Pancreatic Histological Scores Research Articles

Activation of dorsal motor nucleus cholinergic neurons ameliorates the severity of acute pancreatitis

Clusters of neuron cell bodies, termed nuclei, residing in the brainstem are the origin of cranial nerves which transmit action potentials controlling organ function. Neurons residing in the brainstem dorsal motor nucleus (DMN) project in the vagus nerve to communicate with the pancreas, liver, gastrointestinal tract and other organs. Cholinergic signaling in the vagus nerve‐mediated inflammatory reflex also controls immune system responses by inhibiting the production of cytokines in the spleen, although the function of DMN neurons in regulating pancreatic inflammation is not known. Here, we demonstrate that selective activation of cholinergic neurons in the DMN attenuates pancreatitis severity. Pancreatitis was induced with two intraperitoneal injections of the cholecystokinin analogue caerulein (50 mcg/kg), given one hour apart. A fiber‐optic cannula was inserted under stereotactic guidance into the DMN in transgenic mice expressing light‐responsive ion channel, channelrhodopsin, in cholinergic neurons under the choline acetyltransferase promoter. Animals were subjected to either optogenetic stimulation (473nm, 20 Hz, 25% duty cycle, 8‐12 mW total power) or sham stimulation (no light) for five minutes. Optogenetic stimulation but not sham stimulation of the cholinergic neurons in the DMN significantly attenuates serum amylase (4043mU/mL ± 264.4 vs. 2940mU/mL ± 170.9, p=0.0074; n=9‐11 mice/group) and pancreatic IL‐6 levels (1907pg/mg ± 879.3 vs. 1046pg/mg± 288.1, p=0.0330; n=9‐11 mice/group). The decreased severity of pancreatitis in optogenetically stimulated mice is further demonstrated by a significant improvement in pancreatic histologic severity score (6.86 ± 1.67 vs. 5.35 ± 1.44, p = 0.0462; n = 9‐11). Pharmacological blockade and surgical ablation of the vagus nerve signaling inhibit protective effects of DMN cholinergic neurons activation. Pre‐treatment with mecamylamine, a nicotinic receptor antagonist, attenuates the reduction in serum amylase following light stimulation (Sham stimulation vs. DMN vs DMN + Mecamylamine: 5047 ± 315.4 vs. 3769 ± 241.5 vs. 5620 ± 385.9, p = 0037; n = 10 mice/group). Additionally, mice with subdiaphragmatic vagotomy has no difference in serum amylase levels following optogenetic stimulation (2761mU/mL ± 787.3 vs. 2517mU/mL, p= 0.300; n=3), whereas sham surgery controls show a significant reduction in serum amylase levels (3224mU/mL ± 593.1 vs. 2087 mU/mL ± 951.2, p=0.0303; n=6 mice/group). These studies identify DMN as an important locus that regulates the severity of acute pancreatitis in vagus‐nerve‐dependent fashion, and provide new insights into the identity and central origin of the efferent vagus nerve fibers regulating acute pancreatitis.

Effects of Pioglitazone Pretreatment on the Expression of NF-κB, ICAM-1 and p38MAPK Pathway in Pancreatic Tissue of Rats with Acute Pancreatitis

To investigate the effects of pioglitazone pretreatment on the expression of nuclear factor kappa B and intercellular adhesion molecule-1 and p38 mitogen activated protein kinase pathway in pancreatic tissue of rats with acute pancreatitis. 72 specific pathogen-free adult female Sprague–Dawley rats and male Sprague–Dawley rats were randomly divided into sham operation group, model group and pioglitazone pretreatment group (pretreatment group), with 24 rats in each group. Compared with sham operation group, the amount of ascites in model group was significantly increased, the levels of serum and ascites amylase, serum tumor necrosis factor-alpha, interleukin-6, pancreatic gross score, pancreatic histological score, nuclear factor kappa B and intercellular adhesion molecule-1 in pancreatic tissue were significantly increased. Compared with the model group, the amount of ascites in the pretreatment group was significantly reduced and the levels of serum and ascites amylase, serum tumor necrosis factor-alpha, interleukin-6, pancreatic gross score and pancreatic histological score, the expression levels of nuclear factor kappa B, intercellular adhesion molecule-1 and phospho-p38 mitogen activated protein kinase in pancreatic tissue were significantly decreased (p<0.05). In the sham operation group, the pancreatic tissue structure was clear with occasional inflammatory cells or mild hyperemia and edema and the acinar lobules were intact; in the model group, the pancreatic stroma showed hyperemia and edema, even necrosis, with obvious inflammatory cell infiltration and acinar lobule structure disorder and the pathological changes were gradually aggravated with the extension of time; in the pretreatment group, the pancreatic tissue inflammatory cell infiltration and other pathological changes were observed compared with the model group, it was significantly improved. Pioglitazone pretreatment can inhibit the inflammatory response, reduce the level of amylase, inhibit the expression of nuclear factor kappa B and intercellular adhesion molecule-1 and inhibit the activity of intercellular adhesion molecule-1 signaling pathway in rats with acute pancreatitis.

