Induction Of Acute Necrotizing Pancreatitis Research Articles

Polyethylene Glycol 35 (PEG35) Protects against Inflammation in Experimental Acute Necrotizing Pancreatitis and Associated Lung Injury.

Acute pancreatitis is an inflammatory disorder of the pancreas. Its presentation ranges from self-limiting disease to acute necrotizing pancreatitis (ANP) with multiorgan failure and a high mortality. Polyethylene glycols (PEGs) are non-immunogenic, non-toxic, and water-soluble chemicals composed of repeating units of ethylene glycol. The present article explores the effect of PEG35 administration on reducing the severity of ANP and associated lung injury. ANP was induced by injection of 5% sodium taurocholate into the biliopancreatic duct. PEG35 was administered intravenously either prophylactically or therapeutically. Three hours after ANP induction, pancreas and lung tissue samples and blood were collected and ANP severity was assessed. To evaluate the inflammatory response, gene expression of pro-inflammatory cytokines and chemokine and the changes in the presence of myeloperoxidase and adhesion molecule levels were determined in both the pancreas and the lung. To evaluate cell death, lactate dehydrogenase (LDH) activity and apoptotic cleaved caspase-3 localization were determined in plasma and in both the pancreatic and lung tissue respectively. ANP-associated local and systemic inflammatory processes were reduced when PEG35 was administered prophylactically. PEG35 pre-treatment also protected against acute pancreatitis-associated cell death. Notably, the therapeutic administration of PEG35 significantly decreased associated lung injury, even when the pancreatic lesion was equivalent to that in the untreated ANP-induced group. Our results support a protective role of PEG35 against the ANP-associated inflammatory process and identify PEG35 as a promising tool for the treatment of the potentially lethal complications of the disease.

High-mobility group box-1 inhibition stabilizes intestinal permeability through tight junctions in experimental acute necrotizing pancreatitis.

In acute necrotizing pancreatitis (ANP), bacterial translocation (BT) from the gastrointestinal tract is the essential pathogenesis in the development of septic complications. Although high-mobility group box-1 (HMGB1) is associated with BT and organ dysfunction in ANP, the mechanism of HMGB1 in the intestinal barrier dysfunction and BT has not been well addressed. In this study, we intend to address the role of HMGB1 in ANP involving BT and intestinal barrier dysfunction. Experimental ANP was achieved in male Sprague-Dawley rats through a retrograde injection of taurocholate into the common biliopancreatic duct following a laparotomy operation. HMGB1 blockade intervention was conducted with a subcutaneous injection of anti-HMGB1 antibody immediately before the laparotomy procedure. Twenty-four hours after ANP induction, pancreatic and intestinal tissues and blood samples were collected for a histopathological assessment and lipid peroxidation or glutathione (GSH) evaluation. AP-induced barrier dysfunction was determined by an intestinal permeability assessment. Tight junction proteins and autophagy regulators were investigated by western blotting, immunohistological analysis and confocal immunofluorescence imaging. ANP developed as indicated by microscopic parenchymal necrosis and fat necrosis, which were associated with intestinal mucosal barrier dysfunction. HMGB1 inhibition played a protective role in intestinal mucosal barrier dysfunction, protected against microbiome changes in ANP, and relieved intestinal oxidative stress. Additionally, HMGB1 inhibition attenuated intestinal permeability; preserved the expression of TJs, such as claudin-2 and occludin; and decreased autophagy. Furthermore, the autophagy regulator LC3 and TJ protein claudin-2 were both upregulated in ANP according to dual immunofluorescence analysis. HMGB1 inhibition ameliorated the severity of experimental ANP though beneficial effects on BT, mainly involving in TJ function.

