benzyloxycarbonylleucyl-leucyl-leucine-aldehyde and Pancreatitis

To observe the effect of proteasome inhibitor MG-132 on severe acute pancreatitis (SAP) and associated lung injury of rats.. Male adult SD rats were randomly divided into SAP group, sham-operation group, and MG-132 treatment group. A model of SAP was established by injection of 5% sodium taurocholate into the biliary-pancreatic duct of rats. The MG-132 group was pretreated with 10 mg/kg MG-132 intraperitoneally (ip) 30 min before the induction of pancreatitis. The changes in serum amylase, myeloperoxidase (MPO) activity of pancreatic and pulmonary tissue were measured. The TNF-alpha level in pancreatic cytosolic fractions was assayed with an enzyme-linked immunosorbent assay (ELISA) kit. Meanwhile, the pathological changes in both pancreatic and pulmonary tissues were also observed.. MG-132 significantly decreased serum amylase, pancreatic weight/body ratio, pancreatic TNF-alpha level, pancreatic and pulmonary MPO activity (P < 0.05). Histopathological examinations revealed that pancreatic and pulmonary samples from rats pretreated with MG-132 demonstrated milder edema, cellular damage, and inflammatory activity (P < 0.05).. The proteasome inhibitor MG-132 shows a protective effect on severe acute pancreatitis and associated lung injury of rats.

Topics: Acute Disease; Amylases; Animals; Cysteine Proteinase Inhibitors; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Leupeptins; Lung; Lung Diseases; Male; Organ Size; Pancreas; Pancreatitis; Peroxidase; Proteasome Endopeptidase Complex; Proteasome Inhibitors; Rats; Rats, Sprague-Dawley; Severity of Illness Index; Taurocholic Acid; Tumor Necrosis Factor-alpha

To establish the therapeutic potential of proteasome inhibition, we examined the therapeutic effects of MG132 (Z-Leu-Leu-Leu-aldehyde) in an experimental model of acute pancreatitis.. Pancreatitis was induced in rats by two hourly intraperitoneal (ip) injections of cholecystokinin octapeptide (CCK; 2 x 100 microg/kg) and the proteasome inhibitor MG132 (10 mg/kg ip) was administered 30 min after the second CCK injection. Animals were sacrificed 4 h after the first injection of CCK.. Administering the proteasome inhibitor MG132 (at a dose of 10 mg/kg, ip) 90 min after the onset of pancreatic inflammation induced the expression of cell-protective 72 kDa heat shock protein (HSP72) and decreased DNA-binding of nuclear factor-kappaB (NF-kappaB). Furthermore MG132 treatment resulted in milder inflammatory response and cellular damage, as revealed by improved laboratory and histological parameters of pancreatitis and associated oxidative stress.. Our findings suggest that proteasome inhibition might be beneficial not only for the prevention, but also for the therapy of acute pancreatitis.

Topics: Acute Disease; Animals; Body Weight; Cholecystokinin; Cysteine Proteinase Inhibitors; Cytokines; HSP72 Heat-Shock Proteins; Leupeptins; Male; NF-kappa B; Organ Size; Oxidative Stress; Pancreas; Pancreatitis; Peroxidase; Proteasome Inhibitors; Rats; Rats, Wistar

To observe the protective effect of the proteasome inhibitor MG-132 in rats with severe acute pancreatitis (SAP) and the associated lung injury.. In rat models of the SAP established with injection of 5% sodium taurocholate into the biliary-pancreatic duct, the changes of the serum amylase and myeloperoxidase (MPO) activity in the pancreatic and lung tissues were evaluated. The pathological changes of the pancreatic and lung tissues were also observed.. MG-132 significantly decreased serum amylase, pancreatic weight/body weight ratio, and pancreatic and pulmonary myeloperoxidase activity (P<0.05). Histopathological examinations revealed milder edema, cellular damage, and inflammation in the pancreatic and lung tissues of rats pretreated with the peptide (P<0.05).. MG-132 ameliorates SAP and the associated lung injury in rats.