Octreotide alleviates pancreatic damage caused by paraquat in rats by reducing inflammatory responses and oxidative stress

This study explores the efficacy and mechanism by which octreotide (OCT) alleviates paraquat (PQ)-induced pancreatic injury. Twenty-four adult male rats were randomly divided into three groups: the normal control (NC), PQ poisoning, and OCT treatment groups. The PQ-induced pancreatic injury rat model was established by administering PQ (120 mg/kg). Treatment group rats received OCT (8 μg/kg body weight) every 8 h by subcutaneous injection, 1 h after PQ administration. Rats were euthanized 24 h after PQ injection. Serum amylase, lipase, tumor necrosis factor-α, and interleukin-6 levels were markedly increased in the PQ group versus the NC group. In pancreatic tissue, PQ poisoning drastically induced necrosis and increased inflammatory cytokine and oxidative stress marker levels. Compared with the PQ group, OCT reduced pancreatic damage and histological scores, serum amylase, lipase, and inflammatory cytokine levels, as well as oxidative stress. OCT demonstrates protective effects against PQ-induced pancreatic damage through anti-inflammatory and antioxidant actions.

SRT1720 ameliorates sodium taurocholate-induced severe acute pancreatitis in rats by suppressing NF-κB signalling.

Severe acute pancreatitis (SAP) is a medical emergency that is often associated with multiple organ failure and high mortality. Although an SAP diagnosis requires prompt treatment, therapeutic options remain limited. SRT1720 is a newly formulatedSIRT1 activator that exerts multiple pharmacological activities with beneficial health effects. However, its potential as an SAP treatment has not been explored. The current study assessed the effect of SRT1720 on a rat model of sodium taurocholate-induced SAP and explored the underlying mechanism. SAP was induced in rats by retrograde injection of a 3.5% sodium taurocholate solution (1 ml/kg) in the biliopancreatic duct. SRT1720 (5 mg/kg) was administered intraperitoneally after sodium taurocholate exposure. Serum samples were analysed for inflammatory cytokine levels and select enzymatic activities using the enzyme-linked immunosorbent assay and commercial enzyme activity assay kits, respectively; protein expression levels were evaluated by western blotting; mRNA levels of biomarkers were determined by quantitative real-time PCR; histopathological changes were analysed by haematoxylin and eosin staining and immunohistochemistry.SRT1720 treatment significantly reduced serum amylase, lipase, pancreatic histological scores, proinflammatory cytokine (TNF-α and IL-6) levels, and expression of NF-κB and p65 in sodium taurocholate-induced SAP rats. Importantly, the treatment stimulated SIRT1 and IκBα levels in pancreatic tissue. Our data suggest that SRT1720 protects rats from sodium taurocholate-induced SAP by suppressing the NF-κB signalling pathway.

Astaxanthin ameliorates cerulein-induced acute pancreatitis in mice

BackgroundA various of pharmacological effects of astaxanthin has been confirmed. However, the mechanism underlying protective effect of astaxanthin on acute pancreatitis (AP) induced by cerulein still unclear. The present study is to investigate the mechanism underlying the effect of astaxanthin on autophagy and apoptosis via the JAK/STAT3 pathway. MethodsIntraperitoneal injection of cerulein at hourly intervals followed by lipopolysaccharide injection were used in Balb/C mice. Vehicle or astaxanthin, which intraperitoneal injected in two doses (20 mg/kg and 40 mg/kg), were injected in mice 1 h before the first cerulein injection. At 3 h after the last injection, when the pathological changes were most severe, pancreatic tissue was analyzed by pathologically scored and hematoxylin and eosin (H&E) staining. The severity of AP was assessed by histological grading, proinflammatory cytokine levels, biochemistry, myeloperoxidase (MPO) activity, and analysis of JAK/STAT3 activity. ResultsAstaxanthin administration markedly reduced serum digestive enzyme activities, pancreatic histological scores, proinflammatory cytokine levels (tumor necrosis factor-α (TNF-α), Interleukin-1β (IL-1β), and Interleukin-6 (IL-6)), MPO and JAK/STAT3 activity. ConclusionCollectively, these results indicate that astaxanthin inhibits pancreatic injury in AP by targeting JAK/STAT3-mediated apoptosis and autophagy.

