Intravenous antioxidant modulation of end-organ damage in L-arginine-induced experimental acute pancreatitis

Modulatory action of Moringa oleifera Lam. on L-arginine induced acute pancreatitis

OBJECTIVES

Acute pancreatitis (AP) is an inflammatory disease of the pancreas with high morbidity and mortality. This study investigates the effect of Moring oleifera (MO) on L-arginine-induced AP in Wistar rats.

METHODS

Male Wistar rats were randomly divided into seven groups. Control, AP, Magnesium groups, all fed with standard rat diet, MO leaf groups (5% MLF and 15% MLF), and MO seed groups (5% MSD and 15% MSD) were fed with five or 15% MO leaf or seed supplemented diet for four weeks prior to induction of AP. AP was induced by administration of double doses of L-arginine (320 mg/100 g i.p.) at 1 h interval. All animals were sacrificed 72 h thereafter.

RESULTS

Weekly mean feed consumption and body weight were significantly higher in MO groups compared to the control. Amylase level, MDA, MPO, and NO were significantly higher in the AP group than in the control but decreased in Mg and MO groups. While CAT, SOD, GSH, and SH-group were significantly depleted in AP groups, which was attenuated in MO groups. Rats in AP groups showed severe inflammation, necrosis, and edema. These effects were significantly improved in MO groups resulting in lower histological scores compared to the AP group.

CONCLUSIONS

Pretreatment with MO could attenuate AP via its antioxidant and anti-inflammatory action.

Research Progress of Antioxidant Nanomaterials for Acute Pancreatitis

Acute pancreatitis (AP) is a complex inflammatory disease caused by multiple etiologies, the pathogenesis of which has not been fully elucidated. Oxidative stress is important for the regulation of inflammation-related signaling pathways, the recruitment of inflammatory cells, the release of inflammatory factors, and other processes, and plays a key role in the occurrence and development of AP. In recent years, antioxidant therapy that suppresses oxidative stress by scavenging reactive oxygen species has become a research highlight of AP. However, traditional antioxidant drugs have problems such as poor drug stability and low delivery efficiency, which limit their clinical translation and applications. Nanomaterials bring a brand-new opportunity for the antioxidant treatment of AP. This review focuses on the multiple advantages of nanomaterials, including small size, good stability, high permeability, and long retention effect, which can be used not only as effective carriers of traditional antioxidant drugs but also directly as antioxidants. In this review, after first discussing the association between oxidative stress and AP, we focused on summarizing the literature related to antioxidant nanomaterials for the treatment of AP and highlighting the effects of these nanomaterials on the indicators related to oxidative stress in pathological states, aiming to provide references for follow-up research and promote clinical application.

Pharmacological prevention of post-operative pancreatitis: systematic review and meta-analysis of randomized controlled trials on animal studies

BACKGROUND

Postoperative pancreatic fistula (POPF) remains a significant complication of pancreatic resection with recent evidence showing a strong association between post-operative pancreatitis and subsequent development of POPF. Incidence and severity of pancreatitis following endoscopic therapy has been effectively reduced with indomethacin prophylaxis, however further agents require evaluation. We present a systematic literature review and meta-analysis of the prophylactic treatment with corticosteroids or n-acetyl cysteine (NAC) of induced pancreatitis in rodent models.

METHODS

A systematic literature search was conducted using Pubmed, Medline, Embase and Cochrane library to identify eligible randomized control trials (RCT) involving animal models that examined NAC or corticosteroids. The primary outcome was the subsequent effect on serum amylase and IL-6 and the histopathological markers of severity such as pancreatic oedema and necrosis.

RESULTS

Four RCTs (n = 178) met inclusion criteria examining NAC and eight RCTs (n = 546) examining corticosteroid agents (dexamethasone, hydrocortisone, methylprednisolone). Prophylactic administration of all corticosteroid agents showed a net effect in favour of reducing markers of severity of pancreatitis. NAC showed a significant reduction in severity of amylase and necrosis.