Quercetin protects against intestinal barrier disruption and inflammation in acute necrotizing pancreatitis through TLR4/MyD88/p38 MAPK and ERS inhibition

ObjectiveTo investigate the effects of quercetin on intestinal barrier disruption and inflammation in acute necrotizing pancreatitis (ANP) in rats, and its possible mechanism. MethodsANP was established by retrograde injection of 3.5% sodium taurocholate into the biliopancreatic duct, and quercetin (50 mg/kg × 3) was administered by intraperitoneal injection prior to and after ANP induction. Pancreatitis was assessed by pancreatic histopathology, plasma amylase, pancreatic myeloperoxidase (MPO) activity, IL-1β, TNFα and IL-6 levels. Injury of the distal ileum was assessed by histological evaluation. The ultrastructural changes of ileal epithelial cells were examined by transmission electron microscope (TEM). Intestinal barrier function was estimated by plasma diamine oxidase (DAO), d-lactate, endotoxin; and intestinal tight junction proteins including zonula occludens-1 (ZO-1), claudin 1, occludin; and bacterial translocation. Intestinal inflammation was determined by IL-1β, TNFα and IL-17 A expression. TLR4, MyD88, pp38 MAPK, and endoplasmic reticulum stress (ERS)-related molecules (Bip, p-IRE1α, sXBP1, p-eIF2α, ATF6) were measured by immunohistochemistry and WB. ResultsQuercetin intervention attenuated pancreatic and ileal pathological damages in ANP (P < 0.05), ameliorated intestinal barrier disruption and inflammation (P < 0.05). Meantime, QE significantly suppressed intestinal TLR4/MyD88/p38 MAPK pathway and ERS activation. ConclusionsQuercetin plays a protective role against intestinal barrier disruption and inflammation in ANP, probably partly by inhibiting TLR4/MyD88/p38 MAPK and ERS activation.

N-acetylcysteine amid reduces pancreatic damage in a rat model of acute necrotizing pancreatitis

BackgroundInflammatory explosion and oxidative stress are important mechanisms of injury in acute necrotizing pancreatitis (ANP). This study investigated the effects of N-acetylcysteine amid (NACA), a novel cell-permeant antioxidant with anti-inflammatory activity, on experimental ANP in rats. Materials and methodsFifty-two adult male Sprague–Dawley rats were used, and ANP was induced by cerulein. The animals were divided into four groups which were sham + saline, sham + NACA, ANP + saline, and ANP + NACA. NACA (2.2 mg/kg, i.p) was administered for 6 h, after the induction of ANP. The extent of acinar cell injury, mortality, systemic cardiorespiratory variables, functional capillary density, renal/hepatic functions, and changes in some enzyme markers for pancreas and lung tissues were investigated. ResultsInduction of ANP increased mortality from 0% in the sham group to 43.75% in the ANP + saline group (P < 0.05), and administration of NACA significantly reduced mortality to 12.5% (P < 0.05). Induction of ANP also caused increases in pancreatic necrosis, serum amylase, alanine aminotransferase (ALT), interleukin-6, LDH in bronchoalveolar lavage fluid, serum urea, tissue myeloperoxidase in pancreas and lung tissues and malondialdehyde. There was less pronounced increase in these parameters in NACA treated group. Compared with ANP group, ANP + NACA group had lower levels of pancreatic necrosis (0.5 ± 0.2 versus 1.45 ± 0.2, P < 0.05) and inflammation (0.6 ± 0.2 versus 1.29 ± 00.3, P < 0.05) scores. ConclusionsAdministration of NACA significantly decreased the ANP-induced mortality and also provided significant improvements in hemodynamic changes. The obtained positive effects of NACA on the course of pancreatitis indicates its potential usefulness in the management of ANP.

