Abdominal paracentesis drainage ameliorates myocardial injury in severe experimental pancreatitis rats through suppressing oxidative stress

BACKGROUND Abdominal paracentesis drainage(APD) is a safe and effective strategy for severe acute pancreatitis(SAP) patients. However, the effects of APD treatment on SAPassociated cardiac injury remain unknown.AIM To investigate the protective effects of APD on SAP-associated cardiac injury and the underlying mechanisms.METHODS SAP was induced by 5% sodium taurocholate retrograde injection in SpragueDawley rats. APD was performed by inserting a drainage tube with a vacuum ball into the lower right abdomen of the rats immediately after SAP induction.Morphological staining, serum amylase and inflammatory mediators, serum and ascites high mobility group box(HMGB) 1, cardiac-related enzymes indexes and cardiac function, oxidative stress markers and apoptosis and associated proteins were assessed in the myocardium in SAP rats. Nicotinamide adenine dinucleotide phosphate oxidase activity and mRNA and protein expression were also examined.RESULTS APD treatment improved cardiac morphological changes, inhibited cardiac dysfunction, decreased cardiac enzymes and reduced cardiomyocyte apoptosis,proapoptotic Bax and cleaved caspase-3 protein levels. APD significantly decreased serum levels of HMGB1, inhibited nicotinamide adenine dinucleotide phosphate oxidase expression and ultimately alleviated cardiac oxidative injury.Furthermore, the activation of cardiac nicotinamide adenine dinucleotide phosphate oxidase by pancreatitis-associated ascitic fluid intraperitoneal injection was effectively inhibited by adding anti-HMGB1 neutralizing antibody in rats with mild acute pancreatitis.CONCLUSION APD treatment could exert cardioprotective effects on SAP-associated cardiac injury through suppressing HMGB1-mediated oxidative stress, which may be a novel mechanism behind the effectiveness of APD on SAP.     

Early prediction of intestinal mucosal barrier function impairment by elevated serum procalcitonin in rats with severe acute pancreatitis

ObjectivesThe aim of this study was to evaluate serum procalcitonin (PCT) levels as a prognostic indicator of intestinal barrier function impairment in rats with severe acute pancreatitis (SAP).MethodsThirty-six male Sprague Dawley rats were randomly grouped into SAP group (injected sodium taurocholate via biliopancreatic duct), Gln group (gavaged with glutamine after modeling), and control group. Blood, pancreatic, and terminal ileum tissues were obtained from the rats after 6 h of modeling. Serum amylase (Amy) levels were determined using an automatic biochemical detector, while endotoxin (ET), diamine oxidase (DAO), and PCT levels were measured by ELISA test. The pathology of pancreatic and small intestine tissues were observed. PCT protein expression in intestinal tissues were detected by immunohistochemistry and western blot.ResultPancreatic and intestinal injuries in Gln group were significantly lower than SAP group. Serum amylase, DAO, and PCT levels in SAP and Gln groups differed greatly and were significantly higher than control group. Immuno-histochemistry and western blot results showed that PCT protein expression levels in small intestine tissues of SAP group were higher than Gln group and control group. Serum PCT levels had a significant correlation with serum endotoxin, DAO levels and intestinal mucosal injury scores.ConclusionPCT expression in serum and intestinal tissues in SAP rats increased significantly in the early stages of SAP, and was closely related to the onset and degree of intestinal barrier function impairment. Thus, our results showed that measuring serum PCT can be used to predict intestinal mucosal barrier function impairment in SAP rats.     

Abnormal Expression of Toll-Like Receptor 4 Is Associated with Susceptibility to Ethanol-Induced Gastric Mucosal Injury in Mice

Background and Aims

Toll-like receptor 4 (TLR4) contributes to ethanol-induced gastric mucosal injury. This study aimed to determine its precise role in this pathogenic state and the related signaling pathway.