CONCLUSION

The RCTs examined suggest that prophylactic administration of corticosteroid agents and NAC can reduce the severity of pancreatitis as indicated by histopathologic markers, serum amylase and IL-6 levels.

The Challenges and Effects of Ascorbic Acid Treatment of Acute Pancreatitis: A Systematic Review and Meta-Analysis of Preclinical and Clinical Studies

Background: Oxidative stress has been implicated in the pathogenesis of acute pancreatitis (AP), and ascorbic acid (AA), as an important endogenous antioxidant substance, has been shown to reduce AP severity in preclinical studies. However, the effects of AA supplementation in clinical settings remain controversial. Methods: PubMed, EMBASE, MEDLINE, and SCOPUS databases were searched, and both preclinical and clinical studies were included. For clinical trials, the primary outcome was incidence of organ failure, and for preclinical studies, the primary outcome was histopathological scores of pancreatic injuries. Results: Meta-analysis of clinical trials showed that compared with controls, AA administration did not reduce the incidence of organ failure or mortality during hospitalization but was associated with significantly reduced length of hospital stay. Meta-analysis of preclinical studies showed that AA supplementation reduced pancreatic injury, demonstrated as decreased histological scores and serum amylase, lipase levels. Conclusion: AA administration has no effect on survival or organ failure in patients with AP but may reduce the length of hospital stay. However, the evidence to date remains sparse, scattered, and of suboptimal quality, making it difficult to draw any firm conclusion on the clinical benefits of AA in AP.

Experimental Acute Pancreatitis Models: History, Current Status, and Role in Translational Research

Acute pancreatitis is a potentially severe inflammatory disease that may be associated with a substantial morbidity and mortality. Currently there is no specific treatment for the disease, which indicates an ongoing demand for research into its pathogenesis and development of new therapeutic strategies. Due to the unpredictable course of acute pancreatitis and relatively concealed anatomical site in the retro-peritoneum, research on the human pancreas remains challenging. As a result, for over the last 100 years studies on the pathogenesis of this disease have heavily relied on animal models. This review aims to summarize different animal models of acute pancreatitis from the past to present and discuss their main characteristics and applications. It identifies key studies that have enhanced our current understanding of the pathogenesis of acute pancreatitis and highlights the instrumental role of animal models in translational research for developing novel therapies.

Diclofenac Sodium Treatment Ameliorates Extrapancreatic Organ Injuries in a Murine Model of Acute Pancreatitis Induced by Caerulein

Aim

We determined the effects of diclofenac sodium, octreotide, and their combination on extrapancreatic organ injuries in caerulein-induced acute pancreatitis in mice.

Methods

A total of 58 BALB-C male mice (25 g) were divided into seven groups and used to create a caerulein-induced acute pancreatitis model. Diclofenac sodium, octreotide, and their combination were given for treatment of caerulin-induced acute pancreatitis in mice. At the end of the experiment, the lung, liver, kidney, and stomach were removed for histopathologic assessment.

Results

Histopathologic investigation revealed a statistically significant difference between the groups in mean congestion, edema, tubular injury, perirenal fat tissue inflammation, and tubular stasis scores in kidney tissue (P < 0.001, P < 0.001, P < 0.001, P < 0.001, and P = 0.048, respectively); mean congestion, edema, neutrophil inflammation, mononuclear inflammation, and emphysematous change scores in the lung (P < 0.001, P < 0.001, P < 0.001, P = 0.030, and P < 0.001, respectively); mean congestion, edema, and neutrophil inflammation scores in the stomach (P = 0.008, P = 0.014, and P < 0.001, respectively); and mean congestion and hydropic degeneration scores in the liver (P = 0.029 and P = 0.002, respectively).

Conclusion

Diclofenac sodium alone ameliorates lung edema due to caerulin-induced acute pancreatitis.