Pathophysiological Effects of Pancreatic Sympathetic Denervation in Acute Necrotizing Pancreatitis in Dogs

The aim of this study was to investigate the influence of the greater splanchnic nerve (GSN) transection on the pathophysiological process of acute necrotizing pancreatitis (ANP). The dogs were divided into a sham operation (SO) group, ANP group, and ANP with bilateral GSN transection (GSNT) group. Dogs in the GSNT group underwent bilateral GSNT immediately after ANP induction. The levels of serum pancreatic amylase (AMY), calcium, high-sensitivity C-reactive protein (HCRP), tumor necrosis factor α (TNF-α), interleukin 10 (IL-10), and neutrophile granulocyte (NEU) counts were monitored dynamically, and the pathological examinations of the pancreas was performed at postoperative day 7. All the parameters among the 3 groups showed no differences before the experiment (P > 0.05). At different postoperative times, the NEU count and serum AMY, TNF-α, HCRP, and IL-10 were significantly increased; however, the serum calcium had decreased in the ANP group versus SO (P < 0.05). The postoperative serum IL-10 and calcium levels were higher, and TNF-α, HCRP, and NEU counts were lower in the GSNT group compared with those in the ANP group (P < 0.05); as for AMY, no significant difference was found between the 2 groups (P > 0.05). The pancreas pathological scoring of the GSNT group was lower versus the ANP group (P < 0.05). Greater splanchnic nerve transection can alleviate development of pathophysiological processes in ANP.

Pyrrolidine Dithiocarbamate Inhibits Nuclear Factor κB and Toll-Like Receptor 4 Expression in Rats with Acute Necrotizing Pancreatitis.

Background/AimsTo investigate the expression of Toll-like receptor 4 (TLR4) in the pancreases of rats with acute necrotizing pancreatitis (ANP) and any changes upon treatment with pyrrolidine dithiocarbamate (PDTC), an inhibitor of nuclear factor κB (NF-κB), as well as to determine the relationship between TLR4 and NF-κB in ANP pathogenesis.MethodsA total of 72 SD rats were randomly divided into three groups, namely, the control (sham-operation), ANP, and ANP with PDTC pretreatment groups. The PDTC-pretreated group was intraperitoneally injected with PDTC at a dose of 100 mg/kg 1 hour before the induction of ANP. The expressions of TLR4 and NF-κB in pancreatic tissue were evaluated by immunohistochemistry and Western blot analysis. The mRNA levels of cytokines tumor necrosis factor α, interleukin (IL)-1β, and IL-6 were measured by reverse transcription polymerase chain reaction.ResultsThe expressions of TLR4, NF-κB, and cytokine (NF-κB target) genes in the pancreatic tissue increased more significantly in the ANP groups than in the sham-operation group at 3, 6, and 12 hours. Pretreatment with PDTC alleviated the inflammatory activation in the pancreas with ANP, causing a significant decrease in the expressions of TLR4, NF-κB, and cytokine genes in the pancreatic tissue.ConclusionsThe expressions of TLR4 and NF-κB were increased in the pancreases of rats with ANP. PDTC not only inhibits NF-κB but also suppresses the expression of TLR4 and downregulates the expression of the related cytokine genes.

Beneficial effect of splanchnic nerve transection and harmful effect of vagotomy on acute necrotizing pancreatitis in the dog.

The nervous system interacts dynamically with the immune system to modulate inflammation through humoral and neural pathways. However, the influence of visceral nerve (VN) on acute necrotizing pancreatitis (ANP) has drawn little attention. To investigate the influence of VN on the pathophysiological process of ANP in dogs. The dogs were divided into a sham operation (SO) group, ANP group, ANP + vagal nerve trunk transection (VNTT) group, and ANP + greater splanchnic nerve transection (GSNT) group. The VNTT and GSNT groups underwent VNTT and GSNT respectively immediately after ANP induction. The levels of serum pancreatic amylase (AMY), calcium, high-sensitivity C-reactive protein (HCRP), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-10 (IL-10) were monitored dynamically and the pathological examinations of the pancreas was performed at postoperative day 7. All serum parameters among the four groups showed no differences before the experiment (p > 0.05). At different postoperative times, the serum TNF-α, IL-1β, HCRP, and AMY were significantly increased, however, the serum calcium and IL-10 had dropped in the ANP group versus SO group (p < 0.05); an alike variation trend occurred between the VNTT group and ANP group (p < 0.05); an opposite variation trend occurred between the GSNT group and the ANP group (p < 0.05). The pancreas pathological scoring of VNTT group was highest in the four groups (p < 0.05) and GSNT group was lower versus ANP group (p < 0.05). The GSNT has been shown to alleviate development of ANP, however, VNTT may exacerbate the ANP.