Methods

Ethanol-induced gastric mucosal injury models were generated in TLR4^?/? mice (C3H/HeJ: point mutation; C57BL/10ScNJ: gene deletion), their respective TLR4^+/+ wild-type counterparts, and heterozygous TLR4^+/? mice. Lipopolysaccharide (LPS) or pyrrolidine dithiocarbamate (PDTC) was injected intraperitoneally 1 h or 30 min before ethanol administration. At 1 h post-ethanol treatment, gastric or serum specimens were evaluated.

Results

Ethanol intra-gastric administration induced significant gastric mucosal injury in all mice, but the damaged area was larger in TLR4^?/? mice. LPS preconditioning and up-regulated TLR4 expression led to significantly larger areas of gastric mucosal damage. Upon ethanol administration, TLR4^+/+, and not TLR4^?/?, mice showed significant increases in TLR4, myeloid differentiation factor 88 (MyD88), cytoplasmic high mobility group box 1 (HMGB1), and nuclear factor-kappa B p65 (NF-κB p65). PDTC pretreatment significantly attenuated the ethanol-induced gastric mucosal damaged areas, inhibited nuclear NF-κB p65 expression, and suppressed HMGB1 translocation out of the nucleus. In addition, PDTC pretreatment reduced ethanol-stimulated expression of the inflammatory modulators, interleukin-1β (IL-1β) and tumor necrosis factor-alpha (TNF-α), in serum.

Conclusions

Both deficient and excessive expression of TLR4 promotes ethanol-induced gastric mucosal injury. The underlying mechanism involves the MyD88/NF-κB signaling pathway and the HMGB1, TLR4 activator ligand. The increased expression of HMGB1 may lead to increased secretion and binding to TLR4, further stimulating the TLR4/MyD88/NF-κB signaling pathway and aggravating the ethanol-induced gastric mucosal injury.     

抑制JAK／STAT信号通路对实验性急性胰腺炎大鼠肝损伤的保护作用

背景：JAK／STAT细胞内信号通路广泛参与细胞的增殖、分化、凋亡以及炎症、肿瘤的发生等多种生理、病理生理过程，然而关于其在重症急性胰腺炎（SAP）急性肝损伤中作用的研究尚少。目的：观察抑制JAK〈STAT通路对实验性急性胰腺炎（AP）大鼠肝损伤的保护作用。方法：56只Sprague-Dawley大鼠随机分为正常对照组、3组AP模型组和3组JAK特异性抑制剂AG490干预组。以4％牛磺胆酸钠胰胆管逆行注射诱导AP模型。分批处死各组大鼠，动态测定血清丙氨酸氨基转移酶（ALT）、天冬氨酸氨基转移酶（AST）水平，观察肝脏大体和组织学表现，以免疫组化染色和蛋白质印迹法检测肝组织中JAK2的定位和表达。结果：与正常对照组相比，AP模型组各时间点血清ALT、AST水平均显著升高；肝组织大体和组织学损伤随病情进展而逐渐加重；肝组织JAK2表达逐渐增强，于18h时达高峰。经AG490预处理的大鼠，上述各项指标均较同时间点AP模型组显著改善。结论：JAK2参与了大鼠实验性AP肝损伤的病理过程，抑制肝组织JAK／STAT通路活化有助于SAP急性肝损伤的防治。     

Interleukin-22 Attenuates Acute Pancreatitis-Associated Intestinal Mucosa Injury in Mice via STAT3 Activation