Animal models of gastrointestinal and liver diseases. Animal models of acute and chronic pancreatitis

Animal models of pancreatitis are useful for elucidating the pathogenesis of pancreatitis and developing and testing novel interventions. In this review, we aim to summarize the most commonly used animal models, overview their pathophysiology, and discuss their strengths and limitations. We will also briefly describe common animal study procedures and refer readers to more detailed protocols in the literature. Although animal models include pigs, dogs, opossums, and other animals, we will mainly focus on rodent models because of their popularity. Autoimmune pancreatitis and genetically engineered animal models will be reviewed elsewhere.

Effect of tiron on remote organ injury in rats with severe acute pancreatitis induced by L-arginine

Acute pancreatitis (AP) is an acute inflammatory disorder of the pancreas that can be complicated by involvement of other remote organs. Oxidative stress is known to have a crucial role in the development of pancreatic acinar damage and one of the main causes in multisystem organ failure in experimental AP. The aim of the study was to determine the effect of tiron on pancreas and remote organ damage in L-arginine (L-Arg) induced AP rat model. Thirty-two male rats were divided in random into four groups: control, tiron, L-Arg, and tiron with L-Arg. At the end of the experiment, blood samples were withdrawn for biochemical analysis. The pancreas, lung, kidney, and liver were collected for histopathological examination. Estimation of pancreatic water content was done. Analysis of pulmonary, hepatic, renal, and pancreatic lipid peroxide levels (MDA), superoxide dismutase (SOD), and reduced glutathione (GSH) were carried out. Finally, nuclear factor kappa B (NF-κB) and transforming growth factor β1 (TGF-β1) expression in pancreatic tissue was determined. Results indicated that treatment with tiron significantly decreased lipid peroxide levels and markedly increased both SOD activity and GSH level. Moreover, histopathological analysis further confirmed that administration of tiron relatively ameliorates pancreatic acinar cells and remote organ damage. Increased immunoreactivity of NF-κB and TGF-β1 were reduced also by tiron treatment. These findings pointed out the protective role of the mitochondrial antioxidant, tiron against AP induced by L-Arg.

Oxidative stress and inflammatory signaling in cerulein pancreatitis

Oxidative stress is considered to be an important regulator of the pathogenesis of acute pancreatitis. Reactive oxygen species (ROS) regulate the activation of inflammatory cascades, the recruitment of inflammatory cells and tissue damage in acute pancreatitis. A hallmark of the inflammatory response in pancreatitis is the induction of cytokine expression, which is regulated by a number of signaling molecules including oxidant-sensitive transcription factors such as nuclear factor-κB (NF-κB) and activator protein-1 (AP-1), signal transducer and activator of transcription 3 (STAT3), and mitogen-activated protein kinases (MAPKs). Cross-talk between ROS and pro-inflammatory cytokines is mediated by NF-κB, AP-1, STAT3, and MAPKs; this crosstalk amplifies the inflammatory cascade in acute pancreatitis. Therapeutic studies have shown that antioxidants and natural compounds can have beneficial effects for patients with pancreatitis and can also influence the expression of proinflammatory cytokines in cerulein-induced pancreatitis. Since oxidative stress may activate inflammatory signaling pathways and contribute to the development of pancreatitis, antioxidant therapy may alleviate the symptoms or prevent the development of pancreatitis. Since chronic administration of high doses of antioxidants may have deleterious effects, dosage levels and duration of antioxidant treatment should be carefully determined.

Oxidative stress in acute pancreatitis: lost in translation?

Oxidative stress has been implicated in the pathogenesis of acute pancreatitis, a severe and debilitating inflammation of the pancreas that carries a significant mortality, and which imposes a considerable financial burden on the health system due to patient care. Although extensive efforts have been directed towards the elucidation of critical underlying mechanisms and the identification of novel therapeutic targets, the disease remains without a specific therapy. In experimental animal models of acute pancreatitis, increased oxidative stress and decreased antioxidant defences have been observed, changes also detected in patients clinically. However, despite the promise of studies evaluating the effects of antioxidants in these model systems, translation to the clinic has thus far been disappointing. This may reflect many factors involved in the design of both preclinical and clinical evaluations of antioxidant therapy, not least the fact that most experimental studies have focussed on pre-treatment rather than post-injury assessment. This review has examined evidence relating to the involvement of oxidative stress in the pathophysiology of acute pancreatitis, focussing on experimental models and the clinical experience, including the experimental techniques employed and potential of antioxidant therapy.