Clinical trials in progress of chemotherapy for unresectable pancreatic cancer in Japan

The aim of this study was to investigate the role of hypertriglyceridemia for acute kidney injury (AKI) in the course of acute pancreatitis.Patients with acute pancreatitis were retrospectively divided into four groups according to admission triglyceride: normal group, mild HTG group, moderate HTG group and severe HTG group. Clinical characteristics were compared among these groups. Wild type (WT) mice and Human ApoC III transgenic (ApoCIIItg) mice were used in the next animal experiments. Severe acute pancreatitis (SAP) model was established by retrograde injection of 0.5% sodium taurocholate (0.1 ml/100 g) from duodenum to pancreatic duct. Histological scores, serum amylase, creatinine, usea nitrogen were compared between WT mice and ApoCIIItg mice.Two hundred and sixty-two patients were classified into 4 groups: normal TG (104, 39.7%), mild HTG (72, 27.5%), moderate HTG (47, 17.9%), and severe HTG (39, 14.9%) groups. The proportions of AKI were 13.5% (14/104, normal), 13.9% (10/72, mild), 21.3% (10/47, moderate), and 38.5% (15/39, severe), respectively. After establishing SAP model, the levels of serum amylase (P < 0.05) and pancreatic histological score (P < 0.05) of ApoCIII-SAP-9h group were significantly higher than that of WT-SAP-9h group, respectively. ApoCIII-SAP-9h group had significantly higher levels of serum creatinine (P < 0.001), usea nitrogen (P < 0.001), and kidney histological score (P < 0.05) than that of WT-SAP-9h group, respectively.Mild HTG has little adverse impact on disease severity of acute pancreatitis; severe HTG can aggravate kidney injury in the course of acute pancreatitis. ApoCIII-SAP mice have more serious pancreatic damage and kidney injury than WT-SAP mice.

The role of hypertriglyceridemia for acute kidney injury in the course of acute pancreatitis and an animal model

ObjectiveThe aim of this study was to investigate the role of hypertriglyceridemia for acute kidney injury (AKI) in the course of acute pancreatitis. MethodsPatients with acute pancreatitis were retrospectively divided into four groups according to admission triglyceride: normal group, mild HTG group, moderate HTG group and severe HTG group. Clinical characteristics were compared among these groups. Wild type (WT) mice and Human ApoC III transgenic (ApoCIIItg) mice were used in the next animal experiments. Severe acute pancreatitis (SAP) model was established by retrograde injection of 0.5% sodium taurocholate (0.1 ml/100 g) from duodenum to pancreatic duct. Histological scores, serum amylase, creatinine, usea nitrogen were compared between WT mice and ApoCIIItg mice. ResultsTwo hundred and sixty-two patients were classified into 4 groups: normal TG (104, 39.7%), mild HTG (72, 27.5%), moderate HTG (47, 17.9%), and severe HTG (39, 14.9%) groups. The proportions of AKI were 13.5% (14/104, normal), 13.9% (10/72, mild), 21.3% (10/47, moderate), and 38.5% (15/39, severe), respectively. After establishing SAP model, the levels of serum amylase (P < 0.05) and pancreatic histological score (P < 0.05) of ApoCIII-SAP-9h group were significantly higher than that of WT-SAP-9h group, respectively. ApoCIII-SAP-9h group had significantly higher levels of serum creatinine (P < 0.001), usea nitrogen (P < 0.001), and kidney histological score (P < 0.05) than that of WT-SAP-9h group, respectively. ConclusionsMild HTG has little adverse impact on disease severity of acute pancreatitis; severe HTG can aggravate kidney injury in the course of acute pancreatitis. ApoCIII-SAP mice have more serious pancreatic damage and kidney injury than WT-SAP mice.

PropyleneGlycolAlginateSodiumSulfateAlleviates Cerulein-InducedAcutePancreatitisbyModulating theMEK/ERKPathwayinMice.