Effects of glutamine alone on the acute necrotizing pancreatitis in rats

BackgroundThe effects of the glutamine on the acute pancreatitis are controversial in the clinical and experimental studies. The aim of this study was to investigate the influence of glutamine alone on acute necrotizing pancreatitis (ANP) induced by glycodeoxycholic acid in rats. Material and methodsFifty-two male Sprague–Dawley rats weighing 300-350 g were used. Rats were divided into four groups as sham + saline, sham + glutamine, ANP + saline and ANP + glutamine. ANP in rats was induced by glycodeoxycholic acid. The extent of acinar cell injury, mortality, systemic cardiorespiratory variables, functional capillary density, renal/hepatic functions, and changes in some enzyme markers for pancreatic and lung tissue were investigated during ANP in rats. ResultsThe induction of ANP resulted in a significant increase in the mortality rate, pancreatic necrosis, and serum activity of amylase, alanine aminotransferase, interleukin-6, lactate dehydrogenase in bronchoalveolar lavage fluid, serum concentration of urea, and tissue activity of myeloperoxidase and malondialdehyde in the pancreas and lung, and a significant decrease in concentrations of calcium, blood pressure, urine output, pO2, and functional capillary density. The use of glutamine alone improved these changes. ConclusionsGlutamine demonstrated beneficial effect on the course of ANP in rats. Therefore, it may be used by itself in the treatment of acute pancreatitis.

Effects of 17ß-Estradiol on the Acute Necrotizing Pancreatitis after Onset in Rats

The aim of this study was to investigate the influence of 17ß-estradiol (E2) on acute necrotizing pancreatitis (ANP) induced by glycodeoxycholic acid in rats. Rats were divided into six groups as sham + saline, sham + single dose E2 (SDE2), sham + multiple dose E2 (MDE2), ANP + saline, ANP + SDE2, and ANP + MDE2. ANP in rats was induced by glycodeoxycholic acid. The extent of acinar cell injury, mortality, systemic cardiorespiratory variables, functional capillary density (FCD), renal/hepatic functions, and changes in some enzyme markers for pancreatic and lung tissue were investigated during ANP in rats. The induction of ANP resulted in a significant increase in the mortality rate, pancreatic necrosis, and serum activity of amylase, alanine aminotransferase (ALT), interleukin (IL)-6, lactate dehydrogenase (LDH) in bronchoalveolar lavage (BAL) fluid, serum concentration of urea, and tissue activity of myeloperoxidase (MPO) and malondialdehyde (MDA) in the pancreas and lung, and a significant decrease in concentrations of calcium, blood pressure, urine output, p02, and functional capillary density (FCD). The use of E2 did not alter these changes. E2 demonstrated no effect on the course of ANP in rats. Therefore, it has no value in the treatment during acute pancreatitis.