Effect of L-cysteine on remote organ injury in rats with severe acute pancreatitis induced by bile-pancreatic duct obstruction

BACKGROUND

Remote organ failure occurs in cases of acute pancreatitis (AP); however, the reports on AP induced by pancreatic duct obstruction are rare. In this study we determined the effect of L-cysteine on pancreaticobiliary inflammation and remote organ damage in rats after pancreaticobiliary duct ligation (PBDL).

METHODS

AP was induced by PBDL in rats with 5/0 silk. Sixty rats were randomly divided into 4 groups. Groups A and B were sham-operated groups that received injections of saline or L-cysteine (10 mg/kg) intraperitoneally (15 rats in each group). Groups C and D were PBDL groups that received injections of saline or L-cysteine (10 mg/kg) intraperitoneally (15 rats in each group). The tissue samples of the pancreas and remote organs such as the lung, liver, intestine and kidney were subsequently examined for pathological changes under a light microscope. The samples were also stored for the determination of malondialdehyde and glutathione levels. Blood urea nitrogen (BUN), plasma amylase, ALT and AST levels were determined spectrophotometrically using an automated analyzer. Also, we evaluated the effect of L-cysteine on remote organ injury in rats with AP induced by retrograde infusion of 3.5% sodium taurocholate (NaTc) into the bile-pancreatic duct.

RESULTS

Varying degrees of injury in the pancreas, lung, liver, intestine and kidney were observed in the rats 24 hours after PBDL. The severity of injury to the lung, liver and intestine was attenuated, while injury status was not changed significantly in the pancreas and kidney after L-cysteine treatment. Oxidative stress was also affected by L-cysteine in PBDL-treated rats. The concentration of tissue malondialdehyde decreased in the pancreas and remote organs of PBDL and L-cysteine administrated rats, and the concentration of glutathione increased more significantly than that of the model control group. However, L-cysteine administration reduced the severity of injury in remote organs but not in the pancreas in rats with NaTc-induced AP.

CONCLUSION

L-cysteine treatment attenuated multiple organ damage at an early stage of AP in rats and modulated the oxidant/antioxidant imbalance.

Experimental and clinical evidence of antioxidant therapy in acute pancreatitis

Oxidative stress has been shown to play an important role in the pathogenesis of acute pancreatitis (AP). Antioxidants, alone or in combination with conventional therapy, should improve oxidative-stress-induced organ damage and therefore accelerate the rate of recovery. In recent years, substantial amounts of data about the efficiency of antioxidants against oxidative damage have been obtained from experiments with rodents. Some of these antioxidants have been found beneficial in the treatment of AP in humans; however, at present there is insufficient clinical data to support the benefits of antioxidants, alone or in combination with conventional therapy, in the management of AP in humans. Conflicting results obtained from experimental animals and humans may represent distinct pathophysiological mechanisms mediating tissue injury in different species. Further detailed studies should be done to clarify the exact mechanisms of tissue injury in human AP. Herein I tried to review the existing experimental and clinical studies on AP in order to determine the efficiency of antioxidants. The use of antioxidant enriched nutrition is a potential direction of clinical research in AP given the lack of clues about the efficiency and safety of antioxidant usage in patients with AP.

Lung injury in acute pancreatitis: mechanisms underlying augmented secondary injury

Acute lung injury (ALI) and its more severe form, the acute respiratory distress syndrome (ARDS), are common complications of acute pancreatitis (AP). ALI/ARDS contribute to the majority of AP-associated deaths, particularly in the setting of secondary infection. Following secondary pulmonary infection there can be an exacerbation of AP-associated lung injury, greater than the sum of the individual injuries alone. The precise mechanisms underlying this synergism, however, are not known. In this review we discuss the main factors contributing to the development of augmented lung injury following secondary infection during AP and review the established models of AP in regard to the development of associated ALI.

