Vascular endothelial growth factor induces inflammatory injury of pancreatic tissue by activating autophagy in hyperlipidemic acute pancreatitis rats / 生理学报

This study was to investigate the changes of autophagy in pancreatic tissue cells from hyperlipidemic acute pancreatitis (HLAP) rats and the molecular mechanism of autophagy to induce inflammatory injury in pancreatic tissue cells. Male Sprague Dawley (SD) rats were intraperitoneally injected with caerulein to establish acute pancreatitis (AP) model and then given a high fat diet to further prepare HLAP model. The HLAP rats were treated with autophagy inducer rapamycin or inhibitor 3-methyladenine. Pancreatic acinar (AR42J) cells were treated with caerulein to establish HLAP cell model. The HLAP cell model were treated with rapamycin or transfected with vascular endothelial growth factor (VEGF) siRNA. The inflammatory factors in serum and cell culture supernatant were detected by ELISA method. The histopathological changes of pancreatic tissue were observed by HE staining. The changes of ultrastructure and autophagy in pancreatic tissue were observed by electron microscopy. The expression levels of Beclin-1, microtubule- associated protein light chain 3-II (LC3-II), mammalian target of rapamycin complex 1 (mTORC1), and VEGF were measured by immunohistochemistry and Western blot. The results showed that, compared with control group, the autophagy levels and inflammatory injury of pancreatic tissue cells from HLAP model rats were obviously increased, and these changes were aggravated by rapamycin treatment, but alleviated by 3-methyladenine treatment. In HLAP cell model, rapamycin aggravated the autophagy levels and inflammatory injury, whereas VEGF siRNA transfection increased mTORC1 protein expression, thus alleviating the autophagy and inflammatory injury of HLAP cell model. These results suggest that VEGF-induced autophagy plays a key role in HLAP pancreatic tissue cell injury, and interference with VEGF-mTORC1 pathway can reduce the autophagy levels and alleviate the inflammatory injury. The present study provides a new target for prevention and treatment of HLAP.

Eeffect of melatonin on cerulein-induced pancreatitis in adult male albino rats: histological and histochemical study

Acute pancreatitis [AP] is a complex disease associated with significant complications and a high rate of mortality. The aim of this work was to study the effect of the antioxidant melatonin on cerulein-induced pancreatitis in adult male albino rats. Thirty two adult male albino rats were used and randomly divided into four groups: first group [control]; second group [melatonin treated]; third group [cerulein treated] and fourth group [melatonin and cerulein treated group]. At sacrifice, blood samples were drawn for biochemical study and pancreas specimens were prepared for histological, and histochemical study. Melatonin reduced serum amylase and lipase activities, which were highly significantly elevated in cerulein induced pancreatitis. Histologically there was wide separation between pancreatic lobules, the acinar cells showed degeneration and vacuolation and lost their zymogen granules. There was dilatation and congestion of blood vessels, interstitial hemorrhage and cellular infiltration. Ultrastructurally, there was disorganized dilated rough endoplasmic reticulum [RER], marked decrease in zymogen granules, mitochondrial damage and cytoplasmic vacuoles. Immunohistochemically, pancreatic sections of cerulein treated rats showed a strong immune reaction for transforming growth factor-beta [TGF-beta] and vascular endothelial growth factor [VEGF]. Melatonin improved the biochemical, histological, and histochemical picture of pancreas. In conclusion, melatonin was found to be effective in cerulein-induced acute pancreatitis by preventing oxidative stress so prevents other pathological mechanisms of AP from being developed inside acinar cells

Pancreatic capillary blood flow during caerulein-induced pancreatitis evaluated by a laser-doppler flowmeter in rats

Purpose: The pancreatic capillary blood flow (PCBF) was studied to determine its alterations during caerulein-induced pancreatitis in rats. Methods: Twenty rats were divided in groups: control and caerulein. A laser-Doppler flowmeter to measure PCBF continuously was used. Blood pressure (BP) and heart rate (HR) were monitored. Serum biochemistry analyses were determined. Histopathological study was performed. Results: The PCBF measured a mean of 109.08 ± 14.54 percent and 68.24 ± 10.47 percent in control group and caerulein group, respectively. Caerulein group had a mean decrease of 31.75 ± 16.79 percent. The serum amylase was 1323.70 ± 239.l0U.I-1 and 2184.60 ± 700.46U.I-1 in control and caerulein groups, respectively. There was a significant difference in the PCBF (p<0.05) and serum amylase (p<0.05) when compared to control and caerulein groups. Although micro and microvacuolization were seen in 30 percent in caerulein group, no significant difference was seen between the groups. Conclusion: A decrease in the PCBF may be one of the leading events and it is present before histopathological tissue injury had been established in this model of acute pancreatitis.

Reactive oxygen species inactivation improves pancreatic capillary blood flow in caerulein-induced pancreatitis in rats

Purpose: Reactive oxygen species (ROS) inactivation was studied to determine alterations in the pancreatic capillary blood flow (PCBF) during caerulein-induced pancreatitis in rats. Methods: A laser-Doppler flowmeter to measure PCBF and N-t-Butyl-Phenylnitrone (PBN) compound to inactivate ROS were used. Forty rats were divided in groups: 1) control; 2) caerulein; 3) PBN; 4) caerulein+PBN. Serem biochemistry and histopathological analyses were performed. Results: PCBF measured a mean of 109.08 ± 14.54 percent, 68.24 t 10.47 percent, 102.18 ± 10.23 percent and 87.73 ± 18.72 percent in groups 1, 2, 3 and 4, respectively. PCBF in groups 2 and 4 decreased 31.75 ± 16.79 percent and 12.26 ± 15.24 percent, respectively. Serum amylase was 1323.70 ± 239.10 U/l, 2184.60 ± 700.46 U/1, 1379.80 t 265.72 U/1 and 1622.10 ± 314.60 U/1 in groups 1, 2, 3 and 4, respectively. There was a significant difference in the PCBF and serem amylase when compared groups 2 and 4. Cytoplasmatic vacuolation was present in groups 2 and 4. Otherwise, no qualitative changes were seen. Conclusion: ROS inactivation improves PCBF and minimizes the serem amylase increase during caerulein-induced pancreatitis. ROS effect may be one of the leading causative events in this model of acute pancreatitis.

Modelo simplificado de inducao de pancreatite aguda experimental com uso de dose supramaxima de ceruleina / Simplified model of produced experimental acute pancreatitis with use of supra-maximal dosis of cerulein

A administracao de ceruleina tanto por via endovenosa como intraperitonial, tem sido extensivamente utilizada para inducao de pancreatite aguda experimental. Com objetivo de se testar uma nova metodologia de inducao de pancreatite aguda, que fosse de facil e rapida execucao, assim como de boa reprodutibilidade , 40 ratos Wistar foram distribuidos em quatro grupos: GRUPO I - animais que receberam infusao continua de ceruleina (15µ/Kg) GRUPO II - animais que receberam infusao continua e salina GRUPO III - animais submetidos a duas injecoes (SC+CV) de ceruleina (40µ/Kg) GRUPO IV - animais submetidos a duas injecoes (SC+CV) de salina. Apos a realizacao de dosagens bioquimicas, nao houve diferenca estatisticamente significativa entre os grupos I e II nas concentracoes teciduaias de tripsionogenio, quimiotripsinogenio, proelastase , catepsina e tambem amilase serica; ocorrendo diferenca somente entre os valores de porcentagem de agua no tecido pancreatico...