Background/AimsInterleukin-22 (IL-22) is an important cytokine maintaining homeostasis at barrier surfaces. In this study, the role of IL-22 in acute pancreatitis-associated intestinal injury was further explored.MethodsSevere acute pancreatitis (SAP) was induced by administration of L-arginine in Balb/c mice at different time gradients. Histopathological examinations were made in both the pancreas and small intestine. Furthermore, recombinant murine IL-22 (rIL-22) was administrated to L-arginine-induced SAP mice by intraperitoneal injection. The mRNA levels of IL-22R1, Reg-IIIβ, Reg-IIIγ, Bcl-2, and Bcl-xL were detected in the small intestine by real-time polymerase chain reaction, and protein levels of total and phosphorylated STAT3 were assessed via Western blot.ResultsCompared with normal control group, 72 hours of L-arginine exposure induced the most characteristic histopathological changes of SAP, evidenced by pathological changes and serum amylase levels. Meanwhile, significant pancreatitis-associated intestinal mucosa injury was also observed. The gene expression levels of antimicrobial proteins Reg-IIIβ, Reg-IIIγ and anti-apoptosis proteins Bcl-2, Bcl-xL were downregulated in small intestine. Furthermore, L-arginine-induced SAP was attenuated by rIL-22 treatment. Importantly, pancreatitis-associated intestinal mucosa injury was also ameliorated, reflected by improved pathological changes and significant increase in gene expression levels of Reg-IIIβ, Reg-IIIγ, Bcl-2 and Bcl-xL. Consistently, serum amylase levels and mortality were decreased in mice treated with rIL-22. Mechanistically, the upregulated expressions of these protective genes were achieved by activating STAT3.ConclusionsExogenous rIL-22 attenuates L-arginine-induced acute pancreatitis and intestinal mucosa injury in mice, via activating STAT3 signaling pathway and enhancing the expression of antimicrobial peptides and antiapoptotic genes. (Gut Liver 2021;15-781)     

TLR4信号传导通路与胰腺炎

胰腺炎的发病机制长期以来一直是基础和临床研究的一个重要课题,然而至今尚不完全明确.研究证实TLRs(Toll-like receptors)家族成员中TLR4可与G-菌内毒素脂多糖(lipopolysaccharide,LPS)结合,通过NF-κB信号通路激发多种炎症因子的合成进而参与多种器官疾病的发病过程.在鼠类模型和临床研究中已经显示TLR4信号通路在急性胰腺炎(acute pancreatitis,AP)的发病过程中起着重要的作用;上调TLR4信号通路可诱导致炎细胞因子大量释放参与重症急性胰腺炎(severe acute pancreatitis,SAP)病程中多器官功能障碍综合征的形成.因此,进一步明确TLR4信号通路在胰腺炎发病机制的作用,有可能通过阻断TLR4信号通路使胰腺炎获得疗效.     

Abdominal paracentesis drainage improves outcome of acute pancreatitis complicated with intra-abdominal hypertension in early phase

BackgroundIntra-abdominal hypertension (IAH) is an important risk factor for organ dysfunction, and it occurs in the early phase of severe acute pancreatitis (SAP). We have reported a novel step-up approach and shown the benefit of performing abdominal paracentesis drainage (APD) ahead of percutaneous catheter drainage (PCD) when treating Patients with SAP with fluid collections. This study aimed to evaluate the efficacy of APD in Patients with SAP complicated with IAH in the early phase.MethodsIn the present study, 206 AP patients complicated with IAH in the early phase were enrolled in hospital between June 2017 and December 2020. The patients were divided into two groups: 109 underwent APD (APD group) and 97 were managed without APD (non-APD group). We retrospectively compared the outcomes of the APD and non-APD groups for IAH treatment. The parameters including mortality, infection, organ failure, inflammatory factors, indications for further interventions, and drainage-related complications were observed.ResultsThe demographic data and severity scores of the two groups were comparable. The mortality rate was lower in the APD group (3.7%) than in the non-APD group (8.2%). Compared with the non-APD group, the intra-abdominal pressure and laboratory parameters of the APD group decreased more rapidly, and the mean number of failed organs was lower. However, there was no significant difference in incidence of infections between the two groups.ConclusionsApplication of APD is beneficial to AP patients. It significantly attenuated inflammation injury, avoided further interventions, and reduced multiple organ failure.     

