture supernatant of control group was (18.83±7.10) pg/mL,(14.20±3.79) pg/mL,(10.03±2.85) U/L and (39.48±8.62) pg/mL,respectively.Those of AP group significantly increased at first hour ((62.13±11.25) pg/mL,F=3.32,P＜0.01 ; (30.98±7.11) pg/mL,F=3.05,P＜0.05; (25.06±6.82) U/L,F=2.90,P＜0.05 and (128.51± 18.30) pg/mL),F=2.62,P＜0.01,at fourth or sixth hour reached peak (IL-1 at fourth hour:(71.96± 15.82) pg/mL,F=7.25,P＜0.01;TNFα at sixth hour:(39.92±8.94) pg/mL,F=4.93,P＜0.05; amylase at fourth hour:(28.83 ± 8.31) U/L,F=2.06,P＜0.05; TAP at fourth hour:(146.29± 29.36) pg/mL,F=0.14,P＜0.01) and then gradually decreased.At fourth and sixth hour,the expression of LC3 at mRNA level in AP group was 3.18±0.82,1.71±0.14,respectively,while the expression of Beclin-1 rnRNA at first,fourth hour was 2.44±0.34 and 4.13±0.30,all of them were significantly increased compared with those of control group (0.21±0.04 and 0.30±0.08,LC3 mRNA F=0.79、0.06; Beclin mRNA F=2.31、0.36,all P＜ 0.05).There were no significant differences at other time points.The numbers of autophagosome and zymophagosome of AP group were significantly higher than those of control group under transmission electron microscopy.Conclusion Zymophagy occurred during AP cell model induced by caerulein,which suggested that zymophagy might involve in the mechanism of AP. Key words: Acute pancreatitis; Autophagy; Trypsinogen

Epiplakin deficiency aggravates murine caerulein-induced acute pancreatitis and favors the formation of acinar keratin granules.

Epiplakin, a member of the plakin protein family, is exclusively expressed in epithelial tissues and was shown to bind to keratins. Epiplakin-deficient (EPPK−/−) mice showed no obvious spontaneous phenotype, however, EPPK−/− keratinocytes displayed faster keratin network breakdown in response to stress. The role of epiplakin in pancreas, a tissue with abundant keratin expression, was not yet known. We analyzed epiplakin’s expression in healthy and inflamed pancreatic tissue and compared wild-type and EPPK−/− mice during caerulein-induced acute pancreatitis. We found that epiplakin was expressed primarily in ductal cells of the pancreas and colocalized with apicolateral keratin bundles in murine pancreatic acinar cells. Epiplakin’s diffuse subcellular localization in keratin filament-free acini of K8-deficient mice indicated that its filament-associated localization in acinar cells completely depends on its binding partner keratin. During acute pancreatitis, epiplakin was upregulated in acinar cells and its redistribution closely paralleled keratin reorganization. EPPK−/− mice suffered from aggravated pancreatitis but showed no obvious regeneration phenotype. At the most severe stage of the disease, EPPK−/− acinar cells displayed more keratin aggregates than those of wild-type mice. Our data propose epiplakin to be a protective protein during acute pancreatitis, and that its loss causes impaired disease-associated keratin reorganization.

Bilateral vagotomy attenuates the severity of secretagogue-induced acute pancreatitis in the rat

PurposeWe assessed the effect of bilateral vagotomy (BV) on the course of acute caerulein-induced pancreatitis (AP) in the rat. Material/methodsThe study was performed on Wistar rats surgically prepared by subdiaphragmatic BV. Control group underwent sham operation. Four days later, AP was induced by subcutaneous injection of caerulein (25μg/kg/5h) to the conscious animals with or without BV. After administration of caerulein the blood samples were taken for determination of serum lipase activity and interleukin-10 (IL-10) concentration. Pancreatic tissue samples were subjected to histological examinations and to the measurement of lipid peroxidation products (MDA+4-HNE) concentration and the activity of an antioxidant enzyme – glutathione peroxidase (GPx). After application of caerulein pancreatic blood flow was measured by laser Doppler flowmetry. ResultsAP was manifested by oedema and neutrophil infiltration of the pancreatic tissue and accompanied by significant increases of serum lipase activity, serum concentration of IL-10 and pancreatic concentration of MDA+4HNE (ca. 50×, 2× and 4× respectively p≥0.05). Pancreatic activity of GPx and pancreatic blood flow were decreased (both by 60%). In vagotomised rats with AP serum lipase activity and pancreatic concentration of MDA+4-HNE were lower whereas Il-10 concentration and pancreatic activity of GPx, as well as pancreatic blood flow were significantly higher as compared to AP rats with intact vagal nerves. In AP rats with vagotomy all histological signs of pancreatitis were significantly reduced. ConclusionsBilateral vagotomy resulted in the significant attenuation of caerulein-induced pancreatitis in the rat.