Effects of Clotrimazol on the Acute Necrotizing Pancreatitis in Rats

This study aims to investigate the influence of clotrimazol (CLTZ) on acute necrotizing pancreatitis (ANP) induced by glycodeoxycholic acid in rats. Rats were divided into five groups as sham + saline, sham + CLTZ, sham + polyethylene glycol, ANP + saline, and ANP + CLTZ. ANP in rats was induced by glycodeoxycholic acid. The extent of acinar cell injury, mortality, systemic cardiorespiratory variables, functional capillary density (FCD), renal/hepatic functions, and changes in some enzyme markers for pancreatic and lung tissue were investigated during ANP in rats. The use of CLTZ after the induction of ANP resulted in a significant decrease in the mortality rate, pancreatic necrosis, and serum activity of amylase, alanine aminotransferase, interleukin-6, lactate dehydrogenase in bronchoalveolar lavage fluid, serum concentration of urea, and tissue activity of myeloperoxidase, and malondialdehyde in the pancreas and lung and a significant increase in concentrations of calcium, blood pressure, urine output, pO2, and FCD. This study showed that CLTZ demonstrated beneficial effect on the course of ANP in rats. Therefore, it may be used in the treatment of acute pancreatitis.

N-Acetylcysteine Improves Pancreatic Microcirculation and Alleviates the Severity of Acute Necrotizing Pancreatitis

Background/AimsTo investigate the beneficial effect of N-Acetylcysteine (NAC) on pancreatic microvascular perfusion in acute necrotizing pancreatitis (ANP).MethodsFifty-four rats were divided into a control group, an ANP group and an NAC-treated group. The ANP model was established by a retrograde injection of 3% sodium taurocholate into the pancreatic duct. The NAC-treated group received an intravenous infusion of NAC just 2 hours before and 30 minutes after the induction of ANP. The pancreatic microvascular perfusion was measured with laser Doppler flowmetry and pancreatic samples were collected for histological examination.ResultsThe microvascular perfusion in the NAC-treated group decreased slightly and exhibited a significant increase compared to the ANP group (p<0.01). A pathological examination revealed that edema and inflammatory infiltration decreased, and the hemorrhaging and necrosis of the pancreas were significantly reduced.ConclusionsNAC could improve pancreatic microvascular perfusion and alleviate the severity of sodium taurocholate-induced ANP, possibly representing a new therapeutic approach to prevent the progression of ANP.

Melatonin ameliorates acute necrotizing pancreatitis by the regulation of cytosolic Ca2+ homeostasis

ObjectivesThis study aims to investigate the relationship between the protective effects of melatonin in pancreas and the expression of sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) and Na+/Ca2+ exchanger (NCX) in rats with acute necrotizing pancreatitis (ANP), to verify whether melatonin ameliorates ANP by alleviating calcium overload. MethodsNinety-six male Sprague-Dawley rats were randomly divided into four groups (sham operation group, ANP group, melatonin treatment group, melatonin contrast group). ANP was induced by the retrograde injection of 4% taurocholate (1 ml/kg body weight) into the biliopancreatic duct. Melatonin (50 mg/kg body weight) was administered 30 min before the induction of ANP in the melatonin treatment group. Rats in each group were euthanized at 1, 4, and 8 h after ANP induction. Pancreatic tissues were removed to measure SERCA and NCX levels and cytosolic calcium ion (Ca2+) concentration ([Ca2+]i). ResultsAt each time point, SERCA and NCX levels in the melatonin treatment group were significantly higher than that in the ANP group, and lower than that in the sham group and the melatonin contrast group. These levels did not differ between the 4- and 8-h time points in the ANP group. [Ca2+]i in pancreatic acinar cells was higher in the melatonin treatment group than in the sham group and the melatonin contrast group, but lower than in the ANP group, at each time point. ConclusionMelatonin can reduce pancreatic damage via the up-regulation of SERCA and NCX expression, which can alleviate calcium overload in pancreatic acinar cells.