L-Arginine-induced acute pancreatitis results in mild lung inflammation without altered respiratory mechanics

Acute lung injury is a common complication of acute pancreatitis (AP) and contributes to the majority of AP-associated deaths. Although some aspects of AP-induced lung inflammation have been demonstrated, investigation of resultant changes in lung function is limited. The aim of this study was to characterize acute lung injury in L-arginine-induced AP. Seven groups of male Sprague-Dawley rats (n = 4-10/group) received 2 intraperitoneal (i.p.) injections of L-arginine (250 mg/100 g) at 6, 12, 24, 36, 48, or 72 hours before measurement of lung impedance mechanics. Control rats (n = 10) received i.p. saline. Bronchoalveolar lavage (BAL), plasma, and pancreatic and lung tissue were collected to determine pancreatic and lung measures of acute inflammation. AP developed between 6 and 36 hours, as indicated by increased pancreatic abnormal acinar cells, myeloperoxidase (MPO) activity, edema, and plasma amylase activity, before beginning to resolve by 72 hours. In the lung, MPO activity increased (2.4-fold) from 12 hours, followed by a modest increase in lung edema at 48 hours, with increased BAL cell count (2.5-fold) up to 72 hours (P < .05). In contrast, no significant changes in lung mechanics were evident over the same period. Despite measurable lung inflammation, no significant deterioration in respiratory function resulted from L-arginine-induced AP.

Protective effects of the free radical scavenger edaravone on acute pancreatitis-associated lung injury

Impaired lung function is the primary contributor to most deaths associated with severe acute pancreatitis. It is widely accepted that oxidative stress plays a central role in the pathogenesis of pancreatitis and associated complications. Therefore, in the present study, we investigated whether therapeutic treatment with the free radical scavenger edaravone could protect rats against acute pancreatitis and the associated lung injury. Acute pancreatitis was induced by infusion of 1ml/kg of sodium taurocholate (3% solution) into the biliopancreatic duct. Edaravone (8mg/kg) was administered 1h and 13h after inducing pancreatitis, the severity of pancreatic and pulmonary injuries was evaluated 24h after inducing pancreatitis. Edaravone treatment significantly reduced the elevated malondialdehyde levels in rat lungs after acute pancreatitis, suggesting an important role for free radicals in acute pancreatitis-associated lung injury. In addition, edaravone showed significant protective effects against neutrophil infiltration and tissue injury in both pancreas and lung, as demonstrated by serum amylase levels, myeloperoxidase activity and histopathological analysis. Edaravone treatment also attenuated the elevated mRNA levels of pro-inflammatory cytokines interleukin (IL)-6 and tumor necrosis factor alpha (TNF-alpha) in rat lungs after acute pancreatitis. In conclusion, edaravone protects rats against acute pancreatitis-associated lung injury, probably through its antioxidant and anti-inflammatory effects. Thus, edaravone shows promise as a treatment for lung injury in patients with acute pancreatitis.

Green tea polyphenols ameliorate pancreatic injury in cerulein-induced murine acute pancreatitis

OBJECTIVE

Green tea polyphenols (GTPs) are naturally occurring antioxidants acting through pathways that include reactive oxygen species and nuclear factor kappa B (NF-kappaB). This study investigates the effect of GTPs in a cerulein-induced murine model of acute pancreatitis (AP).

METHODS

Male CD mice (median weight, 37.7 g) were divided into 4 groups: mice administered with cerulein alone, cerulein and GTP, saline alone (sham), and GTP alone. Acute pancreatitis was induced by serial intraperitoneal administration of cerulein (50 microg/kg, x6). Green tea polyphenol was administered intraperitoneally at 25 mg/kg on the first, third, and sixth hours after pancreatitis induction.We analyzed histologic and biochemical features of AP, NF-kappaB pathway activity, leukocyte-mediated damage, cytokine levels, oxidative stress injury, lipid peroxidation, expression of poly-(adenosine diphosphate-ribose) synthetase, and presence of apoptosis.