Electron-microscopic evidence of macroautophagy (including Mitochondriae) in caerulein-induced acute pancreatitis in mice

Electron-microscopic evidence of macroautophagy (including Mitochondriae) in caerulein-induced acute pancreatitis in mice

Duration of injury correlates with necrosis in caerulein-induced experimental acute pancreatitis: implications for pathophysiology.

Pancreatic acinar cell necrosis is indicative of severe pancreatitis and the degree of necrosis is an index of its outcome. We studied whether the dose and duration of injury correlates with severity, particularly in terms of necrosis, in caerulein-induced acute pancreatitis (AP) in Swiss albino mice. In addition to control group 1 (G1), groups 2 and 3 received four injections of caerulein every hour but were sacrificed at five hours (G2) and nine hours (G3) respectively, and group 4 received eight injections and was sacrificed at nine hours (G4). The severity of pancreatitis was assessed histopathologically and biochemically. The histopathological scores of pancreatitis in groups 3 and 4 were significantly higher than in groups 1 and 2 (4 vs. 1, 4 vs. 2, 3 vs. 1, 3 vs. 2; P<0.05). TUNEL-positive apoptotic cells were significantly higher in groups 2 and 3 compared with groups 1 and 4 (P<0.05). Necrosis was significantly more in group 4 than other groups (37.49% (4.68) vs. 19.97% (1.60) in G2; 20.36% (1.56) in G3; P=0.006 for G 2 vs. 4 and P=0.019 for G 3 vs. 4). Electron microscopy revealed numerous autophagosomes in groups 2 and 3 and mitochondrial damage and necrosis in group 4. The pancreatic and pulmonary myeloperoxidase activity in group 4 was significantly higher than that in the other groups (P<0.01). Hence, severity of pancreatitis is a function of the dose of injurious agent, while inflammation is both dose and duration dependent, which may also explain the wide spectrum of severity of AP seen in clinical practice.

Acute pancreatitis decreases the sensitivity of pancreas‐projecting dorsal motor nucleus of the vagus neurones to group II metabotropic glutamate receptor agonists in rats

Recent studies have shown that pancreatic exocrine secretions (PES) are modulated by dorsal motor nucleus of the vagus (DMV) neurones, whose activity is finely tuned by GABAergic and glutamatergic synaptic inputs. Group II metabotropic glutamate receptors (mGluR) decrease synaptic transmission to pancreas-projecting DMV neurones and increase PES. In the present study, we used a combination of in vivo and in vitro approaches aimed at characterising the effects of caerulein-induced acute pancreatitis (AP) on the vagal neurocircuitry modulating pancreatic functions. In control rats, microinjection of bicuculline into the DMV increased PES, whereas microinjections of kynurenic acid had no effect. Conversely, in AP rats, microinjection of bicuculline had no effect, whereas kynurenic acid decreased PES. DMV microinjections of the group II mGluR agonist APDC and whole cell recordings of excitatory currents in identified pancreas-projecting DMV neurones showed a reduced functional response in AP rats compared to controls. Moreover, these changes persisted up to 3 weeks following the induction of AP. These data demonstrate that AP increases the excitatory input to pancreas-projecting DMV neurones by decreasing the response of excitatory synaptic terminals to group II mGluR agonist.

The protective effects of Shen-Fu injection on experimental acute pancreatitis in a rat model.