Octreotide Ameliorates Intestinal Dysmotility by Interstitial Cells of Cajal Protection in a Rat Acute Necrotizing Pancreatitis Model

Intestinal motility is impaired in acute necrotizing pancreatitis (ANP). The aim of present study was to investigate the effects of octreotide on the small intestinal motor function during experimentally induced ANP. L-Ornithine was intraperitoneally injected to induce ANP. Octreotide was administrated subcutaneously every 8 hours. The small intestine migrating myoelectrical complexes and slow waves in vivo were recorded before and after (24, 48, and 72 hours) ANP induction. The morphological alterations of interstitial cells of Cajal (ICCs) in deep muscular plexus were evaluated by immunohistochemistry and Western blots. Disturbed migrating myoelectrical complex cycle length and decreased dominant frequency of slow waves exacerbated gradually with time. The bolus applications of octreotide per 8 hours attenuated these functional abnormalities. The result of morphological study suggested that octreotide might ameliorate the damage of ICCs at 48 and 72 hours after ANP induction. Decreased expression of c-Kit protein at 72 hours was also attenuated by octreotide. The pathogenesis of the ileus in ANP may be related to the sustained deficiencies in ICCs. Octreotide may ameliorate the severity of ileus by minimizing the injury of ICCs.

The effects of p53 inhibition using pifithrin-α on acute necrotizing pancreatitis in rats

To investigate the effects of p53 inhibition using pifithrin-\alpha (PFA) on acute necrotizing pancreatitis (ANP) induced by glycodeoxycholic acid in rats. The role of p53 during acute pancreatitis is unclear. Materials and methods: Rats were divided into 4 groups, 2 of which were initially given only saline (the sham group) and 2 of which were given glycodeoxycholic acid in order to induce ANP. Each group was then identified according to treatment plan: sham+saline, sham+PFA, ANP+saline, or ANP+PFA. The study then investigated the extent of acinar cell injury, apoptosis, mortality, systemic cardiorespiratory variables, functional capillary density (FCD), renal/hepatic functions, and changes in some enzyme markers for pancreatic and lung tissue during ANP in rats. Results: The induction of ANP resulted in a significant increase in mortality rate, pancreatic necrosis, apoptosis, serum activity of amylase, alanine aminotransferase (ALT), interleukin (IL)-6, lactate dehydrogenase (LDH) in bronchoalveolar lavage (BAL) fluid, serum concentration of urea, and tissue activity of myeloperoxidase (MPO) and malondialdehyde (MDA) in the pancreas and lung. In addition, ANP induction caused a significant decrease in concentrations of calcium, blood pressure, urine output, pO2, and functional capillary density (FCD). The use of PFA did not alter these changes. Conclusion: PFA demonstrated no effect on the course of ANP in rats. Therefore, it has no value in the treatment of acute pancreatitis.

Poly (ADP-ribose) Polimerase (PARP) Inhibition in Experimental Acute Necrotizing Pancreatitis

Purpose: Inhibition of poly (ADP-ribose) polimerase (PARP) is shown to reduce inflammation in several entities. Thus, we designed a study to evaluate the efficacy of benzamide (B), a PARP inhibitor, in an experimental model of acute necrotizing pancreatitis (ANP). Methods: Thirty Sprague-Dawley rats were divided into 3 groups: sham, ANP, ANP+B groups. ANP was induced by infusing of 1 mL/kg of 3% sodium taurocholate into the common biliopancreatic duct. ANP+B group received 100 mg/kg/day benzamide i.p. for a total of 3 days after induction of ANP. The surviving animals were killed at the 4th day and their pancreas was harvested for biochemical, microbiological and histopathological analysis. Blood samples from animals were also obtained. Results: In the ANP group, a clear increase in serum amylase and neopterin levels and tissue oxidative stress indices were present; almost all of these changes were found to be reversed near to their normal values in ANP+B group. Histopathologic injury scores were significantly high in ANP group (p<0.05, ANP vs. sham) which were significantly lower in ANP+B group (p<0.05, ANP+B vs. ANP). Evaluation of bacterial translocation presented significantly less infected sites in ANP+B group than in ANP animals (p<0.01). Conclusion: Our data showed that inhibition of PARP with benzamide reduced the severity, the mortality, bacterial translocation rates and neopterin levels in the experimental ANP model of rats.Figure

Damage of the interstitial cells of Cajal and myenteric neurons causing ileus in acute necrotizing pancreatitis rats