Previous studies have focused on the effects of propylene glycol alginate sodium sulfate (PSS) against thrombosis, but the anti-inflammatory potential is unknown. Therefore, we specifically focused on the protective effects of PSS on cerulein-induced acute pancreatitis (AP) using a mouse model, and investigated the mechanism of PSS on autophagy and apoptosis via the Mitogen-activated protein kinase (MEK)/extracellular signal-regulated kinase (ERK) pathway. Cerulein (100 ug/kg) was used to induce AP by ten intraperitoneal injections at hourly intervals in Balb/C mice. Pretreatment with vehicle or PSS was carried out 1 h before the first cerulein injection and two doses (25 mg/kg and 50 mg/kg) of PSS were injected intraperitoneally. The severity of AP was assessed by pathological score, biochemistry, pro-inflammatory cytokine levels, myeloperoxidase (MPO) activity and MEK/ERK activity. Furthermore, pancreatic histological scores, serum amylase and lipase activities, tumor necrosis factor-α (TNF-α), interleukin (IL)-1β interleukin (IL)-6 levels, and MPO activity were significantly reduced by PSS via up-regulated MEK/ERK activity. The representative molecules of apoptosis and autophagy, such as Bcl-2, Bax, Lc-3, Beclin-1, P62, were remarkably reduced. Taken together, these results indicate that PSS attenuates pancreas injury by inhibiting autophagy and apoptosis through a mechanism involving the MEK/ERK signaling pathway.

Effects of vagotomy on pathophysiology in dog's acute necrotizing pancreatitis model

Objective To study the effect of cutting vagus nerves on pathophysiology in dog model of acute necrotizing pancreatitis (ANP).Methods Twenty-six male adult hybrid dogs with good health were randomly divided into sham operation group (SG),control group (CG) and vagotomy group (VG).ANP model was induced by the retrograde injection of 5％ sodium taurocholate and trypsin into the pancreatic duct.The serum levels of pancreatic amylase (AMY),high-sensitivity C-reactive protein (HCRP),tumor necrosis factor α (TNF-α) and interleukin 10 (IL-10) were monitored at different time-points after the operation,and then all the animals were sacrificed on postoperative day 7.The pancreas specimens were collected for pathological examinations,and histologic score were assessed.The dogs which died during the study period were recorded,and the causes of death were analyzed.Results There was no significant difference between these three groups on the level of serum AMY、HCRP、TNF-α and IL-10 before the operation (P ＞ 0.05).We found that the level of serum AMY、HCRP、TNF-a and IL-10 in CG group were increased compared with SG group after the success of the moulding.The levels of TNF-a and HCRP were significantly higher in VG than in CG group (P =0.001),but the level of IL-10 was lower than CG group (P =0.023).However,there was no significant difference between VG and CG in terms of the levels of serum AMY (P =0.158).Pancreatic histologic score of SG was the lowest,and pancreatic histologic score of VG was significantly higher than CG (P =0.03).Two dogs in CG group died in the experiment,four dogs in VG group died,and no death occurred in SG group.Conclusions The result implies the vagus nerve as a regulating role in the early stage of ANP.Cutting vagus nerves could exacerbate the development of ANP. Key words: Vagotomy; Acute necrotizing pancreatitis (ANP) ; Cytokines

Shikonin ameliorates cerulein-induced acute pancreatitis in mice

Ethnopharmacological relevanceShikonin, a highly liposoluble naphthoquinone pigment isolated from the traditional medical herbs Lithospermum erythrorhizon (LE), was considered to exhibit an anti-inflammatory property. While the potential of shikonin to ameliorate acute pancreatitis (AP) is unknown. Our aim was to investigate the effects of shikonin in a murine model of cerulein-induced pancreatitis. Materials and methodsAP was induced in mice by six intraperitoneal injection of cerulein (50μg/kg) at hourly intervals. Vehicle or shikonin (50mg/kg) was pretreated 2h before the first cerulein injection. After 6h, 9h and 12h of the first cerulein injection, the severity of acute pancreatitis was assessed by biochemistry, myeloperoxidase activity, histological grading, proinflammatory cytokines levels and nuclear factor kappa B (NF-κB) activity. ResultsShikonin administration significantly reduced serum amylase and lipase activities, pancreatic histological scores, TNF-α, IL-1β, IL-6 levels, MPO activity and NF-κB activity. ConclusionTaken together, these results suggest that shikonin might protect against experimental pancreatitis by reducing release of inflammatory cytokines via inhibition of NF-κB activity. The therapeutic role of shikonin in AP needs further investigation.

Dynamic changes of cytokines and the effect of pioglitazone on them in early stage of severe acute pancreatitis