Objectives. In the present study, we investigated the protective effects of Shen-Fu injection (SFI) on a caerulein-induced rat pancreatitis (AP) model. Methods. SFI was given to rats in the SFI treated group through intraperitoneal injection. Blood and pancreas samples were collected for serological and histopathological studies. Results. Our results showed that AP caused significant decrease in tissue glutathione (GSH) and serum IL-4 and IL-10, while pancreatic malondialdehyde (MDA) and myeloperoxidase (MPO) were increased. Furthermore, TNF-α, IL-1β, amylase, and lipase levels were also significantly increased. On the other hand, SFI treatment reserved all these biochemical indices as well as histopathologic alterations that were induced by caerulein. Conclusion. Our findings suggest that the SFI protects against caerulein-induced AP in rats via modulation of cytokines, oxidative stress, and Nuclear Factor-kappa B (NF-κB) activity.

Effects of GamiChungYi-tang on the Caerulein-induced Acute Pancreatitis in Rats

In this study, we aimed to investigate the effect of GamiChungYi-tang(GCY-t) on caerulein-induced acute pancreatitis (AP). It is performed by detecting oxidative stress markers and observing histopathological examination. Thirty adult male rats(Sprague-Dawley) were divided into six groups as follows: normal (NOR,n=5), caerulein-induced (CON,n=5), caerulein+Cefotaxime Sodium(CT,n=5), caerulein+GCY-t (130 ㎎/㎏, CHA,n=5), caerulein+GCY-t (260 ㎎/㎏, CHB,n=5) and caerulein+GCY-t (520 ㎎/㎏, CHC,n=5) groups. Pancreatic tissues of rats from all groups were removed for apoptosis and light, and electron microscopic examination. Blood of rats from all groups were collected for oxidative stress markers inspection and pathological examination. Pancreatic oxidative stress markers were evaluated by the measurements of leukocyte, serum amylase and platelet activating factor (PAF), Interleukin-6 (IL-6) levels were determined spectrophotometrically. CON group has a significant increase (p<0.05) in amylase compared with NOR, but CT and CHA, CHB, CHC groups reduced the levels of these enzyme. The levels of Platelet activating factor (PAF) were increased in CON compared with NOR, but decreased in CT and CHA, CHB, CHC groups compared with CON. Interleukin-6 (IL-6) levels were increased significantly in CON compared with NOR, but reduced in CT and CHA, CHB, CHC groups. In the observations of Optical microscopy and electron microscopy, The experimental groups showed the significant decreases in pancreatic tissue inflammation, edema, vacuolization, necrosis compared to the control group. After all, GCY-t is potentially capable of limiting pancreatic damage produced during AP by restoring the fine structure of acinar cells and tissue.

The effect of CSE gene deletion in caerulein-induced acute pancreatitis in the mouse

Hydrogen sulfide (H2S) has been reported to be involved in the signaling of the inflammatory response; however, there are differing views as to whether it is pro- or anti-inflammatory. In this study, we sought to determine whether endogenously synthesized H2S via cystathionine-γ-lyase (CSE) plays a pro- or anti-inflammatory role in caerulein-induced pancreatitis. To investigate this, we used mice genetically deficient in CSE to elucidate the function of CSE in caerulein-induced acute pancreatitis. We compared the inflammatory response and tissue damage of wild-type (WT) and CSE knockout (KO) mice following 10 hourly administrations of 50 μg/kg caerulein or saline control. From this, we found that the CSE KO mice showed significantly less local pancreatic damage as well as acute pancreatitis-associated lung injury compared with the WT mice. There were also lower levels of pancreatic eicosanoid and cytokines, as well as reduced acinar cell NF-κB activation in the CSE KO mice compared with WT mice. Additionally, in WT mice, there was a greater level of pancreatic CSE expression and sulfide-synthesizing activity in caerulein-induced pancreatitis compared with the saline control. When comparing the two saline-treated control groups, we noted that the CSE KO mice showed significantly less pancreatic H2S-synthesizing activity relative to the WT mice. These results indicate that endogenous H2S generated by CSE plays a key proinflammatory role via NF-κB activation in caerulein-induced pancreatitis, and its genetic deletion affords significant protection against acute pancreatitis and associated lung injury.