Topics: Acute Disease; Amylases; Animals; Cysteine Proteinase Inhibitors; Leupeptins; Lung; Lung Injury; Pancreas; Pancreatitis; Peroxidase; Rats; Rats, Sprague-Dawley

The cell-permeant MG132 tripeptide (Z-Leu-Leu-Leu-aldehyde) is a peptide aldehyde proteasome inhibitor that also inhibits other proteases, including calpains and cathepsins. By blocking the proteasome, this tripeptide has been shown to induce the expression of cell-protective heat shock proteins (HSPs) in vitro. Effects of MG132 were studied in an in vivo model of acute pancreatitis. Pancreatitis was induced in male Wistar rats by injecting 2 x 100 microug/kg cholecystokinin octapeptide intraperitoneally (ip) at an interval of 1 h. Pretreating the animals with 10 mg/kg MG132 ip before the induction of pancreatitis significantly inhibited IkappaB degradation and subsequent activation of nuclear factor-kappaB (NF-kappaB). MG132 also increased HSP72 expression. Induction of HSP72 and inhibition of NF-kappaB improved parameters of acute pancreatitis. Thus MG132 significantly decreased serum amylase, pancreatic weight/body weight ratio, pancreatic myeloperoxidase activity, proinflammatory cytokine concentrations, and the expression of pancreatitis-associated protein. Parameters of oxidative stress (GSH, MDA, SOD, etc.) were improved in both the serum and the pancreas. Histopathological examinations revealed that pancreatic specimens of animals pretreated with the peptide demonstrated milder edema, cellular damage, and inflammatory activity. Our findings show that simultaneous inhibition of calpains, cathepsins, and the proteasome with MG132 prevents the onset of acute pancreatitis.

Topics: Acute Disease; Amylases; Animals; Body Weight; Cysteine Proteinase Inhibitors; Cytokines; HSP72 Heat-Shock Proteins; Leupeptins; Lung; Male; NF-kappa B; Oxidative Stress; Pancreas; Pancreatitis; Pancreatitis-Associated Proteins; Proteasome Inhibitors; Rats; Rats, Wistar; Sincalide

Neutrophil infiltration into the pancreas is a key event in pancreatitis. Here we show that intercellular adhesion molecule-1 (ICAM-1), which regulates neutrophil adhesion, is present on rat pancreatic acinar cells, is upregulated by a hormone (cerulein) and mediates direct binding of neutrophils to acinar cells. ICAM-1 was upregulated in pancreas of rats with experimental pancreatitis induced by supramaximal doses of cerulein. Furthermore, cerulein time and dose dependently stimulated expression of ICAM-1 mRNA and protein in isolated pancreatic acinar cells. Inhibitory analysis showed that activation of transcription factor nuclear factor-kappaB (NF-kappaB) was involved in ICAM-1 upregulation by cerulein, but NF-kappaB did not mediate basal expression of ICAM-1 mRNA in acinar cells. With an adhesion assay, we found that neutrophils bind to isolated pancreatic acinar cells and that cerulein upregulates the extent of adhesion. Neutralizing ICAM-1 antibody blocked neutrophil binding to both control and cerulein-stimulated acinar cells, suggesting ICAM-1 involvement in this adhesion. Thus the acinar cell is capable of targeting neutrophils to its surface, a process that may be important for inflammatory and cell death responses in pancreatitis and other pancreatic disorders.

Topics: Animals; Cell Adhesion; Cell Nucleus; Cells, Cultured; Ceruletide; Cysteine Proteinase Inhibitors; Gene Expression Regulation; Intercellular Adhesion Molecule-1; Kinetics; Leupeptins; Male; Neutrophils; Pancreas; Pancreatitis; Rats; Rats, Sprague-Dawley; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Transcription, Genetic