RESULTS

Treatment with GTP reduced the histologic and biochemical features of AP. Western blot revealed significant NF-kappaB inactivation. Immunostaining for P selectin and intercellular adhesion molecule 1, tumor necrosis factor alpha, transforming growth factor beta, vascular endothelial growth factor, nitrotirosine, poly-(adenosine diphosphate ribose) synthetase, and malondialdheide levels were significantly reduced. There was a significant down-regulation of apoptotic markers.

CONCLUSIONS

Our results demonstrated that GTP significantly ameliorated the effects of cerulein-induced AP in mice. These effects of GTP are mediated by actions at the NF-kappaB/IkB (inhibitor kB) proteins and oxidative stress pathways.

Medical treatment of severe acute pancreatitis with multiple organ dysfunction syndrome

Severe acute pancreatitis (SAP) is one of the crucial acute abdominal diseases. Multiple organ dysfunction syndromes (MODS) is the main cause of death in SAP patients. The medical treatment measures include the fundamental cure such as fluid resuscitation, correction of the internal environment disorder and hyoxemia, and preferred application of somatostatin, adequate use of trypsin inhibitors, antibiotics and early enteral nutrition. In addition, immunomodulation, antioxidants, blood purification and endoscopic interventional therapy may be selective to improve the prognosis of SAP.

Transsulfuration pathway defects and increased glutathione degradation in severe acute pancreatitis

Glutathione depletion is a consistent feature of the progression of mild to severe acute pancreatitis. In this study, we examined the temporal relationship between cysteine, homocysteine, and cysteinyl-glycine levels; total reduced erythrocyte glutathione; gamma-glutamyl transpeptidase activity; and disease severity. Initially, cysteine concentration was low, at levels similar to those of healthy controls. However, glutathione was reduced whilst cysteinyl glycine and gamma-glutamyl transpeptidase activity were increased in both mild and severe attacks. As the disease progressed, glutathione and cysteinyl glycine were further increased in mild attacks and cysteine levels correlated with homocysteine (r = 0.8, P < 0.001) and gamma-glutamyl transpeptidase activity (r = 0.75, P < 0.001). The progress of severe attacks was associated with glutathione depletion, reduced gamma-glutamyl transpeptidase activity, and increased cysteinyl glycine that correlated with glutathione depletion (r = 0.99, P = 0.01). These results show that glutathione depletion associated with severe acute pancreatitis occurs despite an adequate cysteine supply and could be attributed to heightened oxidative stress coupled to impaired downstream biosynthesis.

Relationship between acute pancreatitis and oxidative stress

Under the imbalance between generation of reactive oxygen species and inadequate antioxidant defense systems, oxidative stress can cause cell damage either directly or indirectly through altering signaling pathways. It is the etiopathogenisis and also the consequence of many diseases. Oxidative injury plays an important role not only in the pathogenesis of acute pancreatitis (AP) but also in pancreatitis-induced damages of other organs such as heart, liver, lung, kidney, alimentary canal and so on. Oxidative stress can produce a higher level of reactive oxygen species (ROS) and reactive nitrogen species (RNS), which induce inflammatory reaction and microcirculation disturbance, and cell necrosis or apoptosis, leading to pancreatic inflammation and multiple organ dysfunction syndromes. The antioxidants can decrease the production of oxygen free radicals (or directly scavenge them), protect the antioxidant enzyme activity, reinforce the antioxidative capacity of bodies, and consequently play an obvious therapeutic effect on AP.