The loss of αSNAP downregulates the expression of occludin in the intestinal epithelial cell of acute pancreatitis model

Background and objectiveIntestinal barrier damage is an important event during the occurrence and progression of severe acute pancreatitis. The expression of occludin, one of the main components of the intestinal barrier proteins, is regulated by various factors related to intestinal barrier formation and the remodeling process. The αSNAP, as a novel membrane protein, is ubiquitously expressed in intestinal epithelial cells. This study aimed to investigate the role of αSNAP in acute pancreatitis and the relationship between occludin and αSNAP.MethodsMild and severe acute pancreatitis models were established by retrograde injections of 0.5% and 3.8% sodium taurocholate solutions, respectively, into rat pancreaticobiliary ducts. The animals were killed at 1, 2, and 3 days after the injection, and the pathological changes of the pancreas and intestinal mucosa, the changes in intestinal permeability, and the protein expression of occludin and αSNAP were assessed. Cultured epithelial IEC-6 cells were further infected with lentiviral αSNAP shRNA, cell apoptosis was determined with flow cytometry (FCM), and any changes in occludin expression were detected by Western blotting and immunofluorescent staining.ResultsThis pathologic study of a rat acute pancreatitis model indicated pancreatic tissue necrosis and inflammatory cell infiltration; the intestinal villi in the severe acute pancreatitis (SAP) group demonstrated edema, lodging, atrophy, and intestinal epithelial cell necrosis, and shedding. The intestinal permeability in rats with pancreatitis increased significantly. The SAP group showed significantly increased levels of serum TNF-α and endotoxins. The results of immunofluorescent staining and Western blotting revealed that compared with the SO (sham operation) and MAP (mild acute pancreatitis) groups, the SAP group displayed significantly downregulated protein expressions of αSNAP and occludin in the intestinal epithelial cells. After the lentiviral transduction of αSNAP shRNA, apoptosis in IEC-6 cells was drastically increased, whereas the expression of occludin was decreased significantly.ConclusionThe downregulated expression of αSNAP in intestinal epithelial cells leads to reduced occludin expression and enhanced apoptosis of intestinal epithelial cells. Hence, the permeability of the intestinal barrier may be increased in a severe acute pancreatitis model.     

Delayed ethyl pyruvate therapy attenuates experimental severe acute pancreatitis via reduced serum high mobility group box 1 levels in rats

AIM： To investigate the effect of delayed ethyl pyruvate （EP） delivery on distant organ injury, survival time and serum high mobility group box 1 （HMGB1） levels in rats with experimental severe acute pancreatitis （SAP）.
METHODS： A SAP model was induced by retrograde injection of artificial bile into the pancreatic ducts of rats. Animals were divided randomly into three groups （n = 32 in each group）： sham group, SAP group and delayed EP treatment group. The rats in the delayed EP treatment group received EP （30 mg/kg） at 12 h, 18 h and 30 h after induction of SAP. Animals were sacrificed, and samples were obtained at 24 h and 48 h after induction of SAP. Serum HMGB1, aspartate arninotransferase （AST）, alanine arninotransferase （ALT）, blood urea nitrogen （BUN）, and creatinine （Cr） levels were measured. Lung wet-to-dry-weight （W/D） ratios and histological scores were calculated to evaluate lung injury. Additional experiments were performed between SAP and delayed EP treatment groups to study the influence of EP on survival times of SAP rats.
RESULTS： Delayed EP treatment significantly reduced serum HMGB1 levels, and protected against liver, renal and lung injury with reduced lung W/D ratios （8.22 ±0.42 vs 9.76 ± 0.45, P 〈 0.01）, pulmonary histological scores （7.1 ± 0.7 vs 8.4 ± 1.1, P 〈 0.01）, serum AST （667 ± 103 vs 1 368 ± 271, P 〈 0.01）, ALT （446 ± 91 vs 653 ± 98, P 〈 0.01） and Cr （1.2 ± 0.3 vs 1.8 ± 0.3, P 〈 0.01） levels. SAP rats had a median survival time of 44 h. Delayed EP treatment significantly prolonged median survival time to 72 h （P 〈 0.01）.
CONCLUSION： Delayed EP therapy protects against distant organ injury and prolongs survival time via reduced serum HMGBllevels in rats with experimental SAP. EP may potentially serve as an effective new therapeutic option against the inflammatory response and multiple organ dysfunction syndrome （MODS） in SAP patients.     