Small intestinal motility is impaired in acute necrotizing pancreatitis (ANP). The present study was designed to detect the impairment in small intestinal motility and to assess the role of interstitial cells of Cajal (ICC), myenteric neurons and the associated mechanism in the pathogenesis of ileus during experimentally induced acute pancreatitis. ANP was induced by intraperitoneal injections of 30% L-ornithine at a dose of 3 g/kg at hourly intervals. The alterations of small intestine electrical activity--migrating myoelectric complexes (MMCs), and slow waves--were measured 24 hr after ANP induction. The spontaneous mechanical activity and the contractile response to ACh, KCl, tetrodotoxin (TTX) and the nitric oxide synthase (NOS) inhibitor NG-nitro-L-arginine (L-NNA) were evaluated by organ bath technique, and the morphologic alterations of the network of ICC, myenteric neurons and neuronal nitric oxide synthase (nNOS) immunoreactive cells were evaluated using the markers of c-Kit, PGP9.5, and nNOS, respectively. To demonstrate the deficiencies in enteric neuronal origin, we also measured nNOS expression in the muscular layer of ileum. L-ornithine-induced necrotizing pancreatitis manifests with multiple symptoms, including decreased amplitude of spontaneous contractions in small intestinal smooth muscle, declined contractile response to ACh, TTX, and L-NNA in vitro, disrupted MMC cycle length, decreased dominant frequency and dominant power of slow waves in vivo. Furthermore, the morphologic studies demonstrated the damage of ICC (ANP group versus control; P = .000), myenteric neurons (ANP group versus control; P = .001) and nNOS immunoreactive neurons (ANP group versus control; P = .000). We also observed a substantial loss in the expression of nNOS protein in muscular layer of the small intestine (ANP group versus control; P = .032). Our results suggest that the pathogenesis of the small intestinal paralysis in ANP may be related to the deficiencies in ICC and nNOS neurons.

A crucial role of nitric oxide in acute lung injury secondary to the acute necrotizing pancreatitis

To investigate the role of nitric oxide (NO) in acute lung inflammation and injury secondary to acute necrotizing pancreatitis (ANP), 5% sodium taurocholate was retrogradely injected into the biliopancreatic duct of rats to ANP model. These ANP rats were given L-Arginine (L-Arg, 100 mg/kg), L-NAME (10 mg/kg), or their combination by intraperitoneal injection 30 min prior to ANP induction. At 1, 3, 6, and 12 hours after ANP induction, lung NO production, and inducible NO synthase (iNOS) expression were measured. Lung histopathological changes, bronchoalveolar lavage (BAL) protein concentration, proinflammatory mediators tumor necrotic factor alpha (TNF-alpha), and lung tissue myeloperoxidase (MPO) activity were examined. Results showed that NO production and iNOS mRNA expression in alveolar macrophages (AMs) were significantly increased along with significant increases in lung histological abnormalities and BAL proteins in the ANP group, all of which were further enhanced by pretreatment with L-Arg and attenuated by pretreatment with L-NAME, respectively. These markers were slightly attenuated by pretreatment with combination of L-Arg + L-NAME, suggesting that NO is required for initiating the acute lung damage in ANP rats, and also that L-Arg-enhanced lung injury is mediated by its NO generation rather than its direct effect. MPO activity and TNF-alpha expression in lung were upregulated in the ANP rats and further enhanced by pretreatment with L-Arg and attenuated by pretreatment with L-NAME, respectively. These results suggest that overproduction of NO mediated by iNOS in the lung is required for the acute lung inflammation and damage secondary to ANP.