Objective To observe the dynamic changes and significances of TNF-α， IL-6 and IL-10 in severe acute pancreatitis (SAP) rats， and assess the effect of pretreatment with pioglitazone on them.Methods 54 male Sprague-Dawley(SD) rats were randomly divided into sham group(C group)， SAP group， and pioglitazone group(P group). (1) SAP group was induced by the retrograde injection of sodium taurocholate (STC) in the pancreatic duct (n＝18)； (2) P group (same as SAP group， but pioglitazone(50 mg/kg) was injected intraperitoneally two hours prior to STC(n＝18)； (3) Sham operation group. Sham-operated animals served as control. Operation was executed， STC was not injected， but pancreas was flipped and striked gently three times. Rats were killed by abdominal aorta exsanguination at 3 h， 6 h and 12 h after the induction of pancreatitis. Serum activities of amylase were measured， the concentrations of inflammatory cyctokines (TNF-α，IL-6 and IL-10) of the blood were measured by ELISA and pancreatic histologic score were assessed.Results Compared with C group， pancreatic histologic score， serum amylase， TNF-α and IL-6 in SAP group were increased significantly (P<0.01) except IL-10 level(P＞0.05). Pretreatment with pioglitazone obviously decreased histologic score and the serum level of amylase， TNF-α， IL-6， and the level of IL-10 was higher than SAP group in early SAP(P<0.05). Conclusions Cytokines play an important role in early progress of SAP； pioglitazone could attenuate the severity of inflammatory response through regulating the balance of pro- and anti-inflammatory cytokines.

Pioglitazone: A Promising Therapeutic Tool in Sodium Taurocholate-Induced Severe Acute Pancreatitis

Studies suggest that peroxisome proliferator-activated receptor γ(PPARγ) ligands may represent a therapeutic option in acute pancreatitis, yet most of them have been prophylactic administrated. To evaluate the therapeutic effect of pioglitazone in rats with severe acute pancreatitis induced by sodium taurocholate. Severe acute pancreatitis (SAP) was induced in male Sprague-Dawley rats by the retrograde injection of 5% sodium taurocholate into the pancreatic duct. After SAP was induced, pioglitazone was injected intraperitoneally and its role on the severity of inflammatory response and pancreatic injury was investigated. Amylase activity, inflammatory cytokines production, pathological changes of pancreas, PPARγ mRNA expression, and the survival rate were examined. Treatment with pioglitazone decreased the level of amylase activity, proinflammatory factors IL-6 and TNF-α, ameliorated pancreatic histological score, and upregulated the expression of PPARγ mRNA. The survival rate in the early stage of severe acute pancreatitis was also improved. Pioglitazone can be used as a therapeutic drug and relieve the damages caused by SAP, which suggests PPARγ ligand-pioglitazone offers a potent approach for the treatment of severe acute pancreatitis.

Crucial role of group IIA phospholipase A2 in pancreatitis-associated adrenal injury in acute necrotizing pancreatitis

This study investigated the mechanistic role of group IIA phospholipase A2 (sPLA2-IIA) in the process of pancreatitis-associated adrenal injury in acute necrotizing pancreatitis. One hundred and sixty male Wistar rats were subdivided into a sham-operated group, a sodium taurocholate-induced pancreatitis group, and a pancreatitis group pretreated with sPLA2 inhibitor (pku-mdl-101). The sPLA2 inhibitor was administered by intravenous injection 30 min before induction of pancreatitis. The severity of pancreatitis was evaluated by serum amylase and pancreatic histological score. The serum corticosterone level was measured. Adrenal injury was evaluated by histological evaluation, as well as by sPLA2 activity and sPLA2-IIA protein analysis. Pancreatitis resulted in a time-related increase in serum amylase and in the pancreatic histological score. At first, serum corticosterone increased after 3 h and decreased rapidly after 6 h in pancreatitis. Adrenal injury aggravated during the observation period. The sPLA2 activity in the serum and adrenal glands, as well as the expression of sPLA2-IIA protein in adrenal glands increased and peaked 6 h after the induction of pancreatitis. Pretreatment of sPLA2 inhibitor significantly reduced the severity of pancreatitis and adrenal histological injury, improved the 24-h serum corticosterone levels, and effectively inhibited sPLA2 activity and sPLA2-IIA expression in adrenal glands. The sPLA2 inhibitor attenuated the severity of pancreatitis and pancreatitis-associated adrenal injury. The observations indicate that sPLA2-IIA plays a crucial role in pancreatitis-associated adrenal injury in acute necrotizing pancreatitis.