Blockade of high mobility group box-1 protein attenuates experimental severe acute pancreatitis

INTRODUCTIONIn severe acute pancreatitis (SAP), multiple organ dysfunction syndrome (MODS) in the early phase[1,2] and complications of infection (infected pancreatic necrosis and sepsis) in the late phase are contributors to high mortality in SAP[3,4]. M…     

Betaine Protects Against High-Fat-Diet-Induced Liver Injury by Inhibition of High-Mobility Group Box 1 and Toll-Like Receptor 4 Expression in Rats

Background and Objectives

Previous studies have shown that betaine prevents alcohol-induced liver injury and improves liver function. The purpose of this study was to investigate the hepatoprotective effects of betaine on nonalcoholic fatty liver disease (NAFLD) and to observe changes of HMGB1/TLR4 signaling.

Methods

Thirty rats were randomly divided into control, model, and betaine groups. The rats in the model and betaine groups were fed a high-fat diet for 12 weeks to induce an animal model of NAFLD. The rats in the betaine group were then intragastrically administered betaine solution at a dose of 400 mg/kg per day for four weeks. Liver histology was examined. Serum levels of ALT, AST, TC, TG, HDL-C, LDL-C, FFA, HMGB1, NF-κB, TLR4, and tHcy were determined and intrahepatic TC, TG, and Hcy levels were assayed. mRNA expression and protein levels of HMGB1, NF-κB, and TLR4 in liver tissue were also determined.

Results

Compared with the control group, rats in the model group developed severe liver injury, accompanied by significant increases in serum levels of ALT, AST, TC, TG, LDL-C, FFA, HMGB1, NF-κB, and TLR4, intrahepatic TC, TG, and Hcy content, histological scores for steatosis, inflammation, and necrosis, and mRNA expression and protein levels of HMGB1, NF-κB, and TLR4, and a significant decrease in serum HDL-C (P < 0.05). Compared with the model group, all these indicators were significantly improved by administration of betaine (P < 0.05).

Conclusions

Betaine effectively protects against high-fat-diet-induced NAFLD and improves liver function; the mechanism is probably related to inhibition of HMGB1/TLR4 signaling pathways.     

Caspase inhibitor zVAD-fmk protects against acute pancreatitis-associated lung injury via inhibiting inflammation and apoptosis

Background/objectivesPulmonary apoptosis is an important pathogenic mechanism of acute lung injury induced by many factors. This study aims to investigate whether the caspase inhibitor zVAD-fmk has a protective effect against lung injury in the severe acute pancreatitis model (SAP) in rats.MethodsSeventy-two Sprague-Dawley rats were randomly divided into Sham, SAP, and SAP + zVAD-fmk groups. The SAP model was established by injection of 5% sodium taurocholate into the pancreatic duct. Animals were sacrificed at 3 h, 6 h, 12 h, and 24 h after operation and then HE staining analysis was performed to assess the lung injury. ELISA was used to detect the activity of myeloperoxidase (MPO) and the concentrations of tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β). Western blotting was used to detect the expression of cleaved caspase-3 in the lung tissues.ResultsRats in SAP group showed obvious lung injury through pathologic examination. Pretreatment with zVAD-fmk significantly inhibited a post-SAP increase in the activation of MPO, TNF-α, IL-1β, and caspase-3, and decreased lung injury induced by SAP as determined by the pathologic score.ConclusionOur results suggest that apoptosis plays an important role in acute pancreatitis-associated lung injury (APALI), and inhibition of caspase activity may represent a new therapeutic approach for the treatment of APALI.     

