Effect And Mechanism Of Intestinal Epithelial Oxidative Stress And Autophagy On Intestinal Mucosal Barrier In Severe Acute Pancreatitis

Objective:Intestinal mucosal barrier dysfunction can be caused by severe acute pancreatitis(SAP).It is normally associated with the changes of mucosal autophagy and oxidative stress.The aim of this study was to investigate the correlation between autophagy and oxidative stress on the intestinal mucosal barrier of severe acute pancreatitis(SAP)rat model.Methods:Forty healthy male Wistar rats were acclimated to our animal laboratory for more than 2weeks and divided randomly into two groups: SAP group(n=30)and sham operation(SO)group(n=10).Rats were weighed then anesthetized by intraperitoneal injection with 3%sodium pentobarbital(20 mg/kg body weight).The abdominal cavity was opened,the biliopancreatic duct was occluded with a vascular clip at the hepatic hilum level and then were cannulated transduodenally using a 24-gauge catheter.SAP was induced by retrograde injection of sodium taurocholate(5%)into the biliopancreatic duct.All rats were sacrificed24 h after SAP induction.Bacterial translocation(BT)was detected by 16 S r DNA sequencing analysis.Morphological alterations in the pancreas and gut were determined by hematoxylin-eosin(HE)staining;serum amylase and lipase levels were also evaluated.Oxidative stress status was determined by measuring the level of intestinal malondialdehyde(MDA),superoxide dismutase(SOD)and glutathione peroxidase(GPx).Western blot and RT-PCR were preformed to analyze the expression of Tight-junction(TJ)proteins.Autophagy was analyzed by Western blot.We detected the distribution of intestinal TJ proteins and LC3 II by immunofluorescent staining with confocal microscopy.Results:According to the results of 16 S r DNA sequencing analysis,rats in SAP group were divided into two subgroups: BT(+)group(n=9)and BT(-)group(n=8).Pancreatic and intestinal injuries in SAP group were significantly higher than SO group.The level of serum amylase and lipase was consistent with the degree of pancreatic injury.The content of MDA was clearly elevated and SOD as well as GPx activities were decreased in BT(+)group as compared with BT(-)group.The expression of LC3 II and Beclin1 in SAP groups washigher than that observed in SO group,while the level of LC3 II and Beclin1 in BT(-)group was obviously higher than BT(+)group.In contrast,BT(+)group had a higher level of claudin-2 and a lower level of zonula occluden-1(ZO-1),occludin and claudin-1 than BT(-)group.Conclusion:These results suggest that activated autophagy may attenuate intestinal mucosal barrier dysfunction by preventing and reducing the oxidative stress in SAP.