Effect of prom activated receptor-2 on severe acute pancreatitis

Objective To investigate effect of protease activated receptor-2 (PAR-2) on pancreatic pathological damage in severe acute pancreatitis (SAP) in rats. Methods Experimental necrotic acute pancreatitis model was established by injection of 3.5% sodium taurocholate via the pan-creatic duct. A total of 36 rats were randomized into the control group, SAP group and pancreastitis with PAR-2 activating peptide group (PAR-2 group). All the rats were sacrificed 3 hours after injec-tion of sodium taurocholate. Immunohistoehemical analysis was used to test the expression of PAR-2 in pancreas before and after the induction of SAP. Histological score of pancreatic tissue specimen was assessed microscopically. Meanwhile, the ratio of pancreatic wet dry weight, the contents of my-eloperoxidase (MPO) and Evans blue leakage rate were determined. Interleukin-6 (IL-6) in serum was tested using ELISIA. Results PAR-2 was weakly expressed in cytoplasm and membrane before SAP was induced, and the expression increased after inducing of SAP. Activating PAR-2 significantly re-duced pancreatic histological score, MPO content, wet dry weight ratio and EB leakage rate. There was correlation between pancreatic histological score and IL-6. Conclusion The expression of PAR-2 increases after inducing of SAP. PAR-2 can reduce the severity of pancreatic inflammation and plays a protective role in the local pancreatic injury. Key words: Pancreatitis; Sodium taurocholate; Protease activated receptor-2

Effects of N-acetylcysteine on mRNA expression of monocyte chemotactic protein and macrophage inflammatory protein 2 in acute necrotizing pancreatitis: experiment with rats

To explore the potential role of monocyte chemotactic protein 1 (MCP-1) and macrophage inflammatory protein 2 (MIP-2) in the pathogenesis of acute necrotizing pancreatitis (ANP), and to study the effect of N-acetylcysteine (NAC) on the mRNA expression of MCP-1 and MIP-2. Thirty-five SD rats were randomly divided into 3 groups: sham-operation (SO) group (n = 5), acute necrotizing pancreatitis (ANP) group (n = 15), and NAC-pretreated group (n = 15), ANP were induced by retrograde injection of 4% sodium taurocholate into the biliopancreatic duct. The NAC- groups underwent intraperitoneal injection of NAC 500 mg/kg 30 minutes before the induction of sodium taurocholate. The ANP and NAC groups were re-divided into 3 equal subgroups respectively: 3 h, 6 h, and 12 h subgroups. 3, 6, and 12 hours after the establishment of models heart blood samples were collected from 5 rats from each model group to detect the serum amylase. Then the rats were killed by blood letting with their pancreases taken out. HE staining and microscopy were used to observe the pathological changes of the pancreas. The wet/dry ratio of pancreas was determined. Enzyme histochemical method was used to detect the activity of myeloperoxidase (MPO) in the pancreas. RT-PCR was used to examine the mRNA expression of MCP-1 and MIP-2. The levels of serum amylase, wet/dry ratio of pancreas, pancreatic MPO activity, and histological score of pancreas of the ANP group increased time-dependently, all the levels at different time-points were significantly higher than those of the SO group (all P < 0.01). The expression levels of MCP-1 mRNA at the time points 3, 6, and 12 h of the ANP group were 0.3653 +/- 0.0213, 0.5890 +/- 0.0225, and 0.7164 +/- 0.0275 respectively, all significantly higher than that of the SO group (0.1492 +/- 0.0036, all P < 0.01). The expression levels of MIP-2 mRNA at different time points of the ANP group were 0.3871 +/- 0.0286, 0.6040 +/- 0.0448, and 0.7692 +/- 0.0620 respectively, all significantly higher than that of the SO group (0.1593 +/- 0.0117, all P < 0.01). The intrapancreatic MPO levels at the time points 3 h, 6 h, and 12 h of the NAC group were 0.63 +/- 0.03, 0.88 +/- 0.05, and 1.31 +/- 0.09 respectively, all significantly lower than those of the ANP groups (0.89 +/- 0.03, 1.42 +/- 0.14, and 1.94 +/- 0.07, all P < 0.05). The MCP-1 mRNA expression levels at different time points the NAC group were 0.2497 +/- 0.0168, 0.4457 +/- 0.0097, and 0.6306 +/- 0.0423 respectively, and the MIP-2 mRNA expression levels at the time points 3 h, 6 h, and 12 h of the NAC group were 0.2436 +/- 0.0099, 0.4312 +/- 0.0221, and 0.6302 +/- 0.0288 respectively, all significantly lower than those of the ANP group (all P < 0.05). The pancreatic histological scores at different time points of the NAC group were 3.50 +/- 0.61, 5.60 +/- 0.65, and 7.50 +/- 0.79, all significantly lower than those of the ANP group (5.10 +/- 0.42, 7.50 +/- 0.50, and 9.90 +/- 0.96, all P < 0.05). The MCP-1 mRNA expression and MIP-2 mRNA expression were both correlated with the severity of pancreatic injury (r = 0.76 and 0.82, both P < 0.05). The chemokines of MCP-1 and MIP-2 are overexpressed at the early stage of acute pancreatitis. Both of them may play an important role in the pathogenesis of AP. NAC may have beneficial effects on AP through downregulation of the expression of MCP-1 and MIP-2.