Protective effect of clodronate-containing liposomes on intestinal mucosal injury in rats with severe acute pancreatitis

BACKGROUND: Severe acute pancreatitis (SAP) can result in intestinal mucosal injury. This study aimed to demonstrate the protective effect of clodronate-containing liposomes on intestinal mucosal injury in rats with SAP. METHODS: Liposomes containing clodronate or phosphate buffered saline (PBS) were prepared by the thin-film method SAP models were prepared by a uniform injection of sodium taurocholate (2 mL/kg body weight) into the subcapsular space of the pancreas. Sprague-Dawley rats were randomly divide...     

SOCS3在实验性急性胰腺炎急性肺损伤大鼠肺组织中的表达和作用

背景：细胞因子信号转导抑制分子3（SOCS3）在多种疾病的各种器官损伤中起重要的调节作用,可通过对JAK/STAT信号通路的负反馈作用调节炎症因子的释放,从而起一定的抑炎作用。目前关于SOCS3在重症急性胰腺炎（SAP）急性肺损伤中的表达和作用尚未见报道。目的：探讨SOCS3在实验性急性胰腺炎（AP）合并急性肺损伤大鼠肺组织中的表达变化及其可能的作用。方法：32只Sprague-Dawley大鼠随机分为对照组和AP 6 h、12 h、18 h组。以4%牛磺胆酸钠胰胆管逆行注射诱导AP模型。动态测定各组血清淀粉酶（AMY）水平、肺湿/干重比;光学显微镜下观察肺组织学表现;ELISA法检测血清白细胞介素（IL）-6、IL-18含量;免疫组化法和蛋白质印迹法检测肺组织中SOCS3的定位和表达。结果：与对照组相比,各AP模型组血清AMY水平、肺湿/干重比均明显升高（P〈0.05）;肺组织损伤随病情进展而逐渐加重;血清IL-6、IL-18水平显著上调（P〈0.05）;肺组织SOCS3表达逐渐增强（P〈0.05）,于18 h时达高峰。结论：SAP急性肺损伤导致的炎症反应可诱导SOCS3在肺组织中表达,并随着肺组织损伤和炎症反应严重程度的增加而逐渐增高,提示可能与其负反馈调节JAK/STAT信号通路介导的炎症反应的作用存在一定的联系。     

急性胰腺炎患者血清高迁移率族蛋白B1水平的变化及意义

目的 检测急性胰腺炎(AP)患者血清高迁移率族蛋白B1(high mobility group box-1protein,HMGB1)的水平变化,探讨HMGB1在AP发生发展中的作用.方法 以33例重症急性胰腺炎(SAP)、38例轻症急性胰腺炎(MAP)以及28例健康体检者为研究对象,在发病72 h内收集血标本,采用ELISA法检测血清HMGB1水平,分析其与患者性别,年龄,病因,发病时间,Ranson评分,Balthazar CT评分,血清C-反应蛋白(CRP)、乳酸脱氢酶(LDH)、肌酐、总胆红素等指标,局部和(或)全身并发症的关系.结果 健康对照组、MAP组、SAP组血清HMGB1水平分别为(1.82±0.64)μg/L、(6.13±5.80)μg/L、(11.48±6.94)μg/L,SAP组显著高于MAP组,MAP组又显著高于健康对照组(P值均<0.05).在发病24 h内患者血清HMGB1水平开始增高,48 h内达峰值,后开始下降,至72 h仍维持在高于正常值水平.血清HMGB1水平与患者性别、年龄、病因无关;与Ranson评分、Balthazar CT评分、CRP、LDH、血肌酐值呈正相关关系.有局部和(或)全身并发症患者血清HMGB1水平高于无并发症者,但差异不显著.结论 HMGB1是一种晚期炎症介质,与AP病情的严重程度相关,并可能参与了SAP时肾功能不全的发生.     