Anti-inflammatory Effects of Tacrolimus in a Rat Model of Acute Pancreatitis

The present study investigated the treatment effects of the immunosuppressive agent, tacrolimus (FK506), on rats with acute necrotizing pancreatitis (ANP). We used the taurocholate-induced model of acute necrotizing pancreatitis (ANP) in rats that were divided into seven groups: The sham group included animals that underwent sham operations. The ANP group contained ANP rats induced by taurocholate. The tacrolimus groups contained ANP rats treated with tacrolimus at three different time points (prior to the induction of ANP, immediately after the induction of ANP, one hour after the induction of ANP). The somatostatin group included ANP rats treated with somatostatin. The glucocorticoids group contained ANP rats treated with glucocorticoids. At 3, 6 and 12 hours after the induction of taurocholate, blood samples were collected for TNF-alpha, IL-1beta and amylase assays, and lung and pancreas tissues were harvested for histopathological study and edema evaluation. Tacrolimus administered prior to the induction of ANP and immediately after the induction of ANP caused a significant decrease in the twenty two-hour mortality rate (p<0.05). However, tacrolimus did not decrease the mortality rate when administered one hour after the induction of ANP (p>0.05). Treatment with all three drugs (tacrolimus, somatostatin and glucocorticoids) resulted in a significant decrease of serum amylase, lung edema, and serum TNF-alpha and IL-1beta levels. Pancreatic and pulmonary morphological alterations were improved. Tancrolimus can decrease pancreatic and pulmonary injury. The effect of tacrolimus treatment is the same as that of somatostain and glucocroticoids. It is also more effective to administer the drug earlier.

Efficacy of Hyperbaric Oxygen Therapy and Medical Ozone Therapy in Experimental Acute Necrotizing Pancreatitis

Our aims were to evaluate the efficacy of ozone therapy (OT) in an experimental rat model of acute necrotizing pancreatitis (ANP) and to compare its effects with hyperbaric oxygen (HBO) therapy in this entity. Forty Sprague-Dawley rats were divided into sham-operated, ANP, ANP + HBO, and ANP + OT groups. Acute necrotizing pancreatitis was induced by infusing 1-mL/kg 3% sodium taurocholate into the common biliopancreatic duct. Hyperbaric oxygen was administered twice daily at a 2.8-atm pressure for 90 minutes. Ozone therapy was set as daily intraperitoneal injections of 0.7-mg/kg ozone/oxygen gas mixture. Hyperbaric oxygen and OT were continued for 3 days after the induction of ANP. The surviving animals were killed at the fourth day, and their pancreases were harvested for biochemical, microbiological, and histopathologic analyses. Serum amylase/lipase and neopterin levels and tissue oxidative stress parameters were similar to sham's values in both the ANP + HBO and the ANP + OT groups. Histopathologic injury scores were significantly lower in the treatments groups than in the ANP group. When compared with the ANP group, the number of infected rats was significantly lesser in the ANP + HBO and the ANP + OT groups. Hyperbaric oxygen and OT reduce the severity and the mortality in the experimental rat model of ANP, and a greater benefit was received for OT comparing with HBO.

Effects of Enalaprilat on Acute Necrotizing Pancreatitis in Rats

The aim of this study was to investigate the influence of enalaprilat on acute necrotizing pancreatitis (ANP) induced by glycodeoxycholic acid in rats. The induction of ANP resulted in a significant increase in the mortality rate, pancreatic necrosis, serum activity of amylase, alanine aminotransferase (ALT), and interleukin-6 (IL-6), lactate dehydrogenase (LDH) in bronchoalveolar lavage (BAL) fluid, serum concentration of urea, and tissue activity of myeloperoxidase (MPO) and maondialdehyde (MDA) in the pancreas and lung, and a significant decrease in concentrations of calcium, blood pressure, urine output and p0(2). The use of enalaprilat inhibited the changes in urine output, blood pressure, serum concentration of urea, p0(2), and tissue activity of MPO and MDA in the pancreas and lungs. It reduced the mortality and pancreatic damage. Enalaprilat demonstrated a beneficial effect on the course of ANP in rats; therefore, it may be used in the treatment of acute pancreatitis.