Effect of inhibition of prostaglandin E2 production on pancreatic infection in experimental acute pancreatitis

Objective. Acute pancreatitis is one the important causes of systemic inflammatory response syndrome (SIRS). SIRS results in gut barrier dysfunction that allows bacterial translocation and pancreatic infection to occur. Indomethacin has been used to reduce inflammatory process and bacterial translocation in experimental models. The purpose of this study was to determine the effect of inhibition of prostaglandin E2 (PGE2) production on pancreatic infection. Materials and methods. An experimental model of severe acute pancreatitis (AP) was utilized. The animals were divided into three groups: sham (surgical procedure without AP induction); pancreatitis (AP induction); and indomethacin (AP induction plus administration of 3 mg/kg of indomethacin). Serum levels of interleukin (IL)-6 and IL-10, PGE2, and tumor necrosis factor (TNF)-α were measured 2h after the induction of AP. We analyzed the occurrence of pancreatic infection with bacterial cultures performed 24h after the induction of AP. The occurrence of pancreatic infection (considered positive when the CFU/g was >105), pancreatic histologic analysis, and mortality rate were studied. Results. In spite of the reduction of IL-6, IL-10, and PGE2 levels in the indomethacin group, TNF-α level, bacterial translocation, and pancreatic infection were not influenced by administration of indomethacin. The inhibition of PGE2 production did not reduce pancreatic infection, histologic score, or mortality rate. Conclusion. The inhibition of PGE2 production was not able to reduce the occurrence of pancreatic infection and does not have any beneficial effect in this experimental model. Further investigations will be necessary to discover a specific inhibitor that would make it possible to develop an anti-inflammatory therapy.

Pioglitazone attenuates the severity of sodium taurocholate-induced severe acute pancreatitis

To determine the effect of pioglitazone, a specific peroxisome proliferator-activated receptor-gamma (PPARgamma) ligand, on development of severe acute pancreatitis (SAP) and expression of nuclear factor-kappa B (NF-kappaB) and intercellular adhesion molecule-1 (ICAM-1) in the pancreas. Male Sprague-Dawley (SD) rats (160-200 g) were randomly allocated into three groups (n = 18 in each group): severe acute pancreatitis group, pioglitazone group, sham group. SAP was induced by retrograde infusion of 1 mL/kg body weight 5% sodium taurocholate (STC) into the biliopancreatic duct of male SD rats. Pioglitazone was injected intraperitoneally two hours piror to STC infusion. Blood and ascites were obtained for detecting amylase and ascitic capacity. Pancreatic wet/dry weight ratio, expression of NF-kappaB and ICAM-1 in pancreatic tissues were detected by immunohistochemical staining. Pancreatic tissue samples were stained with hematoxylin and eosin (HE) for routine optic microscopy. Sham group displayed normal pancreatic structure. SAP group showed diffuse hemorrhage, necrosis and severe edema in focal areas of pancreas. There was obvious adipo-saponification in abdominal cavity. Characteristics such as pancreatic hemorrhage, necrosis, severe edema and adipo-saponification were found in pioglitazone group, but the levels of those injuries were lower in pioglitazone group than those in SAP group. The wet/dry pancreatic weight ratio, ascetic capacity, serum and ascitic activities of anylase in the SAP group were significantly higher than those in the sham group and pioglitazone group respectively (6969.50 +/- 1368.99 vs 2104.67 +/- 377.16, 3.99 +/- 1.22 vs 2.48 +/- 0.74, P < 0.01 or P < 0.05). According to Kusske criteria, the pancreatic histologic score showed that interstitial edema, inflammatory infiltration, parenchyma necrosis and parenchyma hommorrhage in SAP group significantly differed from those in the sham group and pioglitazone group (7.17 +/- 1.83 vs 0.50 +/- 0.55, 7.67 +/- 0.82 vs 6.83 +/- 0.75, P < 0.01, P < 0.05. The expression of NF-kappaB and ICAM-1 in sham group was lower than that in SAP group and pioglitazone group (0.50 +/- 0.55 vs 33 +/- 1.21, P < 0.01). There was a significant difference in the expression of NF-kappaB and ICAM-1 between SAP group and pioglitazone group (7.50 +/- 1.05 vs 11.33 +/- 1.75, 0.80 +/- 0.53 vs 1.36 +/- 0.54, P < 0.01 or P < 0.05) at 12 h after the induction of pancreatitis. Pioglitazone attenuates the severity of SAP. The beneficial effect of pioglitazone is multifactorial due to its anti-inflammatory activities, most likely through the inhibition of ICAM-1 expression and NF-kappaB activation. Specific ligands of PPARgamma may represent the novel and effective means of clinical therapy for SAP.