High-mobility group box 1 protein and its role in severe acute pancreatitis

The high mobility group box 1(HMGB1),which belongs to the subfamily of HMG-1/-2,is a highly conserved single peptide chain consisting of 215 amino acid residues with a molecular weight of approximately 24894 Da.HMGB1 is a ubiquitous nuclear protein in mammals and plays a vital role in inflammatory diseases.Acute pancreatitis is one of the most common causes of acute abdominal pain with a poor prognosis.Acute pancreatitis is an acute inflammatory process of the pancreas(duration of less than six months),for which the severe form is called severe acute pancreatitis(SAP).More and more studies have shown that HMGB1 has a bidirectional effect in the pathogenesis of SAP.Extracellular HMGB1 can aggravate the pancreatic inflammatory process,whereas intracellular HMGB1 has a protective effect against pancreatitis.The mechanism of HMGB1 is multiple,mainly through the nuclear factor-κB pathway.Receptors for advanced glycation endproducts and toll-like receptors(TLR),especially TLR-2 and TLR-4,are two major types of receptors mediating the inflammatory process triggered by HMGB1 and may be also the main mediators in the pathogenesis of SAP.HMGB1 inhibitors,such as ethyl pyruvate,pyrrolidine dithiocarbamate and Scolopendra subspinipes mutilans,can decrease the level of extracellular HMGB1 and are the promising targets in the treatment of SAP.     

肠道菌群失衡在急性胰腺炎肠黏膜屏障损伤中的作用

急性胰腺炎（acute pancreatitis,AP）是临床常见的急腹症,其发病率呈逐年增高趋势。AP病情进展迅速,15%~ 20%的患者发展为重症急性胰腺炎（severe acute pancreatitis, SAP）,病死率高达20%~30%。SAP常可导致肠道功能障 碍,包括肠黏膜屏障损伤和肠道动力障碍,引起肠道细菌移位至其他器官,加重全身炎症反应,对胰腺和机体造成“二 次打击”,导致患者多器官功能衰竭甚至死亡。近年来,肠道菌群作为人体的第2大基因组,与人类健康和疾病的关系 受到人们的广泛关注。正常肠道菌群参与人体多种生命过程,在肠道发育和稳态、肠道免疫系统的建立及防御病原 体入侵等多种生理过程中发挥着重要作用。肠道菌群失衡可能参与多种疾病的发生发展,如在AP早期即存在肠道 菌群的失衡。文章主要就肠道菌群失衡在AP肠黏膜屏障损伤中的作用作一阐述。     

Effects of Peroxisome Proliferator-Activated Receptor-γ Activation on Apoptosis in Rats with Acute Pancreatitis

Purpose

To investigate the effects and mechanisms of peroxisome proliferator-activated receptor-γ (PPAR-γ) activation on the induction of apoptosis in rats with acute pancreatitis.

Methods

Severe acute pancreatitis (SAP) and mild acute pancreatitis (MAP) were induced and pre-treated with pioglitazone, which is a ligand of PPAR-γ. The expression of inflammatory factors (TNF-α and IL6) of the pancreas was detected by ELISA. The apoptosis in pancreas were detected by TUNEL assay and the activity of caspase 3 was determined. Phosphorylation of p65 in pancreas of SAP or MAP was determined by western-blot.

Results

Expression levels of PPAR-γ proteins were elevated in the pancreases of SAP or MAP rats pre-injected with pioglitazone intraperitoneally. Downregulation of the expression TNF-α and IL6 and relief of pathological changes in the pancreas suggested that pioglitazone had protective effects on acute panceatitis. In pioglitazone pre-treated groups, a TUNEL assay indicated a high level of apoptosis in SAP but little apoptosis in MAP, showing pioglitazone could promote taurocholate-induced apoptosis but inhibit ceruleininduced apoptosis in pancraeatic aniniar cells. Furthermore, caspase 3 activity was high in SAP but low in MAP, implying that the apoptotic mechanism in pancreatic acinar cells of AP rats was correlated with caspase 3 activity. Phosphorylation of p65 was reduced in SAP or MAP group pretreated with pioglitazone, indicating that pioglitazone reduced the inflammation reaction by inhibiting the activation of the NF-κB.