Development of a new mouse model of acute pancreatitis induced by administration of L-arginine

The pathogenesis of acute pancreatitis is not fully understood. Experimental animal models that mimic human disease are essential to better understand the pathophysiology of the disease and to evaluate potential therapeutic agents. Given that the mouse genome is known completely and that a large number of strains with various genetic deletions are available, it is advantageous to have multiple reliable mouse models of acute pancreatitis. Presently, there is only one predominant model of acute pancreatitis in mice, in which hyperstimulatory doses of cholecystokinin or its analog caerulein are administered. Therefore, the aim of this study was to develop another mouse model of acute pancreatitis. In this study, C57BL/6 mice were injected intraperitoneally with L-arginine in two doses of 4 g/kg each, 1 h apart. Serum amylase, myeloperoxidase, and histopathology were examined at varying time points after injection to assess injury to the pancreas and lung. We found that injection of L-arginine was followed by significant increases in plasma amylase and pancreatic myeloperoxidase accompanied by marked histopathological changes. The injury to the pancreas was slow to develop and peaked at 72 h. Subsequent to peak injury, the damaged areas contained collagen fibers as assessed by increased Sirius red staining. In contrast, D-arginine or other amino acids did not cause injury to the pancreas. In addition, acute inflammation in the pancreas was associated with lung injury. Our results indicate that administration of L-arginine to mice results in severe acute pancreatitis. This model should help in elucidating the pathophysiology of pancreatitis.

Acute pancreatitis: animal models and recent advances in basic research

Acute pancreatitis (AP) is characterized by edema, acinar cell necrosis, hemorrhage, and severe inflammation of the pancreas. Patients with AP present with elevated blood and urine levels of pancreatic digestive enzymes, such as amylase and lipase. Severe AP may lead to systemic inflammatory response syndrome and multiorgan dysfunction syndrome, which account for the high mortality rate of AP. Although most (>80%) cases of AP are associated with gallstones and alcoholism, some are idiopathic. Although the pathogenesis of AP has not yet been elucidated, a common feature is the premature activation of trypsinogen within pancreatic tissues, which triggers autodigestion of the gland. Recent advances in basic research suggest that etiologic factors including cyclooxygenase-2, substance P, and angiotensin II may have novel roles in this disease. Basic research data obtained thus far have been based on animal models of AP ranging from mild edematous pancreatitis to severe necrotizing pancreatitis. In view of this, an adequate selection of experimental animal models is of paramount importance. Notwithstanding these animal models, it should be emphasized that none of these models mimic the clinical situation where varying degrees of severity usually occur. In this review, commonly used animal models of AP will be critically evaluated. A discussion of recent advances in our knowledge about AP risk factors is also included.

Role of Kupffer cells in acute hemorrhagic necrotizing pancreatitis-associated lung injury of rats

AIM: To investigate the role of Kupffer cells (KCs) in acute hemorrhagic necrotizing pancreatitis-associated lung injury (AHNP-LI).

METHODS: Forty-two rats were allocated to four groups [sham operation, AHNP model, gadolinium chloride (GdCl₃) pretreatment, GdCl₃ control]. In GdCl₃ pretreatment group, GdCl₃ was administered by caudal vein injection 24 h before the AHNP model induction. Blood from the iliac artery, alveolar macrophages and tissues from the pancreas and lung, were collected in six animals per group 3 and 6 h after acute pancreatitis induction. TNF-α, IL-1 of serum, myeloperoxidase (MPO) of lung tissue, NF-κB activation of alveolar macrophages were detected. Serum AST and ALT in sham operation group and GdCl₃ control group were tested. In addition, histopathological changes of the pancreas and lung were observed under light microscope.

RESULTS: MPO of lung tissue and TNF-α, IL-1 levels of serum were all reduced significantly in GdCl₃ pretreatment group compared to those in AHNP group (P <0.01). NF-κB activation of alveolar macrophages was also attenuated significantly in GdCl₃ pretreatment group compared to that in AHNP group (P <0.01). The pathological injury of the lung was ameliorated obviously in GdCl₃ pretreatment group compared to that in AHNP group. Nevertheless, the serum amylase level did not reduce and injury of the pancreas was not prevented in GdCl₃ pretreatment group.

CONCLUSION: Pulmonary injury induced by AHNP is mediated by KC activation and AHNP-LI can be significantly ameliorated by pretreatment with GdCl₃ and KCs play a vital role in AHNP-LI.