A mouse model of severe acute pancreatitis induced with caerulein and lipopolysaccharide

To establish a non-traumatic, easy to induce and reproducible mouse model of severe acute pancreatitis (SAP) induced with caerulein and lipopolyasccharide (LPS). Thirty-two healthy mature NIH female mice were selected and divided at random into four groups (each of 8 mice), i.e., the control group (NS group), the caerulein group (Cn group), the lipopolysaccharide group (LPS group), and the caerulein+LPS group (Cn+LPS group). Mice were injected intraperitoneally with caerulein only, or LPS only, and caerulein and LPS in combination. All the animals were then killed by neck dislocation three hours after the last intraperitoneal injection. The pancreas and exo-pancreatic organs were then carefully removed for microscopic examination. And the pancreatic acinus was further observed under transmission electron microscope (TEM). Pancreatic weight, serum amylase, serum nitric oxide (NO) concentration, superoxide dismutase (SOD) and malondialdehyde (MDA) concentration of the pancreas were assayed respectively. (1) NS animals displayed normal pancreatic structure both in the exocrine and endocrine. In the LPS group, the pancreas was slightly edematous, with the infiltration of a few inflammatory cells and the necrosis of the adjacent fat tissues. All the animals of the Cn group showed distinct signs of a mild edematous pancreatitis characterized by interstitial edema, infiltration of neutrophil and mononuclear cells, but without obvious parenchyma necrosis and hemorrhage. In contrast, the Cn+LPS group showed more diffuse focal areas of nonviable pancreatic and hemorrhage as well as systemic organ dysfunction. According to Schmidt's criteria, the pancreatic histologic score showed that there existed significant difference in the Cn+LPS group in the interstitial edema, inflammatory infiltration, parenchyma necrosis and parenchyma homorrhage in comparison with those of the Cn group, LPS group and NS group (P<0.01 or P<0.05). (2) The ultrasturcture of acinar cells was seriously damaged in the Cn+LPS group. Chromatin margination of nuclei was present, the number and volume of vacuoles greatly increased. Zymogen granules (ZGs) were greatly decreased in number and endoplasmic reticulum exhibited whorls. The swollen mitochondria appeared, the crista of which was decreased in number or disappeared. (3) Pancreatic weight and serum amylase levels in the Cn +LPS was significantly higher than those of the NS group and the LPS group respectively (P<0.01 or P<0.05). However, the pancreatic wet weight and serum amylase concentration showed no significant difference between the Cn+LPS group and the Cn group. (4) NO concentration in the Cn+LPS group was significantly higher than that of NS group, LPS group and Cn group(P<0.05 or P<0.01). (5) The SOD and MDA concentration of the pancreas in the Cn+LPS group were significantly higher than those of NS, LPS and Cn groups (P<0.05 or P<0.01). The mouse model of severe acute pancreatitis could be induced with caerulein and LPS, which could be non-traumatic and easy to induce, reproducible with the same pathological characteristics as those of SAP in human, and could be used in the research on the mechanism of human SAP.

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

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

Single doses of FK506 and OKT3 reduce severity in early experimental acute pancreatitis.

To find out if two immunomodulatory drugs used in organ transplantation (FK506 (tacrolimus) and OKT3 (Orthoclone) would reduce early inflammatory complications in experimental acute pancreatitis. Laboratory study. University hospital, Germany. 36 Balb/c mice. Pancreatitis induced by 7 intraperitoneal injections of cerulein 50 microg/kg at hourly intervals followed by FK506 0.32 mg/kg, OKT3 0.6 mg/kg, or 0.9% sodium chloride (controls) (n = 12 in each group). 12 hours after induction of pancreatitis the animals were killed. Serum amylase activity and interleukin-6 (IL-6) concentrations; histological damage to pancreas and lungs, apoptotic cells in pancreas; and myeloperoxidase activity in lungs. No animal died during the experiment. At 12h serum amylase activity and IL-6 concentrations were increased in all 3 groups, but highest in the OKT3 group. The pancreatic histological score, apoptosis, and inflammatory infiltration were lower in the two experimental groups than controls, but the degree of vacuolisation of acinar cells was similar. Packed cell volume was higher in the control than the experimental groups, and pulmonary damage and myeloperoxidase activity were less in the experimental groups than the controls. Single therapeutic doses of FK506 and OKT3 reduced the early severity of pancreatitis, pulmonary damage, and haemoconcentration in mice. Single doses of FK506 or OKT3 may therefore be effective in preventing the early complications of pancreatitis.