Conclusions

These results indicated that activation of PPAR-γ induced apoptosis in pancreatic acinar cells of SAP rats but inhibited apoptosis in pancraeatic acinar cells of MAP rats, which demonstrated that PPAR-γ may be an efficiently therapeutic target in pancreatic inflammation.     

血清高迁移率族蛋白1与急性胰腺炎严重程度相关性研究

目的 观察急性胰腺炎(AP)患者血清高迁移率族蛋白1 (high mobility group box chromosomal protein-1,HMGB1)的水平,探讨HMGB1水平与AP严重程度的相关性。方法 收集62例患者入院即刻及入院后24、48 h血标本,应用ELISA方法检测血清HMGB1水平,并分析其与AP病情严重程度的相关性。以20例健康成年人作为对照组。结果 62例AP患者入院即刻及入院后24、48 h血清HMGB1水平分别为(8.05±1.60)、(8.04±1.39)、(8.25±1.56) ng/ml,均显著高于对照组的(2.20 ±0.57) mg/ml(P值均＜0.01)。其中重症急性胰腺炎(SAP)35例,轻症急性胰腺炎(MAP) 27例。SAP组患者血清HMGB1水平分别为(7.99±1.69)、(8.12±1.40)、(8.13±1.34) ng/ml;MAP组患者为(8.12±1.52)、(7.92±1.40)、(8.39±1.81) ng/ml。两组间差异无统计学意义。结论 AP患者的血清HMGB1水平显著高于正常人群,但其与AP的严重程度无平行关系。     

Toll-like receptor 2 controls mucosal inflammation by regulating epithelial barrier function

BACKGROUND & AIMS: Toll-like receptors (TLRs) represent a class of transmembrane pattern recognition receptors essential for microbial recognition and control of innate immune responses. Commensal bacteria play an important role in maintaining tolerance and active stability of the intestinal epithelial barrier by suppressing intestinal inflammation, yet the mechanisms of action are unknown. The aim of this study was to determine the functional relevance of TLR2 to control tight junction (TJ)-associated intestinal epithelial barrier integrity to balance mucosal homeostasis against inflammatory stress-induced damage. METHODS: TLR2 ligand (synthetic Pam(3)Cys-SK4 [PCSK])-induced activation of signaling cascades and TJ-associated distribution was assessed by using Western blotting and confocal microscopy combined with functional transfection and inhibitor studies in model intestinal epithelial cell (IEC) lines (IEC-6, Caco-2) or primary IEC cultured short-term ex vivo. DSS colitis was induced by standard protocol in wild-type, TLR2-/-, and MyD88-/- mice. Spontaneous apoptosis was assessed by terminal deoxinucleotidyl-transferase-mediated dUTP-biotin nick end-labeling. RESULTS: Data from in vitro and ex vivo models of intestinal epithelial cells revealed that TLR2 stimulation effectively preserves TJ-associated barrier assembly against stress-induced damage through promotion of PI3K/Akt-mediated cell survival via MyD88. Furthermore, in vivo studies underscored that TLR2-mediated TJ regulation critically determines susceptibility to intestinal injury and inflammation. Inflammatory stress in mice deficient of TLR2 or MyD88 induced early TJ-associated disruption interrelated with anti-apoptotic failure of the intestinal epithelial barrier. Oral treatment of colitis with the TLR2 ligand PCSK significantly suppressed mucosal inflammation and apoptosis by efficiently restoring TJ-associated integrity of the intestinal epithelium in vivo. CONCLUSION: TLR2 may provide a target to pharmacologically modulate mucosal injury and intestinal inflammation.